Making a solar filter.

[DazC]

Just a quick question,

I'm thinking of making a solar filter for my dob. I've been advised to make one that is not full aperture and off centre.

So would I be okay to just use the end cap of the scope with the removable smaller cap on it and tape some solar filter film on the inside making sure no light came through the edges of the tape or the outer edge of the full aperture cap?

D.C

[spaceboy]

Taping the film over the smaller hole in the dust cover is what most do as it is quick and simple. Just make sure you use good quality tape like Gorilla as some tapes can loose their stick when things start heating up.

[DazC]

Thanks for the advice space boy, the heat affecting the tape hadn't even occurred to me.

D.C

[ArmyAirForce]

If you are wanting to photograph the Sun, you are better off with a full aperture mask. The attached picture was taken with an off axis mask. You end up with a bright spot off centre on the Suns disc, making the Sun look Sun lit itself! This image has the gamma curve stretched to show the effect more. While the original mask did me well for a couple of years, I've since made a new full aperture mask.

[PeterW]

Use white or light coloured materials, the end cap is usually black.... Want to stop things getting hotter than they need to get!

PeterW

[DazC]

Thanks for the advice.

I'd not thought of any of this stuff.

Glad I asked now.

D.C