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Observing report, January 11, 2013

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#1 Eric A Jensen

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Posted 13 January 2013 - 02:48 PM

As the weather cleared this weekend we went to our dark sky site with my 22-inch f/4.1 Starmaster. The air was very dry, and the winter Milky Way high above. Seeing became fair as the evening progressed. It was chilly though, -8 degrees Centigrade. I felt this in my fingers having to switch eyepieces and manipulate set screws all the time. We started observing after 22.30.

M42, the Orion Nebula: This had culminated, so we started on this. At 85x magnification unfiltered, including its outer edge, it filled almost the entire field of a 31mm Nagler like a huge bubble. I have described this object in previous reports, suffice to say it was incredibly detailed and contrasty. It was noted that M43 just to the north would really be a considered a highlight object in its own right, if it hadn't been overshadowed by its illustrious neighbour. But, since we are actually talking about the same nebular complex, the separate catalogue numbers are artificial in any case. M42 was also fine and structured in the 10x70 finder, though on a completely different scale.

NGC 1999, reflection nebula in Orion: This is just over a degree south-south-east of the Orion Nebula. Requires fairly dark skies to be seen well, but was good tonight. I had been made aware of this object recently at last year's Heart of America Star Party in Missouri. It was round and of moderate contrast, with a dark patch suggested at 120x. At 250x this patch was seen with direct vision, and was very explicit with a small amount of averted. It had an uneven, three-pronged, roughly triangular outline. The reflection nebula brightened abruptly just on the east-edge of the dark patch, before the intensity fell to zero. A star was located near one edge. A weird object, especially since the dark region apparently is not a dust cloud, but an actual hole in the reflection nebula!

M78, reflection nebula in Orion: Large, bright and extended, with two stars superimposed. Sky-glow did however affect contrast on the object. Roughly fan-shaped and ending abruptly on the northern edge. Just north of it was a separate nebulous region which most likely was NGC 2067 (related to M78), seen in averted vision and of low contrast. 120x.

NGC 278, galaxy in Cassiopeia: Compact at 120x, having high surface brightness and central concentration. I was at first unsure if we were just seeing the core. Increasing to 250x however confirmed that we were seeing the halo in addition, since it suggested spiral structure in the shape of darker/brighter areas.

M82, galaxy in Ursa Major: At 250x huge, very elongated and structured! High-contrast details were seen across its extent, in the shape of bright knots and dark bands criss-crossing.

M81, galaxy in Ursa Major: This very bright galaxy had an elliptical outline and bright core. The spiral is not in fact hard to see, as long as one knows *where* to look – of course provided that it's sufficiently dark and the scope is of some minimum size. Towards the north, at one end of the ellipse, a diffuse condensation was seen. A narrow, diffuse arm of lowish contrast extended out from this condensation a fair ways around. Using averted, it was visibly darker between the arm and the rest of the galaxy. 120x. The other arm was not seen.

Galaxy-trio in Ursa Major: These were beneath the bowl of the Big Dipper, found randomly as we were going to M108. They were NGC 3718 and 3729, as well as UGC 6527. NGC 3718 furthest to the west was obviously the largest and brightest. Diffuse, with moderate surface brightness, it appeared to be a spiral. 3729 had similar surface brightness, was less structured though uneven. Near 3718 was UGC 6527 – at least on the map (U2000). Consulting a photo afterwards revealed a Hickson group. It's a little unclear which of the components was actually seen. 188x.

M108, galaxy in Ursa Major: A fine, large and detailed galaxy. Much like a toned-down version of M82. Several foreground stars were seen, with one notably brighter than others. Elongated dust-segments were seen at 250x.

NGC 2903, galaxy in Leo: Splendid! Large, detailed and very bright, this was a highlight. At 188x it was certainly seen as a spiral, with a bright knot at either end of the elliptical halo. A spiral segment extended from each of these. In averted vision, they curved around a ways and melted into the rest of the halo. Even better at 250x. Darker and brighter areas seen with good contrast.

M67, open cluster in Cancer: This was an evident patch in the 10x70 finder. Through the scope, it was a very rich, well-detached cluster of stars having varying brightness, but none of them very dim or very bright (except one on the eastern side). No central concentration. Covered about 1/2 the field at 120x.

NGC 2359, Thor's Helmet, emission nebula in Canis Major: This had culminated, but at its declination it never rises high from here. Timing was perfect, since it was located between two trees which would otherwise have blocked it. Magnificent at 120x and with OIII-filter! I had never before seen it at a dark site. Easily recognizable from pictures. A central bubble having significant extent (comprising the "helmet") had a brighter edge on the western side. Obvious nebulous extensions pointing west were seen at the bubble's northen and southern ends. The southern extension was brightest and shortest. To the east and north of the main part, a much fainter, diffuse, separated nebulous region was seen. A highlight.

M97, The Owl Nebula, planetary in Ursa Major: The filter already being inserted, we went to this after Thor's Helmet. The round disk was bright and contrasty against the background, with unevveness easily seen at 120x.

NGC 2683, galaxy in Lynx: This elongated edge-on filled about 2/3 of the field at 250x. It was bright, with a farily smooth appearance and no obvious core. A dust lane may have been suggested; in this case it would be on the western side where brightness dropped off most suddenly.

We then observed some galaxies in the dipper-region of Ursa Major: UGC 6767 was a faint patch of small extent at 250x. Low surface brightness and no core. NGC 3945 was round, compact and had a bright core. No further details were seen. NGCs 4036 and 4041 were close to the previous one. 4036 was lenticular with a bright core. 4041 was smaller and oblong, having lower surface brightness, but also with a core. Further north-east was IC 758, seen as a faint glow. Increasing to 250x, 4036 was actually quite a nice lenticular of considerable extent.

M51, galaxy in Canes Venatici: Contrast may have been better on certain other occasions, but the view was nonetheless very nice. Huge in the field at 250x, with very good separation between the well-defined arms. The spiral itself had uneven intensity as we followed it around visually.

M106, galaxy in Canes Venatici: One of the very nicest objects in this galaxy-filled constellation. At 250x, the spiral structure was evident, shaped like a diffuse stretched-out "S", due to the angle at which we're looking in. Near the core was a small darker patch/region which may have been a dustlane or just a drop-off in density. In all, very uneven across the halo's extent.

The last deep-sky object of the evening was M101 in Ursa Major. Contrast was fair, relatively speaking, even though darker skies would have improved it. It was uneven and quite patchy, with the spiral visible. However, individual arms were hard to follow around. Low surface-brightness disk.

We ended on Jupiter. The seeing here was poor, the planet descending towards the west. The two equatorial bands were very evident, but finer details were washed out.

We packed up around one o'clock. A successfull, rewarding astronomical start to the new year. We also returned the next night. A report for January 12 will follow.

Eric

#2 MG1962

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Posted 13 January 2013 - 03:04 PM

Very nice report, sounds like an exceptionally productive session. What sort of scope do you have?

#3 Sasa

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Posted 14 January 2013 - 03:12 AM

NGC 1999, reflection nebula in Orion: This is just over a degree south-south-east of the Orion Nebula. Requires fairly dark skies to be seen well, but was good tonight. I had been made aware of this object recently at last year's Heart of America Star Party in Missouri. It was round and of moderate contrast, with a dark patch suggested at 120x. At 250x this patch was seen with direct vision, and was very explicit with a small amount of averted. It had an uneven, three-pronged, roughly triangular outline. The reflection nebula brightened abruptly just on the east-edge of the dark patch, before the intensity fell to zero. A star was located near one edge. A weird object, especially since the dark region apparently is not a dust cloud, but an actual hole in the reflection nebula!


Nice and detailed report Eric, thanks. Speaking of NGC1999, I was not aware that the black spot is actual hole. For example, O'Meara writes in his "Hidden Treasures" that this is cold molecular cloud (Bok globule) - remnants from which the star was born. Apparently, it surprised not only me but also professional astronomers. Thanks for pointing that out!

#4 northernontario

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Posted 20 January 2013 - 12:17 AM

Sounds like a great night.

I enjoy reading observing reports.

You hit some of my favorite galaxies. And gave me a reminder that I still haven't seen Thor's Helmet.

Thanks

jake






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