NGC 7789

NGC 7789 in Cassiopeia is one of the richest galactic star clusters in the sky. It consists of over 1000 stars of magnitude 10.7 and fainter in an area half the size of the full moon. This cluster was first discovered by Caroline Herschel (William's sister and assistant) near the end of the 1700s.

NGC 7789, Wright-Newtonian photograph.

Exposure Data

Instrument: 9.5" f/4.9 Newtonian
F/stop: 5.6
Exposure: 2 x 5 min + 2 x 2 min + 1 min + 30 sec
Camera: Nikon D70 with Baader UV-IR-Cut-Filter
Sensitivity: ISO 1600
Date: August 15, 2006
Exposure start: 23:40 MESZ
Location: Sophienalpe, Vienna
Conditions: Visual limiting magnitude 5.0 mag, Seeing 4/10, Temperature 15°C, no wind, moderate humidity
Autoguider: Meade Pictor 216 XT, max. error: 1" (RA), 1" (Dec)
Enhancement: Basic data reduction, combine, logarithmic curves, star size reduction, dynamic range extension, noise filtering, crop
Notes: Moon up in the sky. The exposure series was cut short by incoming clouds.