Hemisphere:  Northern  ·  Constellation: Monoceros (Mon)  ·  Contains:  12 Mon  ·  NGC 2237  ·  NGC 2238  ·  NGC 2239  ·  NGC 2246  ·  NGC2237  ·  NGC2238  ·  NGC2239  ·  NGC2244  ·  NGC2246  ·  Rosette A  ·  Rosette B  ·  Rosette Nebula  ·  Rosette nebula  ·  Sh2-275  ·  The star 12Mon
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NGC 2237 - Rosette Nebula, 


            Paul Ricker
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NGC 2237 - Rosette Nebula

Getting plate-solving status, please wait...
NGC 2237 - Rosette Nebula, 


            Paul Ricker
Powered byPixInsight

NGC 2237 - Rosette Nebula

Imaging telescopes or lenses: Apertura 60EDR

Imaging cameras: ZWO ASI183MM-Pro

Mounts: iOptron iEQ45 Pro

Guiding cameras: ToupTek ToupCam GCMOS01200KMA  ·  QHYCCD QHY5-III 178M

Software: Photoshop CC  ·  StarTools  ·  Deep Sky Stacker (DSS)

Filters: Asronomik Ha CCD filter 6nm  ·  ZWO new B  ·  ZWO new G  ·  ZWO new R  ·  ZWO new L

Accessory: Apertura Field Flattener  ·  ZWO EFW Mini

Dates:Dec. 31, 2019Nov. 5, 2020

Asronomik Ha CCD filter 6nm: 24x300" (gain: 100.00) -5C bin 1x1
ZWO new B: 22x60" (gain: 0.00) -5C bin 2x2
ZWO new G: 22x60" (gain: 0.00) -5C bin 2x2
ZWO new L: 23x60" (gain: 0.00) -5C bin 2x2
ZWO new R: 23x60" (gain: 0.00) -5C bin 2x2

Integration: 3.5 hours

Darks: ~25

Flats: ~25

Avg. Moon age: 12.09 days

Avg. Moon phase: 52.55%

Bortle Dark-Sky Scale: 2.80

Astrometry.net job: 4017645

RA center: 6h 32' 3"

DEC center: +4° 58' 33"

Pixel scale: 1.349 arcsec/pixel

Orientation: -18.475 degrees

Field radius: 0.867 degrees

Resolution: 3704x2764

Locations: Backyard, Champaign, IL, United States; Everglades National Park, Homestead, FL, United States

Data source: Traveller


The Rosette Nebula, NGC 2237 (and assorted other NGC numbers). An HII region in the Monoceros molecular cloud whose center has been evacuated by the open cluster NGC 2244.

Used about 1 1/2 hours of LRGB data from a trip to the Everglades last year and 2 hours of Halpha from home this month to make an L(HaR)GB image, blended with a version in which I had regularized the bright stars with StarTools, and then used the processed Halpha data to blend 50% luminosity.

I often get strange stars with this scope, especially in cold weather. They will show an "iron cross" 4-point diffraction pattern, and sometimes they are elliptical and tilted. Not a tracking issue, I think, since it occurs even when tracking is good. I've tried backing off the forward collimation screws and stopping down the aperture a few millimeters, and that helps with the cold weather issue, but not the stretching. So for some images with this scope I first make a processed version of the image, then use the Repair function in StarTools to redistribute each star into a Gaussian (?) shape. This makes stars that look a little too perfect, so I blend it with the original processed image. The result looks better than what I am able to achieve with deconvolution. Ultimately it's a hardware issue of some kind, of course -- perhaps focuser tilt?


Sky plot

Sky plot


NGC 2237 - Rosette Nebula, 


            Paul Ricker