Deep sky observing report (2008 Apr 10-12)

posted: 3500 days ago, on Saturday, 2008 Apr 19 at 13:03
tags: astronomy, deep sky, observing report, Sutherland, Carol Botha.

Observer: Auke Slotegraaf

Deep sky observing report: session notes from Sutherland, 2008 April 10–12. Set up with Carol Botha, in the back yard of the "Skrywershuisie" guest house.

Ironically, the only troublesome light comes from the neighbour's house, an individual very much active in the astronomy community…

The second night we were set up in the old quarry.

NGC 5156

Date: 2008 April 10, Thursday night
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

Tonight's first target, this galaxy is just over a degree due south of Omega Centauri, making for an easy star-hop. It is conventiently placemarked by a 7.7th mag star (HD 117036) four arcminutes south-southwest.

The galaxy is readily seen at 60x as a small round glow, just under an arcminute across, and growing not much brighter towards the middle.

Between HD 117036 and NGC 5156 lies a small square of stars (rough field sketch); the galaxy is larger than this square.

RC3: D= 2.3x2.0, B=12.49, SB=14.02

NGC 5234

Date: 2008 April 10, Thursday night
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

This galaxy lies about 3 degrees southeast of Omega Centauri.

At 60x it appears as a faint, small, approximately round glow, 0.9 arcminutes across. Very close south-east is a very faint star, with another further north-east, as the rough field-sketch shows.

This latter star appears double on the DSS image.

RC3: D=1.3x 0.8, B=13.97, SB=13.74

ESO 220-23

Date: 2008 April 10, Thursday night
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

This galaxy lies about 3 degrees southeast of Omega Centauri.

At 60x it appears as a very faint smudge, perhaps oval SW-NE (see rough field sketch), about 0.7 arcminutes long (the same size as stars B-C).

A: TYC 8269-02686-1, V=10.6
B: TYC 8269-02828-1, V=10.5
B-C = 0.7 arcminutes.

ESO 220-22 close south wasn't noticed.

RC3: D=1.6x 0.4, B=14.42, SB=13.71.

IC 4312

Date: 2008 April 10, Thursday night
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

Star-hopping from Omega Centauri

This galaxy appears as a faint, very small (0.7 arcmin), round glow, like a faint unfocussed star. North and south-east lies two faint stars (see rough sketch); the galaxy is one-quarter of this separation in size.

The star to the north is TYC 8273-00376-1 (V=11.3) and the two stars are 2.6' apart.

Nearby IC 4311 and ESO 220-28 are not plotted on the MSA 953 chart I used; I didn't notice them, either.

RC3: D=1.3x1.1, B=13.39, SB=13.51.

ESO 220-19

Date: 2008 April 10, Thursday night
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

See rough eyepiece sketch: I star-hopped to the two stars A & B (which are 6 arcmin apart) and immediately noticed the striking Diamond Cross asterism south-east of B, and drew these in on my rough field-sketch. Knowing that the galaxy made a 90-degree triangle with the pair, I saw it right away and plotted its position: but then realized I was seeing a pB star instead – one not shown on MSA 953 ('C' on the sketch). With attention, a faint roundish glow is seen due south of this star, which turns out to be the hunted-for galaxy.

A: TYC 8269-00464-1 (V=11.0)
B: TYC 8269-00706-1 (V=10.5)
C: TYC 8269-02792-1 (V=10.8)
RC3: D=1.5x0.5, B=14.50, SB=13.99

ESO 220-08

Date: 2008 April 11, 00:01 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

This lovely galaxy lies about half a degree due south of Omega Centauri, lying pretty much between two 10th magnitude stars that are about 6 arcminutes apart (see rough sketch).

Just after the church bell struck midnight, I'd finished sketching the field around this beautiful spindle-galaxy, which is at least 1.5 arcminutes long and about 0.1 arcminutes thick (thin?) and readily seen at 60x.

RC3: D=1.9x0.5, B=14.05, SB=13.79.

ESO 219-41 & ESO 219-39

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

Two and a half degrees southwest of Omega Centauri lies this pair of galaxies. As the church bell struck "one", I found the duo, which appear as very faint, very small glows, each with a star involved or otherwise very nearby.

The southern of the two, ESO 219-41, is easier to see, with a small star at its northwestern side.

ESO 219-39 is more uncertain though – it looks like perhaps only two or three faint stars?

No field sketch was made; the DSS image of the pair confirms my visual impression: -41 is much brighter, as does the PGC/RC3 catalogue information:

(PGC) ESO 219-39: B=14.3, D=1.1x0.3, SB=12.84.
(RC3) ESO 219-39: B=13.94, D=1.0x0.3, SB=12.36
(PGC) ESO 219-41: B=13.2, D=2.8x0.9, SB=13.94.
(RC3) ESO 219-41: B=12.9, D=2.8x0.9, SB=13.72

NGC 4976

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

This galaxy lies 3.5 degrees southwest of Omega Centauri and just half a degree due east of NGC 4945. It is conventiently signposted by a bright star due east (HD 114102, V=7.8, 4.5 arcmin away). The galaxy itself is readily seen at 60x, appearing as a pretty bright, round, glow.

No field sketch was made.

RC3: D=5.6x3.0, B=11.04, SB=14.06.

NGC 5064

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

This small galaxy lies in the shadow of Omega Centauri, just over one degree east.

It is readily seen but only as a small, round, glow.

RC3:D=2.5x1.1, B=12.90, SB=13.74.

ESO 269-80

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

One of three small galaxies about a degree east of Omega Centauri. A fourth galaxy, ESO 269-80, is not plotted on MSA 953.

ESO 269-80, westernmost of three, looks like a soft-focus, very faint star.

Field sketch not made, which is a pity, because these galaxies (ESO 269-80, -85, -90) are within 18 arcmin of each other.

RC3: D=1.3x1.2, B=12.70, SB=14.06

ESO 269-85

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

One of three small galaxies about a degree east of Omega Centauri. A fourth galaxy, ESO 269-80, is not plotted on MSA 953. From west to east these are ESO 269-80, -85, -90.

ESO 269-85 warranted a "Wow!" comment added to my rough sketch. This galaxy is a large, 1.8 x 1.1 arcminutes, soft glow, obvious at 60x. Very small stars, 12th magnitude, are scattered around it, as the rough sketch shows. Just north-northeast of the galaxy is a bright star (TYC 8252-03535-1, V=9.6), signposting it conveniently. Not that it needs a signpost.

Field sketch not made, which is a pity, because these galaxies (ESO 269-80, -85, -90) are within 18 arcmin of each other.

RC3: D=2.4x1.5, B=12.75, SB=13.89.

ESO 269-90

Date: 2008 April 11, 01:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

One of three small galaxies about a degree east of Omega Centauri. A fourth galaxy, ESO 269-80, is not plotted on MSA 953. From west to east these are ESO 269-80, -85, -90.

ESO 269-90 appears as a roughly round, faint, glow, 0.3 arcminutes across. Northwest list a bright star, labelled "A". Due south, very close to it, or involved with it, is a faint (13th mag?) star, as the rough sketch shows.

Field sketch not made, which is a pity, because these galaxies (ESO 269-80, -85, -90) are within 18 arcmin of each other.

A: TYC 8252-03017-1, V=9.81.
B: TYC 8252-02793-1, V=11.95.
RC3: D=1.5x0.8, B=13.77, SB=13.73.

NGC 5244

Date: 2008 April 11, 02:00 SAST, Friday morning
Location: Sutherland (town, Jurg's guest house)
Sky conditions: Dark, clear
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 953, star hopping from Omega Centauri.

Two and a half degrees north-east of Omega Centauri lies this little galaxy, which appears at 60x as faint, small and round. A small star lies on its northern tip.

This was the last object for the evening, when dew started collecting on the scope and star maps. For closing, I slewed to NGC 4945, and showed Carol. Good grief.

RC3: D=1.7x0.6, B=13.32, SB=13.04.

NGC 6231

Date: 2008 April 11, 21:15, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, moonlight.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov

While waiting for the Moon to set, I aimed the 12-inch at NGC 6231, which was pretty much on the horison at the time. Low enough, in fact, that I could comfortably sit in the camp chair and sketch the cluster.

Essentially, NGC 6231 is eight or so bright stars, arranged in a roughly east-west elongated grouping, at least 10 arcminutes long and 5 arcminutes wide. Scattered in and amongst these primary stars are about 100 fainter stars. Scattered to the south, and east, is a large field of faint stars, like a dim extension (well-shown on the DSS image).

ESO 324-24

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

An easy star-hop almost 2 degrees north-northeast of Centaurus A lies this galaxy, the first target of tonight's session.

Despite being very easy to locate, just 8 arcminutes due east of a bright star (HD 116835, V=5.7), I'm not sure I see it. At the correct position shown on MSA 933 is what looks like a largish (one-tenth of the 10mm field of view, thus about 1.5 arcminutes) area of either haze, or extremely faint stars scattered about.

This description matches quite well with the DSS image, which shows a diffuse 2-arcminute galaxy; the RC3 classification is IX 9*.

RC3: D=3.2x2.3, B=12.90, SB=14.82.

ESO 324-29

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

A short distance northeast of NGC 5128 lies this galaxy.

At 60x, this galaxy is readily seen as a faint, elongated (1:2 ratio) smudge, 0.6 arcminutes long. But at 150x, this extreme elongation is less certain. The galaxy is brighter in the middle, with a central region that seems mottled at 150x.

RC3: D=2.4x0.8, B=13.26, SB=13.70.

NGC 5237

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

This galaxy appears as a pretty bright, round glow, forming a shallow isoceles triangle with two bright stars to its north (HD 118483, V=7.0 and HD 118337, V=7.4).

RC3: B=1.9x1.6, B=13.23, SB=14.20.

ESO 270-17

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

Not found?!

A curious 60x three-quarter degree field of view: two curved rows of stars, 13 arcmin long (1/3.5 of fov), running northwest to southeast. The two chains are roughly parallel and are separated by 12 arcminutes (1/4 of fov) of rather barren space. According to MSA 933, the galaxy is embedded in the eastern chain of stars – but I couldn't see anything there. Curious.

Fourcade-Figueroa Object, PGC47847, A 1332-45. D=11.5x1.4, B=11.71, SB=14.50.

ESO 270-14

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

Lies about 1.5 arcminutes due east of HD 117034 (V=9.03). Is seen as a very faint, slighty hazy, star.

RC3: D=1.2x0.9, B=13.88, SB=13.78.

NGC 5090

Date: 2008 April 11, Friday night
Location: Sutherland (quarry)
Sky conditions: Clear, dark.
Telescope: 12-inch f/4.9 Dobsonian
Eyepieces: 25mm Sirius Plossl, 60x, 46' fov & 10mm Sirius Plossl, 150x, 14/17' fov
Working on MSA chart 933

One of a fascinating group of galaxies, about a degree south-west of Centaurus A. I counted six galaxies in the field of view, which was wonderful. The brightest of the group is NGC 5090.

However, just as I started to sketch the field, dew ended the session. Rats.

Table 1. Summary of objects observed (with links to DOCdb.net)

N
Object IDDateDescriptionSizeBSB
 
 
1NGC 5156Apr 10/11S,R
2.3x2.012.4914.02
2NGC 5234Apr 10/11F, S, R, 0.9
1.3x 0.813.9713.74
3ESO 220-23Apr 10/11vF, 0.7
1.6x 0.414.4213.71
4IC 4312Apr 10/11F, vS, 0.7, R
1.3x1.113.3913.51
5ESO 220-19Apr 10/11F, R
1.5x0.514.5013.99
6ESO 220-08Apr 10/11B, 1.5 x 0.1
1.9x0.514.0513.79
7ESO 219-41Apr 10/11vF, vS
2.8x0.912.913.72
8ESO 219-39Apr 10/11vF, vS
1.0x0.313.9412.36
9NGC 4976Apr 10/11pB, R
5.6x3.011.0414.06
10NGC 5064Apr 10/11S, R
2.5x1.112.9013.74
11ESO 269-80Apr 10/11vF, vS
1.3x1.212.7014.06
12ESO 269-85Apr 10/11L, 1.8x1.1
2.4x1.512.7513.89
13ESO 269-90Apr 10/11F, R, 0.3
1.5x0.813.77 13.73
14NGC 5244Apr 10/11F, S, R
1.7x0.613.3213.04
15NGC 6231Apr 11/1210 x 5---
16ESO 324-24Apr 11/121.5
3.2x2.312.90 14.82
17ESO 324-29Apr 11/12F, E, 0.6
2.4x0.813.2613.70
18NGC 5237Apr 11/12pB, R
1.9x1.613.2314.20
19ESO 270-17Apr 11/12-
11.5x1.4 11.71 14.50
20ESO 270-14Apr 11/12vF 1.2x0.9 13.88 13.78
21 NGC 5090 Apr 11/12 - - - -
 

Key: (N, col 1): Sequence of observing; (AS description, col 4): summary of my observation from the notes; (SB, col 7) surface brightness, in magnitudes per square arcminute.

nothing more to see. please move along.