DIY Solar Filter Cell

[astro_al]

For those of you who have already built a filter cell mount for your Baader AstroSolar safety film I would appreciate any feedback on my efforts. I just want to be double sure that I am on the right track.

I bought a used metal threaded adapter second hand a while back which connects a Coronado filter to my 60mm scope. This was a bit of an impulse buy as there is no chance of me affording a HA filter at the moment. Anyway, I thought I would use it as the basis of a homemade filter cell for the Baader film I ordered from FLO yesterday. I have used a coffee jar lid with a 70mm hole cut in it and a poster tube cap with a 60mm hole cut in it. The cap fits very tightly into the coffee lid and will hold a cardboard ring with solar film attached to it. Both lid an cap then fit into the metal adapter, again the fit is very, very tight.

I don't see anything falling apart or blowing away but I will put it in a sunny spot on its own today (weather permitting) to see what happens when it warms up. I obviously need to check for any light penetration against an artificial source once the solar film is fitted, however I would appreciate being told if I have missed anything obvious (I am very fond of my eyes ).

Thanks in advance.

AL

[Peter Drew]

Looks to me that you are on the right track, make sure the film is in a relaxed state when fitted, if pulled tight like a drum skin it can distort the image, wrinkles have no adverse effect.

[Merlin66]

Correction: when the film is pulled tight it doesn't affect the image but it does put additional and unecessary stress on the coatings...leave it loose and relaxed.

[astro_al]

Thanks for your replies. I will drop the cardboard ring and double sided tape onto the film and let the wrinkles fall where they may. Good to know that it doesn't affect the performance though.

Cheers

Al

[astro_al]

I also thought I would make a solar finder from an old diagonal and end caps. Not sure how accurate it will be, probably better than watching the telescope's shadow though. Hopefully the Baader film will arrive on Monday and I can test everything out.

[astro_al]

The Baader film arrived from FLO today so I completed the filter. I even got an hours observing in before the sun went down behind next door's house. Enjoyed it after the initial feelings of unease associated with a nagging feeling of doing something stupid went away! The DIY solar finder turned out to be pretty accurate. Looking forward to future sessions.

[Telrad]

I'm going to order one of these soon.. I'm glad eveything went well! Well done!:)

[astro_al]

Thanks. I think it is really good value at £15 for an A4 sheet.