Galaxies
The Triangulum Galaxy
The Triangulum Galaxy (M33) photographed by Pete Lawrence: a spiral 3 million light-years away and one of the most distant naked-eye objects.
Target details
The Triangulum Galaxy (Messier 33) is a spiral galaxy about 3 million light-years away in the constellation Triangulum. It's the third-largest member of the Local Group, after the Andromeda Galaxy and the Milky Way, yet it's also the smallest spiral in the group, and is thought to be a companion of Andromeda given how they move and how close they appear. It's one of the most distant things you can see with the naked eye.
It's about 60,000 light-years across, roughly 40% the size of the Milky Way, and may hold 40 billion stars, compared with 400 billion for the Milky Way and a trillion for Andromeda. Distance estimates range from 2.38 to 3.07 million light-years, with most recent ones putting it slightly further away than Andromeda.
In the upper left corner you can see a very faint galaxy. I can't find much information on it other than its designator which is '2MASS J01350881+3102189'.
Capture details
Data captured across 10 nights between 3rd September & 16th October, 2018.
Imaged as a 1x2 Mosaic.
99x 2 minute exposures with Blue filter (Binned 2x2).
101x 2 minute exposures with Green filter (Binned 2x2).
97x 2 minute exposures with Red filter (Binned 2x2).
246x 3 minute exposures with Luminance filter.
Total Exposure = 22.2 hours.
Equipment details
Skywatcher Quattro 200 CF
NEQ6 Pro
Atik 428EX Mono
Skywatcher ST-80
QHY5L-II
Processing details
This image was processed in Pixinsight & Lightroom.
Calibration and Stacking in Pixinsight using Batch PreProcessing
Dynamic Crop - To remove black edges & integration artifacts. (Each Channel & Pane)
Dynamic Background Extraction - To remove gradients. (RGB & Lum separately)
Channel Combination - To combine RGB channels.
Photometric Colour Calibration - To calibrate colours (Each Pane separately).
SCNR - To remove green cast (Each Pane separately).
Deconvolution - To bring out some fine detail & tighten stars, 50 iterations. (Luminance only, each Pane separately)
LRGB Combination - To blend my luminance image with my RGB image.
Histogram Transformation - To align brightness of both panes.
Star Alignments & Gradient Merge Mosaic - To merge two panes into one image.
Histogram Transformation - To stretch the LRGB image.
TVGDenoise - To denoise background, with inverted rangemask.
Curves Transformation - To boost contrast.
Local Histogram Equalisation - To sharpen with mask in place to exclude stars & background.
Curves Transformation - To boost galacy brightness slightly, with starless range mask.
Curves Transformation - To boost saturation, with starless range mask.
Export as JPEG and import into Lightroom.
Darken Shadows (-75)
Increase Red Saturation (+50)
Export final JPEG for upload.
Quick facts
- What is The Triangulum Galaxy?
- The Triangulum Galaxy (Messier 33) is a spiral galaxy about 3 million light-years away in the constellation Triangulum. It's the third-largest member of the Local Group, after the Andromeda Galaxy and the Milky Way, yet it's also the smallest spiral in the group, and is thought to be a companion of Andromeda given how they move and how close they appear.
- Where is it in the sky?
- In the constellation Triangulum.
- What are its catalogue names?
- M33
- When was this photo taken?
- 16 October 2018
- How long was the total exposure?
- 22.2 hours
- What equipment was used?
- Skywatcher Quattro 200 CF, NEQ6 Pro, Atik 428EX Mono, Skywatcher ST-80, QHY5L-II
- Where was it taken from?
- Lisburn, Northern Ireland.