Wednesday, August 31, 2022

27 august 2022, Oak Park

Observed for the night at a site others have started to call Oak Flat, in the central coast range, where I observed at the end of June.  This time there were about a dozen observers and even two families with small children.  Saw Mark W. and Richard N. after a 5-year gap.  I used my bent refractor again, and chased Sharpless objects the whole night.  The others around me raved about the sky, but my SQML never got above 21.4 and the transparency was definitely off--which matched what I saw in the GOES upper level water vapor satellite before driving down.  I tried to convey this to others but they didn't believe me.  I think they were just excited to be out observing.  

Observing-wise, I finally have the correct encoder settings for the APM MaxLoad (8192 in Alt & Az), so I was able to use the Nexus to find objects.  With the time saved not having to star hop or refer to charts, I observed many more objects than I expected.  I still have a problem achieving more image scale, so anything <5 arcminutes was very challenging.  I also find myself observing mostly with the 4-inch, except when the nebula is bright enough to give some detail, or too faint for the smaller aperature, so I switch to the 8-inch.

Sh2-14: 17 30 18.3 -30 15 46, 2', I observed a very small, faint smudge, with Ha only, best with 8-inch.  However this object is missing from Vogel's catalog, and I find looking elsewhere it is assessed there is no object at these coordinates, and Sh2-14 is supposed to be a duplicate of Sh2-23.  Aladin SHASSA shows some cloudiness in this area, however I defer to SIMBAD that this object isn't there.

Sh2-29/31/32: 18 10 30.5 -23 59 55.  Three bright knots in a large bright curtain of nebulosity, streaked with thin dark lanes and with cloudy streamers trailing from it and connecting to the Lagoon and Trifid nebula.  Sh2-29 is largest and has a bright curving body like a fish.  The other two are smaller puffy clouds with numerous stars intermingled.  4-inch for perspective and 8-inch for detail, Ha.  Vogel: "Sh 2-29, Sh 2-31, and Sh 2-32 all appear to be part of the same nebula complex although the associated CO elocities suggest that these objects may have quite different distances."  

Sh2-30: 18 03 34.1 -23 00 55, 20': Trifid nebula, quite bright, prominent dark lanes, with a fission of reflection nebula spouting from the north end (making it look like a pineapple) and surrounding it on the east and west sides.  Vogel: "The Trifid nebula, M20, is an HII region ionised by the O7.5 star HD 164492A and is divided into three parts by dust lanes. A blue reflection nebula surrounds the HII region and also appears just to the north. It is only 300 thousand years old."

Sh2-35: 18 15 50.3 -20 15 07, 20': Already observed but I didn't have it checked off my list.  It is the wide, large, curving nebulosity near the round Sh3-27, heavily mottled.  Best in the 4-inch, Ha.  Vogel: "Sh 2-35 is part of a 130 thousand solar mass giant molecular cloud."

Sh2-47: 18 17 44.4 -15 36 50, 5': Small, round, patchy nebulosity involved with many faint stars, but dominated by an arc of three similar magnitude stars along its western edge.  Best in 8-inch.  Vogel: "The ionising star for this small nebula is probably the B0.5 III giant star S-47/3, which is at a distance of about 3100 pc."

Sh2-48: 18 22 24.1 -14 35 09, 10': Medium sized, irrgegularly round nebulosity involved with a multitude of faint stars (seen with 642 longpass filter).  Amazingly rich field.  Vogel: "This region may be associated with the Scutum supershell."

Sh2-49: Eagle Nebula.  Very large and bright, a lot of detail.  No doubt saw "pillars of creation" and the Burnham's lady, but wished I had more image scale as the detail of the dark nebula was very small.  

Sh2-50: 18 25 30.2 -14 42 42, 35': Large, fairly faint, fan shape with narrow end pointed south and scattered nebula to the north, with many involved stars, best in 4-inch.  Vogel: "This may be associated with the Scutum supershell."

Sh2-51: 18 40 46.3 -16 33 30, 35': Barely detected, very faint nebula, large, diffuse and patchy, long and stretched NE-SW, with a thicker band in the SW.  4-inch only, Ha.  In a very rich field.  

Sh2-52: 19 47 46.3 -23 05 15, 2': Abell 65.  Not detected.  Need more image scale.

Sh2-53: 18 25 14.4 -13 13 44, 15': Very faint, diffuse, with many stars involved.  Wing shapes to the west and east, and a prominent (bright) small round structure in between them, which seems to be a bow shock structure.  Best in 8-inch Ha.  Vogel: "This nebula is mentioned in connection to gamma ray source 2EG J1825-1307, which is assigned a distance estimate of 4300 parsecs. SIMBAD identifies this gamma ray source with the pulsar PWN G18.0-0.7 and the supernova remnant SNR 018.0-00.7."

Sh2-54 & Simeis 3-132: 18 17 52.6 -11 43 48, 140': Nest & Egg.  The Simeis object is very bright, dense, mottled and round.  Sh2-54 is large and bright, cupping the Egg from the south with clotted and obvious concentric bands of clouds.  The whole view is filled with nebula.  4-inch for perspective, 8-inch for detail.  Vogel: "This HII region is associated with the Serpens OB2 association and the NGC 6604 star cluster and is the core of the W35 star formation region. It lies, unusually, about 70 parsecs above the galactic plane. Serpens OB2 contains over 100 OB stars with a common age of about 5 million years."

Sh2-55: 18 32 10.5 -11 45 44, 5': Very small, fairly faint mottled small nebula stretching E-W, a little south of a double star.  Vogel: "This HII region, also called LBN 73, may be part of the Scutum supershell. The dark nebula immediately below Sh2-55 is LDN 412. Sh 2-55 is near a large nebular region in hydrogen-alpha that appears to mark the main boundary of the Scutum Supershell.

Sh2-56: 18 31 06.1 -09 42 52, 7': Extremely difficult, small dim streak of featureless nebulosity near trapezium asterism to the NE.  8-inch only, Ha.  Vogel: "This HII region is the luminous water maser GAL 021.88+00.02."  The Wikipedia page on masers must have been written by a fantasy writer, I hardly understand a word.

Sh2-57 / -58: 18 30 32.8 -08 36 58, 2': Large diffuse nebulous region around a triangle of similar magnitude stars, with dark nebula weaving within the field.  Sh2-57 is a very small nebula around the southern triangle star, and -58 is the brightest patch to the NE near one of these stars.  Vogel: "Sh 2-57 and Sh 2-58 are visible together in the sky (as shown by this hydrogen-alpha image), divided by the dark nebula LDN 446 and just east of the Scutum Supershell. However, they seem to be located at quite different distances, with Sh 2-58 at about the same distance as the Supershell and Sh 2-57 in front of this region."

Sh2-59: 18 37 00.6 -07 36 01, 20': Extremely faint, rather large round nebula with diffuse edges, with a wedge of dark nebula intruding from the north.  

Sh2-60: 18 36 40.5 -06 42 04, 20': Very faint, rather large nebula with a very irregular, jagged shape, near a bright star (which is the corner of a triangle of stars, one corner of which is double).  

Sh2-61: Exteremely small but fairly bright knot of nebulosity, comma shaped with a tail to the south, and the northern ball surrounding a star.  Vogel: "This object is sometimes mistaken for a planetary nebula but in fact is a compact HII region ionised by at least 3 B1 stars and embedded in a 23 thousand solar mass molecular cloud. There is a second distance estimate of 1700 parsecs."  8-inch only, Ha.

Sh2-62: 18 27 34.2 -03 51 22, 4': Very difficult, very small faint nebula near two bright stars.  8-inch only.  

Sh2-63: 19 57 42.5 -14 06 57, 55': Extremely faint, very large drape of nebulosity, vaguely triangle shaped.  4-inch only.  Vogel: "This is the high latitude molecular cloud MBM 159, which is located at a distance of about 220 pc and may form part of the Aquila rift."

Sh2-65: 18 46 58.0 -03 44 35, 7': Very faint small streak of nebulosity running NE-SW, with a bubble at the NE end, it seems to run through a line of stars.  

Sh2-66:  18 45 30.0 -01 59 47, 8': Extremely faint, slightly boxy, rather small, it lies within a triangle of stars.  

Sh2-67: 18 49 24.4 -02 21 13, 10': Extremely faint, rather small featureless patch within a group of bright stars. 

Sh2-68: 18 25 10.8 +00 51 17, 8': Small faint smudge, within a triangle of stars.  8-inch & dual band filter.  This is actually a planetary nebula, Vogel: "The expansion of this planetary nebula has been halted by the surrounding local gas but the central star has continued to move so as a result the star is no longer at the centre of the nebula."

Sh2-69: 18 44 26.1 -00 16, 55": Pretty large, faint, round but with a brighter half to the north.  There is a multitude of faint stars seen within it (when using the longpass filter), very suggestive of an open cluster, and a prominent dark nebula streak / cut off to the nebula's NE.

Sh2-70: 18 14 38.5 +07 03 47, 5': Extrememly faint, small oval patch, E-W, between two stars.  Vogel: "Although usually classified as an HII region, this peculiar high latitude nebula, also called LBN 102, looks more like a dust cloud in this image, and indeed this object is in the same direction as the small molecular cloud [CB88] 124."

Sh2-71: 19 02 02.3 +02 09 35, 3':  Very small but bright, elongated N-S, with irregular edges and looks like the eye of a needle with dark space in the middle.  Appears centered on a star.  The detail photo shows fasinating detail, which I did not see in the scope due to a lack of image scale.  Vogel: "This is an unusual planetary nebula that appears to have a binary central star."  More on the suspected ionizing star and its possible binary companion here. Unfortunately even the Gaia DR3 data has too much of an error for the 19th magnitude star ("B" in the article) to pin down its exact parallax.

Sh2-72: 19 03 50.2 +02 18 50, 25': Large, round with a dark cut off to the east (between it and Sh2-71, which is in the same field), dark lane intrusions into the nebula, and and streams of fainter nebulosity flowing from it to the east.  Globular cluster NGC 6749 in the same field and is brilliant and compact.

Sh2-73: 16 11 06.9 +21 52 26, 75': Large, layered clouds of nebulosity flowing NW-SE, flows out of the FOV.  Best in 4-inch.  Vogel: "This local molecular cloud is also known as LBN 105, MBM 40 and IREC 53. MBM 40 is located at a distance of 120 parsecs and contains 20 to 40 solar masses of gas. There are no signs of star formation. Like several other local molecular clouds, MBM 40 has a pronounced hairpin shape."

Sh2-74: 19 08 48.5 +05 36 32, 3' Patchy faint nebula, butterfly shaped with a dark lane in the middle, and a dark cut-off along its western edge (which with the 642nm longpass filter shows clearly as a dark nebula). (The 3' size reference in the Sharpless catalog probably refers to the brightest cloud in the center of the image.)  Vogel: "This nebula is either the location of the powerful radio source W50, or sits in front of it, depending upon the authority. The microquasar SS 433 is part of W50. This bizarre object, also called V1343 Aquilae, is spewing out two jets of material at more than one-quarter the speed of light."

Sh2-75: 18 59 14.7 +07 07 12, 10': Extremely faint, small, bean shaped nebula with ragged edges.  8-inch Ha.  Vogel: "There is very little to report about this faint, obscured nebula except that ammonia was detected in this direction in a 1996 study."

Sh2-76: 18 56 24.9 +07 48 48, 7': Very faint, small smudge, an unremarkable puff.  Vogel: "Distance: 1734 pc, Size: 1.8 pc...This is in the same approximate direction as W45."

Sh2-77: Difficult, very faint, seen only when changing filters and noticing change in contrast in the sky, confirmed as the nebula moves with the scope.  8-inch only and best in dual band filter.  

Sh2-78: 19 03 10.6 +14 07 46, 12': Extremely difficult, medium size squarish glow noticed after matching the star pattern in the photo with the field.  8-inch only Ha.  Vogel: "This is the old planetary nebula CTSS 3 and actually lies at a distance of 700 parsecs."

Sh2-79: 19 23 18.2 +13 58 34, 40': Large, extremely faint, very patchy and seems broken into two large sections, seen when changing filters and noticing the change in background brightness, 4-inch dual band.  Very rich field.  Vogel: "The very faint nebula in the image is associated with the supernova remnant G 49.2-0.7 (also called W51C) and is believed to be at a distance of 6 kpc."

Sh2-80: 19 11 28.5 +16 51 57, 2': 8-inch unfiltered, appears as a very small fried egg, pretty bright, round, ragged edges.  Very small scale and I wish I used more magnification.  = M1-67, WR shell.  Vogel: "This is a ring nebula surrounding the Wolf Rayet star WR 124, also known as Merrill's star."

Sh2-81: 20 01 12.7 +11 47 33, 10': In the 4-inch, seen with filter change, the sky is mottled and this nebula is a small, brighter diffuse roundness than the rest of the sky background, around one of the many bright stars in the field.  Pretty difficult.  Vogel: "Distance: 2000 pc, Size: 5.8 pc.  Essentially nothing appears in the scientific literature on this nebula, which is located far below the galactic plane. The most interesting object in this direction is the low mass X-Ray binary V1408 Aquilae, which may include a black hole. V1408 Aquilae appears to the right (west) of this nebula, but appears to be located at a distance of about 7000 parsecs - far beyond the nebula."

Sh2-82: 19 30 20.4 +18 16 31, 9': Fairly small, pretty faint, with a uniform round glow around a star making it looks like a planetary nebula, and with a much fainter curved hook coming off the northern edge.  Seen with the 4-inch but better with the 8-, Ha only.  Vogel: "This combination HII region and reflection nebula, also called LBN 129 and DG 159, is ionised by the B0.5V star HD 231616. With the current distance estimate, it appears to be near the Vulpecula OB4 association."

Sh2-83: 19 24 32.1 +20 47 45, 2': Very small, round, seen as a glow appearing when changing filters and not were a star was before adding the filter.

Sh2-84: 19 49 04.0 +18 24 01, 15': Small, very faint curved glow between two stars as identified in the photo, 8-inch only, Ha.  Globular cluster M71 nearby, bright and compact.  Vogel: "Distance: 5000 pc, Size: 21.8 pc.  This nebula, also called LBN 131, is near in the sky to the Wolf-Rayet star WR 128, and Sharpless associated the two objects in his catalog. However, there is some controversy about whether Sh 2-84 is part of the ring nebula surrounding this star or lies at another distance."

Sh2-85: 19 03 16.6 +25 49 49, 6': Very small, extremely faint, very difficult and barely detected haze around a 7th magnitude star.  8-inch & Ha.  Vogel: "This very faint nebula is ionised by the B3 V star HD 177347." [edit 4/14/2024: It seems this nebula does not exist -- it is a fault in the POSS plate.  And I probably was fooled by the typical bloated glow which appears with bright stars when using night vision.]

Sh2-86: 19 43 08.8 +23 17 15, 40': Proabably the view of the night.  Large, pretty bright, very heavily mottled, brighter to the NE with an obvious long tendril of dark nebula intruding from the east, very like the Elephant Trunk.  The nebula fades slowly to the SW and there are many stars involved.  Vogel: "Distance: 1900 pc, Size: 22.1 pc.  NGC 6820 is the radio source W55 and is associated with the star cluster NGC 6823 and Vul OB1."  4-inch for perspective, 8-inch for detail, Ha.  

Sh2-87: 19 46 24.4 +24 37 41, 10': Fairly bright, triangle shaped, mottled nebulosity with a small cluster of stars on the southern end.  Vogel: "Distance: 2144 pc, Size: 2.4 pc.  This is a massive star formation region associated with a 7000 solar mass molecular cloud and many sources in the far infrared." 

Sh2-89 & -90: -19 50 02.2 +26 29 10, 5';  19 49 12.7 +26 52 04, 6': 89 is a very weak, small sheet of nebulosity, surrounded by a much wider and even fainter round shell (which is not part of the designation proper), that connects it on the northern end with the bright, irregularly C-shaped nebula -90, curled like a shrimp and very lumpy in appearance. -89 in the 4-inch and -90 best in the 8-inch.  Vogel: "Distance: 2400 pc, Size: 2.1 pc.  Sh 2-90 is a blister on a 60 thousand solar mass molecular cloud and appears to be affected by gas streaming from the Vulpecula OB1 association. It contains a cometary elephant trunk structure on its eastern edge which appears to have originated from a past disturbance from the southwest. Sh 2-86, Sh 2-87, Sh 2-88 and Sh 2-89 are part of the HI supershell GS061+00+51. Sh 2-89 and Sh 2-90 lie at the north-east boundary of the dark nebula Lynds 798."



No comments:

Post a Comment