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Observing report, February 1, 2013

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#1 Eric A Jensen

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Posted 02 February 2013 - 02:08 PM

I and two observing friends took the 22-inch f/4 Starmaster to our local dark sky site for more observing. We also took the club's 6-inch f/5 achromat on a customized alt-az mount for widefield observing. However, myself being the "operator" of the 22-inch, the objects described below were seen through it, except where otherwise noted.

Conditions were as usual for the place, with the Milky Way clearly visible, although the brighter parts of it seen during fall were on their way down. Galaxy season is arriving. Seeing started out rather mediocre, but improved. Temperature was -3 to -4 degrees C.

We started at ten to nine on the Orion Nebula. It showed excellent contrast, size and wealth of detail at 85x. Otherwise, see previous descriptions that have been posted.

M35 and NGC 2158, open clusters in Gemini: At 120x the bright stars of the Messier-cluster filled much of the field. This magnification was rather excessive. NGC 2158 right by is actually the more interesting of the two, being small, but very densely filled with stars. At 250x it was well-resolved, and the brightest stars were arranged across a roughly triangular area.

M37 in Auriga was also rich and of considerable extent, its individual stars being fairly bright. 120x.

NGC 7789 in Cassiopeia by comparison was even richer, but the stars much fainter. However, they did stand out well and were easily seen individually. Very rich, having an irregular distribution.

We also viewed M31, which was now on its way down towards the Stavanger light dome in the north-west, so viewing was not optimal. Albeit, one dustlane as well as a suggestion of the next one further out, was seen.

M109, galaxy in Ursa Major: At 250x this showed a core and darker areas further out, within its halo – these being the space between the bar and spiral arms. As it was quite a ways from culminating, sky-contrast was not optimal.

We then viewed the Rosette Nebula in Monoceros, both in the big telescope as well as the 6 inch refractor. The 6-inch, using an OIII-filter in a 40mm Pentax XL, showed the entire nebula with very good margin. The shape was easily recognizable – a roundish/squarelike patch with a central hole containing stars. In the 22-inch this overall shape was difficult to catch. 85x with an OIII-filter revealed a lot of unevenness and dark structures, but the scope had to be swept to see it all.

NGC 6503 in Draco was a bright, not-quite-edge-on spiral at 250x. It was very elongated, showing subtle irregularity. Mainly, it had a smooth appearance without a core.

We then proceeded to an interesting little group of galaxies in Ursa Major: NGC 2805 had moderate-low surface brightness and significant extent with averted vision. No obvious core. Just north of it was a tight trio of galaxies; NGC 2814, 2820 and IC 2458. The two NGCs were obviously brighter than the IC-galaxy, being quite elongated and narrow. NGC 2814 was considerably smaller than 2820, which had a fair extent. IC 2458 was a glow having a core and small halo. 250x.

NGC 2950, galaxy in Ursa Major: Very different from the previous group, it was roundish, small and had very high surface brightness – especially in the almost stellar core. 250x.

NGC 4605, galaxy in Ursa Major: This one has joined the ranks of favourites. I saw it for the first time this January. At 250x it was asymmetrical, elongated and had a weakly bent appearance. Thicker towards the center, and averted vision unambiguously revealed subtle darker areas. Quite large.

NGC 4157, galaxy in Ursa Major (Right by Canes Venatici): At 250x it appeared as a very nice edge-on spiral! Long and very narrow, increasing towards center up to a core region which was itself narrow. It had an uneven brigthness profile, and a dust lane was suggested.

A bit to the east-north-east of 4157 was NGC 4187 in Canes Venatici, which was much more compact. Round, with a core and halo. Quite high surface brightness. Not much more to say about it.

We viewed M82 fairly briefly this time, and only at 120x. At this low magnification, its apparent surface brightness reached almost unreal levels, contrasting very well against its dust lanes. As always an impressive object.

NGC 4485 and 4490, galaxy pair in Canes Venatici: We have viewed this pair a fair bit throughout the years, but it had been a while. They were both larger and brighter than I remembered. NGC 4490 was especially impressive, having high surface brightness, a prominent core and thickly elongated shape. They were not high up yet, but in averted, 4490 could be seen to bend towards its smaller companion NGC 4485. 4485 was much smaller and had a fainter core, but was nonetheless fairly bright. The two made a notable impression in the field. 188x.

We now went to the Orion Nebula again while waiting for Thor's Helmet (NGC 2359) to appear in the gap between two trees. At 120x and using OIII-filter, M42 had an absurd intensity and contrast, the "wings" being seen all the way around.

NGC 2359, Thor's Helmet, Wolf-Rayet-star (nebula) in Canis Major: At 120x with OIII-filter, this was very nice. It was quite bright and had obvious, easily recognizable details. The central bubble had a narrow, uneven periphery curving round, and two extensions (the helmet's "horns") pointed westwards. To the east, fainter regions appeared. An interesting object that it was worthwhile spending some time on. Foreground/background stars were seen against it; more would no doubt have been seen without the filter.

M94, galaxy in Canes Venatici: A very bright galaxy with an extended halo. The "inner" halo was bright and contained a darker ring before coming up to the intense core. 250x.

NGC 2903, galaxy in Leo: Another well-known highlight. A large, bright galaxy that especially reveals a wealth of detail with time and careful observing. It had an elliptical outline and a bright core. To either side of the core, at the outer visible edges, a bright patch was located. These were connected with spiral structure that was seen in much of the halo. The (barred) spiral was seen as a whole, especially in averted vision, rather than each individual arm standing out explicitly. Their direction was obvious. NGC 2903 is a sublime sight, possibly the best galaxy (beside M66) in Leo. 250x.

We ended at 23.10, M3 in Canes Venatici being the last object of the night. The globular had now cleared the horizon quite well, and its many densely-packed stars were well-resolved.

It was a very rewarding night that afforded us many fine views!

Eric

#2 northernontario

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Posted 02 February 2013 - 03:19 PM

Nice report.

You spent some time in Ursa Major....I did too last night. Sometimes, I'll cover the entire bowl with no specific target in mind and just see where the scope takes me.

Again, I am reminded to see Thor's Helmet.

Thanks for the excellent report.

jake

#3 Edward E

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Posted 05 February 2013 - 11:04 AM

Very nice report; thanks for posting!

Lately, reading reports like this is as close to observing as I can get. Every new Moon Saturday since Oct has been either cloudy except January which was clear but had temps of -3 to -12 C, way to cold for me.






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