Quote:
Originally Posted by jjjnettie
Just use the aperture reduction hole on the dust cap of the scope. It is around 2" in diameter. Just tape the film over that. It's more than enough.
If you make a full aperture filter, you will end up with a big floppy piece of film over the front of your scope, there is more chance of it sagging, flapping in the breeze and the tape pulling and coming apart. Resulting in instant blindness to the observer or a fried sensor on your camera.
It's one of the very few times in Astronomy that less is more.
As proof, this image was taken through an 80mm scope , stopped down to 50mm. The film was taped over the hole in the dust cap.
The camera was set at ISO100, exposure time 1/750th of a second.
The lid off the can of spray paint or similar is almost exactly the right size to slip over a standard 50mm finder scope. Cut a 20mm hole in the end, and tape down the film to the inside using dbl sided tape and reinforce with regular tape.
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Bump - Resurrecting an old thread....
Hi JJJ (and anyone else who can offer advice),
I would like to use my 12" Sky Watcher Collapsible GoTo Dob to view the Venus Transit in June. I wish to use the method quoted above to safely view the Sun. The plastic dust cover on the 12" Dob has two off axis 50mm Dia holes, one with a removable cap.
If I purchase some solar film and fix it over the 50mm dia dust cover hole, will I be able to achieve the same level of viewing quality as JJJ's 80mm scope has in the image attached to the last post?
Thanks.