Hemisphere:  Southern  ·  Constellation: Sagittarius (Sgr)  ·  Contains:  M 20  ·  M 21  ·  NGC 6514  ·  NGC 6531  ·  Trifid Nebula
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Trifid Nebula in LRGB, 


Trifid Nebula in LRGB
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Trifid Nebula in LRGB

Getting plate-solving status, please wait...
Trifid Nebula in LRGB, 


Trifid Nebula in LRGB
Powered byPixInsight

Trifid Nebula in LRGB

Technical card

Imaging telescopes or lenses: APM LZOS 130/780

Imaging cameras: ZWO ASI294MM Pro

Mounts: iOptron CEM70

Guiding telescopes or lenses: APM LZOS 130/780

Guiding cameras: ASI290MM Mini ASI 290 Mini

Focal reducers: Riccardi RIRED-M63

Software: Aries Production astro pixel processor  ·  Photoshop CC  ·  StarTools 1.7

Filters: Baader 36mm Red  ·  Baader 36mm Green  ·  Baader 36mm Blue  ·  Baader 36mm Lum

Accessory: ZWO ASI OAG  ·  ZWO EAF Focuser  ·  ZWO EFW 36mm  ·  PrimaLuceLab ECCO ECCO  ·  PRIMALUCE LAB Eagle 3s

Dates:July 8, 2021

Baader 36mm Blue: 80x90" (2h) bin 2x2
Baader 36mm Green: 80x90" (2h) bin 2x2
Baader 36mm Lum: 150x45" (1h 52' 30") (gain: 120.00) -5C bin 2x2
Baader 36mm Red: 80x90" (2h) bin 2x2

Integration: 7h 52' 30"

Darks: 25

Flats: 25

Bias: 50

Avg. Moon age: 28.10 days

Avg. Moon phase: 2.30%

Bortle Dark-Sky Scale: 6.00

Temperature: 12.00

Basic astrometry details

Astrometry.net job: 4722383

RA center: 18h 2' 36"

DEC center: -22° 59' 42"

Pixel scale: 1.615 arcsec/pixel

Orientation: 89.201 degrees

Field radius: 0.761 degrees

Resolution: 2776x1950

Locations: Backyard, Brisbane, Queensland, Australia

Data source: Backyard


I imaged this one in SHO narrowband a few weeks ago but not happy with result then as it doesnt really bring out the colour and extent of the reflection nebula so gave it a go in LRGB... no moon as such but glaring lights from neighbours house a bit of a bane, so had to run fairly short exposures - 45s for L and 90s for RGB. This is around 7-8 hours total integration; lost track a bit and would go deeper but it's stressing my PC processing so many hundred shots ;-)

I'm sure I can do better with bringing in some Ha accent, but haven't got round to it so will post this up as is (LRGB only) for now.

My guiding/tracking is a case of one step forward and one back ...using an OAG seems to be helping with more round stars even at zenith, but the periodic error on my CEM70 mount seems to be growng ...originally as per spec was 7 arc second peak top peak, but more like 15 in recent months and last night 24 peak to peak... not sure what is going on, but it means i need to run aggressive PhD2 settings to keep up which isn't great. I've given up trying to correct tilt as it varies througout the night convincing me it's flex in my focuser... i've finally bit the bullet there and have ordered a Moonlite 3.5in Nightcrawler, so hopefully in 6 weeks time I'll have a more rigid focuser.

Anyway, the journey continues :-)

Stacked this in APP and partially processed to TIF in APP as well. Separate channel stacks then processed in Startools 1.8 alpha and then blended in PS...most of the result here is Startools but I haven't mastered stars in ST yet (I have been overblowing the cores) and blending in stars from APP that appear more natural.

One thing about LRGB is I do like the range and natural look to star colours over narrowband... light pollution and moons mean SHO will remain my mainstay for now I fear.


Sky plot

Sky plot


Trifid Nebula in LRGB,