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Messier 66, Leo Triplet


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Here is M66, NGC 3627, part of the Leo triplet of galaxies.  Mono RGB and Ha composite.

The exposures were done almost 3 years ago(!) but until recently had taken too many stupid pills to get anything out them.  Cloudy nights and freezing weather I wasn't stupid enough to go out in means they came to the top of the to-do list.

I might have another go this Spring - telescope has been fed and fettled and looking for a challenge.


M66 is the largest and brightest member of the Leo triplet of galaxies, a grouping of three gravitationally interacting galaxies in the constellation of Leo.

Photograph taken in Astronomik RGB broadband filters, Ha narrow band filter. Total exposure time 7.5 hrs.

R 2x2 bin - 15x300s = 1.3hrs, 22 March 2020
G 2x2 bin - 11x420s = 1.3 hrs, 23 March 2020
B 2x2 bin - 18x420s = 2.1 hrs, 24 March 2020
Ha 2x2 bin - 11x900s = 2.8 hrs, 26 March 2020

Imaging scope: SW Startravel 150mm F5 Refractor, 2.5x Celetron Luminos 2inch imaging barlow, Atik 460EX mono

Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera

Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex)

Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted.  Spring loaded DEC axis gearing.

Other gadgets: ST4 based anti vibration shutter, ST4 based PEC

PixInsight: Lights, Darks, Flats, Biases, Align Calibration, StarNet2 star removal/star layer
GradXpert: Gradient removal
Topaz DeNoise AI: Noise removal
Affinity Photo: 32 bit image processing (curves, high pass masking, selective colour)


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Thanks for the comment Martin, and yes, a chronic problem of  mine :) 

I was trying to converge on this Adam Block image from the 0.8m Mount Lemmon Schulman Telescope


It seems to go with the territory using a mono cam.  And irrecoverable errors get baked in early on, a bit like beginning lumps in gravy.  

Still, I was pleasantly surprised at the details that were lurking and came out: 0.15m vs 0.8m.  I will have to reprocess and see if it takes a different path...



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