Ive a question about Baader film tension im hoping is a non issue,
Ive re-modded a filter I made a few yrs. ago and when I added the ring w/the double sided tape the filter material drew taught with no wrinkles, pretty much tight as a drum really to be honest. Will this be a dangerous issue when subjected to the warmth of the Sun? Im assuming it will if anything slacken when heated not shrink anymore, or not change at all but,............ safety is more importaint then a few bucks, if I did a no-no I can buy a new filter for about $12. Has anyone done this or seen this who knows the particulars why not to have it taught?
Dave
Baader Solar film tension
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swisswalter
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Re: Baader Solar film tension
Hi David
the baader foil should be used without any tension applied to it due to optical reasons. Check for pinholes by naked eye. If there any, you may want to replace the old one.
the baader foil should be used without any tension applied to it due to optical reasons. Check for pinholes by naked eye. If there any, you may want to replace the old one.
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Merlin66
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Re: Baader Solar film tension
If you over tension the film a couple of things come to mind...the effect of the tension on the film v's stability (thinking in terms of thickness) and putting addition "pressure" on the reflective coatings - maybe premature failure??
If the film is OK then I'd continue to use it.
My Baader solar film must be getting on to 9-10 YO - stored in a dust proof container when not it use. I've yet to experience any pinholes.....
If the film is OK then I'd continue to use it.
My Baader solar film must be getting on to 9-10 YO - stored in a dust proof container when not it use. I've yet to experience any pinholes.....
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Helimanb41
Re: Baader Solar film tension
Hmmm ok,
I don't have any pinholes in the film. Im going to do a test when it gets sunny & warm out & place the filter outside for an hr. in direct sun to be certain it dosen't draw any tighter and tear or get pinholes & is safe to trust. I can then do a visual test of it to see if it did effect it visually after im certain it won't split or tear etc...They now sell Baader film already installed in a card you just cut to size & place in a cap so that this kind if prob does not happen I may just go that rout if I see any visual issues. If it does effect the visual use of the filter being taught Ill say so here after ive had a chance to use it, may be a while weather here is awful as usual...............Thanks for the input fellas.
Dave
I don't have any pinholes in the film. Im going to do a test when it gets sunny & warm out & place the filter outside for an hr. in direct sun to be certain it dosen't draw any tighter and tear or get pinholes & is safe to trust. I can then do a visual test of it to see if it did effect it visually after im certain it won't split or tear etc...They now sell Baader film already installed in a card you just cut to size & place in a cap so that this kind if prob does not happen I may just go that rout if I see any visual issues. If it does effect the visual use of the filter being taught Ill say so here after ive had a chance to use it, may be a while weather here is awful as usual...............Thanks for the input fellas.
Dave
Re: Baader Solar film tension
This is some good info here! I am working on a replacement for my old ETX glass filter using baader nd3.8 film. The glass popped out, and I silicone glued a lexan ring to the not stretched film, cut it out and then mounted the ring inside the alum cell. First light will be soon!
Chris Schur
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Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
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Birch Mesa Observatory, Payson Arizona
Clear Creek Canyon Observatory, Happy Jack, Arizona
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Helimanb41
Re: Baader Solar film tension
Seems I have a good outcome here.
I had done my film mod in my cold basement & at room temp the wrinkles came back like originally & have stayed. The cold basement must have shrunken everything during assembly & now its loose again. Ya! Took it outside & did a peek thru my refractor, everything looks normal, actually even better now that im using it on an APO verses the achro I was using before. I didn't have this filter material when I owned my Mak but id bet with the hi focal ratio its a superb combo. You will definatly see improvement over a glass filter, ive used them in the past. Next test is using my Continuum filter with this scope combo, can hardy wait for a clear calm day now (and time away from work cough, ahem, ....)!
I had done my film mod in my cold basement & at room temp the wrinkles came back like originally & have stayed. The cold basement must have shrunken everything during assembly & now its loose again. Ya! Took it outside & did a peek thru my refractor, everything looks normal, actually even better now that im using it on an APO verses the achro I was using before. I didn't have this filter material when I owned my Mak but id bet with the hi focal ratio its a superb combo. You will definatly see improvement over a glass filter, ive used them in the past. Next test is using my Continuum filter with this scope combo, can hardy wait for a clear calm day now (and time away from work cough, ahem, ....)!