Cahill Rooftop Observatory
Observing With Solar Filters
Three of our telescopes – the Questar, the C-8, and the C-14 – come with solar filters that can be used for daylight observing. While no special skill is required for solar observing, pointing any optical instrument at the Sun can be very dangerous. To check out a solar filter, you must show that you are familiar with the following procedures to ensure both your safety and that of the equipment.
Warnings
- Check the solar filter every single time you use it.
- Do not touch the filter material, or place the solar filter so the filter material is resting against something – it is very delicate and easy to damage.
- Keep the telescope well away from the Sun until all filters and covers are in place. Even briefly slewing across the Sun's disk can cause damage.
- Do not look at the Sun, even without the telescope, without adequate eye protection. For example, never try to point the telescope by sighting along the tube.
Setup (C-8 and C-14)
Always hold the filter away from the film
Examine the film for pinholes
Cover the finder before pointing at the Sun
Insert the filter, rubber side first, before pointing at the Sun
Filter should go all the way on
Point the telescope at the Sun using its shadow
Check that there's no projection
Setup (Questar)
Always hold the filter away from the glass
Examine the filter for pinholes
Move the finderscope filter into place before pointing at the Sun
Ensure the eyepiece is not in finderscope mode
Screw in the filter before pointing at the Sun
Align the telescope using its shadow
Check that there's no projection
Shut-Down
Point the telescope away from the Sun
Remove the filter
Put the filter in a safe location