2014 programme

Variable Star Photometry with a DSLR Camera

Mark Blackford

ASNSW, VSS, AAVSO

Crucial to our understanding of variable stars is the accurate measurement of their brightness variations over time. Experienced amateur astronomers equipped with CCD cameras are now contributing professional quality data, often in pro-am collaborations. However astronomical CCD cameras and associated additional hardware, such as photometric filters and automated filter wheels, are quite expensive.

In recent years standard commercial DSLR cameras have been employed as relatively low cost stellar photometers with surprisingly good results. So much so that the American Association of Variable Star Observers (AAVSO) ran a workshop in 2013 to write a DSLR Observing Manual to promote their use in variable star observing.

DSLR cameras equipped with standard telephoto lenses are well suited to monitoring stars that are too bright or with small amplitude that are difficult for CCD or visual observers, respectively. However, there are both advantages and disadvantages to DSLR cameras which will be briefly illustrated with examples from observing programs on eclipsing binary and Cepheid variables. This work has been in collaboration with Australian and New Zealand amateur and professional astronomers and has led to several publications.