Solar Filter Making Help for LX200 SCT

[BlackWidow (Mardy)]

I have just purchased a sheet of Seymour Solar Optical Film. The size of the film is 9 inches x 10 inches. I have a 10" LX200 SCT. I have made two rings that fit inside the reflector housing and with the film to go between them. The hole in the center is just under 9" so the film fits inhside to give me a nice large Solar Filter just a smidge under 9" round... However when I got the product information sheet it advises on 8" or larger SCT Telescopes to make an Off-Axis filter Cell. I am sure that I can remember placing one of those I made for my DOB and it did not work..

Can I Please have some advice from those who have made thier own filter before I cut the Solar Sheet and make it bigger than it needs to be. Is thier a formula for the size of the offset hole for it to work, or a pref hole location (I know to the side of the Cell)

Any help would be great.

Cheers
Mardy

[scopemankit (Chris)]

My filter for my 8" sct is offset sub diameter. The size is dictated by the gap between the secondary and the edge of the tube. NB The mylar is double thickness. Don't be overly worried over creases in the film.Two pics are worth 2000 words.

The rim fits over the outside of the tube, if it fits inside there's always the possibility of stray sunlight creeping past. Better safe!

[BlackWidow (Mardy)]

Thanks Chris, that's a great help. I am reading that you find it better to use 2 layers of film in the cutout?

Yes I can see the advantage of overlapping the outside of the SCT to be safe. It seems I may have some spare film to make a filter for my friend who has an ETX125. I think he will be happy.

Thanks for taking the time to add pictures for me. Appreciated.


Regards
Mardy

[BlackWidow (Mardy)]

Well I have a Great way of making my filter and this could be a help to others. I did not want to just make the filter using Cardboard as it is bound to get damaged over time. I decided to walk the rows in Bunnings to see what I could find that would fit over the end of my LX200 10" scope like the metal cover. I could then cut a hole in it for the Solar film and it would look like a bought one...

Item Found.... I love Bunnings..... One 20 Liter trade Quality HANDY PAIL. Made by SFN of NSW Phone 1300734714. It fits like a glove on the end of the 10" scope and make a perfect base for your solar filter as shown in the pictures by Chris below... You will need to paint it with vinyl or plastic paint so that it is black and won't let light pass through..

Happy Man I am !


cheers
Mardy

[scopemankit (Chris)]

My frame is not made out of cardboard but corrugated plastic. Comes in all colours, is light, waterproof and can be used for light baffles as well. Available from plastic distributors. Often used in the advertising business as backing board for posters.