Celestial hemisphere:  Northern  ·  Constellation: Cassiopeia (Cas)  ·  Contains:  IC 1805  ·  LBN 654  ·  LDN 1366  ·  LDN 1368  ·  LDN 1369  ·  Sh2-190
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Melotte 15 (SHO), 


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Getting plate-solving status, please wait...
Melotte 15 (SHO), 


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Acquisition details

Oct. 20, 2021
Astrodon H-alpha 5nm: 34×900(8h 30′) -250°C bin 1×1
Astrodon OIII 5nm: 36×900(9h) -25°C
Astrodon SII 5nm: 34×900(8h 30′) -25°C
Avg. Moon age:
14.64 days
Avg. Moon phase:

RA center: 02h34m44s.672

DEC center: +61°3228.22

Pixel scale: 0.727 arcsec/pixel

Orientation: 87.802 degrees

Field radius: 0.533 degrees

WCS transformation: thin plate spline

More info:Open 

Resolution: 3973x3470

File size: 562.4 KB

Data source: Own remote observatory

Remote source: Sierra Remote Observatories


Melotte 15 is the open cluster at the center of the Heart Nebula but really it's the nebula that is still the, um, star here. So maybe this should be called, "The Center of IC 1805" or more poetically, "The Heart of the Heart". Whatever one calls it, it's a beautiful bit o' nebula. My spouse who not only tolerates but supports my obsession though not sharing it has become familiar enough with these things to look at this and say, "Isn't that the one on the shower curtain?" That was a reference to Messier 16, which is, indeed on our shower curtain. And the similarity is certainly there! 

Data was acquired from 14 to 29 October 2021. Smoke out west marred a good chunk of this. We ended up gathering twice as much data as I ultimately used. 

But, enough about that, here's how this was processed:

S, H and O masters:
dynamic crop
star Xterminator (extracting stars)
histogram transformation
tgv denoise

channel combination (SHO)
histogram transformation (to align peaks)
channel combination in lum
pixel math in stars

channel combination (SHO)
histogram transformation

used copy of starless H as luminance
LHE (2 scales)
MLT sharpening
curves (contrast)