Bubble Nebula - NGC7635

[vincentnm]

Hi All,

Capured this last night until 2am when the clouds rolled in.

Scope: C8 hyperstar 3

Mount: EQ6

Camera: SXV M8C

Guiding: ST80 with DFK

Exposure: 5 minutes X 16 subs

Tried hyperstar collimation using CCD Inspector for the first time. Works like a treat.

There's a bit of trailing. Suggestions for improvement are welcome please.

Thanks,

Vincent.

[SteveL]

Hi Vincent

I think you have just clipped the black point on this image. There is a fair amount of red data hidden in the image.

I also see some hot pixel trails in the image (red one halfway down the left, blue one two thirds down the right side). You may want to try a stacking procedure that uses sigma reject to remove/reduce these issues

Lastly, you need to update your sig

[SteveL]

[Tim]

Looks like the hyperstar is working well for you Vincent.

I have been thinking about CCD inspector, as I find collimating my fast newts, as well as the SCT to be a fiddly chore. Does it enable it to be done live, ie, looking at the results live on screen as you fiddle?

Thanks

TJ

[vincentnm]

Thanks for the mod Steve. There's was so much of red to be picked out.

I've had these RGB trails before, dint realise they were hot pixels trailing in the stacked image. There must be some RA drift, flexure problems? Anyway, I've followed your advice, used Sigma Kappa combine in DSS and they've disappeared.

Tried not to clip the dark point. But wondering if Gradient Exterminator or "Light Pollution Removal" in Noels Actions go very near the dark point. I check the "Show Clipping" box in Curves Dialog and could not spot any hint of clipping.

Here's the re-processed image.

Thanks,

Vincent.

[vincentnm]

Looks like the hyperstar is working well for you Vincent.

I have been thinking about CCD inspector, as I find collimating my fast newts, as well as the SCT to be a fiddly chore. Does it enable it to be done live, ie, looking at the results live on screen as you fiddle?

Thanks

TJ

Thanks TJ. Still 1/3 way to climb up the hyperstar learning curve. Sorted out focussing and collimation after 3 months. Now have to do something about temperature compensation! Small changes throw the hyperstar out of focus.

CCD Inspector does not give you live view. But almost. You need to take an exposure of 30-60 seconds. As soon as the image gets downloaded, CCD Inspector gives you an error readout on collimation. It will even tell you which knob to turn!

Cheers

Vincent.

[Tim]

Thanks for that, i'll take a look at it I think.

But the question in the back of my mind is, is it best to collimate so the scopes mirrors are exactly aligned, or is collimating to the camera better?

I know that ideally the focusser will hold the camera totaly square and central to the light path, but at least with my kit, I find that doesnt happen often.

Any thoughts anybody? Would the collimation to the camera result in a slight loss of contrast?

Thanks

TJ

[Tim]

oh, I'd stay away from noels light removal, you'll lose loads of data. If you send me the stacked tiff i'll run it through Pixinsight if you like? pm for email

[vincentnm]

Thaks Tim for offering. Here's the stacked and zipped TIF - http://www.easy-share.com/1907013326/Bubble_Neb_DSS_Flats_Sigma_Kappa.zip (11MB)

Thanks,

Vincent.