Deep Sky Object in Winter
Around M50, Sh2-291 (Open Cluster & Diffused Nebula in Monoceros)
Click on image to enlarge
| Date & Time: | Nov 23 2025, from 24:57 to 26:17 JST(+0900) |
| Composed 11 shots with 8 minutes exposed |
| Optical: | TAKAHASHI 16cm(6.3") epsilon (f=530mm, F3.3) |
| with IDAS LPS-D1 light-pollution suppression filter |
| Auto-guided with TAKAHASHI JP Equatorial+SBIG STV |
| CMOS Camera: | ZWO ASI2600MC Pro (Cooled temp.: -20°C) |
| Location: | Ooizumi, Hokuto city, Yamanashi pref. |
| Camera Settings: | Recording format...16bit FITS, converted to 16bit TIFF(6248×4176) |
| Device Size...23.5×15.7mm, Gain...100 |
Objects around M50, Sh2-291 |
The object visible at the left edge of the image is M50, an open cluster located in the southern part of Monoceros.
This image captures several inconspicuous nebulae scattered to its west. First, the faint Hα nebula in the upper right of the frame is Sh2-291, which has an almost circular shape with a span of just under 10 arcminutes.
It is the most distant of the nebulae shown here, with an estimated distance of about 27,000 light-years.
The small nebula toward the top of the image is NGC 2316. Although it appears as a white reflection nebula in the image, it is classified as a composite structure containing red Hα emission.
Next, the nebula slightly to the right of center in the frame is LBN 1022. It spans about 20 arcminutes and is a mixture of reflection nebula and red Hα-emitting nebula.
In the foreground, a dark nebula with a complex structure appears to obscure part of the red nebula behind it.
In the Lynds Bright Nebula (LBN) catalog, the listed position is actually offset 18 arcminutes west of the true location, but this nebula is recognized as LBN 1022.
Finally, the circular reflection nebula located 40 arcminutes southwest of M50 is LBN 1023.
Although it is known only by its LBN designation, it appears to be the brightest nebula among those shown here.
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| M50 (NGC2323) / Open Cluster, type e, II 3 r |
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| R.A. | 07h 03m 12.0s (2000.0) |
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| Dec. | -08° 20' 00" (2000.0) |
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| Apparent Size | 16' |
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| Real Size | 12 light yrs. |
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| # of Stars | 80 |
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| Magnitude | 6.9 |
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| Distance | 2600 light yrs. |
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|
| Sh2-291 / Diffused Nebula, type 5 E |
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| R.A. | 06h 55m 21.9s (2000.0) |
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| Dec. | -08°00' 25" (2000.0) |
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| Apparent Size | 9.4' |
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| Real Size | 75 light yrs. |
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| Magnitude | - |
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| Distance | 27.7 thousand light yrs. |
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| Other IDs | LBN 1020 |
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|
| NGC2316 / Reflection Nebula, type 3 E+R |
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| R.A. | 06h 59m 41.2s (2000.0) |
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| Dec. | -07°46' 28" (2000.0) |
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| Apparent Size | 1.5' |
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| Real Size | 1.3 light yrs. |
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| Magnitude | - |
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| Distance | 3000 light yrs. |
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| Other IDs | LBN 1021 |
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|
| LBN 1022 / Diffused Nebula, type 3 E+R |
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| R.A. | 06h 56m 00.0s (2000.0) |
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| Dec. | -08°18' 00" (2000.0) |
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| Apparent Size | 22.0×15.0' |
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| Real Size | 19×13 light yrs. |
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| Magnitude | - |
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| Distance | 3000 light yrs. |
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|
| LBN1023 / Reflection Nebula, type 2 E+R |
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| R.A. | 07h 00m 30.0s (2000.0) |
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| Dec. | -08°52' 00" (2000.0) |
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| Apparent Size | 3.0' |
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| Real Size | N/A |
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| Magnitude | - |
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| Distance | N/A |
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