Hemisphere:  Northern  ·  Constellation: Monoceros (Mon)  ·  Contains:  12 Mon  ·  12.45  ·  238 Hypatia  ·  NGC 2237  ·  NGC 2238  ·  NGC 2239  ·  NGC 2244  ·  NGC 2246  ·  NGC 2252  ·  Rosette nebula  ·  Sh2-275  ·  The star 12Mon
Getting plate-solving status, please wait...
Rosette Nebula (NB), 


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Getting plate-solving status, please wait...
Rosette Nebula (NB), 


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Acquisition details

Jan. 19, 2020 ·  Jan. 20, 2020 ·  Jan. 21, 2020 ·  Jan. 22, 2020 ·  Jan. 23, 2020
Astrodon H-alpha 3nm: 56×300(4h 40′) (gain: 139.00) -15°C bin 1×1
Astrodon OIII 3nm: 56×300(4h 40′) (gain: 200.00) -15°C bin 1×1
Astrodon SII 3nm: 58×300(4h 50′) (gain: 200.00) -15°C bin 1×1
14h 10′
Flat darks:
Avg. Moon age:
26.21 days
Avg. Moon phase:
Bortle Dark-Sky Scale:

RA center: 06h32m14s.40

DEC center: +04°5356.7

Pixel scale: 1.623 arcsec/pixel

Orientation: -179.854 degrees

Field radius: 1.315 degrees

More info:Open 

Resolution: 4656x3520

File size: 1.8 MB

Locations: Home, Broadlands, VA, United States

Data source: Backyard


This is my first narrowband image and has me quite excited! My collection of 3nm filters is complete and there were four clear nights in a row last week. That never happens so I had to take advantage. In the early part of the evening I worked on Ha for M33 which I hope to do soon a part of each night was on the Rosette.

Processing on the individual filter masters was:

mure denoise


The masters were combined with pixel math in these proportions:

r: 0.8*ha + 0.2*s2

g: 0.2*ha + 0.4*s2 + 0.2*o3

b: o3

I wanted to do something different than the conventional Hubble palette and I liked how this produced warm tones and made the nebula feel energetic (at least to me).

Remaining processing:

background neutralization

histogram transformation

local histogram equalization (80, 1.1, 0.33)

local histogram equalization (180, 1.5. 0.5)

curves transformation (contrast & saturation)

dark structure enhance


I was pretty happy with this for a first attempt. The 3nm filters block a lot of light so exposures are up to 5 minutes (from 1 in broadband) and the contrast of the individual subs is great!

For a video on the processing see: https://youtu.be/qwMUiVE1oAE