First Guided Image Image - M13

[saac]

Well it's taken me a few years to get to this stage but last month I finally got my setup equipped with a guiding capability (Starwave 50mm Guide Scope & GPCAM Mono Guide Camera working with PHD2).  After a few trial and errors I think I have PHD2 doing what it is supposed to be doing.  So here it is, my very first posted astro image - why is this making me anxious   It is a single 40 min exposure of M13 captured with a Starlight Express SXVR H9C attached to a SW 80mm Equinox Pro ED.  Post processing is minimal, debayerd, background extracted, and adjustment of Histogram curves - I think also some smoothing. All on PixInsight - I followed one of the beginner tutorials on You Tube. There are no dark or flat frames just the single 40 mm exposure (camera was cooled at -10oC).  For a first attempt I'm quite pleased although I would have liked to have drawn more colour.  I also need to find out how to subtract the hot pixels, of which there appears to be many.   I've uploaded it as a jpeg - not sure if that is the best way. Anyway, please, as much constructive criticism as possible. What can I do to improve on this both in capture and processing. Any advice gratefully received.  

 

A couple of specific questions. I used the Starlight Express capture software and noticed that there is no gain control - would it be normal to vary gain with CCD cameras?  With no gain control would I be right in thinking my camera was set at "unity gain"?  I've also since tried the camera with SharCap and the interface there is a little more modern in terms of how it provides access to file menus /functions etc. What do people normally do - do you tend to use the camera software or do you control the camera using a third party solution?

Jim 

 

 

[Stub Mandrel]

That's very good, but despite the deep wells of a CCD it does look blown out in the core.

I suspect stacking eight five-minute subs would have given you more detail in the core and more colour?

Darks will get rid of hot pixels.

[red dwalf]

nice, it`s dead easy to blow out the core on this target some subs at smaller time frames and add them as a layer, you can still clearly see the propeller though in this image

[wimvb]

Congratulations on your first astro pic, and welcome to the dark side (& bottomless pit).

40 minutes is probably a bit much for one single exposure, but it shows what your gear can do.

Ccd cameras are set to a fixed gain. The value differs between models. The gain is chosen such that the full well value (electrons) matches the largest digital number (usually 2^16 - 1 = 65535).

[Demonperformer]

Agree with what others have said - nice pic and interesting experiment, but splitting the same integrated time into somewhat shorter subs will be more useful in practice.

[saac]

Thanks for the comments and advice everybody, all very helpful and gratefully received. So shorter and more subs is the next step, and experiment with removing the hot pixels in PixInsight. Wim, thanks for the advice on CCD gain, it's an area in which I have little knowledge.  I'm going to preserver with this target rather than move on to something else; I'll come back and post whatever I get.  It's good to have posted my first photograph but your right again Wim I suspect I've just doped over the event horizon - I hope I don't get spaghettified    Fingers crossed for some more clear sky; not looking good over next couple of days though. Thanks again everybody.

 

Jim