NGC 6735 and Berkeley 81(Lund 875) Open Clusters in Aquila

Center of field at approximately: RA 19 hours 00 minutes 45 seconds, Dec -00 degrees 27 minutes 20 seconds

Size: 8.0' and 5.0' Magnitude: -- and -- Class: -- and II 2 r

North is up

West to the right

Telescope:

8" f5 Newtonian reflector

Camera:

 ST-8XME, self-guided, binned 1x1, temp -10c, camera control MaxIm DL 4.56

Image:

Lumicon Red filter, 300 minutes (30 x 10 minute subs), 09/31 & 10/1/2008; seeing 2.5-3.1 FWHM per CCDStack

Processing:

CCDStack 1.3.7, Photoshop 7.0

Location:

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

Notes: Berkeley 81 is the object to the east (left) that *looks* like an open cluster ... My plotting software (Megastar v5.0.12) does not plot Berkeley 81. I only 'discovered' it by downloading a DSS image of NGC 6735, which is a very non-descript NGC open cluster around the 'bright' star to the west (right). In the Arizona Database v9, NGC 6735 is listed as "cluster of 35 stars surrounding SAO 142915".

From the NGC / IC Project:

Contemporary Visual Observation for NGC 6735
NGC 6735
19 00 37 -00 28.5
V = 7.5;  Size 14

17.5": about 50 mag 13 stars in a 10' field which are very uniform in 
brightness.  The exception is a mag 7.2 multiple star (SA0 142915) on the N side 
which has three faint companions including a mag 13.4 star at 10" and a mag 12 
companion at 22".  This is a large but basically faint group.  The outliers form 
a circular pattern and the W to N side is well-defined by a semicircle of stars.

Discovered by JH (h2025). This is a cluster of ~30 stars surrounding SA0 142915.  
Listed as nonexistent in RNGC.  Description and position given by JH are a 
perfect match.

- by Steve Gottlieb
Historical Research Notes / Correction for NGC 6735
NGC 6735 is a clustering of stars around SAO 142915 (JH's position refers to
this star), though the center of the cluster seems to be a bit southwest of 
the star.  It matches JH's description quite well, and would probably stand 
out nicely in a wide-field eyepiece. - Dr. Harold G. Corwin, Jr.