I could not find anything after a quick search of the fourms.

Mylar, Film, Glass????

What are the advantages, vs, disadvantages.

I'm certian I want to stay away from glass.

I found a company called Thousand Oaks Optical that sales film.

I've already figured out how to make my own filter out of the film. :-)

But all the prebuilt filters are made from Mylar.

I'm less concerned about quality, vs. keeping my eyes nice and safe on a very tight budget. (sigh)

I also know enough to stay far, far, away from eye peice filters.

Thanks for any advice.

Most solar observers, including me, feel that the BAADER AstroSolar™ Safety Film is the best white light filter available.

http://www.kendrickastro.com/astro/solarfilters.html

http://www.astro-physics.com/index.htm?products/accessories/solar_acc/astrosolar

Dave Mitsky

I made my own solar filter last night using Baader Solarfilm. The process was pretty painless using the sort of procedures used by school children in art classes - glue, tape and cardboard!

I even took a photograph with it today and to my delight could see some sunspots!!

What is the main problem with glass filters.? I have a JMI glass filter on my Meade SCT

Glass filters? Don't they have a problem with craking?

I agree the mylar film by baader is an excellent white light filter.

The film is cheap to buy, if you plan on making your own; it also has excellent optical quallities.

I purchased a sheet from Astro-physics, and received in a timely manner.

Advanteges are:
inexpensive, very light weight, easily adaptable to most telescopes optics.

Disadvanteges are:
The mylay can be punctured more easily than glass filters. (it is recomended that the filters be checked before each observing session.)

I received an e-mail from Astro-physics about a week ago, that indicated there might be a problem with a certain batch, due to improper packaging. The offered to test anything made with the suspected batch, and to replace anything that did not meet their standards.

There are 2 types of mylar sold; 1 is for visual use, and the other is for photographic use ONLY.
Make sure you order the correct type for your application.

According to the data sheet that shipped with my 'Baader Planetarium AstroSolar Safety Film' the "Safety Film is a specially manufactured streak- and blister-free foil (no Mylar)" stressing that it is not made of Mylar and they follow this up later on by again stating that it is not made of Mylar.

I only post this information for completeness - I have no opinion on whether Mylar is good or bad, only that Baader seem to want the buyer to know that they do not use it!

I found it quite easy to make the filter and now that it is stored in a plastic food container, I should be able to keep it in good condition for a long time. I do intend checking it as advised by the manufacturer before every session - you only get one chance with your eyes!

QUOTE: Originally posted by Mamoru

Glass filters? Don't they have a problem with craking?


No more chances of cracking or scratching than the baader has of getting a pinhole. So long as the filter is taken care of properly and inspected before use on the sun there is really no risk factor. I have had the baader film filter before and currenly own the thousandoaks type ll glass filter. Its just a matter of prefrence, both are safe so long as they are used properly. The only unsafe commercially sold solar filters are the eyepiece filters. You always want a solar filter to cover the main objective.

To give an indication of what a home built solar film filter looks like, this is the one I built for my 80mm Skywatcher Refractor. Essentially, I made two cardboard rings, one a tight fit on the lens tube, the second a slightly loose fit on the first and then 'sandwiched' the film between the two with glue and then wrapped the whole thing in insulating tape.

This simple process (detailed on the data sheet supplied with the film) works very well but the finished filter is relatively fragile so needs to be looked after.

Mylar produces a bluish solar image, aluminized glass an orangish one. The AstroSolar material yields a white image with greater resolution than Mylar or glass.

Dave Mitsky

One more advantage of making a solar filter from Baader film, is you can also make a filter for your finder scope. Although a solar finder is not vital, you should have enough film, left over from the main filter construcion, to construct one, at very little additional cost.

I haven't made a filter for my finder scopes, at least not yet; I usually point the scope at the Sun, and align the scope with the scope's shadow.

I thought about making a filter for the finder too but I would also have to make a 'shield' to block out the sun for an area around it unless it has a right angled eye piece ( mine is 'in line' ) as with the finder scope you are looking through it in a direct line with the Sun.

And my Solar filter always goes back in its box when not in use. Don't want to take a chance just leaving it around to get damaged.
Mine is mylar from Kendricks astronomical. Depending on the exposure I've used I get either the blueish surrounding image as mentioned earlier or a nice black background. Unfortunately, I don't remember which setting I used to acheive the black background. I usually do 2 or three images, with speeds of 500, 250, and maybe a 100.
cooltech

Just a note on the finder idea. I always keep my finder scope cap on. I don't want to take the chance of not having proper protection in place and making the mistake of looking.
If all you have to worry about is covering the optic lense, less possibility for a serious mistake.
Plus, viewing through the finder still leaves plenty of periphrial area for sunlight to disturb you eye.
Just a thought to consider.
cooltech

A couple of good points on finder scopes...I didn't consider the need for shielding the area surounding the finder.

It would be pretty simple to make a utility finder (zero magnification finder) that uses solar film mounted on plexi-glass that is either removable or can be folded up/down. This could also be used in front of a conventional finderscope, but some effort should be made on making this idiot-proof.

For now I'll continue to use the sun's shadow method, but might try to make one if I get bored...

QUOTE: Originally posted by DaveMitsky

Most solar observers, including me, feel that the BAADER AstroSolar™ Safety Film is the best white light filter available.

http://www.kendrickastro.com/astro/solarfilters.html

http://www.astro-physics.com/index.htm?products/accessories/solar_acc/astrosolar

Dave Mitsky


I was wondering if there is a solar filter for binoculars. Could I make a fiter out of astrosolar film? If so, how?

Orion has solar filters for binoculars, but there are filtered binoculars from coronado. The cheapest one is around $100 US.
You could make it for binoculars just like for telescopes, except you'll need two.

Yup, very simple to make couple for your binoculars - HOWEVER, you will also need to make a tight fitting light-proof shield for the same reasons indicated above regarding finder 'scopes! Don't take any chances with your eyes.

QUOTE: Originally posted by Mamoru

Glass filters? Don't they have a problem with craking?


Glass solar filters are fine it's the eyepiece solar filters that are dangerous and crack.