new to this and not sure what issues I'm seeing here?

Questions and answers about processing in StarTools and how to accomplish certain tasks.

new to this and not sure what issues I'm seeing here?

Postby Lawrence Saville » Fri Aug 03, 2018 1:41 pm

Dear all

I'd appreciate some guidance and advice on what I'm seeing here having AutoDev'd the stacked image.

For info, Camera QHY8, Baader MPCC coma corrector, CGEM mount, SW 200P OTA, SharpCap image capture.

This is 120 x 30s subs, 60 x 30s darks, no flats or bias, stacked using DSS - not using the parameters as stated in the Star tools guide.

I initially wondered if this was vignetting but added the coma corrector as I'm aware the Newts are susceptible (and I could see in earlier test images) and wondered if it would also help on the alleged vignetting. To be honest I think it may be worse now with the MPCC? but anyways,

Couple of things concerning me - not least of which is the big hole in the centre!! - the left side looks coma-ish/star trailed to me yet the RHS seems fine? The noise 'free' hole is off centre......

Given that the hole was fairly central before MPCC I'm wondering if the plane of the camera and MPCC is now skewed slightly and this may also explain the LHS 'slurring' of the stars.

But that still leaves the 'why' for the Big Hole effect !!

All comments and suggestions gratefully received, in the meantime I'll crop and play anyway to get familiar with Star Tools (which is fab by the way Ivor!)

Image

I think I've added an image correctly, I'll check when posted

Rgds
Lawrence
Lawrence Saville
 
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Re: new to this and not sure what issues I'm seeing here?

Postby Lawrence Saville » Fri Aug 03, 2018 7:17 pm

Think I may have a lead - it's most likely dew on the QHY8 IR filter - found some threads on this, took the camera out and can see evidence of now dried damp.

Given the current hot, humid weather and a TEC running at -20C then DUH!

Dew heater to the rescue, also noticed camera was not quite square set in the focus tube, slight but noticeable. Offset 'hole' in the image is most likely just due to OTA orientation at the time and where the lens mists up.

Fitting dew heater impacts the coma spacing so reset this and probably better now so hoping coma improved and seating the camera square should resolve the differences in left/right smearing - fingers crossed

Why was it so Blue? Least of my problems!!

Will try more image capture tonight with revised kit and see what we shall see, see, see.

L
Lawrence Saville
 
Posts: 2
Joined: Thu Aug 02, 2018 8:10 pm

Re: new to this and not sure what issues I'm seeing here?

Postby happy-kat » Sun Aug 05, 2018 8:06 pm

Hope your changes see improvements, though this looks more like setup issues rather then processing yet.
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