Hemisphere:  Northern  ·  Constellation: Taurus (Tau)  ·  Contains:  16 Tau  ·  17 Tau  ·  19 q Tau  ·  20 Tau  ·  22 Tau  ·  23 Tau  ·  24 Tau  ·  25 eta Tau  ·  Alcyone  ·  Barnard's Merope Nebula  ·  Celaeno  ·  Electra  ·  IC 349  ·  LBN 770  ·  LBN 771  ·  LBN 772  ·  M 45  ·  Maia  ·  Maia Nebula  ·  Merope  ·  Merope Nebula  ·  NGC 1432  ·  NGC 1435  ·  Pleiades  ·  Sterope II  ·  Taygeta  ·  The star Celaeno (16Tau)  ·  The star Electra (17Tau)  ·  The star Merope (23Tau)  ·  The star Taygeta (19Tau)  ·  And 1 more.
Getting plate-solving status, please wait...
Messier 45 (LRGB HDR), 



    
        

            Linda
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Getting plate-solving status, please wait...
Messier 45 (LRGB HDR), 



    
        

            Linda
Powered byPixInsight

Acquisition details

Dates:
Dec. 8, 2021 ·  Dec. 11, 2021 ·  Dec. 12, 2021 ·  Jan. 1, 2022 ·  Jan. 2, 2022 ·  Jan. 3, 2022 ·  Jan. 4, 2022 ·  Jan. 5, 2022 ·  Jan. 6, 2022 ·  Jan. 9, 2022 ·  Jan. 10, 2022
Frames:
Astrodon Gen2 I-Series Tru-Balance Blue: 89×120(2h 58′) -25°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Blue: 11×600(1h 50′) -25°C bin 2×2
Astrodon Gen2 I-Series Tru-Balance Green: 88×120(2h 56′) -25°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Green: 23×600(3h 50′) -25°C bin 2×2
Astrodon Gen2 I-Series Tru-Balance Lum: 113×120(3h 46′) -25°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Lum: 26×900(6h 30′) -25°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Red: 64×120(2h 8′) -25°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Red: 30×600(5h) -25°C bin 2×2
Integration:
28h 58′
Avg. Moon age:
9.44 days
Avg. Moon phase:
25.69%

RA center: 03h46m06s.535

DEC center: +24°0836.61

Pixel scale: 0.727 arcsec/pixel

Orientation: 91.672 degrees (flipped)

Field radius: 0.566 degrees

WCS transformation: thin plate spline

More info:Open 

Resolution: 3956x3968

File size: 433.7 KB

Data source: Own remote observatory

Remote source: Sierra Remote Observatories

Description

The first image of 2022! Though of course, a good chunk of the data is from December 2021... This target is really tight for the FoV of this system but a teammate wanted to try it so try it we did. I suggested we try an HDR experiment where we would take some short and long exposures to blend. None of us had tried this before so we weren't entirely sure what to do and as it turned out we chose short and long and we should have gone for really short and short (or long or all three). All the intensity is really right around the stars and I'm not sure that our HDR really added much to the image (though it probably did help keep noise under control in the fainter areas). But it did teach me a lot about how HDRComposition works in PI and that was valuable education. I'll be better armed for the next version.

It's a bit hard to judge the total time in this image since it's a blend of the short and long. The areas around the stars comes from the short exposures and that was a total of 11.8 hours of LRGB.

The rest of the image comes from the long exposures and that totals 17.2 hours and that's probably a more representative time than what astrobin is reporting.

We went through a stretch of bad weather that really slowed things down and cost a bunch of data and by the end we had acquisition fatigue on this one or we might have gone back to do some really short exposures to see if we could avoid clipping the brightest stars. 

I used the Generalized Hyperbolic Stretch script for this (https://github.com/mikec1485/GHS). It really helped protect the highlight end of the histogram and kept the stars under control. I definitely recommend checking that out.

Here's how I processed:

short L:
deconvolution

long L:
deconvolution

HDR L:
HDRComposition of short and long L
generalized hyperbolic stretch script (multiple iterations)
HDRMultiscaleTransform

short RGB:
channel combination

long RGB:
channel combination

HDR RGB
HDRComposition of short and long RGB
generalized hyperbolic stretch (multiple iterations)
HDRMultiscaleTransform
LRGBCombination in HDR L
LHE (2 scales)
AdvSharpening script (very mild)
Curves (color and very gentle contrast adjustments)
Clone Stamp to fix a few star cores that HDRMT or LHE messed up

Overall I was trying to showcase the wispiness of the dust and the blue reflections from said dust and leave things subtle and understated.

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