A little while back now I set out to snap a shot of something a little off the beaten track this time, something that doesn’t usually get the limelight. So, let me introduce you to RCW 105, or as named Gum 51. It’s a pretty but sort of under-the-radar, emission nebula hanging out in the constellation Norma.

You won’t stumble across too many pictures of this object online or on Astrobin, which is kinda surprising given how beautiful it looks.

Peering into its cosmic makeup, there’s a healthy dash of Ha, a pinch of Sii, and just a smidge of Oiii. These Oiii and Sii emissions may be faint, but they sure do contribute to the nebula’s beauty in processing.

Now, the Oiii might be playing hard to get, but when it’s mixed into the SHO palette, it serves up this really neat color contrast that evels up the nebula’s charm. Sure, it’s not adding tons to the detail of the image, but it’s definitely worth acquiring.

So, when I was getting down to the image processing, I decided to let the Hydrogen-alpha (Ha) emission take the wheel as for the luminance layer for details. I hope you appreciate the end result of this often overlooked nebula, a nod to the under appreciated gems of the cosmos.

Dates: 18 May 2023


Antlia 3nm Narrowband H-alpha 1.25″: 36×600″(6h)

Antlia 3nm Narrowband Oxygen III 1.25″: 47×600″(7h 50′)

Antlia 3nm Narrowband Sulfur II 1.25″: 28×600″(4h 40′)

Antlia Blue Pro: 20×60″(20′)

Antlia Green Pro: 20×60″(20′)

Antlia Red Pro: 20×60″(20′)

Integration: 19h 30′

RA center: 16h10m01s.10

DEC center: -49°06′08″.7

Pixel scale: 1.046 arcsec/pixel

Orientation: 0.349 degrees

Field radius: 0.755 degrees

Resolution: 4191×3072

Locations: Bentleigh, Victoria, Australia

Sky Plot