NGC 6781 (PK 41-2.1) Planetary Nebula in Aquila

Located at: RA 19 hours 18 minutes 28 seconds, Dec +06 degrees 32 minutes 15 seconds

Size: 1.8' Magnitude: 11.8 photographic Class: 3+3

North is up

West to the right

Telescope:

 8" f5 Newtonian reflector

Camera:

 ST-8XME, self-guided, binned 1x1, temp -20c, camera control MaxIm DL 4.55

Image:

 Red (Hoya 25A) filter, 150 minutes (15 x 10 minute subs), 08/25/2006

Processing:

 CCDStack 1.1, Photoshop 7.0

Location:

  Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes:

This is another rather small object for my 1000mm focal length, like M 1. See the 14.5" version.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6781

NGC 6781 = PK 41-2.1 = PN G041.8-02.9
19 18 28.2 +06 32 23
V = 11.6;  Size 111"x109"

18" (8/14/04): at 225x, appears moderately bright, fairly large, round, at least 
1.5' diameter.  A mag 13.5 star is at the NE edge of the rim with a fainter star 
off the NNW edge.  The rim is clearly brighter, particularly along the entire 
south side, with the rim fading on the north side giving an asymmetric or 
crescent appearance. A large central "hole" appears slightly  darker.  At 160x, 
one or possible two extremely faint stars flickered on and off within the 
interior of the disc but did not appear to be the central star .

17.5" (6/30/00): at 220x unfiltered this fairly bright PN has a 1.5' round halo.  
The rim is brightest and more well-defined along an arc on the S and SE rim.  
The central 45" hole is slightly darker and irregular in surface brightness.  A 
mag 13 star is at the NE edge and once or twice I caught a fainter glimmer of an 
interior star north of center.

17.5" (7/12/99): at 100x appears fairly bright, round, ~1.6' diameter with a 
darker center.  I used a variety of magnifications and filters but the most 
interesting view was at 220x using a UHC filter.  With this combination the PN 
is slightly elongated E-W and clearly brighter along the southern rim with the 
brightening tapering towards the ends so this brighter portion had a crescent 
appearance.  Because of this asymmetric rim the darker center seems offset and 
only weakly brightens at the NW rim.  A mag 13 star is just off the NE edge 1' 
from center.

17.5": at 222x and UHC filter; very large, about 1.8' diameter, much brighter on 
the SW portion of the rim, darker center.  A mag 13 star is just off the NE 
edge.

13": brighter rim mainly on the SW side, slightly annular appearance.  A faint 
star is off the E edge.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 6781
NGC 6781.  The position is for a very faint, very blue star -- the 
southeastern of two -- near the geometric center of the planetary.  The star
is not seen at all in any of the 2MASS images, but is clear on the DSS2B 
image. - Dr. Harold G. Corwin, Jr.