DSLR photometry
The emergence of Digital Single Lens Reflex (DSLR) cameras as cost effective astronomical imaging platforms has been underway for some years now. However, it has become clear that these cameras can be used for scientific work such as photometry in addition to their more traditional role in taking “pretty pictures”. participants of VSS are actively involved in exploring their use in this away and have identified key areas of research in which they are more suitable than traditional CCD cameras.
A tutorial for those learning DSLR photometry can be found on this site here.
Projects for DSLR photometry
Note that like Visual Observing, this area of research within VSS is based around the technique of observing, rather than purely the nature of the objects being studied. Some of the projects below therefore overlap with the research areas that focus purely on specific types of variable stars.
Bright Southern Cepheids for DSLR & Similar Cameras
Project Leaders: Mark Blackford & Stan Walker
This project is the second stage of the Bright Cepheid project. It makes use of the advantages of standard DSLR cameras: wide fields and the ability to make measures in three colour bands simultaneously. It is limited by the camera’s sensitivity which appears to be about magnitude 8 with exposures of 20-30 seconds. But this still allows about 80 targets south of the equator. A list of all such objects can be found at Southern Cepheids to Magnitude 8. This is divided into several categories: low amplitude; long period (>10.0 days) which are mostly large amplitude objects with frequent period changes; and assorted Cepheids which are neither of these types. Previously many of these objects had been monitored by the ASAS project but this appears to have ceased around 2008 so that there is now no ongoing observational study of these stars. We plan to fill this need.
Eclipsing Binaries – Insight into Stellar Evolution
Coordinator: Tom Richards
“Everybody knows” that wide, visually separated binaries provide an indispensable first step to astrophysics as well as the distance scale ladder. All we need to know is their distance by parallax methods, their orbital period P, and the apparent size of the orbit. True orbit follows, then their masses. Magnitudes at that distance give true luminosities which with their colour gives temperatures, thence their size. There’s no other way of making this first interstellar step.
Eta Carinae Photometric Campaign: 2019+2021
Principal Investigator: Augusto Damineli VSS Coordinator: Mark Blackford
Eta Carinae is now so bright that its 400-year long history of photometry risks being interrupted. Ironically, this could happen in a phase when we finally can see the central stars almost un-obscured. Very few CCD observers today are able to continue this historical monitoring since the star saturates with 1 sec exposure time even using small aperture telescopes.
Continued visual estimations are strongly encouraged to monitor long term trends; however, Augusto Damineli and other professional astronomers also require precision photometry data for their models.