Solar Instruments for Observing the Sun
David Groski
Mt Cuba Observatory
•Why Observe The Sun ?
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 ! The Sun is bright !
Magnitude -23 Never leave your telescope
unattended Cap the finder scope Make sure your filters are
secularly attached
The Filter needs to reduce the brightness by 10,000 to 1 across the FULL spectrum
How To Observe the Sun
Projection White Light Filters Color Filters Dedicated telescope Coronagraph Narrow Band Filter Spectroscopic
Projection
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
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
White Lights Filters 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 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
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)
Blocks the Disk of Sun
Greatly reduces stray light
Gives the best views of Prominences
Narrow Band filters
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 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