Solar Instruments for
Observing the Sun
David Groski
Mt Cuba Observatory
•Why Observe The Sun ?
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It is the only Star were we can directly
observe the surface
The Sun is very Dynamic. Surface features
can change in as little as a few minutes
Observation can be used to explain a
number of concepts in Physics, Chemistry
and Astrophysics
The Sun directly effects us.
It’s WARM and Sunny in the daytime !
Safety !
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The Sun is bright !
Magnitude -23
Never leave your telescope
unattended
Cap the finder scope
Make sure your filters are
secularly attached
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The Filter needs to
reduce the
brightness by
10,000 to 1 across
the FULL spectrum
How To Observe the Sun
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Projection
White Light Filters
Color Filters
Dedicated telescope
Coronagraph
Narrow Band Filter
Spectroscopic
Projection
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The Simplest
Fairly Safe
Gives Good
Resolution
Use with Apertures of
4” or less
Don’t use with
Expensive eyepieces !
Don’t use with SCT or
Maks !
White Light Filters
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Metalized Film
Safe
 Gives an excellent
image for money
 Can be used with
any type of telescope
 Can be used at the
full aperture of the
telescope
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White Lights Filters
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Herschel Wedge
Gives Excellent
Image, better then
Film
Needs to used with
telescopes of 4” or
less
Needs additional
Filtration
Some Safety
Concerns
Color Filters
Colored Filters
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Must be Used with
Additional Filter
Green filters like
Wratten #58 used to
improve Sunspot
Detail
Blue filters used
improve faculae
Also can improve
general image
sharpness by
narrowing the
spectrum
Dedicated Solar Telescope
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Designed to give the
best possible image
Built in Safety
Uncoated Primary,
Secondary and
Herschel Wedge
Easily Tune the
brightness by the use
of crossed Polarized
Light
Coronagraph (Promscope)
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Blocks the Disk of
Sun
Greatly reduces stray
light
Gives the best views
of Prominences
Narrow Band filters
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For H-alpha need
below 1 Angstrom ( 1
x 10^-10 meters)
For Calcium K need
below 10 Angstroms
Usually Expensive
($500 to $10,000)
Spectroscopic
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Shows 100’s of absorption lines
Was used to observe Prominences without
an Eclipse
Helium was discovered on the Sun before
being found on the Earth
Zeeman effect used to determine the
magnetic fields of Sun spots