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Contains:  NGC 1027, IC 1805, IC 1795, NGC 896
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IC1805 Heart Nebula SHO Wide Field Image, 





    
        

            Ben Koltenbah
IC1805 Heart Nebula SHO Wide Field Image

IC1805 Heart Nebula SHO Wide Field Image

Technical card

Resolution: 4325x3316

Dates:Sept. 24, 2018Sept. 26, 2018

Frames:
Astrodon 3nm Ha: 18x900" -30C bin 1x1
Astrodon 3nm OIII: 26x900" -30C bin 1x1
Astrodon 3nm SII: 24x900" -30C bin 1x1

Integration: 17.0 hours

Avg. Moon age: 15.14 days

Avg. Moon phase: 98.81%

Astrometry.net job: 2291595

RA center: 38.818 degrees

DEC center: 61.365 degrees

Pixel scale: 2.331 arcsec/pixel

Orientation: 1.397 degrees

Field radius: 1.764 degrees

Locations: Ben's Backyard, Federal Way, WA, United States

Data source: Backyard

Description

This is IC1805, the Heart Nebula, in Cassiopeia. It lies some 7500 ly distant. This is an emission nebula, where the central part is comprised of open cluster Melotte 15. (See an image I made of the nebula center several years ago.) The bright knot to the upper right is NGC896, sometimes referred to as the Fish Nebula. Just off to the left (outside this view) from the Heart Nebula is IC1848, the Soul Nebula, which is of similar size and composition. In time I'd like to make a mosaic featuring these two extensive regions.

An interesting feature that I'd never noticed before is a small planetary nebula, PN G135.6+1.0, also designated WeBo 1, which is just to the middle left of the boundary wall of IC1805. This is actually a ring-like planetary nebula surrounding a young barium star. It happens to appear blue in my image, showing up more significantly in blue through the OIII filter than the other NB filters. (I first discovered it right here in my very own data, but, as I quickly suspected, I was certainly not the first to notice it as it's been extensively studied.)

I've been eager to make a wide field of view image of IC1805, the Heart Nebula, for some time now. I wanted to process in the SHO palette and not suppress the Ha green color as much as I have done in the past. I'm fairly satisfied with result. NGC896 shows up nicely with some well-separated Ha, OIII and even SII gases.

There are several processing steps that I'd like to record here. First, this is my first serious image in which I made my initial stretch using the ArcsinhStretch process. I've been late coming to understand and appreciate this process. It helps to control stars from become overly stretched and saturated in the final image. Some of the brighter stars are, of course, hopelessly saturated to begin with, but many more need not become saturated in the end so long as this process is not overdone.

Second, I masked off the stars and then applied an UnsharpMask step in PixInsight. I find that protecting the stars helps keep them from being over sharpened into flat, uninteresting discs. I was able to be more aggressive with the nebula without destroying the stars.

And third, I used an old PixelMath step at the end to change purple stars to white. Someday I will play around with mixing in true RGB color to try to blend in natural star colors in my NB images, but not being able to do that yet, I much prefer simply eradicating the purple stars and making them white.

Comments

Author

BenKolt
Ben Koltenbah
License: None (All rights reserved)
1793
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Revisions

  • Final
    IC1805 Heart Nebula SHO Wide Field Image, 





    
        

            Ben Koltenbah
    Original
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            Ben Koltenbah
    B
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            Ben Koltenbah
    C
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            Ben Koltenbah
    D
  • IC1805 Heart Nebula SHO Wide Field Image, 





    
        

            Ben Koltenbah
    E

B

Luminance Image

C

Inverted Luminance Image

D

Inverted SHO Image

E

Annotated Luminance Image - Zoom in to see the location of the PN.

Sky plot

Sky plot

Histogram

IC1805 Heart Nebula SHO Wide Field Image, 





    
        

            Ben Koltenbah

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