Magellan Observatory, New South Wales 4/4/08-4/12/08

Steve Gottlieb

After arriving home from observing last night at Willow Springs, I finally finished entering my notes from a week in Australia over the April new moon period. I planned this trip about 9 months when I discovered that the week-long spring break at the high school where I teach (Albany High), fell close to the new moon, instead of converging with Easter. This was my third week-long observing trip to Australia (July '02 and July '05) and the first time I had gone solo. As I didn't want to lug along a larger scope (I've done that twice to Costa Rica), I decided to spend the week at the Magellan Observatory in the Southern Tablelands of NSW (http:// home.goulburn.net.au/~magellan/) where I had observed twice before using an 18-inch split-ring equatorial (JMI). About a year ago, Zane Hammond, who runs this rural astro-lodge, upgraded to a 24" f/3.7 SDM telescope (http://www.sdmtelescopes.com.au/) with a fast Kennedy mirror and a Servocat/ArgoNavis GoTo system which I was dying to use. So, I snatched up a frequent flyer ticket for April 2nd (playing hookey from work for a couple of days) and reserved the large scope (dubbed Dobzilla by Zane) for 9 nights!

To prepare for the trip, I made up a large list of deep-south NGC's and IC's that I had not previously observed (mostly south of -50 degrees dec) and printed a couple of hundred Megastar-generated charts, to go along with a large number that I had used on the previous southern hemisphere trips. Observing in early April was ideal for early evening access to the Large Magellanic Cloud and bright galaxies in Horologium, Reticulum and Dorado. Mid-evenings brought perfect access to the rich starfields, clusters and nebulae in Carina and Centaurus and early morning access to the center of galaxy (Norma, Scorpius, Sagittarius) very high in the southwest. Zane's scope and observing accessories (everything from red flashlight (that's a "torch" to Aussies), to observing books/atlases as well as a full complement of Nagler eyepieces and Lumicon OIII/UHC/ H-beta filters on a filter slide. Still, I brought along my observing lists and charts, a photocopied version of the U2000 southern sky charts, the Mati Morel charts of the LMC (http:// members.ozemail.com.au/~morel/) and a few of my favorite eyepieces -- a 31mm Nagler, a 13mm Ethos, a 10mm Pentax XW and 7.5 and 5mm Takahashi LEs.

The weather was somewhat a mixed bag as had been the case on previous trips. Of the 9 nights in Australia, I was clouded out completely on two nights. On the positive side, three were all-nighters (6 to 7.5 hours of dark skies) another two had 4 hours of clear skies. The final two were both short 2-hour sessions. The accurate Servocat/ ArgoNavis TPAS system to scooted quickly around the sky (targets were typically less than 10' from center). Because I was organized with observing targets and charts, nearly all available hours was spent glued at the eyepiece and taking detailed notes and some sketches on 300 deep sky objects including about a 100 objects in the LMC. The one type of DSO that I decided to place low priority on were southern open clusters such as the Jewel Box and Gem Cluster as I had viewed most the Carina/Crux/Centaurus open clusters several times on previous trips. So, to start off this series of observing reports, here are the highlights from 15 southern galaxies that were fascinating in the 24".

Steve Gottlieb

NGC 1313
03 18 15.5 -66 29 51
V = 8.7; Size 9.1x6.9; Surf Br = 13.1; PA = 39d

24" (4/4/08 - Magellan Observatory, Australia): this was the first object I decided to take a look at in the 24" f/3.7 as it was probably the brightest remaining galaxy that I had not observed. I was amazed to find a striking, two-armed barred spiral with obvious bright HII knots in the arms! At 200x the main body of the galax appeared as a bright oval or wide bar ~4.5'x3.5' oriented SSW-NNE with a central bulge. Emerging from the SSW end is a relatively short arm that hooks towards the NW. Embedded with this extension is a brighter elongated HII knot, ~30"x20". A mag 15 star is west of the NW end of this arm. Just east of the NNE end of the main bar is a brighter HII knot, ~30"x15", oriented E-W. A faint star (or stellar knot) is less than 1' NW. This bright HII region is embedded in a diffuse arm that curves gently ESE from the N end of the bar. After the bright knot, this extension dims but ends at a third bright knot, ~15" diameter, that is isolated the end of this arm (nearly due E of of the core). This object is on a small list of Starburst galaxies with young globular-cluster-like clusters (SSC's).

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IC 1954
03 31 31.4 -51 54 17
V = 11.6; Size 3.2x1.5; Surf Br = 13.2; PA = 66d

24" (4/5/08 - Magellan Observatory, Australia): at 260x this was a surprisingly bright and detailed IC galaxy that was missed by John Herschel! Appears elongated ~2:1 WSW-ENE, ~2.8'x1.4' with a broad concentration to a large, brighter core. With direct vision a small brighter nucleus was visible at the center. There was a strong impression of spiral structure with slightly enhanced arcs (probably portions of spiral arms) extending east of the core on the south side and west of the core on the north side (this is consistent with images of the galaxy).

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NGC 1365
03 33 35.9 -36 08 24
V = 9.6; Size 11.2x6.2; Surf Br = 14.1; PA = 32d

24" (4/5/08 - Magellan Observatory, Australia): this is the best visual barred spiral in the sky and although it was only at 33° elevation (well past the meridian), the view was stunning at 200x with its long sweeping arms making a slashing cosmic "Z" in the eyepiece. I was also surprised by the structure in the fairly small, extremely bright core that is embedded in the 3' E-W bar. On the north edge of the mottled core, a very short, hooking appendage extended towards the NE with a fainter counterpart on the SW end. This gave the small core the appearance of a tiny barred spiral! At the west end of the bar a bright arm emerges, dramatically sweeping back to the NNE (sharp 110° angle) beyond a mag 12.5 star that is situated near the 1/3 mark of its total length. The counterpart on the east end of the bar shoots to the SW, reaching a faint star at its end. The total distance between the tips of the arms is roughly 10'.

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NGC 1511 03 59 36.7 -67 38 07 V = 11.3; Size 3.5x1.2; Surf Br = 12.7; PA = 125d

24" (4/4/08 - Magellan Observatory, Australia): at 200x appeared fairly bright, fairly large, elongated 3:1 NW-SE, ~2.5'x0.8'. Contains a bright, elongated core with a small very bright nucleus. Two stars mag 14-15 stars bracket the galaxy just 54" east and 1.3' west of center and just north of the center. The NE flank of the galaxy appears slightly brighter and more sharply defined and there is an impression of a dust lane on the south side. At 260x the galaxy has a mottled appearance and is slightly warped or asymmetric at the tips. A mag 10.8 star lies 3.5' SSE and a fainter edge-on, N1511A, is in the field 11' SSE. Member of a small group that includes N1473 and N1511A.

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NGC 1672
04 45 42.5 -59 14 50
V = 9.7; Size 6.6x5.5; Surf Br = 13.4; PA = 170d

24" (4/5/08 - Magellan Observatory, Australia): this gorgeous barred spiral appeared very bright and large with the main body elongated E- W, ~3.5'x2.0'. An obvious spiral arm is attached at the east end of the E-W bar and hooks to the north, wrapping around a star to the NE of the bar. Three additional fainter stars are sandwiched to the west of the brighter star, between the arm and the bar. A second arm begins to emerge on the west side, barely sweeping towards the south, but then quickly terminates. So the second "arm" is really more of a hooking appendage off the west end. The central bar itself is sharply concentrated with a dramatic, brilliant nucleus, ~25" diameter, that increases gradually to the center. This galaxy is a member of the Dorado group which includes N1515, N1533, N1536, N1543, N1546, N1553, N1566, N1574, N1596, N1617 and IC 2056. Possible additional members include N1559, N1602, N1672, N1688, N1703 and N1705.

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NGC 1705
04 54 14.1 -53 21 38
V = 12.4; Size 1.9x1.4; Surf Br = 13.3; PA = 50d

24" (4/5/08 - Magellan Observatory, Australia): at 260x appears moderately bright and large, elongated 4:3 SW-NE, 1.2'x0.9', broad concenctration. This starburst galaxy contains a super-star cluster (SSC 1750-A) that appears as a 14th magnitude "star" offset to the west of center. In good seeing at 350x using the 13mm Ethos and a 2x barlow, the SSC just west of center was easily visible and generally appeared stellar, though at moments there was an impression it spanned a couple of arcseconds. A short string of four faint stars is collinear to the NW. Located 30' ENE of the bright double star Iota Pictoris (5.6/6.4 at 12"). N1705 is a nearby blue dwarf starburst galaxy at a distance of 17 million light years.

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NGC 2442 = Meat-hook Galaxy
07 36 23.9 -69 31 48
V = 10.4; Size 5.5x4.9; Surf Br = 13.9

24" (4/4/08 - Magellan Observatory, Australia): I was amazed how prominent the sweeping spiral arms appeared at 260x giving a stunning "S" appearance. The main bar of the galaxy is fairly bright and extended ~2:1 in a SW to NE orientation with a length of ~3'. The bar has just a weak, broad concentration with no real core but it rises sharply at the center to a very small, brighter nucleus. The main arm is attached at the NE end of the bar and extends a short distance in that direction before dramatically bending sharply to the west (turning nearly 150°) and extending ~3.5' in length towards a mag 12.9 star. At the NW end this well-defined arm fades and broadens a little, terminating just SE of the 13th magnitude star. At the SW end of the bar, a thick arm emerges extending to the SW where it more gently curves around towards the east while fanning out. This arm is not as sharply defined as the inside (east) portion of the curve blends with a diffuse glow extending from the bar. The total distance between the tips of the arms spans nearly 5'. In the same field, 10' ENE, lies ESO 59-11 and N2534 is 16' NNW. The field also includes a number of mag 9 to 11 stars that frame the galaxy.

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NGC 2997
09 45 38.6 -31 11 25
V = 9.4; Size 8.9x6.8; Surf Br = 13.7; PA = 110d

24" (4/10/08 - Magellan Observatory, Australia): at 215x, this beautiful, asymmetric face-on spiral extended ~7'x4.5' and was sharply concentrated with a very bright 40" core. The spiral structure is unusual with a very long, relatively thick arm that curves from west to east on the north side of the core. This arm then bends south on the west side and contains a very faint 20" HII knot which is NW of the core and symmetrically placed opposite a star in the outer halo on the SW side. A fainter star is near the end of this arm, due west of the core. To the east of the end of this arm the light level noticeably dips (this is a gap between the arms) on the south side of the galaxy giving an asymmetric appearance.

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IC 2554
10 08 50.6 -67 01 51
V = 11.8; Size 3.1x1.3; Surf Br = 13.1; PA = 7d

24" (4/4/08 - Magellan Observatory, Australia): at 260x this is a remarkable interacting double with a very close pair of edge-ons with just slightly different orientations (both ~SSW-NNE) that run into each other. The southern member is brighter and larger, ~1.4'x0.3' with the northern member perhaps half as long, though they are nearly merged so difficult to clearly distinguish. With averted vision, the appearance is even more confusing as there is a strong impression of an additional component in the chain. Located 27' NE of N3136.

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NGC 4027
11 59 30.5 -19 15 44
V = 11.1; Size 3.2x2.4; Surf Br = 13.2; PA = 167d

24" (4/10/08 - Magellan Observatory, Australia): at 260x this is a strange looking one-armed spiral. Overall it appeared quite bright and large with a very irregular shape, 3'x2', and sharply concentrated with a fairly small, round core. The core gradually increases to the center. Emerging from the core on the NW end is a fairly well-defined arm that initially extends north in the direction of a mag 11.8 star located 3.7' NNW of the center of the galaxy. This arm then sharply curves back counter-clockwise ~135°, bending around to the SW and ends just on the outside of a mag 13.5-14 star situated close NE of the core. On the SE end of the core, a second arm begins to emerge but it suddenly terminates, creating a very asymmetric appearance with the other long, wrapping arm. A faint companion, N4027A, lies 4' S. At 260x, the companion appeared faint, fairly small, slightly elongated ~N-S, 25"x20", low even surface brightness. A very faint star is attached at the south end. The Ring-tail galaxy, N4038/4039 lies 40' NE.

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NGC 4038 = Antennae Galaxy = Ring-Tail Galaxy
12 01 52.9 -18 52 08
V = 10.3; Size 5.2x3.1; Surf Br = 13.1; PA = 80d

24" (4/10/08 - Magellan Observatory, Australia): this was an amazing object in the 24" at 350x. The main, bright northern component (N4038) was partially annular, with a very bright knotty rim and a darker center giving a truly unique appearance for a galaxy. At least 3 knots were visible embedded along its rim. On the south side is the brightest knot which appeared faint, small, ~12" diameter. A second fainter knot is on the SW side and was only ~6" in size. Finally, a third very faint 6" knot is on the N side. The three knots were roughly spaced out 120° apart along the outer portion of this tortured galaxy. Attached on the east end is a long "tail" or arm (interacting companion N4039) that curves around on the south side towards the southwest. Another very faint, but slightly larger 20" knot is embedded along the main portion of the tail roughly halfway along its length. At the tip of the main tail was a relatively large, brighter knot that at times appeared double. Surrounding the SW portion of the tail is a much fainter outer halo extended SW-NE. This fainter halo extends beyond the tail for a few arc minutes and widens to a bulbous shape at the end. This was by far the most detailed view I've seen of the Ring-tail galaxy. Another disturbed galaxy, N4027, lies SW.

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NGC 4945
13 05 27.5 -49 28 06
V = 08.6; Size 20.0x3.8; Surf Br = 13.2; PA = 43d

24" (4/11/08 - Magellan Observatory, Australia): remarkable spiral at 200x as it extended SW to NE over nearly 2/3 of the 30' field. I didn't take detailed notes on this observation but the galaxy had just a broad concentration with no defined core region. The galaxy is very slightly wider through the center and only tapers towards the tips. Along the south edge, just SW of center, is a brighter linear streak forming a sharp edge (the dust lane is just beyond). The main body of the galaxy fades a bit in this area and then brightens again further SW. Near the NE tip the major axis appears slightly warped or bent towards the north. On the south side of the NE end, some very faint haze is visible. The DSS image reveals this is the portion of the galaxy south of the dust lane.

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M83
13 37 00.3 -29 51 58
V = 07.5; Size 12.9x11.5; Surf Br = 12.8

24" (4/11/08 - Magellan Observatory, Australia): M83 had a photographic appearance in the 24" at 200x. The bright "bar" was elongated SW-NE and roughly 3'x1' in size with a well-defined bright, round core, 1' in diameter. The first prominent arm is attached at the NE end of the bar and sweeps south (counter-clockwise) on the east side of the core, wrapping around the southwest side and spreading out a bit as it terminates to the south of the core (~3' from the center). This arm has a high contrast along its outer edge and a couple of faint stars are superimposed near where it attached to the bar. On the southwest end of the bar a second prominent inner arm emerges and abruptly wraps counter-clockwise around the galaxy on the west side as it heads north. This arm continues to wrap around the north side before spreading out on the NE side and merging into the outer halo ~3.5' from center on the NE edge of the halo. A more ill-defined third arm also emerges from the core on the south but sweeps more gently to the west (instead of heading north) on the outside of the second arm. It spreads out and fades into the general glow about 3.5' SW of center near a mag 13-13.5 star. Offshoots of the main arms are difficult to trace and contribute to the general background glow of the halo.

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NGC 5643
14 32 40.7 -44 10 28
V = 10.0; Size 4.6x4.0; Surf Br = 13.0

24" (4/11/08 - Magellan Observatory, Australia): at 260x I was very impressed with this large, bright barred spiral. The halo is slightly elongated, ~3.5'x3.0' and sharply concentrated with a very bright, small, core. Extending through the center is a brighter bar oriented E-W with a star superimposed on this bar to the west of the core. A second superimposed star lies 35" to the south and continuing on this line is a third star just at the edge of the halo, 1.7' S of center. At the east end of the bar a slightly enhanced arc sweeps clockwise to the north and a similar enhancement on the west side sweeps to the south. The faint arc or arms wrap around 180°, making a complete outer ring and along with the central bar these features form the Greek letter "theta". Situated in a fairly rich Lupus star field.

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NGC 6438
18 22 17.7 -85 24 07
V = 11.1; Size 1.6x1.3; Surf Br = 11.8; PA = 156d

24" (4/11/08 - Magellan Observatory, Australia): at 260x, the appearance of this interacting peculiar galaxy is very strange! N6438 is moderately bright, small, round, 0.4' diameter. An elongated glow attached on the E side is a disrupted system (N6438A) with two extensions or arms (it may be two different interacting galaxies). Visually the companion appeared as a faint, diffuse, elongated SW-NE glow attached to N6438, ~0.8'x0.5'. This system is the second closest NGC galaxy to the south celestial pole. Located 4' NE of a mag 9.5 star and 16' NE of mag 8 HD 160820.