Solar flats help please

[spaceboy]

How do I get Ha flats ??? Do I have to use a standard diagonal in replacement of the blocking filter?

[Freddie]

Point at a bland section of the sun and defocus.

[JB80]

Yep, that is the easiest way I have found. Just try and make sure that you have all of the chip covered with the solar surface, defocus it and take about a 300-500 frame avi.

Once you have done that then you load the avi into autostakkert and under the "image calibration" tab you choose "create master stack", and it will ask you to save it as a file.

When you want to use the flat you have to restart autostakkert, load your avi and before you do anything else go back to the "image calibration" menu and choose "load master flat" which will be the saved file from before. Once loaded you just use AS!2 normally.

Hope that helps a bit.

[spaceboy]

Thanks guys will give it a go next clear day.

[michael.h.f.wilkinson]

I have used a different tip from SolarChat: Point the scope to centre disk, don't defocus, but put cling film over the aperture (without touching the optical surfaces, of course). I find four layers of cling film (and a boost of a factor of 3 or so in exposure time) gives good results. I often add a constant value to the image (between 9,000 and 10,000 in a 16 bit flat with maximal value of 55,000 or so) otherwise the edges and corners of the corrected images turn out too bright.