To some, this nebula looks like the head of a fish. However, this colorful cosmic portrait really features glowing gas and obscuring dust clouds in IC 1795, a star forming region in the northern constellation Cassiopeia. The nebula's colors were created by adopting the Hubble false-color palette for mapping narrow emission from oxygen, hydrogen, and sulfur atoms to blue, green and red colors. Not far on the sky from the famous Double Star Cluster in Perseus, IC 1795 is itself located next to IC 1805, the Heart Nebula, as part of a complex of star forming regions that lie at the edge of a large molecular cloud. Located just over 6,000 light-years away, the larger star forming complex sprawls along the Perseus spiral arm of our Milky Way Galaxy. At that distance, this picture would span about 35 light-years from left to right. [Source: APOD (with some edits)].

CAPTURE Information: This is a Two-Panel Mosaic.

The image was captured with the iOptron CEM120 mount , the venerable Meade 12"LX200 SCT, and my Atik 383L+ mono CCD at F7.16 (2182mm FL).

Image subs were taken through Astronomik's narrowband filters of Ha, SII and OIII.

IMAGE information -- 2020

This is a combination of Ha, OIII and SII.

Ha : 90 subs (15.00 hr) on Nov 19th, 20th, 25th, 30th and Dec 4th.

OIII : 40 subs (6.67 hr) on Nov 20th and 25th.

SII : 40 subs (6.67 hr) on Nov 25th, Dec 2nd and Dec 4th.

All exposures were at 10 minutes (600s) each, 1x1 bin and -10C.

Each two panels of Ha, SII and OIII were individually integrated, then merged, and lastly combined. The three assemblies then created the Hubble Palette, using PixelMath and the following “SHO” formula:

Red = SII

Grn = Ha

Blu = OIII

Luminance was created using only subs from the Ha filter.

Processing was done with PixInsight, following (for the most part) kayronjm's tutorial of Feb. 24th from several years back. Credit also goes to Rick Stevenson’s Color Mask Script and Christopher Gomez’s tutorial.

COMMENTS:

I had previously done this target in December of 2013. Unfortunately, this was the dark period when my (less than reliable) Dell Desktop decided to trash out a large part of my data. It not only lost images on its hard drive, but also took out a Western Digital external hard drive that had most of my images on it. Not real happy with Dell.

Anyway, I have only the JPEG image of this object from that time with which to compare. This one’s better.

I have recently done a couple of two-panel mosaics (NGC7380 and NGC281). As previously mentioned, mosaics take a lot of time and I had little interest in doing more. Nevertheless, this one’s another.

I had a deuce of a time taming the star registration. The ultra small stars from Ha, OIII and SII just would not line up. Had to use brute force to minimize their issue.

Lastly, I’ve posted two images. The starry one was done with my conventional methods. The second, with the greatly reduced stars, was done using the Star Net tool and an inverted star mask. Not sure which one I prefer.