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