Photometric Standard Stars II: RGB Color Photometry of Open Clusters between Declination +30° and +70°


This project is dedicated to the photometry of galactic open clusters in the Northern hemispherePhotometry with digital single-lens reflex cameras (DSLR) reflect the astronomical Johnson-Cousins BVRc color magnitude system. Selection of non-variable stars in open cluster fields will also enable a precise color calibration of any DSLR. Continuous observation of the variable stars will provide new data from these clusters.

A Vixen VC200L 20-cm Cassegrain was used for the observations. The telescope setup either used the Vixen focal reducer, or direct focus of the Cassegrain telescope (depending on the observation period). Open clusters have been selected using the WEBDA database. The selection is based on certain criteria: Declinations of clusters shall lie between +30° and +70°. The clusters shall at least contain certain stars with brightnesses in the range of V=8 and V=10. This is also correlated with the distance modulus of the respective cluster. Open clusters listed in the table have been selected and observed with different telescope and camera setup (see table). An overview of observations and cameras used is provided with the table below. Camera denoted by numbers in the table are: No. 1 denotes Canon EOS 40D series model (first light: 09. Feb. 2008). Camera No. 2 denotes Canon EOS 40D modified with clear glass in front of the sensor, and used with Astronomik UV/IR block filter (first light: 04. Aug. 2009). Camera No. 3 is a Canon EOS 60D modified with clear glass in front of the sensor, and used with Astronomik UV/IR block filter (first light: 03. Mar. 2011).

First results have been presented at the "Mitgliederversammlung der BAV" in Jena 21.-23. Sept. 2012. 


ClusterRADEDistModEB-VNotes Camera 
NGC 189305 22 44+33 24 42328014.380.581H-II
NGC 190705 28 05+35 19 30155612.250.415good1, 2, 3
NGC 193105 31 25+34 14 42308614.73 0.738H-II
NGC 693920 31 30 +60 39 42118511.360.320  3
NGC 694020 34 26+28 17 0077010.100.214  3
NGC 716021 53 40 +62 36 1278910.650.375  3
NGC 723522 12 25+57 16 12282315.150.934poor in VRc 3

Table: List of open Clusters selected from WEBDA between declinations from +30° to +70°. 




Paunzen, E. & Stütz, C., 2012. WEBDA, University of Vienna,

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