Discoveries 251 - 275
Suspected deep sky objects that are, to the best of my knowledge, unknown and undesignated. Most of these were stumbled upon on DSS images while compiling CSOG observing guides. A few asterisms, possibly open clusters were seen during observing runs.
Before posting, I check multiple images (DSS, SDSS, DECaLS) to rule out artefacts. Once an object is determined to be real I check SIMBAD, NED, HyperLeda (for suspected galaxies), possible planetary nebulae, historical catalogs (for nebulae) and every available catalog in AstroPlanner.
The majority of these objects were reported on the Deep Sky Hunters group.
Whenever it is brought to my attention that an object that I suspected to be unknown / uncataloged / undesignated was indeed recognized before, I will remove it from my list and update the numbering accordingly.
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251 - 252 - 253 - 254 - 255 - 256 - 257 - 258 - 259 - 260 - 261 - 262 - 263 - 264 - 265 - 266 - 267 - 268 - 269 - 270 - 271 - 272 - 273 - 274 - 275
1-25 - 26-50 - 51-75 - 76-100 - 101-125 - 126-150 - 151-175 - 176-200 - 201-225 - 226-250 - 276-300 - 301 and further
251
R.A. / Dec. - Constellation
23:03:51.6 +56°45'54.0" - Cassiopeia
Suspected nature of object
Reflection nebula
Description
A southwest-northeast elongated nebula northwest of the mag. 7.4 F0 star SAO35109. South-southeast of the emission nebula Courtès 100.
Date, plate or visually
19 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
252
R.A. / Dec. - Constellation
23:33:35.7 +60°28'07.0" - Cassiopeia
Suspected nature of object
Reflection nebula
Description
A small, southwest-northeast elongated nebula northeast of the mag. K0 star SAO20701 that is component A of the double star STFA60 (WDS23336+6028). 14" East-southeast of nr. 255.
On the POSS2 Blue plate, there is an east-west elongated artefact to the southwest of the star.
Date, plate or visually
20 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
253
R.A. / Dec. - Constellation
23:28:45.0 +60°39'10.0" - Cassiopeia
Suspected nature of object
Nebula
Description
A small nebula involving the stars 4UCAC754-080243 (mag. 14.6) and 4UCAC754-080244 (mag. 13.2). 23' West-northwest of nr. 255.
Date, plate or visually
20 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
10' PanSTARRS
254
R.A. / Dec. - Constellation
23:31:48.4 +60°33'05.0" - Cassiopeia
Suspected nature of object
Planetary nebula?
Description
A small, round nebula, approximately 50" in diameter. Not visible in IR. 14" West-northwest of nr. 253 and 23' east-southeast of nr. 254.
Date, plate or visually
20 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
10' PanSTARRS
255
R.A. / Dec. - Constellation
23:39:18 +60°13'50" - Cassiopeia
Suspected nature of object
Emission nebula
Description
An east-west elongated nebula north of the mag. 10.6 star TYC4280-01400-1.
16' North-northeast of the emission nebula Simeis 273.
Date, plate or visually
20 October 2023, plate
10' DSS POSS2 Red
10' DSS POSS1 Red
10' PanSTARRS
256
R.A. / Dec. - Constellation
23:36:26.5 +49°46'20.0" - Andromeda
Suspected nature of object
Reflection nebulae
Description
Two southwest-northeast elongated nebulous streaks: one to the northwest of the position, one to the southeast. Both are approximately 8' in length.
Date, plate or visually
20 October 2023, plate
20' DSS POSS2 Blue
20' DSS POSS1 Blue
257
R.A. / Dec. - Constellation
00:19:00.5 +60°20'07.0" - Cassiopeia
Suspected nature of object
Reflection nebulae
Description
Irregular nebulosity surrounding the mag. 8.0 F0 star SAO11104.
Date, plate or visually
20 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
258
R.A. / Dec. - Constellation
23:54:02.0 +60°31'03.8" - Cassiopeia
Suspected nature of object
Planetary nebula?
Description
A small, round nebula surrounding the mag. 16.1 star 4UCAC753-086599. A distinct annular shape is visible on the PanSTARRS image.
2.5' South of the reflection nebula GN 23.51.5.01, 7' east-northeast of the emission nebula Minkowski 2-74 and 8' north of Sharpless 1-116.
Date, plate or visually
20 October 2023, plate
5' DSS POSS2 Blue
5' DSS POSS1 Blue
5' PanSTARRS
259
R.A. / Dec. - Constellation
23:57:20 +52°47'35" - Cassiopeia
Suspected nature of object
Asterism or open cluster
Description
A small asterism or open cluster, consisting of about 20 stars mag. 12.2 and greater, approximately 4.5' in diameter
Date, plate or visually
20 October 2023, plate
15' DSS POSS2 Blue
15' DSS POSS2 Red
260
R.A. / Dec. - Constellation
23:01:25.8 +61°37'41.2" - Cepheus
Suspected nature of object
Reflection nebula
Description
A small nebula surrounding the mag. 12.3 star TYC4278-00195-1.
Date, plate or visually
26 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
261
R.A. / Dec. - Constellation
03:37:21.3 +54°08'05.9" - Camelopardalis
Suspected nature of object
Nebula
Description
A small, north-south elongated nebula surrounding the mag. 10.5 star TYC3716-00349-1. Fainter nebulosity extends north-northwestwards.
Date, plate or visually
26 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
262
R.A. / Dec. - Constellation
05:45:50.4 +48°57'57.9" - Auriga
Suspected nature of object
Galaxy
Description
A small, extremely elongated galaxy, approximately one arcminute in length. 4' East-northeast of nr. 264.
Date, plate or visually
26 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
263
R.A. / Dec. - Constellation
05:45:29 +48°56'16" - Auriga
Suspected nature of object
Nebula
Description
An extremely faint nebulous spike or arc south-southwest of the mag. 7.5 K0 star SAO40579. 4' West-southwest of nr. 263.
Date, plate or visually
26 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
264
R.A. / Dec. - Constellation
05:32:17.5 +17°01'20.0" - Taurus
Suspected nature of object
Reflection nebula
Description
A faint patch of nebulosity south-southeast of the double star STF730 (WDS05322+1703, A mag. 6.1, B mag. 6.4).
Date, plate or visually
27 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
265
R.A. / Dec. - Constellation
21:13:02.6 +46°22'31.5" - Cygnus
Suspected nature of object
Reflection nebula
Description
A small nebula surrounding the mag. 12.6 star 4UCAC682-098881. 2' West-northwest of GN 21.11.4.
Date, plate or visually
31 October 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
266
R.A. / Dec. - Constellation
06:15:47.2 +19°00'42.8" - Orion
Suspected nature of object
Nebula
Description
A small nebula surrounding a faint star. Clearest on the PanSTARRS image.
Date, plate or visually
13 November 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
10' PanSTARRS
267
R.A. / Dec. - Constellation
03:55:12 +49°04'30" - Perseus
Suspected nature of object
Reflection nebula
Description
A relatively large and bright nebula involving the mag. star 7.0 B3 star SAO39191 (in the southeastern part). Approximately 12'×9' in size.
Date, plate or visually
15 November 2023, plate
30' DSS POSS2 Blue
30' DSS POSS1 Blue
268
R.A. / Dec. - Constellation
16:03:22.5 -43°15'15.0" - Norma
Suspected nature of object
Galaxy?
Description
A suspected galaxy, (visually) to the east-northeast of the dark cloud Sandqvist 181.
Date, plate or visually
15 November 2023, plate
5' DSS POSS2 Blue
5' DSS POSS2 Red
5' DSS POSS2 IR
5' DECaPS2
269
R.A. / Dec. - Constellation
05:50:54.8 +20°14'47.7" - Orion
Suspected nature of object
Nebula
Description
Nebula surrounding the mag. 13.8 star 4UCAC552-019438.
Date, plate or visually
24 November 2023, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
270
R.A. / Dec. - Constellation
06:11:18.1 +19°35'12.2" - Orion
Suspected nature of object
Nebula
Description
Faint nebulosity surrounding the stars 4UCAC548-023641 (mag. 14.8, southwest) and 4UCAC548-023642 (mag. 13.4, northeast).
Date, plate or visually
24 November 2023, plate
5' DSS POSS2 Blue
5' DSS POSS2 Red
271
R.A. / Dec. - Constellation
05:54:54.4 +14°02'15.0" - Orion
Suspected nature of object
Asterism
Description
A visually notable group of mag. 10.5 and fainter stars, 9'×6' in dimensions, elongated southwest to northeast and wider on the southwestern side. On the north-northeastern edge is the double star Skiff 2501.
Date, plate or visually
9 January 2024, visually
15' DSS POSS2 Blue
272
R.A. / Dec. - Constellation
05:24:25.1 +10°53'49.1" - Orion
Suspected nature of object
Reflection nebula
Description
A faint nebula surrounding the mag. 10.7 star TYC0704-00616-1.
Date, plate or visually
16 January 2024, plate
10' DSS POSS2 Blue
10' DSS POSS1 Blue
273
R.A. / Dec. - Constellation
06:16:38.4 +15°48'04.9" - Orion
Suspected nature of object
Reflection nebula
Description
A small, irregular, north-south elongated nebula to the west of the double star Miret & Tobal 13 (WDS06166+1548, A mag. 8.8). Shape is somewhat reminiscent of a seahorse.
Date, plate or visually
16 January 2024, plate
5' DSS POSS2 Blue
5' DSS POSS1 Blue
5' PanSTARRS
274
R.A. / Dec. - Constellation
18:07:10.8 +45°11'06.3" - Hercules
Suspected nature of object
Galaxy
Description
A small, east-west elongated, spiral galaxy, approximately 0.5'×0.3' in size, 20" south of the mag. 10.5 star TYC3524-02069-1.
Date, plate or visually
19 January 2024, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
10' PanSTARRS
275
R.A. / Dec. - Constellation
18:03:18.3 +56°55'55.2" - Draco
Suspected nature of object
Galaxy
Description
A small, north-south elongated, spiral galaxy, approximately 0.4'×0.2' in size, 25" west-southwest of the mag. 7.4 K5 star SAO30720
Date, plate or visually
20 January 2024, plate
10' DSS POSS2 Blue
10' DSS POSS2 Red
10' PanSTARRS
