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Had another go at getting the spacing right on my Imaging Star 80

Some arithmetic on the spacing and making some assumptions about the thickness of components gave me a suggested spacing of 44mm from  the end of the focuser.

The nearest I could get was 46mm, which is still a wee bit too long and there's a lot of tilt to sort out, probably with the Bahtinov mask. Oh, yes and a couple of horrendous dust spots and some localised gradients which I've tried to get rid of with flats, though not entirely successfully.

Total integration time 40min made up of 40 x 30sec and 20 x 60sec. Exposure took place as the sky was getting dark, and I think there were flecks of high cloud coming over as well, hence some of the gradients.

Markarian with flats.png


Suggestions welcome.

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Nice shot. I don't know whether my unguided thread on Markarian's will help: 


The whole field is awash with light and dark areas which at first I mistook for LP. I think you'll only get those if the sky is really dark, difficult at this time of the year. Wait until it's just west of the meridian (around midnight and just on the edge of about as dark as it'll get I think) and fire away. I used 30s, but with a 760mm refractor. Your advantage is a bigger fov; more galaxies. Cheers, clear (dark) skies and good luck.

Edited by alacant
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