NGC 1499 150mm SLR lens (Tom Gray)

NGC 1499 150mm SLR lens

Revision title: HOO with RGB stars

An unexpected clear (all) night gave me an opportunity to have a go at this huge emission nebula with my wide field ‘camera lens’ setup.

I took broadband subs for RGB stars followed by 300s exposures with my UHC-L booster. Seeing was good and guiding steady so I pushed these out to 600s. At 150mm f5.6, my Star Adventurer mount coped admirably.

I processed as HOO (original) in Siril, and using simple stretch/curves in Nebulosity 4 (revision B). Revision C (final) is my favourite, with a false Hubble palette. For this ‘golden cascade’, I extracted the Ha and OIII channels from UHC-L filter then combined these using pixel math with R=Ha, G=0.4*Ha+0.6*OIII, and B=OIII. The golden Ha shows up strongly, with good detail, but I struggled to bring out any blue in OIII - even though the OIII stack looked reasonably strong. Boosting the blue channel just messed up the background - any tips welcome for achieving this with OSC and tri/quad band filter.

Revisions A and B include data from UV/IR giving a total integration of 6 hours. Revision D (mouseover) is pure HOO calibrated, extracted, and processed in Siril - for those who prefer this over Hubble palette.

B

Title: Bin 1x1 processed in Nebulosity

Uploaded: ...

C

Title: Hubble version Bin 2x2

Description: Struggling to bring out the glorious blue OIII in this palette, despite a reasonably strong OIII stack. Bandwidth in my UHC-L filter is large and this may dilute the signal. Any ideas?

Uploaded: ...

D

Title: HOO version calibrated and processed in Siril

Uploaded: ...

E

Title: HOO with RGB stars

Description: I managed to align image scale between my RGB and HOO images by making sequence in Siril and registering these, before cropping. I then made starless version of HOO, applied GHS transformation, Astrosharp, then recombined with starmask from RGB data. Useful learning.

Uploaded: ...

F

Title: Finished in Photoshop

Description: Many thanks to Steve Lantz @astrophotosteve for showing his prowess with photoshop and drawing out some fascinating colour from my image. Thanks Steve

Uploaded: ...

UK Astro-Imaging
Camera Lens Astrophotography
Sky-Watcher Star Adventurer
Altair Astro 183 M/C Hypercams

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Status	Advanced success
Started	...
Astrometry.net job	8891994
PixInsight job	G0HWHDRJMXEJRA9FOWZZ3L0CKYNJ7W2Q
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	04h01m48s.58
RA (top/left)	04h12m02s.14
RA (top/right)	03h51m37s.70
RA (bottom/right)	03h51m59s.99
RA (bottom/left)	04h11m37s.40

Dec (center)	+36°19′30″.9
Dec (top/left)	+37°48′56″.1
Dec (top/right)	+37°49′14″.8
Dec (bottom/right)	+34°47′04″.8
Dec (bottom/left)	+34°46′33″.6

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