Help on ordering solar filter material

[Analog6]

I want to get a sheet of solar filter matierial to make slide in filters for my cameras for the upcoming eclipse in November. I have both lee (100x100mm & Cokin P size filter holders. I plan to fashion my filters using strong card to slide into these holders.

What film shoudl I order? I like the orange coloured result for photos best. I know there is one type that renders the sun white, I'd prefer to avoif that one.

I have found the Thousand Oaks site but am finding it terribly confusing. Should I purchase RG-SOLAR FILTER SHEETS or BLACK POLYMER SOLAR FILTER SHEETS? I'll buy the 12' x 12' size which should give me plenty to play with.

OR there is the Baader-planetarium which sells AstroSolarTM Safety film.

If some kind soul can shed light on my dilemma I'd be very grateful!

[sjastro]

For photography I'd get the Baader Astrosolar film ND3.8.

http://astroshop.com.au/products/details.asp?id=MAS-018F3

It allows short exposures.
A word of warning don't use it as a visual filter you will need the ND5.0 version for that.

Although it produces a white image, you can change the colour balance to produce the desired colour.

Attached is an image using the ND3.8 film and a C5 scope.

Regards

Steven

[Astro_Bot]

The R-G film is similar to the Baader film but thinner and (allegedly) with a sharper image as a result. The black-polymer is older technology and inferior (IMHO). Both produce a yellow-orange image whereas the Baader film produces a white image.

In addition to white balance (which might be simpler), you could also use a colour filter if you want or adjust colour during image processing.

I have the Baader film myself. I haven't compared Baader to Thousand Oaks at all, so I can't say which produces a better image, but my guess is that the limits of seeing will swamp any improvement in sharpness from a thinner film.

[Astro_Bot]

This should be helpful and (IMHO) essential viewing before any solar work.

http://www.youtube.com/watch?v=4RGr9FcBrSM

[frolinmod]

The Baader AstroSolar film is the best. Yes, it produces a white light view. For visual use you can add filters to change the color. A Baader Continuum filter works well. For photography you need to use an UV/IR block to the continuum filter.

[Analog6]

Thanks everyone. After 3 weeks Thousand Oaks Optical finally answered my simple question on postage - they want more for the postage than the cost of what I asked after. Waiting now for a reply from AstroShop.

[ZeroID]

Baader N3.8 ( for photography) and a yellow/orange filter. I used Baader N5 with the green moon filter as it helped cut the brightness a bit further and with the sun gave an almost yellow effect.
I have been advised you could use the N5 visual for photography, just slightly slower shutter speed required or raise your ISO.

[OzEclipse]

Odille,

As you know, a Cokin P holds the filter off the lens with gaps top & bottom. Because a solar filter is so dark, I suspect you'll see stray light entering from the top & bottom if you mount it in in a type P holder. Try it if you've already got it. A black polymer filter might have a better chance of working though using a P holder I suspect you might see something resembling flare or fog. A piece of Baader astrosolar or TO RG film or any other reflective metal coating type will almost certainly show reflections in the P mount.

Solar filters are usually mounted to the optic with a light tight mounting. It must be secure so it doesn't blow off. For a solar eclipse, the secure mounting must be able to be removed quickly and easily during the 15 -30 seconds just before totality without shifting the focus on a camera lens or shifting the pointing of the scope or lens.

There's an article on my web page that describes an easy way to make a light tight easy release mount from thin film.

http://joe-cali.com/eclipses/EQUIPMENT/solarfilters.html

cheers

Joe Cali
http://joe-cali.com/eclipses

[Analog6]

Thanks Joe - that looks interesting and good but frakly I reckon it is a bit beyond me. I will, however, experiment and fashion some type of sleeve to cut the light entering from the side.

ZeroID, I think I'll get the 5, I can cope with slightly slower shutter speeds/faster ISO. I used Thousand oaks Optical glasses to shoot the Transit of venus and the exposure was 1/125 @ ISO 100. Eclipses are darker, of course. Maybe get both and fashion 2 sets. Hhmmm - have to think on this one.

[gbeal]

Another option here
http://www.tan14.com/Baader.htm
Gary