The Astrophotography Manual
A Practical and Scientific Approach to Deep Space Imaging
Chris Woodhouse
First published 2016
by Focal Press
70 Blanchard Road, Suite 402, Burlington, MA 01803
and by Focal Press
2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN
Focal Press is an imprint of the Taylor & Francis Group, an informa business
© 2016 Chris Woodhouse
The right of Chris Woodhouse to be identified as author of this work has been asserted by him in accordance with sections 77 and 78
of the Copyright, Designs and Patents Act 1988.
All rights reserved. No part of this book may be reprinted or reproduced or utilized in any form or by any electronic, mechanical, or
other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval
system, without permission in writing from the publishers.
Notices
Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding,
changes in research methods, professional practices, or medical treatment may become necessary.
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information,
methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own
safety and the safety of others, including parties for whom they have a professional responsibility.
Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without
intent to infringe.
Library of Congress Cataloging in Publication Data
Woodhouse, Chris.
The astrophotography manual : a practical and scientific approach to deep space imaging / Chris Woodhouse.
pages cm
Includes bibliographical references and index.
1. Astronomical photography. I. Title.
QB121.W87 2015
522’.63--dc23
2014047121
ISBN: 978-1-138-77684-5 (pbk)
ISBN: 978-1-138-91207-6 (hbk)
ISBN: 978-1-315-77301-8 (ebk)
Typeset in Adobe Garamond Pro and Myriad Pro by Chris Woodhouse
www.digitalastrophotography.co.uk
Contents
Preface
About the Author
Introduction
5
7
8
Astronomy Primer
The Diverse Universe of Astrophotography 13
Space
16
Catalogs
23
Four Dimensions and Counting
25
Limits of Perception
30
Choosing Equipment
The Ingredients of Success
General Equipment
Imaging Equipment
Setting Up
Hardware Setup
Software Setup
Image Capture
Sensors and Exposure
Focusing
Autoguiding and Tracking
Image Calibration and Processing
Post Exposure
Getting Started in PixInsight
Image Calibration and Stacking
Linear Image Processing
Non-Linear Image Processing
Narrowband Image Processing
First Light Assignments
Practical Examples
M3 (Globular Cluster)
C38 (Needle Galaxy)
M51a/b (Whirlpool Galaxy)
C27 (Crescent Nebula) in Narrowband
M45 (Pleiades Open Cluster)
M31 (Andromeda Galaxy)
IC 1805 (Heart Nebula) in False Color
Jupiter
Appendices
39
56
70
95
111
119
127
131
149
154
162
172
182
197
Diagnostics and Problem Solving
Summer Projects
Templates
Bibliography and Resources
Glossary and Index
Glossary
Index
206
209
213
218
222
228
232
238
243
249
255
262
268
281
284
“Don’t Panic”
Douglas Adams
Preliminaries
5
Preface
A
s a child, I was interested in astronomy and contented
myself with identifying the major constellations. It
was the time of the Apollo missions and the lunar landings in the early ‘70s. In those days, amateur telescopes
were a rarity and even binoculars were an indulgence for
a young boy. My first book on astronomy was a Hamlyn
guide. I still have it today and it is a quaint reminder of
how we viewed the universe and the availability (or lack
thereof) of sophisticated amateur equipment. Today, this
guide is notable by its lack of photographic illustrations
and belongs to the era of the technical illustrator. As a
teenager, a family friend showed me the Moon and Saturn
through a homemade Newtonian reflector. It wobbled
on a wooden tripod and required something resembling
alchemy to re-silver the 6-inch mirror that lay at its heart.
I still have a black-and-white print of the Moon taken
with that telescope. It is a testament to the dedication and
practical necessities of early astrophotographers.
In the ‘90s the seed was sown by a local astronomer
who gave a slide presentation at my photographic club:
It was my first glimpse of what lay beyond the sensitivities of the human eye and at a scale that completely
surprised me. Those images were on Kodak Ektachrome
and although I am saddened by the demise of classical
photography and values, I have to concede that modern
digital sensors are responsible for making astrophotography a vibrant hobby.
Up until this time I was completely engrossed by photography, especially traditional fine-art monochrome. Just
like the early astrophotographers, I found that necessity
was the mother of invention. I designed and later patented
various darkroom accessories and researched film-based
photography for many years. At the same time I started
technical writing: I started with a few magazine articles
and progressed to full scale reference books on traditional
photography. I had yet to point a camera at the night sky.
Fast-forward to the present day and we are in the
midst of an exponential interest in astrophotography in
all its forms. Recent popular television series, Mars expeditions and the availability of affordable high-quality
telescopes and cameras have propelled the fascinating
world of amateur astrophotography. This surge of interest
in a way mirrors the explosion of digital imaging in the
prior decade, but unlike modern digital photography,
astrophotography still appeals to those with a practical
mind and handy skills more than those with a large bank
balance, though it is safe to say, it certainly helps.
In 2011, I took the plunge into the deep end. I was awestruck by what was possible, at the beauty and variety of
the many images on various websites that I had previously
supposed were the work of professional observatories. As I
grappled with this new hobby, I found many books were
out of date on digital imaging techniques and others were
useful overviews but without sufficient detail in any one
speciality. Thankfully, the many friendly astronomy forums were a source of inspiration and I quickly appreciated
just how much there was to learn and go wrong. The other
forum members and I were asking similar questions and
it highlighted the need for a book that stepped through
the whole process of setting up, capturing and processing
images. It occurred to me I had a unique opportunity to
document and share my steep learning curve and combine
it with my photographic and technical skills.
I have already owned several systems, in addition
to using many astronomy applications for Mac OSX,
Windows and Apple iOS. It is too soon to call myself
an expert but it is a good time to write a book while the
research and hard lessons are still fresh in my mind. During this time the constant patient support of my family
has provided the opportunity for research and writing.
So, in the year that Sir Patrick Moore, Bernard Lovell
and Neil Armstrong passed away, I hope to inspire others with this book in some small way and improve the
reader’s enjoyment of this amazing hobby through their
success. The early chapters include a brief astronomy
primer and a nod to those incredible early pioneers. These
set you up for the technical and practical chapters and
give an appreciation of achievements, past and present.
The technical chapters start by looking at the practical limitations set by the environment, equipment and
camera performance. After several practical chapters on
the essentials, equipment choice and setting up, there are
several case studies. These illustrate the unique challenges
with practical details and using a range of software. An
extensive index, glossary, bibliography and supporting
website add to the book’s usefulness and progression to
better things. Clear skies.
Chris Woodhouse 2013
IC1805 (The Heart Nebula)
Preliminaries
7
About the Author
“The story so far:
In the beginning the Universe was created.
This has made a lot of people very angry and been widely regarded as a bad move.” Douglas Adams
C
hris was born in Brentwood, England and from
his teenage years was fascinated by the natural
sciences, engineering and photography, all of which he
found more interesting than football. At the weekend
he could be found building or designing some gadget or
other. At school he used a slide-rule and log books for
his exams at 16. Two years later, scientific calculators
had completely displaced them. He studied Electronics
at Bath University and by the time he had completed his
M.Eng., the computer age was well under way and 8-bit
home computers were common. After a period designing
military communication and optical gauging equipment,
as well as writing software in Forth, Occam, C++ and
Assembler, he joined an automotive company.
As a member of the Royal Photographic Society, he
gained LRPS and ARPS distinctions and pursued a passion for all forms of photography, including landscape
and infrared, as well as portraiture, still life and architectural photography, mostly using traditional monochrome
techniques. Not surprisingly, this hobby coupled with his
professional experience led him to invent and patent several highly regarded f/stop darkroom timers and meters,
still sold throughout the world. During that time digital
cameras evolved rapidly and photo ink-jet printers slowly
overcame their initial limitations. Resisting the temptation of the early optimistic digital promises, he authored
a book on traditional monochrome photography, Way
Beyond Monochrome, to critical acclaim and followed with
a second edition (by which time used prices had soared
to over $500) to satisfy the ongoing demand.
Digital monochrome appeared to be the likely next
avenue for his energy until an eye-opening presentation
on astrophotography renewed a dormant interest in astronomy and the possibilities that digital cameras offered.
This was almost inevitable since astrophotography is the
perfect fusion of science, electronics and photography.
Like many before, his first attempts ended in frustration
and disappointment, but he quickly realized the technical challenges of astrophotography responded well to
methodical and scientific study. He found this, together
with his photographic eye and decades of printing experience, were an excellent foundation to produce beautiful
and fascinating images from a seemingly featureless sky.
Acknowledgements
This book and the accelerated learning that it demands
would not have been possible without the support of my
family and the generosity and contribution of the wider
astrophotography community. I also need to thank Jennifer Wise for making the transatlantic crossing as painless
as possible. I still claim to have a garden (with flowers)
and not a back yard.
It is one of the pleasures of this hobby to share problems and solutions with other hobbyists you will never
likely meet. Coming from the photographic community
it is refreshing to witness an overwhelming generosity of
encouragement and praise to others, irrespective of their
circumstances. In turn I have shared ideas and solutions
with others and where possible I have tried to acknowledge
those contributions that helped me on my way too. As
the image of the nebula suggests, we astrophotographers
are all heart!
This hobby is a never-ending journey of refinement,
knowledge and development. It is a collaborative affair
and I welcome any feedback or suggestions for this book
or the next edition. Please contact me at:
chris@digitalastrophotography.co.uk
8
The Astrophotography Manual
Introduction
“Infinity itself looks flat and uninteresting. Looking up into the night sky is looking into
infinity - distance is incomprehensible and therefore meaningless.” Douglas Adams
A
stronomy is such a fascinating subject that I like to
think that astrophotography is more than just making pretty pictures. For my own part, I started both at
the same time and I quickly realized that my knowledge
of astronomy was deficient in several areas. Reading up
on the subject added to my sense of awe and also made
me appreciate the dedication of astronomers and their
patient achievements over thousands of years. A little history and science is not amiss in such a naturally technical
hobby. Incredibly, the science is anything but static; new
discoveries are being made all the time and an on-going
examination of the Martian surface may reveal secrets
that cause us to re-evaluate extraterrestrial life.
From the earliest days of human consciousness,
mankind has studied the night sky and placed special
significance on eclipses, comets and new appearances.
With only primitive methods, they quickly realized that
the position of the stars, the Moon and the Sun could
tell them when to plant crops, navigate and keep the
passage of time. Driven by a need for astrology as well
as science, their study of the heavens and the belief of
an Earth-centric universe was interwoven with religious
doctrine. It took the Herculean efforts of Copernicus,
Galileo and Tycho, not to mention Kepler, to wrest
control from the Catholic Church in Europe and define the heliocentric solar system with elliptical orbits,
anomalies and detailed stellar mapping.
Astronomers in the Middle east and in south America
made careful observations and, without instruments,
were able to determine the solar year with incredible
accuracy. The Mayans even developed a sophisticated
calendar that did not require adjustment for leap years.
Centuries later, the Conquistadors all but obliterated
these records at a time when ironically Western Europe
was struggling to align their calendars with the seasons.
(Pope Gregory XIII eventually proposed the month of
October be shortened by 10 days to re-align the religious
and hence agricultural calendar with the solar (sidereal)
year. The Catholic states complied in 1583 but others like
Britain delayed until 1752, by which time the adjustment
had increased to 11 days!)
The invention of the telescope propelled scholarly
learning, and with better and larger designs, astronomers
were able to identify other celestial bodies other than
Year
Place
Astronomy Event
2700 BC
England
Stonehenge, in common with other ancient
archaeological sites around the world, is
clearly aligned to celestial events.
2000 BC
Egypt
1570 BC
Babylon
[Circa]
First Solar and Lunar calendars
First evidence of recorded periodicity of
planetary motion (Jupiter) over a 21-year
period.
1600 BC Germany Nebra sky disk, a Bronze age artifact,
which has astronomical significance.
280 BC
Greece
Aristarchus suggests the Earth travels
around the Sun, clearly a man before his
time!
240 BC
Libya
Eratosthenes calculates the circumference
of the earth astronomically.
125 BC
Greece
Hipparchus calculates length of year
precisely, notes Earth’s rotational wobble.
87 BC
Greece
Antikythera mechanism, a clockwork
planetarium showing planetary, solar and
lunar events with extraordinary precision.
150 AD
Egypt
Ptolemy publishes Almagest; this was the
astronomer’s bible for the next 1,400 years.
His model is an Earth-centered universe,
with planet epicycles to account for strange
observed motion.
1543 AD
Poland
Copernicus, after many years of patient
measurement, realizes the Earth is a planet
too and moves around the Sun in a circular
orbit. Each planet’s speed is dependent
upon its distance from the Sun.
1570 AD Denmark Tycho Brahe establishes a dedicated
observatory and generates first accurate
star catalog to 1/60th degree. Develops
complicated solar-system model combining
Ptolemaic and Copernican systems.
1609 AD Germany Kepler works with Tycho Brahe’s astronomical data and develops an elliptical-path
model with planet speed based on its
average distance from the Sun. Designs
improvement to refractor telescope using
dual convex elements.
1610 AD
Italy
Galileo uses an early telescope to discover
that several moons orbit Jupiter and Venus
and have phases. He is put under house
arrest by the Inquisition for supporting
Kepler’s Sun-centered system to underpin
his theory on tides.
fig.1a An abbreviated time-line of the advances in astronomy
is shown above and is continued in fig.1b. The
achievements of the early astronomers is wholly
remarkable, especially when one considers not only
their lack of precision optical equipment but also the
most basic of requirements, an accurate timekeeper.
Year
Preliminaries
Place
Astronomy Event
1654 AD
Holland
Christiaan Huygens devises improved
method for grinding and polishing lenses,
invents the pendulum clock and the achromatic eye-piece lens.
1660 AD
Italy
Giovanni Cassini identifies 3 moons
around Saturn and the gap between the
rings that bear his name. He also calculates
the deformation of Venus and its rotation.
1687 AD
England
Isaac Newton invents the reflector
telescope, calculus and defines the laws of
gravity and motion including planetary
motion in Principia, which remained
unchallenged until 1915.
1705 AD
England
Edmund Halley discovers the proper
motion of stars and publishes a theoretical
study of comets, which accurately predicts
their periods.
1781 AD
England
William Herschel discovers Uranus
and doubles the size of our solar system.
Notable astronomers Flamsteed and Lemonnier had recorded it before but had not
realized it was a planet. Using his 20-foot
telescope, he went on to document 2,500
nebular objects.
[Circa]
1846 AD Germany Johann Galle discovers Neptune, predicted
by mathematical modelling.
1850 AD Germany Kirchoff and Bunsell realize Fraunhofer
lines identify elements in a hot body, leading to spectrographic analysis of stars.
1908 AD
U.S.A.
Edwin Hubble provides evidence that
some “nebula” are made of stars and uses
the term “extra-galactic nebula” or galaxies.
He also realizes a galaxy’s recessional velocity increases with its distance from Earth,
or “Hubble’s law”, leading to expanding
universe theories.
1916 AD Germany Albert Einstein publishes his General
Theory of Relativity changing the course of
modern astronomy.
1930 AD
U.S.A.
Clyde Tombaugh discovers planet Pluto.
In 2006, Pluto was stripped of its title and
relegated to the Kuiper belt.
1963 AD
U.S.A.
Maarten Schmidt links visible object with
radio source. From spectra realizes quasars
are energetic receding galactic nuclei.
1992 AD
U.S.A.
Space probes COBE and WMAP measure
cosmic microwaves and determines the
exact Hubble constant and predicts the
universe is 13.7 billion years old.
2012 AD
U.S.A.
Mars rover Curiosity lands successfully
and begins exploration of planet’s surface.
2014 AD
ESA
Rosetta probe touches down on comet
67P after 12-year journey.
fig.1b Astronomy accelerated once telescopes were in
common use, although early discoveries were
sometimes confused by the limitations of visual
observation through small aperture devices.
9
stars, namely nebula and much later, galaxies. These
discoveries completely changed our appreciation of our
own significance within the universe. Even though the
first lunar explorations are 40 years behind us, very few
of us have looked at the heavens through a telescope and
observed the faint fuzzy patches of a nebula, galaxy or
the serene beauty of a star cluster. To otherwise educated
people it is a revelation when they observe the colorful
glow of the Orion nebula appearing on a computer screen
or the fried-egg disk of the Andromeda Galaxy taken
with a consumer digital camera and lens.
This amazement is even more surprising when one
considers the extraordinary information presented on
television shows, books and on the Internet. When I
have shared back-yard images with work colleagues,
their reaction highlights a view that astrophotography is
the domain of large isolated observatories inhabited with
nocturnal Physics students. This sense of wonderment is
one of the reasons why astrophotographers pursue their
quarry. It reminds me of the anticipation one gets as a
black and white print emerges in a tray of developer.
The challenges we overcome to make an image only
increase our satisfaction and the admiration of others,
especially those in the know.
New Technology
The explosion of interest and the ability of amateurs has
been fuelled by the availability of if not new then certainly applied affordable technology in mechanics, optics,
computers, digital cameras and in no small way, software.
Of these, the digital sensor is chiefly responsible for
revolutionizing astrophotography. Knowledge is another
essential ingredient and the ingenuity and shared experience through the Internet rapidly contribute to the recent
advancement of amateur astrophotography.
It was not that long ago that a bulky Newtonian
reflector was the most popular instrument and large aperture refractors were either expensive or of poor quality.
Computer control was but a distant dream. In the last few
years however, Far east manufacturing techniques have
lowered the cost of high-quality optical cells, mirrors and
motor-driven mounts. Several U.S. companies have taken
alternative folded designs, using mirror and lens combinations, and integrated them with computer-controlled
mounts to make affordable, compact, high-performance
systems.
The same market forces have lowered the price of digital
cameras and the same high-quality camera sensors power
dedicated cameras, optimized with astrophotography in
mind to push the performance envelope further. At the
same time computers, especially laptops, continue to
10
The Astrophotography Manual
reduce in price and with increased performance too, including battery life. The software required to plan, control,
acquire and process images is now available from several
companies at amateur and professional level and from not
a few generous individuals who share their software free
or for a nominal amount. At the same time, collaboration
on interface standards (for instance ASCOM) reduces
software development costs and lead-times.
If that was not enough, in the last few years, tablet
computing and advanced smart phones have provided
alternative platforms for controlling mounts and can
display the sky with GPS-located and gyroscopicallypointed star maps. The universe is our oyster.
Scope of Choice
Today’s consumer choice is overwhelming. After trying
and using several types of telescope and mount, I settled
on a hardware and software configuration that works as
an affordable, portable solution for deep space and occasional planetary imaging. Judging from the current rate of
change, it is impossible to cover all other avenues in detail
without being dangerously out of date on some aspects
before publishing. Broad evaluations of the more popular
alternatives are to be found in this text but with a practical
emphasis and a process of rationalization; in the case of my
own system, to deliver quick and reliable setups to maximize those brief opportunities that the English weather
permits. My setup is not esoteric and serves as a popular
example of its type, ideal for explaining the principles of
astrophotography. Some things will be unique to one piece
of equipment or another but the principles are common.
About this Book
I wrote this book with the concept of being a fast track
to intermediate astrophotography. This is an ambitious
task and quite a challenge. Many astrophotographers
start off with a conventional SLR camera and image
processing software like Photoshop®. In the right conditions these provide excellent images. For those users there
are a number of excellent on-line and published guides
noted in the bibliography. It is not my intention to do
a “me too” book, but having said that, I cannot ignore
this important rung on the ladder either. The emphasis
will be on the next rung up, however, and admittedly at
significantly more cost. This will include the use of more
sophisticated software, precision focusing, cooled CCD
cameras and selective filtering. It is impossible to cover
every aspect in infinite detail. Any single person is limited
by time, budget and inclination. My aim is to include
more detail than the otherwise excellent titles that cover
the basics up to imaging with a SLR.
Year
Astrophotography Event
[Circa]
1840
1850
1852
1858
First successful daguerreotype of Moon
1871
1875
Dry plate process on glass
1882
1883
1889
1920
1935
Spectra taken of nebula for first time
1940
Mercury vapor film treatment used to boost sensitivity
of emulsion for astrophotography purposes
1970
Nitrogen gas treatment used to temporarily boost emulsion sensitivity by 10x for long exposure use
1970
Nitrogen followed by Hydrogen gas treatment used as
further improvement to increase film sensitivity
1974
1989
First astrophotograph made with a digital sensor
1995
By this time, digital cameras have arguably ousted film
cameras for astrophotography.
2004
Meade Instruments Corp. release affordable USB
controlled imaging camera. Digital SLRs used too.
2010
Dedicated cameras for astrophotography are widespread,
with cooling, combined guiders; in monochrome and
color versions. Consumer digital cameras too have
improved and overcome initial long exposure issues.
First successful star picture
First successful wet-plate process
Application of photography to stellar photometry is
realized
Spectra taken of all bright stars
First image to discover stars beyond human vision
First plastic film base, nitro cellulose
Cellulose acetate replaces nitro cellulose as film base
Lowered temperature was found to improve film performance in astrophotography applications
SBIG release ST4 dedicated astrophotography CCD
camera
fig.2 A time-line for some of the key events in astrophotography.
It is now 30 years since the first digital astrophotograph
was taken and I would argue that it is only in the
last 5 years that digital astrophotography has really
grown exponentially, driven by affordable hardware
and software. Public awareness has increased
too, fuelled by recent events in space exploration,
documentaries and astrophotography competitions.
To accomplish this, the book is divided into logical
sections. They quickly establish the basics and become
more detailed as they go on. It starts with a brief astronomy primer suitable for a newcomer or as a refresher.
This sets out a basic understanding of astronomy, explains the terminology and the practical limitations
set by Physics and our Earth-bound location as well as
what is required for success. This subject is a magnet
for specialized terms and acronyms. Getting past the
terminology is an early challenge and an understanding
allows one to confidently participate in forums and ask
the right questions.
The following section sets out the important imaging
priorities and compares general and imaging-specific
equipment and software. There is no one solution for
all and depending on inclination, budget and location,
your own ideal setup will be unique. The aim is to provide sufficient information to enable you to ask the right
questions and make informed purchasing decisions. As
technology advances, this section will be prone to go out
of date, but on the positive side, as real costs come down,
advanced technology, for example mounts fitted with
digital encoders, will become more affordable.
The third section is a systematic guide and explanation of a typical setup. It starts with the physical
assembly and goes on in detail to describe the alignment,
exposure planning and operation of the entire imaging
system, with tips and tricks along the way. Unlike conventional photography, setting the correct exposure in
astrophotography can be a hit and miss affair. There are
many more variables at work and alternative proposals
are discussed and compared.
Not surprisingly, a section dedicated to image calibration and processing follows, using mainly specialized
dedicated imaging applications such as PixInsight®, as
well as some techniques in Photoshop. Image processing is particularly exciting in astrophotography; there
are few rules and everyone has a unique trick up their
sleeve. Some of these are heavyweight image processing
algorithms and others a series of gradual manipulations
to transform a faint fuzzy into a glowing object of beauty.
Each image has its own unique challenges but most can
be systematically analyzed and processed to bring out
the best. This is a vast subject in its own right and there
are several excellent references out there, especially using
Photoshop as the main processing tool. The invention
is amazing and few approaches are the same! I do my
best to rationalize this in the space allowed and provide
references for further reading in the bibliography and
resources in the appendix.
Preliminaries
11
The fifth section is made up of several case studies;
each of which considers their conception, exposure and
processing and an opportunity to highlight various
techniques. A worked example is often a wonderful way
to explain things and these case studies deliberately use
a variety of equipment, techniques and software. These
include Maxim DL, Nebulosity, PHD, PixInsight and
Photoshop, to name a few. The subjects include lunar
and planetary imaging as well as some simple and more
challenging deep-sky objects. Practical examples are even
more valuable if they make mistakes and we learn from
them. These examples have some warts and they discuss
short- and long-term remedies.
On the same theme, things do not always go to plan
and in the appendices before the index and resources, I
have included a chapter on diagnostics, with a small gallery
of errors to help with your own troubleshooting. Fixing
problems can be half the fun but when they resist several
reasoned attempts, a helping hand is most welcome. In my
daytime job I use specialized tools for root cause analysis
and I share some simple ideas to track down gremlins.
Keeping on the light side and not becoming too serious
is essential for astrophotography. In that vein, I found the
late Douglas Adams’ numerous quotes relate to this subject
rather too well and a quote graces each chapter!
Astrophotography and astronomy in general lends
itself to practical invention and not everything is available
off the shelf. To that end, a few practical projects are included in the appendices as well as sprinkled throughout
the book. The other resources in the appendices list the
popular Caldwell and Messier catalogs and an indication
of their season for imaging.
Some of these resources lend themselves to spreadsheets, and my supporting website has downloadable
versions of tables, drawings and spreadsheets as well as
the inevitable errata that escape the technical edits. It can
be found at www.digitalastrophotography.co.uk.
References
Contents
“Don’t Panic” Douglas Adams
268
The Astrophotography Manual
Bibliography and Resources
“First we thought the PC was a calculator. Then we found out how to turn numbers into letters
with ASCII – and we thought it was a typewriter. Then we discovered graphics, and we thought
it was a television. With the World Wide Web, we’ve realized it’s a brochure.” Douglas Adams
Bibliography
Steve Richards, Making Every Photo Count, Self Published, 2011
This is a popular book that introduces digital astrophotography to the beginner. It is now in its second edition and
is been updated to include modern CCD cameras. The emphasis is on using digital SLRs.
Stefan Seip, Digital Astrophotography, Rockynook, 2009
This book gives a wide overview of modern techniques using a range of equipment for Astrophotography. It gives
the reader a flavor for the different specialities and what can be accomplished.
Robin Scagell, Stargazing with a Telescope, Philips, 2010
Robin Scagell is a seasoned astronomer and this comes through in the pages in his book. This is not an astrophotography book as such, but one that places an emphasis on general astronomy equipment as well as choosing and
using telescopes. He offers many practical insights that apply equally to astrophotography.
Greg Parker, Making Beautiful Deep-Sky Images, Springer, 2007
Greg takes you through the planning and execution of his observatory and equipment choices. Using a mixture
of telescope types he showcases many excellent images and goes on to show how some of these are processed using
Photoshop. His fast aperture system helps collect many photons and his trademark are his richly colored images.
Nik Szymanek, Shooting Stars, Pole Star Publications, 2015
This Astronomy Now publication is available as a stand-alone book. Its 130 pages are filled with practical advice on
imaging, and especially processing, deep sky images.
Allen Hall, Getting Started: Long Exposure Astrophotography, Self Published, 2013
This is an up-to-date book which makes use of affordable equipment on a modest budget. It has an interesting section on spectroscopy and includes several practical projects for upgrading equipment and making accessories. It also
features a section on imaging processing, including some of the common tools in PixInsight.
Charles Bracken, The Deep-sky Imaging Primer, Self Published, 2013
This up-to-date work is focused on the essentials of image capture and processing using a mixture of digital SLRs
and astronomy CCD cameras. One of its highlights are the chapters that clearly explain complex technical matters.
Robert Gendler, Lessons from the Masters, Springer, 2013
It is not an exaggeration to say that this book is written by the masters. It provides an insight into specific image
processing techniques, which push the boundaries of image processing and force you to re-evaluate your own efforts.
Highly recommended.
Heather Couper & Nigel Henbest, The Story of Astronomy, Cassell 2011
This book tells the fascinating story of the development of astronomy and is an informative and easy read.
Ruben Kier, The 100 Best Astrophotography Targets, Springer, 2009
This straightforward book lists well- and lesser-known targets as they become accessible during the year. A useful
resource when you wish to venture beyond the Messier catalog.
Appendices
Internet Resources
Less Common Software (or use Internet search)
Maxpilote (sequencing software)
www.felopaul.com/software.htm
PHD2 (guiding software)
www.openphdguiding.org
Focusmax (focusing utility)
www.focusmax.org
Nebulosity (acquisition / processing)
www.stark-labs.com/nebulosity.html
Sequence Generator Pro (acquisition)
www.mainsequencesoftware.com
PixInsight (processing)www.pixinsight.com
Straton (star removal)
www.zipproth.com/Straton
PHDMax (dither with PHD)
www.felopaul.com/phdmax.htm
PHDLab (guiding analysis)
www.countingoldphotons.com
EQMOD (EQ6 ASCOM)
www.eq-mod.sourceforge.net
APT (acquisition)www.ideiki.com/astro/Default.aspx
Cartes du Ciel (planetarium)
www.ap-i.net/skychart/en/start
C2A (planetarium)www.astrosurf.com/c2a/english
Registax (video processing)www.astronomie.be/registax
AutoStakkert (video processing)
www.autostakkert.com
Polar Drift calculator
celestialwonders.com
Processing Tutorials
Harry’s Pixinsightwww.harrysastroshed.com
PixInsight support videos
www.pixinsight.com/videos
PixInsight support tutorials
www.pixinsight.com/tutorials
PixInsight tutorialswww.deepskycolors.com/tutorials.html
PixInsight DVD tutorials
www.ip4ap.com/pixinsight.htm
Popular Forums
Stargazer’s Lounge
www.stargazerslounge.com
(UK)
Cloudy Nightswww.cloudynights.com (US)
Ice in Spacewww.iceinspace.com(AU)
www.progressiveastroimaging.com
Progressing Imaging Forum
Astro buy and sell(regional)
www.astrobuysell.com/uk
PixInsightwww.pixinsight.com/forum
Maxim DLwww.groups.yahoo.com/neo/groups/MaxImDL/info
Sequence Generator Pro
www.forum.mainsequencesoftware.com
FocusMaxwww.groups.yahoo.com/group/FMaxUG
EQMOD (EQ mount software)
www.groups.yahoo.com/group/eqmod
Software Bisque (mounts/software)
www.bisque.com/sc/forums
10Micron (mounts)forum.10micron.eu
Weather
Metcheck (UK)www.metcheck.com
The Weather Channeluk.weather.com
7Timerwww.7timer.com
Clear Sky Chart (N. America)
www.cleardarksky.com
Scope Nights (App for portable devices)
eggmoonstudio.com
The Astrophotography Manual
Book resources and errata
www.digitalastrophotography.co.uk
269
270
The Astrophotography Manual
Messier Objects – suitable for imaging from London latitudes (~50°)
Deep space objects are seasonal. Assuming that you need a good 4 hours or more of imaging per night, in northern
latitudes, it requires low DEC objects to rise in the east and set in the west. The following table selects those Messier
objects above the imaging horizon (30° altitude or more), along with the month in which they first achieve this
altitude at dusk and the likely imaging time span until it sets below 30°.
The items were identified by using a planetarium program, selecting nautical sunset for the middle of each month
and noting which Messier objects first appeared in the east above the imaging horizon. The imaging duration is the
general span of time from astronomical dusk to dawn for that calendar month. This then is the maximum imaging
time available assuming the object rises above the imaging horizon as it gets dark.
M
NGC
constellation
type
RA
[hr]
DEC
[deg]
mag
size
[arcmin]
imaging
visible
from
[hr]
M82
3034 Ursa Major
Galaxy
9.93
69.6833
8.4
11.2
all night
all year
M81
3031 Ursa Major
Galaxy
9.9266
69.0666
6.9
25.7
all night
all year
M35
2168 Gemini
Open Cluster
6.1483
24.3333
5.1
28
11.7
Jan
M45
0000 Taurus
Open Cluster
3.7833
24.1166
0
0
11.7
Jan
M1
1952 Taurus
Nebula
5.575
22.0166
8.4
6
11.7
Jan
M77
1068 Cetus
Galaxy
2.7116
-0.0166
8.8
6.9
11.7
Jan
M40
0000 Ursa Major
Open Cluster
12.3733
58.0833
0
0
10.2
Feb
M108
3556 Ursa Major
Galaxy
11.1916
55.6666
10.1
8.3
10.2
Feb
M97
3587 Ursa Major
Nebula
11.2466
55.0166
11.2
3.2
10.2
Feb
M109
3992 Ursa Major
Galaxy
11.96
53.3833
9.8
7.6
10.2
Feb
M106
4258 Canes Venatici
Galaxy
12.3166
47.3
8.3
18.2
10.2
Feb
M44
2632 Cancer
Open Cluster
8.6683
19.9833
3.1
95
10.2
Feb
M67
2682 Cancer
Open Cluster
8.84
11.8166
6.9
30
10.2
Feb
M78
2068 Orion
Nebula
5.7783
0.05
8
8
10.2
Feb
M43
1982 Orion
Nebula
5.5933
-5.2666
9
20
10.2
Feb
M42
1976 Orion
Nebula
5.59
-5.45
4
66
10.2
Feb
M101
5457 Ursa Major
Galaxy
14.0533
54.35
7.7
26.9
8.3
Mar
M102
5457 Ursa Major
Galaxy
14.0533
54.35
7.7
26.9
8.3
Mar
M51
5194 Canes Venatici
Galaxy
13.4983
47.2
8.4
11
8.3
Mar
M63
5055 Canes Venatici
Galaxy
13.2633
42.0333
8.6
12.3
8.3
Mar
M94
4736 Canes Venatici
Galaxy
12.8483
41.1166
8.2
11
8.3
Mar
M65
3623 Leo
Galaxy
11.315
13.0833
9.3
10
8.3
Mar
M66
3627 Leo
Galaxy
11.3366
12.9833
9
8.7
8.3
Mar
M105
3379 Leo
Galaxy
10.7966
12.5833
9.3
4.5
8.3
Mar
M96
3368 Leo
Galaxy
10.78
11.8166
9.2
7.1
8.3
Mar
M95
3351 Leo
Galaxy
10.7333
11.7
9.7
7.4
8.3
Mar
M48
2548 Hydra
Open Cluster
8.23
-5.8
5.8
54
8.3
Mar
M50
2323 Monoceros
Open Cluster
7.0533
-8.3333
5.9
16
8.3
Mar
M
Appendices
NGC
constellation
type
DEC
RA
[hr]
[deg]
mag
size
[arcmin]
imaging
[hr]
visible
from
M3
5272 Canes Venatici
Glob Cluster
13.7033
28.3833
6.4
16.2
5.9
Apr
M64
4826 Coma Berenices
Galaxy
12.945
21.6833
8.5
9.3
5.9
Apr
M85
4382 Coma Berenices
Galaxy
12.4233
18.1833
9.2
7.1
5.9
Apr
M53
5024 Coma Berenices
Glob Cluster
13.215
18.1666
7.7
12.6
5.9
Apr
M100
4321 Coma Berenices
Galaxy
12.3816
15.8166
9.4
6.9
5.9
Apr
M98
4192 Coma Berenices
Galaxy
12.23
14.9
10.1
9.5
5.9
Apr
M91
4548 Coma Berenices
Galaxy
12.59
14.5
10.2
5.4
5.9
Apr
M99
4254 Coma Berenices
Galaxy
12.3133
14.4166
9.8
5.4
5.9
Apr
M88
4501 Coma Berenices
Galaxy
12.5333
14.4166
9.5
6.9
5.9
Apr
M90
4569 Virgo
Galaxy
12.6133
13.1666
9.5
9.5
5.9
Apr
M86
4406 Virgo
Galaxy
12.4366
12.95
9.2
7.4
5.9
Apr
M84
4374 Virgo
Galaxy
12.4183
12.8833
9.3
5
5.9
Apr
M89
4552 Virgo
Galaxy
12.595
12.55
9.8
4.2
5.9
Apr
M87
4486 Virgo
Galaxy
12.5133
12.4
8.6
7.2
5.9
Apr
M58
4579 Virgo
Galaxy
12.6283
11.8166
9.8
5.4
5.9
Apr
M59
4621 Virgo
Galaxy
12.7
11.65
9.8
5.1
5.9
Apr
M60
4649 Virgo
Galaxy
12.7283
11.55
8.8
7.2
5.9
Apr
M49
4472 Virgo
Galaxy
12.4966
8
8.4
8.9
5.9
Apr
M61
4303 Virgo
Galaxy
12.365
4.4666
9.7
6
5.9
Apr
M92
6341 Hercules
Glob Cluster
17.285
43.1333
6.5
11.2
2.3
May
M13
6205 Hercules
Glob Cluster
16.695
36.4666
5.9
16.6
2.3
May
M5
5904 Serpens
Glob Cluster
15.31
2.0833
5.8
17.4
2.3
May
M52
7654 Cassiopeia
Open Cluster
23.4033
61.5833
6.9
13
0
Jun
M103
581
Open Cluster
1.5533
60.7
7.4
6
0
Jun
M39
7092 Cygnus
Open Cluster
21.5366
48.4333
4.6
32
0
Jun
M29
6913 Cygnus
Open Cluster
20.3983
38.5333
6.6
7
0
Jun
M57
6720 Lyra
Nebula
18.8933
33.0333
9
2.5
0
Jun
M56
6779 Lyra
Glob Cluster
19.2766
30.1833
8.3
7.1
0
Jun
M27
6853 Vulpecula
Nebula
19.9933
22.7166
8.1
15.2
0
Jun
M71
6838 Sagitta
Glob Cluster
19.89667 18.78333
8.3
7.2
0
Jun
M14
6402 Ophiuchus
Glob Cluster
17.62667 -3.25
7.6
11.7
0
Jun
M11
6705 Scutum
Open Cluster
18.85167 -6.26667
5.8
14
0
Jun
M15
7078 Pegasus
Glob Cluster
21.5
6.4
12.3
0.5
Jul
M12
6218 Ophiuchus
Glob Cluster
16.78667 -1.95
6.6
14.5
0.5
Jul
M10
6254 Ophiuchus
Glob Cluster
16.95167 -4.1
6.6
15.1
0.5
Jul
M26
6694 Scutum
Open Cluster
18.75333 -9.4
8
15
0.5
Jul
M76
650
Nebula
1.705
12
4.8
4.6
Aug
Cassiopeia
Perseus
12.16667
51.56667
271
272
The Astrophotography Manual
M
NGC
constellation
RA
type
[hr]
DEC
[deg]
mag
size
[arcmin]
imaging
[hr]
visible
from
M110
205
Andromeda
Galaxy
0.67333
41.68333
8
17.4
4.6
Aug
M31
224
Andromeda
Galaxy
0.71167
41.26667
3.5
178
4.6
Aug
M32
221
Andromeda
Galaxy
0.71167
40.86667
8.2
7.6
4.6
Aug
M2
7089 Aquarius
Glob Cluster
21.55833 -0.81667
6.5
12.9
7.5
Sep
M34
1039 Perseus
Open Cluster
2.7
42.78333
5.2
35
7.5
Sep
M33
598
Triangulum
Galaxy
1.565
30.65
5.7
62
9.5
Oct
M74
628
Pisces
Galaxy
1.61167
15.78333
9.2
10.2
11.2
Nov
M38
1912 Auriga
Open Cluster
5.47833
35.83333
6.4
21
12
Dec
M36
1960 Auriga
Open Cluster
5.60167
34.13333
6
12
12
Dec
M37
2099 Auriga
Open Cluster
5.87333
32.55
5.6
24
12
Dec
Messier Data – full listing
This alternative database lists all the Messier objects and is compiled from various databases on the Internet, including those linked to by SEDS and others. The object size is shown by means of its longest dimension and I noted
that published values vary slightly between sources. Messier only worked in the Northern Hemisphere and his list
excludes those deep space objects visible only from the Southern Hemisphere. For that, the Caldwell Catalog goes
a long way to make amends.
RA
size
[hr min]
[deg min]
DEC
mag
Remnant
5 34.5
22 1
8.4
6
Aqr
G Cluster
21 33.5
0 49
6.5
12.9
CVn
G Cluster
13 42.2
28 23
6.2
16.2
Sco
G Cluster
16 23.6
-26 32
5.6
26.3
5904
SerCap
G Cluster
15 18.6
25
5.6
17.4
6
6405
Sco
O Cluster
17 40.1
-32 13
5.3
15
Butterfly Cluster
7
6475
Sco
O Cluster
17 53.9
-34 49
4.1
80
The Scorpion’s Tail, Ptolemy’s Cluster
8
6523
Sgr
D Nebula
18 3.8
-24 23
6
90
Lagoon Nebula
9
6333
Oph
G Cluster
17 19.2
-18 31
7.7
9.3
10
6254
Oph
G Cluster
16 57.1
-4 6
6.6
15.1
12
6218
Oph
G Cluster
16 47.2
-1 57
6.7
14.5
13
6205
Her
G Cluster
16 41.7
36 28
5.8
16.6
14
6402
Oph
G Cluster
17 37.6
-3 15
7.6
11.7
15
7078
Peg
G Cluster
21 30
12 10
6.2
12.3
16
6611
SerCau
O Cluster
18 18.8
-13 47
6.4
35
associated with the Eagle
Nebula
17
6618
Sgr
D Nebula
18 20.8
-16 11
7
46
Omega, Swan, Horseshoe,
or Lobster Nebula
18
6613
Sgr
O Cluster
18 19.9
-17 8
7.5
9
M
NGC
const.
type
1
1952
Tau
2
7089
3
5272
4
6121
5
[arcmin]
common name
Crab Nebula
Hercules Globular Cluster
Appendices
273
[hr min]
[deg min]
DEC
mag
G Cluster
17 2.6
-26 16
6.8
13.5
Sgr
D Nebula
18 2.6
-23 2
9
28
6531
Sgr
O Cluster
18 4.6
-22 30
6.5
13
6656
Sgr
G Cluster
18 36.4
-23 54
5.1
24
23
6494
Sgr
O Cluster
17 56.8
-19 1
6.9
27
24
6603
Sgr
Patch
18 16.9
-18 29
4.6
5
25
0
Sgr
O Cluster
18 31.6
-19 15
6.5
40
26
6694
Sct
O Cluster
18 45.2
-9 24
8
15
27
6853
Vul
P Nebula
19 59.6
22 43
7.4
15.2
28
6626
Sgr
G Cluster
18 24.5
-24 52
6.8
11.2
29
6913
Cyg
O Cluster
20 23.9
38 32
7.1
7
30
7099
Cap
G Cluster
21 40.4
-23 11
7.2
11
31
224
And
S Galaxy
0 42.7
41 16
3.4
178
32
221
And
E Galaxy
0 42.7
40 52
8.1
8
near Andromeda Galaxy
33
598
Tri
S Galaxy
1 33.9
30 39
5.7
62
Triangulum Galaxy
34
1039
Per
O Cluster
2 42
42 47
5.5
35
35
2168
Gem
O Cluster
6 8.9
24 20
5.3
28
36
1960
Aur
O Cluster
5 36.1
34 8
6.3
12
37
2099
Aur
O Cluster
5 52.4
32 33
6.2
24
38
1912
Aur
O Cluster
5 28.4
35 50
7.4
21
39
7092
Cyg
O Cluster
21 32.2
48 26
4.6
32
40
0
UMa
Binary
12 22.4
58 5
8.4
0.8
41
2287
CMa
O Cluster
6 46
-20 44
4.6
38
42
1976
Ori
D Nebula
5 35.4
-5 27
4
66
Orion Nebula
43
1982
Ori
D Nebula
5 35.6
-5 16
9
20
De Mairan’s Nebula, part
of Orion Nebula
44
2632
Cnc
O Cluster
8 40.1
19 59
3.7
95
Beehive Cluster
45
0
Tau
O Cluster
3 47
24 7
1.6
100
Pleiades
46
2437
Pup
O Cluster
7 41.8
-14 49
6
27
47
2422
Pup
O Cluster
7 36.6
-14 30
5.2
30
48
2548
Hya
O Cluster
8 13.8
-5 48
5.5
54
49
4472
Vir
E Galaxy
12 29.8
80
8.4
9
50
2323
Mon
O Cluster
7 3.2
-8 20
6.3
16
51
5194
CVn
S Galaxy
13 29.9
47 12
8.4
11
52
7654
Cas
O Cluster
23 24.2
61 35
7.3
13
53
5024
Com
G Cluster
13 12.9
18 10
7.6
12.6
54
6715
Sgr
G Cluster
18 55.1
-30 29
7.6
9.1
55
6809
Sgr
G Cluster
19 40
-30 58
6.3
19
M
NGC
const.
type
19
6273
Oph
20
6514
21
22
RA
size
[arcmin]
common name
Trifid Nebula
Sagittarius Star Cloud
Dumbbell Nebula
Andromeda Galaxy
Winnecke 4
Whirlpool Galaxy
274
The Astrophotography Manual
[hr min]
[deg min]
DEC
mag
G Cluster
19 16.6
30 11
8.3
7.1
P Nebula
18 53.6
33 2
8.8
2.5
Vir
S Galaxy
12 37.7
11 49
9.7
5.5
Vir
E Galaxy
12 42
11 39
9.6
5.1
4649
Vir
E Galaxy
12 43.7
11 33
8.8
7.2
61
4303
Vir
S Galaxy
12 21.9
4 28
9.7
6
62
6266
Oph
G Cluster
17 1.2
-30 7
6.5
14.1
63
5055
CVn
S Galaxy
13 15.8
42 2
8.6
12.3
Sunflower Galaxy
64
4826
Com
S Galaxy
12 56.7
21 41
8.5
9.3
Blackeye Galaxy
65
3623
Leo
S Galaxy
11 18.9
13 5
9.3
8
in the Leo Triplett
66
3627
Leo
S Galaxy
11 20.2
12 59
8.9
8.7
in the Leo Triplett
67
2682
Cnc
O Cluster
8 50.4
11 49
6.1
30
68
4590
Hya
G Cluster
12 39.5
-26 45
7.8
12
69
6637
Sgr
G Cluster
18 31.4
-32 21
7.6
7.1
70
6681
Sgr
G Cluster
18 43.2
-32 18
7.9
7.8
71
6838
Sge
G Cluster
19 53.8
18 47
8.2
7.2
73
6994
Aqr
Asterism
20 58.9
-12 38
9
2.8
74
628
Psc
S Galaxy
1 36.7
15 47
9.4 1
0.2
75
6864
Sgr
G Cluster
20 6.1
-21 55
8.5
6
76
650
Per
P Nebula
1 42.4
51 34
0.1
4.8
77
1068
Cet
S Galaxy
2 42.7
01
8.9
7
78
2068
Ori
D Nebula
5 46.7
03
8.3
8
79
1904
Lep
G Cluster
5 24.5
-24 33
7.7
8.7
80
6093
Sco
G Cluster
16 17
-22 59
7.3
8.9
81
3031
UMa
S Galaxy
9 55.6
69 4
6.9
25.7
Bode’s Galaxy
82
3034
UMa
I Galaxy
9 55.8
69 41
8.4
11.2
Cigar Galaxy
83
5236
Hya
S Galaxy
13 37
-29 52
7.6
11.2
Southern Pinwheel
84
4374
Vir
L Galaxy
12 25.1
12 53
9.1
5
85
4382
Com
L Galaxy
12 25.4
18 11
9.1
7.1
86
4406
Vir
L Galaxy
12 26.2
12 57
8.9
7.4
87
4486
Vir
E Galaxy
12 30.8
12 24
8.6
7.2
88
4501
Com
S Galaxy
12 32
14 25
9.6
6.9
89
4552
Vir
E Galaxy
12 35.7
12 33
9.8
4.2
90
4569
Vir
S Galaxy
12 36.8
13 10
9.5
9.5
91
4548
Com
S Galaxy
12 35.4
14 30
0.2
5.4
92
6341
Her
G Cluster
17 17.1
43 8
6.4
11.2
93
2447
Pup
O Cluster
7 44.6
-23 52
6
22
94
4736
CVn
S Galaxy
12 50.9
41 7
8.2
11
M
NGC
const.
type
56
6779
Lyr
57
6720
Lyr
58
4579
59
4621
60
RA
size
[arcmin]
common name
Ring Nebula
Little Dumbbell Nebula
Cetus A
Virgo A
Appendices
[hr min]
[deg min]
DEC
mag
S Galaxy
10 44
11 42
9.7
7.4
Leo
S Galaxy
10 46.8
11 49
9.2
7.1
3587
UMa
P Nebula
11 14.8
55 1
9.9
3.2
4192
Com
S Galaxy
12 13.8
14 54
0.1
9.5
99
4254
Com
S Galaxy
12 18.8
14 25
9.9
5.4
100
4321
Com
S Galaxy
12 22.9
15 49
9.3
6.9
101
5457
UMa
S Galaxy
14 3.2
54 21
7.9
26.9
Pinwheel Galaxy
102
5457
UMa
S Galaxy
14 3.2
54 21
7.9
26.9
duplicates M101
103
581
Cas
O Cluster
1 33.2
60 42
7.4
6
104
4594
Vir
S Galaxy
12 40
-11 37
8
8.3
105
3379
Leo
E Galaxy
10 47.8
12 35
9.3
4.5
106
4258
CVn
S Galaxy
12 19
47 18
8.4
18.2
107
6171
Oph
G Cluster
16 32.5
-13 3
7.9
10
108
3556
UMa
S Galaxy
11 11.5
55 40
0
8.3
109
3992
UMa
S Galaxy
11 57.6
53 23
9.8
7.6
110
205
And
E Galaxy
0 40.4
41 41
8.5
17.4
M
NGC
const.
type
95
3351
Leo
96
3368
97
98
RA
size
275
common name
[arcmin]
Owl Nebula
Sombrero Galaxy
a satellite of the Andromeda Galaxy
Caldwell Catalog
The Caldwell Catalog, by the late Sir Patrick Moore, documents a number of notable omissions from the Messier
list and includes significant objects for observers in the southern hemisphere. The Caldwell Catalog is listed in order
of distance from the North Celestial Pole. The most southern objects are given the highest catalog numbers. It is
not the last word in deep space objects but is a good starting point after the Messier list. Several of the first light
assignments are of Caldwell objects.
Caldwell
NGC
const.
type
RA
DEC
mag.
size
1
188
Cep
Open Cluster
00 44.4
+85 20
8.1
14
2
40
Cep
Planetary Nebula
00 13.0
+72 32
11.6
0.6
3
4236
Dra
Spiral Barred
Galaxy
12 16.7
+69 28
9.7
21
4
7023
Cep
Bright Nebula
21 01.8
+68 12
6.8
18
5
IC 342
Cam
Spiral Galaxy
03 46.8
+68 06
9.2
18
6
6543
Dra
Planetary Nebula
17 58.6
+66 38
8.8
5.8
7
2403
Cam
Spiral Galaxy
07 36.9
+65 36
8.9
18
8
559
Cas
Open Cluster
01 29.5
+63 18
9.5
4
9
Sh2-155
Cep
Bright Nebula
22 56.8
+62 37
7.7
50
10
663
Cas
Open Cluster
01 46.0
+61 15
7.1
16
common name
Bow Tie Nebula
Iris Nebula
Cat’s Eye Nebula
Cave Nebula
276
The Astrophotography Manual
Caldwell
NGC
const.
type
RA
DEC
mag.
size
11
12
7635
Cas
Bright Nebula
23 20.7
6946
Cep
Spiral Galaxy
20 34.8
13
457
Cas
Open Cluster
14
869/884
Per
15
6826
Cyg
16
7243
17
147
18
185
19
common name
+61 12
7
15
+60 09
9.7
11
01 19.1
+58 20
6.4
13
Owl or E.T. Cluster
Open Cluster
02 20.0
+57 08
4.3
30
Double Cluster, h &
chi Persei
Planetary Nebula
19 44.8
+50 31
9.8
2.3
Blinking Planetary
Lac
Open Cluster
22 15.3
+49 53
6.4
21
Cas
Elliptical Galaxy
00 33.2
+48 30
9.3
13
Cas
Elliptical Galaxy
00 39.0
+48 20
9.2
12
IC 5146
Cyg
Bright Nebula
21 53.5
+47 16
10
12
Cocoon Nebula
20
7000
Cyg
Bright Nebula
20 58.8
+44 20
6
120
North America
Nebula
21
4449
CVn
Irregular Galaxy
12 28.2
+44 06
9.4
5
22
7662
And
Planetary Nebula
23 25.9
+42 33
9.2
2.2
23
891
And
Spiral Barred
Galaxy
02 22.6
+42 21
9.9
14
24
1275
Per
Seyfert Galaxy
03 19.8
+41 31
11.6
2.6
25
2419
Lyn
Globular Cluster
07 38.1
+38 53
10.4
4.1
26
4244
CVn
Spiral Galaxy
12 17.5
+37 49
10.6
16
27
6888
Cyg
Bright Nebula
20 12.0
+38 21
7.5
20
28
752
And
Open Cluster
01 57.8
+37 41
5.7
50
29
5005
CVn
Spiral Barred
Galaxy
13 10.9
+37 03
9.8
5.4
30
7331
Peg
Spiral Barred
Galaxy
22 37.1
+34 25
9.5
11
31
IC 405
Aur
Bright Nebula
05 16.2
+34 16
6
19
32
4631
CVn
Spiral Galaxy
12 42.1
+32 32
9.3
15
Whale Galaxy
33
6992/5
Cyg
Supernova Remnant
20 56.4
+31 43
-
60
East Veil Nebula
34
6960
Cyg
Supernova Remnant
20 45.7
+30 43
-
70
West Veil Nebula
35
4889
Com
Elliptical Galaxy
13 00.1
+27 59
11.4
3
36
4559
Com
Spiral Galaxy
12 36.0
+27 58
9.8
10
37
6885
Vul
Open Cluster
20 12.0
+26 29
5.7
7
38
4565
Com
Spiral Barred
Galaxy
12 36.3
+25 59
9.6
16
Needle Galaxy
39
2392
Gem
Planetary Nebula
07 29.2
+20 55
9.9
0.7
Eskimo or Clown
Nebula
40
3626
Leo
Spiral Barred
Galaxy
11 20.1
+18 21
10.9
3
Bubble nebula
Blue Snowball
Perseus A
Crescent Nebula
Flaming Star Nebula
Caldwell
Appendices
NGC
const.
type
RA
DEC
mag.
size
41
-
42
7006
Tau
Open Cluster
04 27.0
Del
Globular Cluster
21 01.5
+16 00
1
330
+16 11
10.6
2.8
43
7814
Peg
Spiral Barred
Galaxy
00 03.3
+16 09
10.5
6
44
7479
Peg
Spiral Barred
Galaxy
23 04.9
+12 19
11
4
45
5248
Boo
Spiral Galaxy
13 37.5
+08 53
10.2
6
46
2261
Mon
Bright Nebula
06 39.2
+08 44
10
2
47
6934
Del
Globular Cluster
20 34.2
+07 24
8.9
6
48
2775
Can
Spiral Galaxy
09 10.3
+07 02
10.3
4.5
49
2237-9
Mon
Bright Nebula
06 32.3
+05 03
-
80
50
2244
Mon
Open Cluster
06 32.4
+04 52
4.8
24
common name
Hyades
Hubble’s Variable
Nebula
Rosette Nebula
51
IC 1613
Cet
Irregular Galaxy
01 04.8
+02 07
9
12
52
4697
Vir
Elliptical Galaxy
12 48.6
-05 48
9.3
6
53
3115
Sex
Elliptical Galaxy
10 05.2
-07 43
9.1
8
54
2506
Mon
Open Cluster
08 00.2
-10 47
7.6
7
55
7009
Aqr
Planetary Nebula
21 04.2
-11 22
8.3
2.5
56
246
Cet
Planetary Nebula
00 47.0
-11 53
8
3.8
57
6822
Sgr
Irregular Galaxy
19 44.9
-14 48
9.3
10
58
2360
CMa
Open Cluster
07 17.8
-15 37
7.2
13
59
3242
Hya
Planetary Nebula
10 24.8
-18 38
8.6
0.25
Ghost of Jupiter
60
4038
Crv
Spiral Galaxy
12 01.9
-18 52
11.3
2.6
Antennae Galaxies
61
4039
Crv
Spiral Galaxy
12 01.9
-18 53
13
3.2
Antennae Galaxies
62
247
Cet
Spiral Galaxy
00 47.1
-20 46
8.9
20
63
7293
Aqr
Planetary Nebula
22 29.6
-20 48
6.5
13
64
2362
CMa
Open Cluster
07 18.8
-24 57
4.1
8
65
253
Scl
Spiral Galaxy
00 47.6
-25 17
7.1
25
66
5694
Hya
Globular Cluster
14 39.6
-26 32
10.2
3.6
67
1097
For
Spiral Barred
Galaxy
02 46.3
-30 17
9.2
9
68
6729
CrA
Bright Nebula
19 01.9
-36 57
9.7
1
69
6302
Sco
Planetary Nebula
17 13.7
-37 06
12.8
0.8
70
300
Scl
Spiral Galaxy
00 54.9
-37 41
8.1
20
71
2477
Pup
Open Cluster
07 52.3
-38 33
5.8
27
72
55
Scl
Spiral Barred
Galaxy
00 14.9
-39 11
8.2
32
73
1851
Col
Globular Cluster
05 14.1
-40 03
7.3
11
Spindle Galaxy
Saturn Nebula
Barnard’s Galaxy
Helix Nebula
Sculptor Galaxy
Bug Nebula
277
278
The Astrophotography Manual
Caldwell
NGC
const.
type
RA
DEC
mag.
size
common name
74
75
3132
Vel
Planetary Nebula
10 07.7
-40 26
8.2
0.8
Eight Burst Nebula
6124
Sco
Open Cluster
16 25.6
-40 40
5.8
29
76
6231
Sco
Open Cluster
16 54.0
-41 48
2.6
15
77
5128
Cen
Peculiar Galaxy
13 25.5
-43 01
7
18
78
6541
CrA
Globular Cluster
18 08.0
-43 42
6.6
13
79
3201
Vel
Globular Cluster
10 17.6
-46 25
6.7
18
80
5139
Cen
Globular Cluster
13 26.8
-47 29
3.6
36
81
6352
Ara
Globular Cluster
17 25.5
-48 25
8.1
7
82
6193
Ara
Open Cluster
16 41.3
-48 46
5.2
15
83
4945
Cen
Spiral Galaxy
13 05.4
-49 28
9.5
20
84
5286
Cen
Globular Cluster
13 46.4
-51 22
7.6
9
85
IC 2391
Vel
Open Cluster
08 40.2
-53 04
2.5
50
86
6397
Ara
Globular Cluster
17 40.7
-53 40
5.6
26
87
1261
Hor
Globular Cluster
03 12.3
-55 13
8.4
7
88
5823
Cir
Open Cluster
15 05.7
-55 36
7.9
10
89
6087
Nor
Open Cluster
16 18.9
-57 54
5.4
12
90
2867
Car
Planetary Nebula
09 21.4
-58 19
9.7
0.2
91
3532
Car
Open Cluster
11 06.4
-58 40
3
55
92
3372
Car
Bright Nebula
10 43.8
-59 52
6.2
120
93
6752
Pav
Globular Cluster
19 10.9
-59 59
5.4
20
94
4755
Cru
Open Cluster
12 53.6
-60 20
4.2
10
95
6025
TrA
Open Cluster
16 03.7
-60 30
5.1
12
96
2516
Car
Open Cluster
07 58.3
-60 52
3.8
30
97
3766
Cen
Open Cluster
11 36.1
-61 37
5.3
12
98
4609
Cru
Open Cluster
12 42.3
-62 58
6.9
5
99
-
Cru
Dark Nebula
12 53.0
-63 00
-
400
Coalsack Nebula
100
IC 2944
Cen
Open Cluster
11 36.6
-63 02
4.5
15
Lambda Centauri
Nebula
101
6744
Pav
Spiral Barred
Galaxy
19 09.8
-63 51
9
16
102
IC 2602
Car
Open Cluster
10 43.2
-64 24
1.9
50
Theta Car Cluster
103
2070
Dor
Bright Nebula
05 38.7
-69 06
1
40
Tarantula Nebula
104
362
Tuc
Globular Cluster
01 03.2
-70 51
6.6
13
105
4833
Mus
Globular Cluster
12 59.6
-70 53
7.3
14
106
104
Tuc
Globular Cluster
00 24.1
-72 05
4
31
107
6101
Aps
Globular Cluster
16 25.8
-72 12
9.3
11
108
4372
Mus
Globular Cluster
12 25.8
-72 40
7.8
19
109
3195
Cha
Planetary Nebula
10 09.5
-80 52
11.6
40
Centaurus A
Omega Centauri
Omicron Vel Cluster
S Norma Cluster
Eta Carinae Nebula
Jewel Box
47 Tucanae
Appendices
Useful Formulae
Most of the relevant formulae are shown throughout the book in their respective
chapters. This selection may come in useful too:
Autoguider Rate
This calculates the autoguider rate, in pixels per second, as required by many
capture programs. The guide rate is the fraction of the sidereal rate:
autoguider rate =
15.04 • guide rate • cos(declination)
autoguider resolution (arcsec/pixel)
Multiplying this by the minimum and maximum moves (seconds) in the guider
settings provides the range of correction values from an autoguider cycle.
Polar Drift Rate
This calculates the drift rate in arc seconds for a known polar misalignment:
declination drift(arcsecs) =
drift time(mins) • cos(declination) • polar error (arcmins)
3.81
Polar Error
Conversely, this indicates the polar alignment error from a measured drift rate:
polar error (arcmins) = 3.81•
declination drift(arcsecs)
drift time(mins) • cos(declination)
Dust Distance
This calculates the optical distance in millimeters, of the offending dust particle,
by its shadow diameter on an image. The CCD pitch is in microns:
distance = CCD pitch • focal ratio • shadow diameter in pixels
Periodic Error
This calculates the periodic error in arc seconds for a given declination and
pixel drift:
periodic error (arc seconds)=
pixel drift • CCD resolution (arcsec/pixel)
cos(declination)
Critical Focus Zone
This alternative equation calculates the zone of acceptable focus for a given set of
seeing conditions and uses a quality factor Q (a percentage defocus contribution
to the overall seeing conditions). (f is the focal ratio.) :
critical focus zone (microns) = seeing (arcsecs) • aperture (mm) • f 2 • Q
279