The Variable Star Section CCD target list

2022 January 29

Roger Pickard

As outlined in an article on the Section web pages (bit.ly/3rUB1Bo), there are two main aims of the CCD target list:

–  To encourage people who have CCD cameras, and who have developed the ability to take reasonable images with them, to point them at variable stars and develop their photometry techniques.

–  To provide some interesting targets and projects to get people involved in doing some real science.

Charts and comparison-star sequences can be downloaded from the American Association of Variable Star Observers Variable Star Plotter: aavso.org/vsp.

Beginner’s category

The beginner’s category contains eclipsing binaries, which show significant brightness variations over a reasonable timescale. These stars are guaranteed to vary. Following one or more of these stars over a few nights allows the beginner to test their photometric system and see some results in a relatively short period. The CCD mentoring scheme also puts beginners in touch with more experienced observers. If you would like to be allocated a mentor, contact the Director (see p.67 of the 2022 February Journal for contact details).

Eclipsing binaries in this category are listed below.

No observations were found in the Variable Star Section Database for EG Boo and those for ER Ori were very scattered, indicating they may be good stars to attempt observations of – perhaps after you have already had a successful run on another star like AC Boo, whose light curve is given below:

Basic CCD data

One field in which the amateur CCD photometrist has made important contributions in recent years is the study of dwarf novae (DNe). These systems have outbursts during which they increase in brightness by at least two magnitudes and often much more; the shortest outburst duration is two to three days.

One example is V452 Cas, for which a light curve is shown here for the last 13 years or so.

Perhaps a good example of a star needing more observations.

Time-resolved photometry

Time-resolved photometry is a technique commonly used in the monitoring of variable stars, especially cataclysmic variables. Again, the technique is relatively simple: a series of images of the target is taken over a period of minutes or hours to look for variations in brightness.

Other targets & projects

Occasionally, the Section organises campaigns to observe particular stars, often in association with professionals. Notifications of these are given via the BAA website, the BAAVSS-alert Forum and the VSS Circulars.

Therefore, do not forget to join the VSS Alert group at baavss-alert+subscribe@groups.io or visit the web page at groups.io/g/baavss-alert.

Roger Pickard, Assistant Director (Director, 1999-2019)

roger.pickard@sky.com