Hemisphere:  Northern  ·  Constellation: Monoceros (Mon)  ·  Contains:  Hubble's Nebula  ·  NGC 2261
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Hubble's Variable nebula, NGC 2261, Caldwell 46, 



    
        

            Steven Bellavia
Hubble's Variable nebula, NGC 2261, Caldwell 46
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Hubble's Variable nebula, NGC 2261, Caldwell 46

Technical card

Imaging telescopes or lenses: TS-Optics PHOTOLINE 115 mm F7 triplet apo

Imaging cameras: ZWO ASI533MC Pro

Mounts: Sky-Watcher EQ-6R Pro SynScan

Guiding telescopes or lenses: The Bellavia Basic 50mm f/6 guidescope

Guiding cameras: ZWO ASI 290MC

Software: Pleiades Astrophoto PixInsight  ·  IDEIKI AstroPhotography Tool (APT)  ·  Topaz Denoise AI  ·  Stark Labs Nebulosity 4.2  ·  Digital Photo Professional  ·  Annie's Astro Actions V7  ·  Noel Carboni's Astro Tools for PhotoShop Noel Carboni Actions  ·  PHD2 Guiding

Filters: Astronomik L2 UV/IR Cut

Accessory: TS-Optics TS FLAT 2,5"


Dates:Jan. 14, 2021

Frames:Astronomik L2 UV/IR Cut: 37x120" (gain: 100.00) -5C bin 1x1

Integration: 1.2 hours

Darks: ~30

Flats: ~30

Flat darks: ~45

Avg. Moon age: 1.37 days

Avg. Moon phase: 2.10%

Bortle Dark-Sky Scale: 4.00

Mean SQM: 20.00

Mean FWHM: 3.00

Temperature: -3.00


Basic astrometry details

Astrometry.net job: 4156726

RA center: 6h 39' 9"

DEC center: +8° 44' 45"

Pixel scale: 0.808 arcsec/pixel

Orientation: 5.371 degrees

Field radius: 0.305 degrees


Resolution: 1920x1920

Data source: Backyard

Description

NGC 2261, Caldwell 46, is called Hubble's Variable Nebula, Discovered by Sir William Herschel in 1783 . It is a fascinating reflection nebula 2,500 light years away, in the constellation Monoceros and associated with the variable star R Monocerotis. The nebula varies in brightness by as much as two magnitudes with no predictable timetable – perhaps due to dark masses shadowing the star. One explanation proposed for the variability is that dense clouds of dust near R Mon periodically block the illumination from the star.

This object was First Light for Palomar Observatory's 200-inch Hale Telescope, and was imaged by Edwin Hubble on January 26, 1949, some 20 years after the Palomar Observatory project began in 1928

It is visible in small telescopes, even from suburban areas. However, a larger telescope in a dark sky will reveal many details.

Comments

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  • Hubble's Variable nebula, NGC 2261, Caldwell 46, 



    
        

            Steven Bellavia
    Original
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    Hubble's Variable nebula, NGC 2261, Caldwell 46, 



    
        

            Steven Bellavia
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Hubble's Variable nebula, NGC 2261, Caldwell 46, 



    
        

            Steven Bellavia