Monthly Archives: July

OR: D.A.R.C. Observatory, 7/25

I went to the D.A.R.C. observatory last Saturday to observe or re-observe a few Herschel 400 summer objects, as well as enjoy some eye candy under a dark sky. I was setup right next to Dennis Beckley and his classic Obsession 18″. Here is a summary of the weather conditions:

  • Wind died down shortly after sunset
  • Temperature in the low 70s
  • Good seeing (6 to 7 on the Pickering scale)
  • Average transparency (the light dome from Los Banos, which I use as an indication of the moisture content in the atmosphere, was fairly conspicuous)
  • NELM 6.7 in Lyra
  • Thin clouds started showing up around 1am from the east

Overall, it was a pretty good night, although not as good as what the D.A.R.C. observatory has proven capable of. Among the highlights of the night, I got to observe Triton for the first time. The Jupiter impact mark was seen very easily, and Jupiter’s satellites were resolved as tiny discs of different diameters. The “ink spot” (Barnard 86 located right next to OC NGC 6520) looked absolutely remarkable. Stephan’s quintet was looking pretty good in my scope, and was easy in Dennis’ 18″ scope. Finally, I really enjoyed looking at V Aql, a fairly bright carbon star of deep orange color with a tinge of red. What is interesting about this star, beyond its striking color, is the presence of planetary nebula NGC 6751 about 30′ SE. It is therefore possible to fit both objects within the same field of view in modest amateur telescopes (8 to 12″), portraying two stages of stellar evolution as the carbon star will eventually become a planetary nebula in a not so distant future.

On Sunday morning, I had an immense satisfaction when I looked at a DSS image of galaxy NGC 6217 (Arp 185), and noticed that my notes (see below) were absolutely right on! I find it absolutely amazing that such wispy details can be detected with such a small aperture under a good dark sky.

I cannot end this report without thanking Dr. Lee Hoglan for letting us observe on his property. Below is my log for the night. Cheers!

Location: D.A.R.C. Observatory [Elevation 1400ft]
Telescope: Meade Lightbridge 12″ F/5
Eyepieces used:
- Televue Panoptic 27mm (56x - 1.2° TFOV)
- Televue Nagler 16mm type 5 (95x - 52′ TFOV)
- Televue Nagler 9mm type 6 (169x - 29′ TFOV)
- Televue Nagler 7mm type 6 (217x - 22′ TFOV)
- Televue Nagler 5mm type 6 (305x - 16′ TFOV)
(All times in PDT)

NGC 6217

NGC 6217 GX UMi 16h32m15.6s +78°10’52″ 11.9 mag 10:15p
Small, faint, elongated 3:2 NW-SE, fairly faint stellar core or super imposed star. Very faint super imposed star about 20″ SE, another one about 2.5′ NW. Hints of two spiral arms, one on the N side going E, and another one on the S side going W. This observation was later beautifully confirmed with a DSS image.

NGC 6834

NGC 6834 OC Cyg 19h52m37.2s +29°26’04″ 9.7 mag 10:30p
Seen as a tiny smudge in a 9×50 finder scope. Small grouping of about 30 moderately bright stars. One brighter star in the middle, with a possible slight yellow tinge. Located in a region with relatively few stars (dark nebula?) in an otherwise crowded milky way star field. For some reason, I found it hard to star-hop to…

NGC 6866

NGC 6866 OC Cyg 20h04m16.1s +44°11’11″ 9.1 mag 10:40p
About 30 fairly bright stars within a region 15′ in diameter. Detected in 9×50 finder scope.

NGC 6910

NGC 6910 OC Cyg 20h23m34.7s +40°48’37″ 7.3 mag 10:45p
Small group of about 15 stars, elongated 2×1 WNW-ESE (dimensions: 10′ x 5′) The two brightest stars have a yellow tinge. Located about 30′ N of Gamma Cyg (Sadr)

NGC 7044

NGC 7044 OC Cyg 21h13m32.8s +42°32’06″ 12.0 mag 10:50p
Small compact group of maybe 50 faint stars (hard to get a reliable star count) scattered within a circular region of about 5′ in diameter.

NGC 6522

NGC 6522 GC Sgr 18h04m14.3s -30°02’08″ 9.9 mag 11:00p
Fairly small, moderately faint, fairly well defined core, halo appears grainy. There is a moderately bright star located about 30″ E which probably does not belong to this cluster. Forms a beautiful couple with globular cluster NGC 6528 located about 15′ E.

NGC 6528

NGC 6528 GC Sgr 18h05m28.3s -30°03’25″ 9.6 mag 11:00p
Fairly small, moderately faint, fairly well defined core, unresolved. Located at the NW edge of B298. Forms a beautiful couple with globular cluster NGC 6522 located about 15′ W. This cluster is slightly dimmer than its neighbor NGC 6522 (some of its light may be absorbed by B298?)

NGC 6818

NGC 6818 PN Sgr 19h44m32.6s -14°07’45″ 10.0 mag 11:25p
Tiny fairly bright disk, almost circular (extremely slightly elongated NS) showing a delicate bluish tinge, especially at low power. At higher magnification, the center of the nebula appears very slightly darker. The central star (mag 15.0) was not seen. Located inside a small triangle of moderately bright stars.

NGC 6664

NGC 6664 OC Sct 18h37m10.4s -07°48’17″ 8.5 mag 11:45p
About 60 moderately faint stars within 15′. This cluster appears slightly elongated N-S, and is located about 25′ NE of Alpha Sct, which has a fairly distinctive yellow tinge.

NGC 6217

NGC 6712 GC Sct 18h53m37.6s -08°41’33″ 8.1 mag 11:50p
Moderately large and bright with a poorly defined core region. Many stars are resolved over a milky background.

NGC 6802

NGC 6802 OC Vul 19h31m02.2s +20°16’59″ 11.7 mag 12:50a
Small (5′ x 2′) compact group of about 25 very faint stars, elongated N-S. Located just east of the famous coat hanger asterism (Cr 399)

NGC 6823

NGC 6823 OC Vul 19h43m35.6s +23°19’27″ 7.1 mag 12:55a
About 30 fairly bright stars scattered within 6′ around a small group of 4 bright stars and a few fainter ones. Not very conspicuous in a crowded star field. Nearby nebula NGC 6820 was not seen (although I did not really look for it and thus was not using a nebula filter)

NGC 6830

NGC 6830 OC Vul 19h51m25.8s +23°07’33″ 8.9 mag 01:00a
Very inconspicuous grouping of about 20 fairly bright stars.

NGC 6934

NGC 6934 GC Del 20h34m41.3s +07°26’22″ 8.9 mag 02:00a
Relatively small, fairly bright, intense core. A great number of stars are resolved throughout at 217x.

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OR: Henry Coe State Park, 7/20

Jim Harper, Stephen Migol and I met up around sunset at the overflow parking lot at Henry Coe state park. I had a pretty bad experience last time I went to Coe, back in January. However, this time around, the transparency was above average and we got some very decent skies. I did a zenithal NELM test in Lyra, and reached mag 6.2, which is not too bad given the amount of light pollution… The seeing was very soft early on, but slightly improved as the night went on. Temps were in the 60s. There was a fairly strong breeze all night long, which was a bit of a problem for my very lightweight dobsonian telescope. However, by using my car as a shield, I was able to somewhat mitigate the impact of wind gusts.

Henry Coe is the perfect location to get a lot of boring open clusters out of the way, or to do some narrow-banding. I worked in Sagittarius all night, and got some pretty decent views in spite of the light pollution emanating from Gilroy. I took off right around 1am, and was soundly asleep by 2… I’m not used to that anymore! Overall, a fairly decent night. See my log below. Cheers!

Location: Henry Coe state park [Elevation 2600 ft]
Telescope: Meade Lightbridge 12″ F/5
Eyepieces used:
- Televue Panoptic 27mm (56x - 1.2° TFOV)
- Televue Nagler 16mm type 5 (95x - 52′ TFOV)
- Televue Nagler 9mm type 6 (169x - 29′ TFOV)
- Televue Nagler 7mm type 6 (217x - 22′ TFOV)
- Televue Nagler 5mm type 6 (305x - 16′ TFOV)
(All times are PDT)

NGC 6569 GC Sgr 18h14m17.9s -31°49’29″ 8.4 mag 09:55p
Moderately small and faint, relatively uniform. The halo takes on a grainy appearance at 219x. Located about 45′ E of smaller and fainter globular cluster NGC 6558, giving a nice comparison.

NGC 6624 GC Sgr 18h24m19.5s -30°21’14″ 7.6 mag 10:00p
Moderately small and fairly bright. Small intense core. Halo resolves in a great number of faint stars during brief moments of better seeing.

NGC 6520 OC Sgr 18h04m02.7s -27°53’20″ 7.6 mag 10:25p
The central region of this open cluster is made up of about 20 fairly bright stars, seemingly arranged in a circle of about 1.5′ in diameter around a pretty bright star with a distinctive orange tinge. A few bright stars are scattered around this area within 8′. Best seen at low power. Amazing contrast with Barnard 86 (a.k.a. the “ink spot”) located just to the west. I’m wondering whether B86 is located in front of or behind NGC 6520.

NGC 6540 OC Sgr 18h06m59.6s -27°47’38″ 14.6 mag 10:30p
Barely noticeable as a faint and tiny (1′) very unimpressive smudge elongated 2×1 E-W. About half a dozen stars are resolved at 219x. PSA says it’s a globular cluster, but it does not look like one and ST mentions it as an open cluster…

NGC 6553 GC Sgr 18h09m55.1s -25°54’26″ 8.3 mag 10:40p
Moderately large, relatively low surface brightness, surprisingly uniform with no obvious core! Appears very slightly elongated NW-SE? Fairly bright (mag 11.8) superimposed star on the NW side. Generally unresolved, very slight grainy appearance maybe? A few stars pop in and out of view during brief moments of better seeing (not sure whether these are actually part of the globular cluster)

NGC 6544 GC Sgr 18h07m57.8s -24°59’52″ 7.5 mag 10:45p
Small (about 1′), moderately bright with a tiny fairly bright core. About a dozen brighter stars are resolved at higher magnification. Surrounded by numerous moderately bright field stars. Both NGC 6544 and M8 should fit within the same field of view of the Panoptic 27, forming an interesting couple, although I did not think of observing both of these objects at once.

NGC 6514 (M 20) OC Sgr 18h03m19.2s -22°58’20″ 5.2 mag 11:10p
Fairly large (about 10′), bright, detected in the finder scope. Absolutely gorgeous at lower magnification with a UHC filter. The dark lanes that split this object in 3 lobes are very well defined. There is a double star in the middle of the nebula. Another nebula, about the same size, is visible, although fainter, slightly to the north.

NGC 6440 GC Sgr 17h49m29.5s -20°21’49″ 9.3 mag 11:15p
Pretty small (1′), moderately faint, moderately well defined core, unresolved. Forms a really beautiful couple with planetary nebula NGC 6445 located about 22′ NNE.

NGC 6445 PN Sgr 17h49m51.5s -20°00’47″ 13.0 mag 11:25p
Pretty small (about 40″), fairly bright, easily found even at low magnification (95x) Forms a really beautiful couple with globular cluster NGC 6440 located about 22′ SSW. At 219x with a UHC filter, appears as a ring very slightly elongated 4:3 NNW-SSE. Brighter arches on the NNW and SSE sides. No central star seen. Moderately faint (mag 12.5) star just 30″ WNW.

NGC 6568 OC Sgr 18h13m20.9s -21°36’10″ 8.6 mag 11:40p
Best seen at low magnification. About 50 moderately bright stars of comparable magnitude, scattered evenly within an area 20′ in diameter. At higher magnification, the stars appear to be forming “chain structures” surrounded by darker regions.

NGC 6583 OC Sgr 18h16m26.0s -22°08’02″ 10.0 mag 11:45p
Compact group made of about 2 dozen stars. Pretty faint, barely noticeable in a crowded star field.

NGC 6629 PN Sgr 18h26m19.8s -23°11’52″ 10.5 mag 12:00a
Careful star hopping is required to found this planetary nebula as it appears almost stellar, especially in below average seeing. Pretty bright, round.

NGC 6642 GC Sgr 18h32m31.4s -23°28’06″ 8.9 mag 12:10a
Small, moderately bright, tiny fairly bright core, halo partially resolved at higher magnification.

NGC 6638 GC Sgr 18h31m34.0s -25°29’25″ 9.2 mag 12:15a
Fairly small, moderately bright, comparatively large core. The halo takes on a grainy appearance during brief moments of better seeing.

NGC 6645 OC Sgr 18h33m12.6s -16°52’34″ 8.5 mag 12:20a
About 50 stars spread within an area roughly 15′ in diameter. Spotted in 9×50 finder scope. Curious oval dark region almost in the middle of the cluster.