PDA

View Full Version : NGC 6881 and 6765 revisited after a year



Jraymond
July 29th, 2016, 01:30 AM
In May of 2015 I attempted both of these from a dark site at a local star party. Please note "East coast dark" is like your dark site under a quarter moon.

6765 in Lyra is not like M57. Not at all. With my 18" at 230x, I found it to be faint and ghostly, challenging, barely visible direct, better with averted vision. . OIII helped to make it steadily viewable directly.

6881 in Cygnus was not seen. Or I saw it and didn't Know it....it's a tiny PN in a rich field. I spent some time looking. I didn't bother blinking the filter. So many other things to view on a rare clear night.

Fast forward to July 1 of 2016.
I do most of observing n my urban backyard where the Milky Way is invisible, and my eyes can't dark adapt due to streetlights. I do the best I can.

I revisited these two challenging PN's. I made sketches this time. I use a 5.5x8.5 spiral bound sketchbook for informal drawing. I have no artistic skill. The circles are drawn in ink with a 2" eyepiece, 6 to a page. Notes are written around the circle in no specific order or format. The light spots are spilled iced tea. Photos of the sketches were inverted for aesthetics.

6765 is just as difficult as before, even more so. This time it's only visible with OIII. It's mostly round with irregular edge.

6881 was easy to find close to the Crescent Nebula, easy to see as a faint star, but challenging to see as non-stellar. I had to use over 300x. The scope doesn't have tracking so sketching at this power is difficult, plus I need reading glasses. Luckily the scope moves smoothly even at 457x, without any stuttering or backlash. (And my stars are round!) 6881 was visible as a tiny grayish round nebula. I confirmed with SkyTools and google image search.

I hope to improve my observing skills. Like John Varley's car with square wheels, if I keep moving the corners will round off eventually.

Regards
John22102211

wvreeven
July 29th, 2016, 09:05 AM
NGC 6765 is an interesting planetary nebula with an unusual structure. It has a central bar-like structure with two wings, one of which is brighter than the other. I had a renewed look at NGC 6765 with my 20" a few weeks ago and managed to catch the bright wing, but not the faint one. My notes read:

Tried with 427x, 545x and 692x. At 427x with UHC and OIII, at the other magnifications OIII only. Best view was at 545x with OIII because the seeing prevents a good view at 692x. The central part of the nebula was seen as a comet like structure with a bright head. The eastern detached bit was visible as a faint, round glow. No further structure seen.

Sue French
August 1st, 2016, 06:05 PM
9-23-03 254/1494mm Newt
22mm Nagler: I could not find this without a filter, but it popped right out when I added an OIII. Once identified, I removed the filter and could faintly see the object with averted vision. 13mm Nagler: Easily visible with a filter and has a brighter spot in it. OIII makes the nebula more apparent, but no further detail is revealed. 9mm Nagler + OIII filter: The planetary is elongated in PA ~ 30° and has two brighter patches. The brighter of the two is in the northerly part. Size ~ 35″ determined by comparing to the separation between two nearby stars measured using MegaStar.

9-11-04 368/2207mm Newt
35mm Panoptic: faintly visible. 13mm Nagler: looks much like a small galaxy elongated NNE-SSW and 40″ long and patchy. Responds well to UHC and even better to an OIII filter, which highlights a brighter patch in the NNE end. 9mm Nagler: Very pleasing view without the filter, and the unusual patchiness shows well. I'd certainly think this was a galaxy if I'd just stumbled across it.

10-2-05 254/1494mm Newt
13mm Nagler: Moderately bright smudge ~ 2′ northeast of a nearly north-south pair mag ~12½ stars. Nebula elongated NE×E - SW×W. 7mm Nagler: Seems oddly bar-shaped and uneven in brightness. Bright, nearly stellar spot in northern end. OIII filter: The bar is patchy and brightest in the northern end. There seems to be a fainter haze around the bar, especially to the east. ~ 35″.

5-29-08 105/610mm apo
7mm Nagler: very small, extremely faint, stands out very slightly better with UHC or OIII. 5mm Nagler: A little more power helps more than filters did. Can be held with averted. Elongated NNE-SSW about ½′, maybe a little more.

Steve Gottlieb
August 2nd, 2016, 05:20 AM
Another observation of NGC 6765

18" (7/16/07): this unusual planetary was picked up at 174x unfiltered as an elongated glow. The view is confused, though, as a star or knot in directly involved at the NE end along with 1 or 2 additional stars around the edges. Excellent contrast gain with an OIII filter as the edges sharpened up and the halo appeared elongated 2:1 SW-NE, ~0.6'x0.3'. At 225x, a mag 14-15 star is just off the NE end and the involved knot seemed to occasionally resolve into a couple of faint stars just north of center near the NE edge. Finally, an extremely faint star occasionally sparkled at the SW end.