solar filter

[roscoe]

someone is selling solar filters made themselves with od 5.0 baader Astro Solar Safety Film .she says it is safe to put this filter over eyepiece only and then look at the sun directly .this doesnt sound safe to me,im sure you would have to have a filter on telescope end also,can anyone advise,thanks

[jimmyjamjoejoe]

It's designed to cover the objective end. The focused light at the eyepiece is a damned sight stronger, so i wouldnt do it. I dont know if the film can withstand that, but gut instinct is telling me its a very bad idea indeed.

[kev]

That sounds a recipe for disaster. Whatever you do, DONT get one.

[Merlin66]

The Baader Solar Film is designed to protect you and your telescope.

It must be fitted to the front of the scope.

[sanmatt]

Yes Merlin is correct, it even says this on the Baader instructions that come with it - telescopes, cameras, video etc etc

Anyway, my question about this film is that I have read there is an extra piece of thin 'something' on one side that needs removing. But I cant work out which side it is on. Can anyone help me on this please?

We're making a solar filter (if that isnt obvious)

ps 5.0 is the one for visual activity, though the instructions still say it can be used to make filters for telecopes AND cameras.

[Bizibilder]

It comes with a clear protective sheet of plastic on one (or both) sides. This must be removed - which can be tricky as it is difficult to see it! 5.0 film is quite suitable for photography.

PS: You should NEVER use solar film at the eyepiece - it is designed to go over the aparture of the telescope so that only "filtered" light reaches any of the optics.

[sanmatt]

Thanks Roger, we found the sheet on one side, and removed it with a scalpel, it came off easily. Coudlnt see evidence of it on the other side though.

So far the filter is looking grand, we've used a 8" female spiral duct work coupler, sticky foam, the cardboard from one of his work's folders. Tools have been: rotring compass, steel ruler, craft knife and scissors, and strong builders tea

"One cup of tea so far" which quite clearly is a dig at me!

[Bizibilder]

I hate to think what "an 8" female spiral ductwork coupler" actually looks like !! Is it legal??

[sanmatt]

haha yes it's legal, my husband is a chartered HVAC engineer and asked one of his 'boys' for it off 'site'.

I have a thread in 'observing Luna/solar' where you can see our filter.

We just had first light, which consisted of it being an argument over whether they were sunspots or muck on the ep. We think they are sunspots.

[ejwwest]

someone is selling solar filters made themselves with od 5.0 baader Astro Solar Safety Film .she says it is safe to put this filter over eyepiece only and then look at the sun directly .this doesnt sound safe to me,im sure you would have to have a filter on telescope end also,can anyone advise,thanks

Under no circumstances use just on the eyepiece: this is more likely to melt and blind the observer. Solar film should be used for the object glass of the telescope (or front aperture on a Newtonian). I have a Celestron made one for my EdgeHD 925, a Thousand Oak 77mm thread black plastic filter for my Canon zoom lens. I home made ones for my 16x80 and 10x50 binoculars using Baader planetarium film for eclipse use (walk on part with them on the April 2006 Sky at Night on the eclipse in Turkey)!. These were made using cardboard rings to fit over the object glass and taping the film onto the rings. I used the 10x50 version with my telescope finderscope. I also sellotape the filters onto the binoculars or finder to prevent wind blowing them off (having forgotten tape for the eclipse in China in 2008, it was rather challenging to explain what I was looking for to the hotel reception on the day of the eclipse!).

If you can't get filters, then the other technique is eyepiece projection but probably not recommended for larger apertures as the amount of energy concentrated on the eyepiece will be large.