Which camera to choose for full disk imaging

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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Which camera to choose for full disk imaging

Post by shadowchaser »

Hello everyone!

I have a Coronado SolarMax II 90mm BF15 telescope and a ZWO 290 MM camera that works fine for details, but now I want to take pictures of the full disk. Which camera do you recommend me?

Thank you!

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Re: Which camera to choose for full disk imaging

Post by rsfoto »

Hi shadowchaser,

In terrestrial photogrphy when using a telephoto lens one calculates the size of the Sun on the by using the telephoto focal length and divide it by 109.

So the Solarmax is an 800 mm telephoto and dividing that by 109 gives you a projected Sun size of 7.34 mm.

OK, then you need a chip size with the shortest side of the chip being at least 8mm.

regards Rainer

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Re: Which camera to choose for full disk imaging

Post by Merlin66 »

Full disk imaging at longer fl - bigger chips, SSD drives....
I went for the ASI 1600MM, 17.7 x 13.4mm chip with 3.8 micron pixels.
Another option is to use a x0.5 reducer - dropping the fl to around 400mm (giving a solar disk approx 4mm diam.)
There are many other options.

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Re: Which camera to choose for full disk imaging

Post by marktownley »

I use a FLIR GH3 U3 916M camera for full disk imaging with my Sm90.

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Re: Which camera to choose for full disk imaging

Post by Astrograph »

I usually use 115 to give the suns disc in mm. I can't remember where I got that from now!

I would caution against the use of reducers. Firstly they will require more in focus which a solarmax might not have. The main reason though is that reducers (like the common 1.25" 0.5x) do not provide much of a corrected field. I bought some of these in for solar but when I tested them, although they provided a bigger FOV, the sharp bit of it was no larger than without it. These things are really made for guide scopes.

Your best bet is to use a larger sensor although you should understand that the output from a solar scope is not corrected. It is intended for visual. Imaging with a small sensor does not show problems but the bigger you go, the more you will see. The SolarMax is basically F9 with some internal optics so it might have a reasonably flat field but how big it is anyone's guess. The Panasonic MN34230 used in the ASI1600, QHY163 and others is a Micro 4/3 sensor and quite large. It will more than cover the BF15 but how much of that image would be corrected you would only find with experimentation.

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