First Light M13 Orion 200 SPX

[Fay]

This was 24x180 secs, plus darks, modified Canon 350D, MPPC, guided PHD, stacked DSS.

Have posted this although I have a problem somewhere. The stars are all elongated. This is the full frame. Still work to be done

[Ian]

well that middle bit is fantastic, but you're right, there's something messing with your stars. You were talking about yor coma corrector playing up?

I'd also like to know where those extra diffraction spikes have come from. Did you add them manually, we all know how popular they are 

I wonder if you've got a pinched primary (or did you pay for it???), it looks a little like astigmatism...

[Fay]

Good grief Ian, a pinched primary!! I did nothing to it, should it only have one set of diffraction spikes on the two main stars? Perhaps this will point the way to the cause of the problem

[JohnP]

Not bad Fay - but definitely something weird somewhere... elongation is all in different directions... Whats a CCPC?

John

[Fay]

Sorry John, have corrected.

[JohnP]

OK - I understand now... thks - John

[MarkS]

Fay,

That's a good globular cluster in spite of your elongated star problem.  It's a lovely subject for a first light - that scope is giving a useful field of view at high magnification.  You have not burnt the core out, which is good.

It is possible that those elongated stars could be a problem with the stacking - do they appear on the subs?  If the stars in the subs are not elongated then it is DSS that is having a problem with aligning the subs.

Oh, and you've also caught at least a couple of background fuzzies.

Mark

[Mac]

wow very nice and sharp.

[Ian]

that's a good question from Mark. Do the subs have all those diffraction spikes?

[Mike]

Nice image Fay.

I think Mark might have hit the nail on the head. It looks like there is a slight rotation between frames and the stacking software is not allowing for the rotation. Do you do a two star alignment first on the subs?

[Fay]

The individual subs are the same, will have a look at spikes. Should there be just 4 spikes each on the two larger stars?

[Ian]

what there should depends on the optical assembly. However, it's distinctly odd that the right hand side star appears to have more spikes than the left hand star...

[Tony G]

Great image Fay, and by the way I like the spikes. 

Tony G

[Rocket Pooch]

Its not pinched optics or the MPCC the elongation is not consistent, odd, Fay I can check the spacers for you this weekend and we can then look at the scope  if I had to put money on it I'd say its the camera moving around a bit.

Its probably a mixture of MPCC spacing and the focuser.

Nice middle bit.

[Fay]

thanks Chris. I ordered some spacers yesterday. To me it looks like it is the same in the cluster as well