NGC 6811 (Lund 897, Cr 402) Open Cluster in Cygnus

Located at: RA 19 hours 37 minutes 13 seconds, Dec +46 degrees 21 minutes 50 seconds

Size: 12' (15') Magnitude: 6.8 Class: III 1 r

North is up

West to the right

Telescope:

8" f5 Newtonian reflector

Camera:

ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.54

Image:

 Red (Hoya 25A) filter, 110 minutes (11 x 10 minute subs), 08/5/2006

Processing:

CCDStack 1.1, Photoshop 7.0

Location:

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

Notes: According to "Star Clusters", by Brent Archinal and Steven Hynes, the size of this open cluster is 15 arc minutes.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6811

NGC 6811 = Cr 402 = Mel 222 = Lund 897
19 37 17 +46 23.3
V = 6.8;  Size 13

17.5" (7/1/00): this a large, beautiful cluster at 100x.  The central section is 
~8' in diameter, roughly triangular and contains a scattering of ~20 10-11th 
magnitude stars.  There are no prominent members - the brightest star (at the 
west edge) has a faint companion.  Perhaps 85 stars are resolved in the 
unconcentrated central region (there is nearly a void in the center) over haze.  
The richest knot of stars is on the NE side.  An isolated 5' tails of stars 
extends NW and another curving string of stars can be traced 8' to the east.

13": fairly large and rich group of approximately 60 stars including many mag 
11-12 stars.  A long trail of stars follows and a bright group of stars is WNW.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 6811
NGC 6811.  JH has two observations of this, separated by nearly a minute of 
time in RA and 6 arcmin in Dec.  The RA of the first observation is correct, 
while the declination of the second is correct.  Unfortunately, the position 
JH adopted for the GC carries the RA of the second, and a Dec 10 arcmin 
further on north.  I think he meant to use only the second observation (he
notes that the first observation refers to "A double star in the southern
part ..."), so the incorrect Dec must be a transcription or typographical 
error.

Once these errors are corrected, though, N6811 turns out to be quite a nice
cluster, ten or twelve arcmin across, with perhaps a hundred stars, many of
the 10th and 11th magnitudes. - Dr. Harold G. Corwin, Jr.