Solar Imaging

[lw24]

Hi all,

I was just wondering whether Solar imaging with a Canon 1100D and 18-55mm kit lens would be at all possible/worth it.

If so, I assume Baader solar film would still be needed?

Thanks,

lw24

[riklaunim]

Astrosolar is always needed - unless you use a solar H-alpha/CaK scope.

[lw24]

Astrosolar is always needed - unless you use a solar H-alpha/CaK scope.

Thanks, as I expected.

Would the 50mm end of the lens achieve anywhere near enough magnification for features to be discernible?

[The Sailor]

I have made a solar filter using Baader film and a Cokin filter holder for the camera lens, used it a few times.

Jim

[lw24]

I have made a solar filter using Baader film and a Cokin filter holder for the camera lens, used it a few times.

Were your solar images taken using the 18-55mm lens?

[The Sailor]

Fraid to say I can't remember and don't appear to have kept any. I have two lenses, the bog standard one which comes with the camera and the next one up, sorry to say I am a non techie when it come to that, also memory fading .

If you mean the images in my albums then no, they were taken with the camera attached to the telescopes.

Jim

[JamesF]

I think you're going to struggle with lack of focal length, to be honest. I don't think you'll be able to see that much detail, though picking out a few sunspots might be possible. A rough calculation suggests that you'll end up with an image about 100 pixels in diameter.

I'd be quite tempted to make a reduced aperture filter for your dob and try that. I'd not be surprised if it were possible to get a decent number of frames of an image perhaps 1000 pixels across that way. I've never tried it, but I reckon it would be worth a go.

James

[JamesF]

Looks like I underestimated. With the 200P you'd probably get an image around 2,000 pixels across.

I'd be tempted to make something like an offset 80mm to 100mm aperture filter and take a fair number of frames either as the Sun drifts across the field of view, or trying to keep it in the frame by nudging. PIPP and Registax v6 are then your friends when it comes to processing.

James

[The Sailor]

James, for me it was just an experiment, as the results were not that good i did not keep any

Jim

[JamesF]

I'm all in favour of experimentation If the OP is up for the challenge though I think the possibility of getting reasonable results with the dob is definitely there. I reckon the image will take up about two thirds of the frame that way so tracking by nudging might be tricky, but perhaps easier than planetary imaging with a webcam using a manual dob.

James

[lw24]

I'm all in favour of experimentation If the OP is up for the challenge though I think the possibility of getting reasonable results with the dob is definitely there. I reckon the image will take up about two thirds of the frame that way so tracking by nudging might be tricky, but perhaps easier than planetary imaging with a webcam using a manual dob.

Thanks for the advice, just to be clear, are we talking about attaching the DSLR to the telescope, as I no longer have my SPC900.

I'm also tempted to buy a used ST80 just for solar imagery on a camera tripod if this would be a better alternative.

[JamesF]

I am talking about attaching the DSLR to the scope, yes.

I'm not convinced about an ST80 for solar imaging. I think the CA might be too obvious on something like the Sun.

James

[lw24]

Ok, how much aperture do you think I'd need for the 200p; would the small hole on the telescope cap be too small?

[Bizibilder]

Make the aparture around 100mm and mount the filter so the light passes between the support legs of the secondary. You will get an image about 2/3 of the sensor width. If you can keep the Sun in view - take as many frames as you can and stack them - you will be surprised at the results you can get!

[JamesF]

Make the aparture around 100mm and mount the filter so the light passes between the support legs of the secondary. You will get an image about 2/3 of the sensor width. If you can keep the Sun in view - take as many frames as you can and stack them - you will be surprised at the results you can get!

That's what I'd try. I think the hole in the cap is too small for good results. Just make sure the filter can't come off accidentally.

James