Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: The Thing on Jun 10, 2020, 10:33:37

Title: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: The Thing on Jun 10, 2020, 10:33:37
Updated: I've brightened the background a bit.

I've tried to emphasise the shape of the good old Pelican while showing the dust and gas in the faint bits.

Stacked in ASTAP with flats, dark flats and no darks. In PixInsight I used ABE, Arcsinh, Decon, HDRMST, PCC, MMT, TGVdenoise (it's another language!)and a final tweak in DarkTable. There are some probable hot pixels lurking around but I don't know how to zap them in PixInsight.

52 x 240s subs, Temp -15C, Gain 120, Offset 4

Telescope aperture and focal ratio: TS1506UNC f4, TS Komakorr
Camera and filters used:   ZWO ASI294MC Pro, IDAS LPS-D1 LP filter
Processing applied:   ASTAP, PixInsight, DarkTable

(http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/normal_PELICANNEBULA_2020_05_25_52x240L_TS01506UNC_ZWO_ASI294MC_Pro__stacked_ABE-arcsinh-decon-hdrmst_colour_denoise_DT_01.jpg) (http://gallery.orpington-astronomy.org.uk/albums/userpics/10050/PELICANNEBULA_2020_05_25_52x240L_TS01506UNC_ZWO_ASI294MC_Pro__stacked_ABE-arcsinh-decon-hdrmst_colour_denoise_DT_01.jpg)
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: RobertM on Jun 10, 2020, 13:43:22
Nice one Duncan, plenty of colour showing there !  The background looks a little dark on my monitor (let me know if the trouble is at my end).  As a matter of interest... why no darks for your lights ?

That's quite a workflow !  BTW. I think you're looking for Cosmetic correction to deal with any hot pixels (not that I could see any).

Robert
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: Carole on Jun 10, 2020, 19:00:07
Looking good Duncan, same question as Robert regarding the darks?

Other than that, there seems to be some sort of flaring on the 2 - 3 o'clock position of the brighter stars, is this a collimation issue (or what?).

Carole 
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: The Thing on Jun 11, 2020, 08:00:29
Just couldn't find any recent 240s darks, they should have been with the flats...

Looks fine on my monitor but dark on my phone Robert. I'll reset my monitor and redo the calibration and maybe post a brighter version.

Carole, that blob in one quadrant of the brighter stars is a mystery. I've had it before and have recolimated since. I'll check for reflections and stuff, but I painted the inside of the OTA last year so it should be fine. It could be a diffraction artifact of some sort. Dunno. But it needs sorting out.
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: Roberto on Jun 11, 2020, 09:14:06
Very nice image Duncan and great framing.  8)

Roberto
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: The Thing on Jun 12, 2020, 12:48:47
Thanks Roberto.
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: MarkS on Jun 12, 2020, 21:38:47
That's a great one Duncan.  Nice and sharp with the colours looking good.

As others have remarked, that's quite some processing sequence!

Mark
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: RobertM on Jun 12, 2020, 23:10:07
Duncan, regarding the 'blob'.  It seems to be at precisely 45 degrees to the orientation of the spider vanes.  Have you got anything on the scope that could impinge on the light before it hits the Primary mirror (as looking down the tube) ?  Am thinking focuser drawer tube in particular...

Robert
Title: Re: Pelican Nebula IC 5070 and IC 5067, 20 May 2020, Manche, France
Post by: Carole on Jun 13, 2020, 08:54:09
QuoteDuncan, regarding the 'blob'.  It seems to be at precisely 45 degrees to the orientation of the spider vanes.  Have you got anything on the scope that could impinge on the light before it hits the Primary mirror (as looking down the tube) ?  Am thinking focuser drawer tube in particular...

I had problems with my SW130PDS with the draw tube impinging the light path, it might be worth doing a defocussed star to see what shape you get on a bright star.  Mine had a bite out of it.  I ended up having to cut a piece off my focusser draw tube.  (Others had done the same thing).

Carole