Projecting the sun - a question

[philipok]

I turned my Zenithstar 66 towards the sun recently, rotated the eyepiece downwards and projected the Sun onto a notepad.. fun. Could make out two prominent sunspot groups and surprisingly a bright facula near the limb.

My question - would it help to put a coloured filter anywhere in there for contrast purposes (i.e yellow)?

cheers

philip

[Merlin66]

Luckily the aperture of your scope makes this feasible ( a Baader Solar film will show so much more) just watch out for the heat build up in your eyepieces...use the cheapest ones you have in case the optics get damaged by the heat. I can't think of any great filters which would make a tremendous difference..maybe a light green or the Baader Continuum - seems to improve the visual contrast, but for projection....don't know.

(remember to cover the finder as well!)

[brianb]

When projecting the Sun, you really need as much light through as you can get, a filter isn't going to help (especially the Baader Solar Continuum which is pretty dark).

As Merlin says, beware of damaging eyepieces by heat build up - modern eyepieces which have cemented glass elements can be ruined if the cement melts, which doesn't take a lot of heat.

It's much safer for your equipment to use a special filter designed for solar observation, mounted over the front end of the scope - Baader solar film is the best stuff there is, and it's perfectly safe for your eyes too, if it's used according to the instructions.