Many observers have CCD cameras and have desired to
try something beyond taking pretty pictures. Photometry is an area that
holds much potential for astronomical CCD work. Getting started can
The July 2007 issue of Sky & Telescope magazine had
a two page article on the fast binary star system SZ Herculis. Where
there are many visual observations of this system, there are not many
photometry observations. This may be a good project to get started with
To start, unfiltered or filtered photometry without
calibration can be done to produce a light curve. Once successfully
completing that phase, the system can be calibrated and filter photometry
can be done. Having gone through this project, more advanced projects
should be easy.
Other objective can be:
Calibrating other comparison stars
Determining best exposure times
Determining best aperture and annulus sizes
The following information should help get started.
Image taken at HPO 9 August 2007. Observatory
temperature at 21:30 was 102 F. Image was taken with a modified DSI
Pro (TEC cooled), F/10 12" LX200 GPS with F/3.3 focal reducer and
V photometric filter. Exposure was 10-8 second exposures stacked with
dark frames subtracted, No flat fielding was done.
RA (2000) 17:39:36.8
Dec (2000) +32:56:47
Spectral types: Ao + G2
Other IDs: AAVSO 1735+33, HIP 86430, AN 174.1908, NSVS 8048731
Algol type eclipsing binary star system
Visual magnitude 10.2 to 12.0. B= ?, R= ?. I= ?
Period 0.81809828 days (19h 38m 0.0615232 s)
Epoch: 30 July 1973 (HJD 2441864.3052 AAVSO)
Ingress: 90 minutes Egress: 90 minutes Total eclipse 180 minutes
Sky & Telescope July 2007 (Pages 58, 59) and June 1997 (Pages 76,
Find new references
Determine comparison stars and magnitudes
Find star system and obtain images (filtered or non-filtered)
Process images and obtain instrumental magnitudes - plot data
Calibrated system, take filtered data, reduce data, plot calibrated
To help with finding the star the AAVSO has a very nice
star chart plotting program. It can be found at
The following is a screen shot of the window that allows
you to create your own customized star chart.