Solar film: off axis or full aperture?

[Ursa Major]

Hello,

I know there have been a lot off threads asking about Baader solar film but I feel that there have been mixed responses.

I have a 5 inch reflector. Would it be best to have a full aperture filter of an off axis (smaller) filter?

I just want a definite answer. I also do not want to waste the film as you only get one sheet and I may want to use it for other stuff (binoculars, another scope)

Thank you.

[Peter Drew]

Full aperture for me! . Larger aperture equals more resolution.

[Damo636]

Full aperture here also.

[Stephen]

Full, nuff said

[Demonperformer]

I'm no expert, but I made a 40mm aperture one to go on my 102mm scope, so that it would be comparable with the psts, scrounging a small piece of film from another member rather than buying a full A4 sheet. Works well.

[RikM]

I made an off axis 70mm cutout for my 150P. I get really nice results and good resolution. Better resolution than the full aperture version I made for my Skymax 127. All the affordable solar scopes are in the 35 - 90mm range. The sun is so bright, you don't need more than that.

[RikM]

Stopping down the apperture increases your focal ratio as well, in theory giving you better contrast. My 150P f/5 = 750mm, with a 70mm filter becomes f/11 for solar.

[tony69]

sorry to jump in but can you tell me please does the film go on the end of the tube or on the lense ?thankyou

[EasyFlier]

I am no expert but all means put the film on the tube!!!

My 114/900 was delivered with solar film attached to the small cover hole of the tube's front cover. I've observed the sun that way and the results were quite remarkable. Waiting on the new lens kit to try it now with the filters.

[tony69]

thanks for that learning as much as i can before i get my scope now to figure out how to make it fit end of scope ie make a frame?

[Demonperformer]

sorry to jump in but can you tell me please does the film go on the end of the tube or on the lense ?thankyou

Absolutely the front.

Think of it this way: you filter the light (and heat) BEFORE you start focussing it onto a point.

If you do it the other way round (like the silly eyepiece filters you get with some scopes) you are focussing all the light (and heat) before you filter it and so everything gets that much hotter (and brittle and more likely to break and more likely to cause irreparable eye damage).

Sorry if this sounds a little OTT, but it is REALLY IMPORTANT

[tony69]

Absolutely the front.

Think of it this way: you filter the light (and heat) BEFORE you start focussing it onto a point.

If you do it the other way round (like the silly eyepiece filters you get with some scopes) you are focussing all the light (and heat) before you filter it and so everything gets that much hotter (and brittle and more likely to break and more likely to cause irreparable eye damage).

Sorry if this sounds a little OTT, but it is REALLY IMPORTANT

no ott at all very important to get it right thankyou for your help.