Thursday, 23 November 2017

Hypercam 183c - Sucking Up Those Photons

Hypercam 183c - Sucking Up Those Photons

Sitting in the aftermath of the news that the 183c had already been superseded by the new 183c v2, I'm still impressed with the capabilities of my Hypercam.  During recent months since I took delivery of the camera, I have written about my first steps of using it.  I've covered areas such as setting it up, getting everything to talk correctly, experimental settings and initial findings of post processing.  I've collected together a bit of experience with the camera now, and so decided it was time to bring together what I had learned so far and spend one night on one target.
A couple of weeks ago, an unexpected evening of clear skies with minimal moon interference presented itself, so I set up out the garden ready to concentrate on one target for the evening.
My chosen target was part of the Veil Nebula in Cygnus, NGC 6960, otherwise known as The Witches Broom.  It's a target that I have photographed before with a DSLR, and was also amongst the initial batch of targets I pictured using the 183c, albeit in mono colour-space format.  So far, with the 183c, I have only spent 60 minutes on any given target, and with reasonable results.  All of the images this far have been taken with unguided 60 second light frames.  I decided to stay unguided, but this time collected 2 hours worth of light frame data in RAW 12.
Initial inspection of some of the flat frames, I could see that I was getting a little trailing in stars, but for a majority everything was kept well in focus with no significant trailing.  I decided that would suffice, and that the batch pre-processing script in PixInsight would deal with and omit any bad frames.  What I ended up with was approximately 100 usable light frames.
This was ago the first time I used a UV/IR filter with the camera, so at the same time, I was also omitting some light pollution from the data I was collecting.

NGC 6960 The Witches Broom Nebula.
~100 light frames
20 flat frames
40 bias frames
10 dark frames
Captured in Sharpcap with 60 second frames and 2000 gain.
The colour has come out really well in processing, and the edges of the nebula are quite crisp.  The extra data seems to have smoothed out the background more than in previous images.  I hope that further light frames will make this better still.
The one thing that lets this image down is the centre star.  It looks somewhat bloated which happens during the initial histogram stretch.  I expect that there is a tool somewhere to remove that effect, but I haven't been able to find it as yet!

What Next?

Things are definitely moving in the right direction with my imaging using the 183c.  As a rough plan for the next session, I think I'll stick to a single target for the night again.  I seem to be able to get constant results in terms of polar alignment with Sharpcap pro, so I will continue making sure I get that part of the process nailed at the beginning.  As I've already mentioned, data is key, so I will go for 150 to 200 frames on the next target, providing it is not too bright.  This should help the background smoothness even more.
As a bit of a preamble to it, I'm going to get vncviewer or teamviewer working again so I will be able to monitor progress from comfort of the living room!  I also want to re-introduce the focal reducer to the light train to be used in conjunction with the UV/IR filter and see if I start to get the halo effect again.  We shall see!
Thanks for reading, and clear skies.

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