Winter 2003
The Journal of the Arunah Hill Natural Science Center Inc.
The 2002 Star Watch Graduates and staff
Inside this issue:
Deep Sky Treasures
Be your own Go-To
Do The Dew
Volume 40
2
Inside This Issue
Winter 2003
Regular Sections
4
Deep Sky Treasures
The Observer’s Notebook
Edited by John Davis
“ Dancing With The Dog ”
Winter 2003 Arunah Hill Calendar:
Jan-Feb-March
Activities at Arunah Hill and a map with directions
to Arunah Hill is on the back of the calendar.
Stick it up on your refrigerator.
Articles
3 The Editor’s Desk
by Steve Pielock
6 Guest Article:
by Rich Volant
“Do the Dew”
7
Guest Article:
by Tom Hoffelder
“Be Your Own Go-To”
Front Cover:
This year’s Star Watch Graduation Photo:
Top Row: Students from left to right.
Susan Vilan
Chris Heon
Kevin Schuck
Richard Hilbert
Veronica Hilbert
Bottom row: Staff from left to right.
Bill Fuller
John Davis
Joe Zuraw
Bruce Blanchard
Steve Pielock
A Note from the Treasurer
I don’t know if you noticed it, but there is
something new on the mailing label. We added
the date that your membership expires. So
please check it (1/2003 means that your
membership expires at the end of Jan 2003). If
the date on your mailing label indicates that
your membership has expired, this will be the
last issue of “The View from Arunah” that you
will receive unless we hear from you. We
value you as a member but if you don’t value
us we can’t continue to bring you the benefits
of membership in the Arunah Hill Natural
Science Center. So, if this applies to you, act
now before you forget, and renew your
membership!
Thank you,
Peter Scherff,
DEEP SKY TREASURES
member, stands off 20 arc min. at the SE edge. The cluster lies
some 2300 light years away.
By John Davis
A number of years ago an amateur astronomer from New
England penned these lines:
Canis M ajor
The great Overdog
That heavenly beast
W ith a star in one eye
Gives a leap in the east
He dances upright
All the way to the west
And never once drops
On his forefeet to rest
I’m a poor underdog
But tonight I will bark
W ith that great Overdog
That romps through the dark
Thus did the renowned American poet, Robert Frost (yes, he
was indeed an amateur astronomer) in lines that are not in any
way “doggerel” salute this celebrated canine denizen of our
winter sky. In addition to the blazing (mag. –1.5) “Dog Star”
Sirius, Canis Major, the “Great Overdog” boasts a nice variety
of deep sky treasures for those of us willing to brave the
winter chill and seek them out, while “dancing with the dog”
on his “way to the west”. And while we’re so engaged we’ll
take a little closer look at just a few of those gems.
Certainly the showpiece among them is the beautiful open
cluster M -41, sparkling from a spot just 4 degrees south of
Sirius. Interestingly, the first recorded historical mention of
this cluster dates back to antiquity, a naked eye observation of
a “star with a tail” or “cloudy spot” near Sirius in the year 325
BC by Aristotle, as described in his “Meteorologies”.
Covering more than 40 arc min., an area larger than the Full
Moon, this “cloudy spot” is at mag. 4.5 easily visible to the
naked eye, provided you view it when it is high enough in a
dark sky. M-41 is easily resolvable in almost any binocular
and is a gorgeous sight in a telescope, or to quote veteran
observer Phil Harrington in his book, The Deep Sky, it “bursts
with splendor”. To a large degree the beauty and appeal of this
cluster is attributable to the diverse range of brightness of its
stars and the noticeable color contrast among its several pairs.
Most notable is the often mentioned reddish “central star”, a
mag. 6.9 K type giant. Several other orange-reddish K type
stars share the scene with blue giant spectral type B stars. Over
twenty of these down to 10 th magnitude are surrounded by
about 100 more points of light in the cluster ranging on down
to 13 th magnitude. A 6 th mag. star, 12 CMa, not a cluster
Photo of M-41
The best way to fully enjoy and appreciate the splendor of M41 is to use a rich field, low power setup. You want to be sure
to get the whole 40-plus arc min. of the cluster and more into
your field of view. Use as low a power and as wide field an
eyepiece as possible, especially in larger, longer focal length
scopes. Most noticeable when you view this cluster is the
pronounced clumping and grouping of the stars into distinct
patterns, but with very little overall central condensation of the
stars. As is the case with many other open or galactic clusters,
you will notice in M-41 numerous chains of stars evident
throughout this aggregation, many here seeming to give the
impression of bursting outward from the center, as if from
some cosmic explosion. This effect is accentuated at the SE,
SW , NW and NE edges of the cluster by the presence of short,
straight rows of 4 or more closely placed fainter stars, each
row radiating out from the center of the cluster.
You can also see other patterns formed by straight and curving
arcs and chains of stars interspersed by dark patches and voids
crisscrossing the cluster. Many observers notice four stars in
the center forming a keystone shape, reminiscent of the one in
Hercules. Others pick up a C-shaped group open to the NE
punctuated by two orange stars just NE of the cluster center.
This formation extends outward to the NE in a short line to
form a very nice backward question mark. From the overall
layout of stars other observers are reminded of another famous
Messier cluster: M-44, “The Beehive”. The keen eyed
observer, author, and “Sky & Telescope” contributing editor
Steve O’Meara sees the figure of a bat in flight made up from
a combination of star chains in this remarkable cluster.
W ithout a doubt M-41 is the type of object which, even if
you’ve already observed it many times you may want to revisit
to fully appreciate its many charms.
There are three other Canis Major objects, two of which we’ve
covered in previous columns that we should mention here as
ones you should try to seek out while you observe in this part
of the sky, but for which space doesn’t permit adequate
coverage here. The one we haven’t discussed previously is a
faint emission nebula, the “Seagull” or “Eagle”, IC-2177
(w/NGC-2327 and Cederblad 90) overlapping the Canis Major
/ Monoceros border. The other two you shouldn’t miss are
NGC-2359 – the “Duck Nebula” or “Thor’s Helmet”, a nice
emission nebula 9 degrees NE of Sirius, and the spectacular
Tau Canis Majoris cluster, NGC-2362, 3 degrees NE of
W ezen (delta CMa).
Next, we’ll move on to find a seldom observed emission
nebula. Just over 3 degrees SSE of 4 th mag. gamma CM a, at
the N corner of a small triangle formed with two N-S aligned
6 th and 7.5 mag. stars lies Sharpless (Sh) 2-301. This little
gem spans just 7’ x 8’ and is elongated W NW -ESE. It is
readily visible in my 10 inch “dob”using a UHC filter, with a
10 th mag. star that can be seen at the SE end. The nebula has
somewhat of a fan shape along which larger apertures show
three projections toward the SE, E and N. There are several
faint stars embedded in the nebulosity, especially running from
near the center toward the N end. An O-III filter will also work
quite well with this nebula, and of course, as is the case with
most diffuse objects, larger apertures (16”-18”and up) will
show more detail.
Scanning further to the east, now, to a spot just under 3 ½
degrees due east of gamma CMa, and just 22’ E of a 5 th mag.
star, we come upon NGC-2360, a very attractive and
delightful open cluster teeming with a rich array of somewhat
fainter stars, mostly in the 10 th to 12 th magnitude range. This
very rich group of 80-100 stars is called “Caroline’s
Cluster”, and was discovered over two centuries ago on a cold
winter evening in 1783 by Caroline Herschel, an accomplished
astronomer who found 8 comets and discovered some 12 deep
sky objects. She was the sister and able assistant to the most
celebrated astronomer of the time, W illiam Herschel.
Incidentally, her story is described in an article by California
amateur Jane Houston Jones in the November, 2002 issue of
“Sky & Telescope” magazine. At a distance of about 4800 LY
and spanning 13 arc min. the cluster glows clearly at mag. 7.2
in a finder scope or binoculars, resting in a fairly rich part of
the Milky Way, into which it blends nicely. Perhaps the single,
most obvious thing that will strike you about NGC-2360 is
that its fairly irregular shape and form is laced throughout with
chains of stars meandering in every direction with
considerable clumping together of some stars into compact
groups and knots. These chains of stars are interspersed with
several very obvious dark patches devoid of stars. T wo of the
chains converge from near the center toward the east enclosing
a prominent dark void that looks somewhat like a carrot.
Obvious are converging lines of stars giving the cluster a
definite triangular shape looking much like an arrowhead.
Other chains and arcs of fainter stars swirl around the
periphery of the cluster to further decorate the scene. One
brighter 9 th mag. star glows at the E end, near the tip of the
“carrot” contrasting with the copious aggregation of fainter
cluster stars showing lesser variation in brightness. In a very
wide field of view, or by sliding your scope you may notice a
long star chain meandering toward the NE, then turning
northward away from the cluster. Needless to say, you’ll not
want to bypass NGC-2360, “Caroline’s Cluster” and miss out
on viewing a superb deep sky treasure!
An entirely different animal is our next open cluster,
Collinder (Cr) 140, shining at mag. 3.5 from about 1000 light
years away. This group of about 30 stars takes us south to
below Aludra (eta CMa), the bright 2 n d mag. luminary marking
the dog’s tail. Just under 3 degrees due south of Aludra lies a
triangle of 5 th mag. stars comprising the brighter members of
Cr 140. This large and coarse cluster spans 42 arc min. in a
rich, Milky W ay setting, making it ideal for binocular viewing.
Its southerly declination may limit your observation unless
you have a dark sky with a good low view toward the south,
and of course, ideally it should be viewed from a southerly
latitude to fully appreciate the rich star field. Two or three 6 th ,
7 th and a number of 9 th mag. on down to 11 th mag. stars
populate the area between and around that triangle of 5 th mag.
stars. Three or four other 5 th and 6 th mag. stars trail off to about
1 1/2 degrees from the cluster toward the ENE. The 5 th mag.
star at the E end of the triangle in the cluster is D unlap 47, a
nice, wide (99”) yellow and blue binocular double of mags.
5.5 and 7.6. Your best bet in viewing this interesting cluster is
with good binoculars or rich field scopes using very low
power.
Speaking of pretty double stars, this constellation harbors a
real beauty that you really can’t appreciate of course until you
see it. Once you have, you’ll likely place it high on the list of
your favorite doubles. I came across it quite by accident
several years ago checking out a new pair of 20x80 binoculars
while star hopping to the Tau Canis Majoris cluster, NGC2362. This double star is designated Herschel 3945 or h-3945
for short (also ADS 5951). It is a glorious orange and blue
pair, so striking that it is often referred to as the “W inter
Albireo”. You can resolve it easily, even in tripod mounted
binoculars, as the mag. 4.8 K5 primary and mag. 6.8 F0
secondary are separated by 27 arc seconds in a position angle
of 342 degrees. You’ll locate it near the dog’s hindquarters by
starting at 2.0 mag. W ezen (delta CM a), hopping 2 ¾ degrees
NE from there to 4.4 mag. tau CMa and its remarkable cluster,
NGC-2362, then N only 25 arc min. to 5 th mag. 29 CMa.
Fourth magnitude h-3945 lies just 1 degree, 20’ NNW from
there and forms the right angle of a triangle with two 6.5 mag.
stars just arc minutes to its NW and SSW .
The “Great Overdog” Canis Major holds several other nice
clusters you might want to check out along with some other
deep sky gems in the neighboring constellation, Puppis just
east of the dog. You can enjoy many of these deep sky
treasures from Arunah Hill’s dark sky location high in the
Berkshires of W estern Mass. W hy not plan to be there for our
winter star parties coming up on January 4 th and again on
February 1 st this winter? W hen the weather and conditions
cooperate, these parties in the past have been a great success,
well worth the effort, and lots of fun!
3
The Editor’s Desk
By Steve Pielock
Hello 2003
Hello Everyone
I can’t believe it but 2002 is now history, where did it go?
It’s amazing how quickly time flies by! Although it’s
winter and snow is in the air, activities at Arunah Hill
continue.
Our next big observing events, weather and conditions
permitting, are our Winter Star Parties scheduled for Sat.,
J an. 4 th and again on Sat., Feb. 1 st, both dates on or near
the New M oon. Check our Website or watch your e-mail
for last minute information. We also have the date set for
this year’s Arunah Hill Days 2003. It will be the last
weekend in August, the 29 th-31 st. Also remember, if you
would like to lend a hand, we welcome volunteers to help
out on the Hill the first Saturday of each month.
On another subject: with the start of the New Year we will
also be starting the 2003 fund raising campaign. We will
be raising money for the Telescope Restoration Building
exterior masonry block walls. It will be the “buy a brick”
campaign for Arunah Hill” W e will be sending out soon a
mailing explaining that effort in greater detail. Stay
tuned…
Enjoy this newest edition of the VFA.
Steve
How to Submit Material to The View
from Arunah
The View from Arunah welcomes
material submitted by guest contributors.
The strength of this publication is its writers
and photographers, so we are always on the
lookout for new contributors. If you have an
idea that you think might make a good
article, or if you are an astrophotographer
who would like others to enjoy your work,
then please consider contacting us. Our staff
will be happy to provide any assistance that
you might need to get your work published
in The View From Arunah.
To submit articles, photographs, or
drawings, please send to them to: Steve
Pielock, 132 Sand Gully Rd, So. Deerfield
MA 01373. Materials submitted via
electronic mail should be sent to
“Pielock@acad.umass.edu”. Comments and
criticisms are always welcome. Letters to
the Editor or any of the section editors are
also welcome.
The Editorial Staff of The View From Arunah
Editor: Steve Pielock
Web Editor: Dan Carnevale
Section Editors
Business and Programs: Joe Zuraw
Astronomy Association:
Alan Rifkin and John Davis
Calendar: Tom Whitney
Columnists
Deep Sky Treasures: John Davis
Barlow Bob’s Corner: Barlow Bob
Photographers
Bob Osgood
Photocopying:
Copy Cat Print Shop of Amherst, MA
Assembly/Distribution
Another snapshot of this year’s Star Watch Class
learning about computer aided astronomy!
Steve Pielock
Bill Naff
Rose Naff
Bruce Blanchard
Peter Scherff
Jim Downing
Janice Kachavos
4
Guest Article
By Rich Volant
Everyone who has a telescope
knows the pain dew is. You’re out there on
a beautiful clear night observing the
wonders of the universe when suddenly, that
spectacular view of Saturn simply
disappears, and for those of us who are truly
addicted to the rare photons, we know the
same condition can also happen as a result
of dew’s ugly cousin, frost.
But do we really know what dew is,
how and why it forms, and most
importantly, why does it seem to have such
an affinity for the most important parts of
our telescope? Everyone knows that a dew
shield and a heat tape helps. But do you
know why? Can we tell when dew is going
to form and how to prepare for it?
Unfortunately dew forms on clear
nights. You know, those rare events that
happen in New England on work nights!
The reason is that when it is cloudy the
clouds act as a blanket and trap the infrared
radiation in, keeping the air and everything
else warmer. On a clear night, the infrared
that every object radiates keeps right on
going out into space. So as the air cools, the
water vapor in the air can begin to condense
on anything that is colder than the
surrounding air.
So why does it condense on the
optics of our fine instruments?
Anything that conducts heat well, such
as metal and glass, will also radiate that
heat away as infrared rather efficiently.
So it is quite easy for the optics to
quickly become colder than the
surrounding air. All that heat just
radiates out into space. If you don’t
believe it, just grab a piece of steel on a
clear night and see how cold it feels!
Fig. 1 as the temperature falls, the
dew point is reached and the cooling process
slows. If there is too much moisture, then
fog will also form.
The formation of dew or frost can
be predicted if the local conditions are
measured. By measuring the temperature
and relative humidity, the local dew point
can be determined. If the temperature is
expected to reach that of the dew point, then
it is time to turn on the dew heaters.
Dew heaters work by replacing the
lost heat that is radiating away and making
the object a little warmer so that the water
vapor doesn’t condense into dew. Dew
shields slow the radiation of the heat by
minimizing the angle of exposure to the sky
and by reducing the amount of moistureladen air circulating at the surface. Thus,
the longer the shield, the better it should
work.
Hair dryers are the weapons of last
resort. They can clear the dew off but if you
don’t use a shield and or heat tape, it will
return. As the scouts say, “Be prepared”.
Guest Article:
By Tom Hoffelder
W ay back in the dark ages (around 1974, when I started
observing) there were no digital setting circles or go-to
telescopes.
The only options were star hopping and
conventional setting circles, both of which were found to be
frustrating and time consuming. Then I discovered something
that allowed me to quickly and easily locate any object within
range of the scope being used. It was found in the book All
About Telescopes (copyright 1967) by Sam Brown and he
called it the Right Angle Sweep (RAS). This method of
locating objects consists of centering a naked eye star in the
eyepiece and moving the scope, first in declination and then in
right ascension, a prescribed number of degrees by watching
stars move through the eyepiece field.
To use the RAS, it is necessary to know the true field of view
of the eyepiece. This can be found by dividing the eyepiece
field stop diameter by the focal length of the telescope and
multiplying by 57.29 (be sure to use the same units for the
field diameter and focal length). The true field can also be
measured by aiming the scope at the celestial equator, noting
the time in minutes that it takes a star to drift across the
diameter of the field and then dividing the time in minutes by
4. If it takes 2 minutes for the star to go from one edge of the
field, through the center and to the opposite edge, the true field
is ½ degree. If it takes 4 minutes, the true field is one degree,
but make sure the star you use is near the celestial equator.
The farther a star is from that location, the longer it will take
to travel one degree. The RAS works best with an eyepiece
that yields approximately a one-degree true field, so let’s
assume we have one.
An equatorial mount is not absolutely necessary, however,
sweep coordinates rely on the telescope slew motion being
right ascension and declination rather than altitude and
azimuth. An equatorial mount definitely helps because then
the two slew motions are coincident with the mount axes. For
now we will assume we have an equatorially mounted scope,
to go along with the one-degree eyepiece, and that the mount
is aligned with the north celestial pole. Conveniently, polar
alignment precision is not essential, and being within a degree
or two is close enough. This can be done in a matter of
moments by centering Polaris in the finder, first with the scope
“on the side” of the mount to set the azimuth, and then “on
top” of the mount to set the altitude of the polar axis.
field. W e have now moved the scope one degree north, and
we know which star that has just appeared on the edge of the
field will pass near the center of the field and disappear on the
far edge of the field as we continue the north motion.
Completing that motion moves us a total of two degrees north.
Repeating this one-degree movement three more times
completes the north sweep of 5 degrees total from the star eta.
Finally, using the same method, but moving the scope east
(rotation of the polar axis only) 2 and 1/3 fields, we find a
large galaxy in the field of view. Carefully moving the
specified distance and direction will result with the object
being centered. And that is all there is to it. And this is what
it would look like in the sky.
W hile reading the instructions above, it may sound a little
complicated but actually trying it will show how simple it is.
W ith a little practice, it takes less time to complete the steps
than it does to read them. And if you are observing in an area
where there are many objects, like Virgo or Sagittarius, you
can sweep from one object to the next instead of going back to
a star each time.
Some homework is required to get the sweep values for a large
number of objects. It is not difficult but it does require some
investment in time, an investment that will pay big dividends
during your observing sessions! The good news is that I have
already invested much of the time for you by preparing a
number of lists (on Excel spreadsheets) that contain enough
objects to keep anyone busy for years. For each object, each
list identifies the locating star, the sweep values and a brief
description of the object. These are the lists:
1.
The next thing we need to know is the star and the sweep for
the object we want to find. As an example, let’s use M101
which is 5 degrees north and 2.3 degrees east of eta Ursa
Majoris. A very basic star chart will show that eta is the star
at the end of the handle of the Big Dipper. Now we are ready
to sweep and the first step is to center eta in the eyepiece.
Next move the telescope slowly north, which is rotation of the
declination axis toward Polaris, until eta reaches the edge of
the field of view. Then pick a star near the center of the field
and repeat the north motion to move this star to the edge of the
2.
3.
4.
5.
6.
Messier M arathon – All 110 Messier objects listed in
order of search
Magnificent 700 – Messier plus the Herschel 400
plus Finest NGC
Magnificent 1000 – The 700 plus the Herschel II
Herschel 3 – 300 Herschel galaxies not in the H 400
or H II
Very Red Stars – 66 Carbon stars
Non Related Double Objects – 40 pairs of objects
located at different distances from us but visible in a
one degree field
7.
8.
Edge on galaxies – 101 of the best!
Burnham’s – All extended objects listed in
Burnham’s Handbook plus selected double and red
stars – more than 2640 objects
Dobsonian or other alt-azimuth mount. Move the scope
toward Polaris for north directions or away for south and then
perpendicular to that motion for the east/west. This works best
when the object is on the meridian.
As you can see, there is some overlap in the lists. For
instance, the Messier objects can be found in 1, 2, 3 and 8, but
you need #1 if you are going to do a Messier M arathon. Lists
2 and 3 are similar except that list 3 adds the Herschel II
objects which are dimmer than the first Herschel list, the
Herschel 400, so list 2 is more for smaller scopes and list 3 for
larger scopes. However, even with a larger scope, you might
sometimes want to look at only brighter objects and then list 2
is easier to use. List 8 has nearly all of the objects listed in 1
through 7 but sometimes it is nice to have them broken down
into the components of the smaller lists. In other words, I find
them all useful.
I know from experience that the RAS is easier to use than
setting circles or star hopping. The following comments from
Dick Parker, who I think some of you know, indicate that he
agrees. "Tom explained this right angle sweep method to me
and after less than an hour I was able to find many new
objects with ease. And by using this method I have started to
learn the various names of the stars in each constellation
which adds to my appreciation and overall knowledge of the
sky. I had been using setting circles to find objects directly by
coordinates, but have found Tom's method easier and much
more reliable especially with portable equipment used at
varied observing sites. I recommend that you give it a try and
we should all thank Tom for freely sharing with us the tables
and references that obviously took him many hours to
assemble."
If you are interested in having any or all of these lists, let me
know by email (tolyho@att.net) and I will send you the files.
Below is a section of the Magnificent 700 to show how the
information is presented in general.
As in this list, the Magnificent 1000 and Burnham’s have the
objects arranged by Constellation. The rest, except for the
Messier Marathon, are listed in order of right ascension - more
or less. The “more or less” is in regard to what I mentioned
earlier about sweeping from one object to the next.
Sometimes maximizing these sweeps causes the objects to be
listed out of order. NGC 205, 221 and 224 above are a good
example of this. Note that “prv” indicates that the sweep is
made from the previous object. Therefore, if you do decide to
use any of these lists, and want to sort the objects for some
reason, make sure you compensate somehow for all the prv
objects, or the sweeps will be wrong for them after you sort.
Also note that the declination sweep is listed first. This is the
way the sweeps were measured. W hen near the celestial
equator, it does not make a difference which you do first.
However, as you move away from the equator it does make
some difference and as you approach the pole, it makes a lot of
difference. So, if you are using any of the lists, it is a good
habit to always do the declination sweep first.
As mentioned previously, the RAS does not require an
equatorial mount. An equatorial mount is a big advantage but
the motion can be approximated with good results if using a
I have not used a “go-to” scope so I can’t compare them to
using the Right Angle Sweep. H owever, from what I have
seen at star parties, the Sweep can be used to locate objects in
the same amount of time, if not more quickly. Even if this is
not true, go-to scopes take away a big part of the enjoyment of
observing, and that is the reward of finding the object yourself.
Plus, you never know what interesting sight you might come
across as you are watching the stars go through the eyepiece
during the sweep. And there is nothing quite so satisfying as
looking up at the night sky and being able to recognize all the
constellations that are visible at any time of the year. If you
cannot do this already, after using the RAS to find a few
objects in each constellation, you will be pleasantly surprised
to find that you will be able to identify any of them with ease.
So, after doing it for over 25 years, I still recommend being
your own go-to!