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Half of NGC 1499 The California Nebula, 2 Dec 2019

Started by The Thing, Dec 09, 2019, 21:05:08

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The Thing

First successfulish light with this scope This is not the best as I got the flattener spacing wrong so the stars are not to be looked at too closely. However I am very happy with this and next time I go to California I will rotate the camera and maybe get it all in! The 600 subs I got on the following night are much much better and I hope to process them tomorrow.

60x60s subs, gain 300, offset 10, 10xFlats, 10xDarks, No bias or flat darks.

Image date, time and location:   2019-12-02 Manche, France
Telescope aperture and focal ratio:   Sharpstar 61EDPH with flattener
Camera and filters used:   ZWO ASI294MC Pro, Baader Neodymnium 1.25" filter
Processing applied:   Pixinsight (New Weighted Batch Pre-Processing, DBE_BN_PCC_SM_Dcon_MLT_SCNR_Arcsinh_PCC_HDRMT_LHE_DSE_DT_IrfanView 0.5 resample), Darktable (final noise reduction, sharpen, local contrast, complex 'filmic' curves)


NoelC

Very good Duncan
(I can't see a problem with the stars).
fantastic star field behind.
Noel
Swapped telescopes for armchair.

The Thing

Thanks Noel.

Wait until eagle eyed :raven: Robert and Mark do a close inspection of those stars...  :alien:

Carole

It's a huge target, and if it had been further up the FOV you might have got most of it in.

Very good for a OSC camera as it is rich in Ha and Sii. 

I just wonder whether the colour balance is quite right, as most of the stars are red and the sky background is a bit red.   

Look forward to the next version with the whole nebula in it. I think the bit you have cut off is far more interesting.

Good to have a scope which will increase the FOV, I think mosaics are tedious, especially in the UK with lack of clear skies, and i don't suppose just across the channel they are much better there either.


The Thing

Thanks Carole, it does look redder in the browser than on my desktop for some reason, but its better than green. I did check the balance of the histogram after Photometric Colour Calibration in PI so it should be right.

RobertM

It looks very red on my monitor as well Duncan, are you sure that the background neutralisation worked correctly ?

Roberto

Duncan

It's a great shot but your monitor needs calibration.  Now on to do the other half!

Roberto

The Thing

Thanks Roberto. My monitor is calibrated frequently with a Spyder 5, it's my eyes that need calibrating! I use PIs Photmetric Colour Calibration on the Average Galaxy preset as a matter of course. I also looked the subject up on the web to find one I liked for this but probably it was quite red as well :{.  I find it hard to be consistent. I would like to take the MarkS route and do it mathematically using camera specific factors for each channel. I think I need to be practical though, not being a mathematician, and pick a reference image to compare colour balance to and use the same reference for every image. Possibly I could image a colour test chart or grey card and work out calibration factors from that.