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Old 23-01-2010, 06:19 PM
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ngcles
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Observing Report NGCLes -- 17th January 2010

Hi All,

It's been a while since I posted an observing report -- mainly because it has been so cloudy and on those nights I did observe I just spent time looking at old favourites.

Last weekend was an interesting one weather-wise in Sydney. The three or four days before had been quite warm and cloudy, but the numerical weather prediction was for it to clear sometime around midnight on Saturday night the 16th-17th after a storm-front passed through during the early evening. A nice pool of clear, cooler air was behind it and the numerical weather predicted good seeing ... and I was desperate for a fix!!

After a good long-look at the satellite animations, particularly the visible-light images I felt 11pm was a good bet for it to clear and my observing buddy Gary, put his money on 10pm.

It felt weird but I packed the car at home in light rain, drove down to Bargo through thunderstorms and arrived there in almost complete darkness well after my normal time at about 9pm -- it was still raining quite a bit. Gary turned up at almost 9.20pm and by then the precipitation had turned to heavy drizzle and then stopped. But the cloud looked solid. After a while when it showed no sign of breaking quickly, someone came up with the brilliant idea that the clouds might go away if we were indoors somewhere not paying attention to them -- and to that end we set off for the Bargo Rec Club about 4km away for a quiet ale (just one) while we waited for the sky to do it's thing.

When we arrived we found the door locked and on ringing the buzzer, were told they were shutting in 20mins and that last drinks had been already served ... hmmm. We though about going to the pub (whch is normally very noisy with a band) when ... a star was seen. Then another ... and then several more.

We headed back to our observing possie!

By the time we got back it was clearing quickly and just 10 mins of standing around persuaded me it was time to get the 'scope out -- it was now 10.30pm. By the time it was all ready to go (about 20 mins) some cirrus drifted in but was soon gone leaving a very nice looking sky with steady naked-eye star images. Then, the dew started -- it was one of the dewiest January nights I can ever remember which probably affected the transparency/sky darkness a bit. The SQM-L reading was 21.22 -- a bit worse than one might expect but it was probably due to the high humidity. Ain't it nice when a plan comes off!!

I spent the first hour just enjoying the 'scope -- looking at M42, the Tarantula (NGC 2070) and a few things in the large cloud and several of the brighter PNe. Also saw Sirius B -- so the seeing was goodish at least -- I gave it a 7/10. Great fun! I then decided, for the first time ever to do a "road test" on my own current Deep Sky Delights in the Feb-Mar 2010 issue of Australian Sky & Telescope ... and I had a good time (but I guess self-praise is no recommendation! It then occured to me a bit after midnight to clean out the small number of remaining objects in the NGC I haven't seen in Antlia ... and here is the notes:

x185 27' TF

IC 2552 Galaxy *
RA: 10h 10m 46.1s Dec: -34° 50' 42"
Mag: 13.4 (P) S.B.: --- B-V: --- Size: 1.6'x1.4' Class: SAB(s)0-:
P.A.: --- Inclination: --- R.V.: +3104

Quite easy to see but small eg found in a fairly rich field with a 10th mag * to the NE by 3'. Between the eg and that star is another much fainter star about mag 13.5. Fairly small, no more than about 40" diameter, looking like a distant elliptical brightening from indefinite edges mod and evenly to centre where I suspect there is a very faint *ar nucleus.


x185 27' TF

IC 2556 Galaxy *
RA: 10h 12m 37.8s Dec: -34° 43' 46"
Mag: 14.3 (P) S.B.: --- B-V: --- Size: 2.0'x0.9' Class: (R')SB(s)d
P.A.: 106 Inclination: --- R.V.: +2351 Source: RC3 *

This eg is found in an adjacent field to IC 2552 (previous) 20' NE. This object is pretty easily seen on the POSS plate but visually is very faint. A very, very LSB object. Seems to be oval in PA 120, evenly illuminated rising hardly at all to centre 40" x 20" in that PA no stars immediately associated and it took a bit of time to nail.


x185 27' TF

IC 2555 (NGC 3157) Galaxy *
RA: 10h 11m 42.3s Dec: -31° 38' 32"
Mag: 13.9 (P) S.B.: --- B-V: --- Size: 2.4'x0.5' Class: SB(s)bc: sp
P.A.: 38 Inclination: --- R.V.: +2850 Source: RC3 *

This neg is about 5-6' N of a 9th magnitude * and has a small lens-shaped, almost edge-on spiral form 2.5' x 10" in PA 45. Grows broadly and slightly towards the axis nr centre with no defined core/nucleus visible . There is a small key-stone asterism of 15th and 16th mag *s immediately underneath the SE flank.



x185 27' TF

IC 2558 Galaxy *
RA: 10h 14m 44.3s Dec: -34° 20' 14"
Mag: 14.3 (B) S.B.: --- B-V: +0.58 Size: 1.1'x0.6' Class: Pec:
P.A.: 13 Inclination: --- R.V.: +2573 Source: RC3 *

This eg is pretty easy to see about 6' to the NW of a 10th mag *. Oval in almost PA 0, perhaps PA 15. Lowish but reasonable SB, 1' x 40" grows broadly and slightly to centre with no apparent core, zones or nucleus.



x185 27' TF

IC 2559 Galaxy *
RA: 10h 14m 45.2s Dec: -34° 03' 32"
Mag: 14.4 (P) S.B.: --- B-V: --- Size: 1.7'x0.7' Class: SB(s)b?
P.A.: 18 Inclination: --- R.V.: +2899

Another very tiny, quite faint very small eg maybe slightly elong in about PA 150??. Small, slightly oval halo 40" x 30" just to the NE of a mag 12.5 * and there are quite a few other fainter *s around. Appears to grow broadly and weakly to centre without zones, core or nucleus.



x185 27'

IC 2570 Galaxy *
RA: 10h 21m 34.2s Dec: -33° 37' 23"
Mag: 16.0 S.B.: --- B-V: --- Size: 0.8'x0.5' Class: SB(rs)bc:
P.A.: 168 Inclination: --- R.V.: --- Source: PGC *

This one took quite a long time to firstly find the asterism close to it in the field and then see. Very, very faint and very tiny. Maybe 10-15" occasionally visible as an almost stellar mote of gossamer nr a 11th mag * immediately to its W by 30". No visible structure -- just a spot.



x185 27'

IC 2573 Galaxy *
RA: 10h 23m 30.2s Dec: -35° 27' 23"
Mag: 15.3 (P) S.B.: --- B-V: --- Size: 1.5'x0.3' Class: SB(s)d: sp
P.A.: 2 Inclination: --- R.V.: --- Source: RC3 *

This is another exceptionally faint and very tiny very elong eg. A tiny thin streak of gossamer maybe 20" long in PA 0. A sliver of the weakest mist with no brightening to centre or structure.



x185 27'

IC 2587 Galaxy *
RA: 10h 30m 59.3s Dec: -34° 33' 48"
Mag: 13.3 (B) S.B.: 13.0 B-V: +0.98 Size: 2.0'x1.4' Class: (R')SB(s)0-
P.A.: 21 Inclination: --- R.V.: +2111 Source: RC3 *

This eg is small but no worse than moderately faint and in a field of many faint *s. Quite LSB. Seems to have a very faint, dilute outer halo about 50" to 1' diameter and round with a very small slightly brighter core and no real nucleus.

I then turned my attention to observing several objects for up-coming articles -- so I won't reproduce them here and then finally went on to several of the nebulae and fainter clusters in Carina.

Spent quite a bit of time on Eta itself and it is fascinating to see how the central star in he Homunculus is really starting to "overwhelm" the nebula surrounding it. Also spent some time on Mars which was as unwhelming as usual and then finally at about 3.30pm my first look at Saturn for the year -- very nice.

Very weary pack-up at 3.45am and arrived home with dawn after driving through several thick fog-patches on the Hume Hwy.

Great to be out observing again hoping this signals the end of the cruddy cloudy weather we've been "enjoying" for months!


Best,

Les D

Last edited by ngcles; 23-01-2010 at 06:37 PM.
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Old 23-01-2010, 07:02 PM
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barx1963 (Malcolm)
Bright the hawk's flight

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Hey Les, great report mate! I have just read your column in the latest S&T and (weather permitting) I am hoping to get out later tonight for a quick look at some objects after moonset. I may be able to add some from this list if the sky gets dark enough!

Interesting your comment on Eta C, I am quite convinced it is changing visibly.

What scope were you using BTW?

Malcolm
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Old 23-01-2010, 07:37 PM
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ngcles
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Hi Malcolm,

Quote:
Originally Posted by barx1963 View Post
Hey Les, great report mate! I have just read your column in the latest S&T and (weather permitting) I am hoping to get out later tonight for a quick look at some objects after moonset. I may be able to add some from this list if the sky gets dark enough!

Interesting your comment on Eta C, I am quite convinced it is changing visibly.

What scope were you using BTW?

Malcolm
It was the 46cm (18") mate. I only ever use the 31cm (12") at home. The 46cm is is much more portable.

Yes Eta is brightening overall at visual wavelengths and I think there is little doubt it is due to the star clearing-out its surroundings that came from the eruption in the 1890's. It is now starting to shine out of the nebula more than shining through it.


Best,

Les D
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Old 24-01-2010, 02:11 PM
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Another top quality installment from you Les

Have looked up DSS plates of some of those objects, great job spotting those 16th mag dust kitties!

cheers
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Old 29-01-2010, 09:01 PM
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Paddy (Patrick)
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Les, I am very impressed at the detail that you can see in some very faint objects. No doubt the benefit of vast experience. I also love the term gossamer that you use. Mind if I borrow it from time to time? Like Malcolm, I'm looking forward to following up your AS&T list for Antlia.

thanks for the report
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Old 29-01-2010, 09:04 PM
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DavidU (Dave)
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Detail city there Les.
Thanks !
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