AAVSO Photometry CHOICE Courses

[Go to CHOICE course calendar]

At present there are two AAVSO CHOICE Photometry courses, one for monochrome CCD/CMOS cameras and one which describes how to use VPhot for photometry. These courses require daily commitments of time from each student to complete successfully. This includes time taking and processing images as well as participation in discussion questions on the forum. Students will be asked to share their results with the instructor and with other students.

CCD Photometry Equipment Requirements

For the Spring 2023 course all images will be provided by the instructor, so there is no basic requirement for equipment other than a suitable set of software to process images and knowledge of how to use that software. However, the more you can take and use your own images, the better the experience. Thus, the following guidelines.

The purpose of the CCD Photometry – Part I (CCD 1) and CCD Photometry Part II (CCD 2) CHOICE courses is to instruct students in basic photometry so that they can carry out research on light variation of stars and star systems and submit their observations to AAVSO, other organizations, or use the results for their own research activities.

DSLR’s and one-shot-color CCD/CMOS cameras are not suitable for CCD1 and CCD2. If you plan to use a monochrome CMOS camera, you should be experienced with making your own decisions on camera gain, offset, and stacking settings.

The CCD/CMOS instructor for Spring 2023 has photometry experience with the CMOS ASI183mm but might not be able to help you with other brands or models of cameras. The instructors will provide images for students with cameras which are not supported by the course and for users of CMOS cameras who need more experience with camera settings.

Students contemplating photometric observations should purchase at least two photometric filters. Johnson V and Johnson B are recommended. Note that these are not useful for OSC or DSLR cameras. Students transitioning from astrophotography are almost uniformly familiar with calibration but may not be familiar with the process constraints photometric analysis. You can use your RBG filters to do most of the tasks in the course and are encouraged to do so, but make sure you also use those images provided by the instructor as well.

When purchasing Johnson-Cousins photometric filters be sure that the transmission curves for your new filters resemble those shown on page 46 of the AAVSO Guide to CCD/CMOS Photometry. Also, review the AAVSO forums discussions on picking photometric filters.

Students in CCD 1 and CCD 2 are assumed to have suitable software and know how to use it for such activities as taking, manipulating, and analyzing images. For photometric analysis the courses actively support the use of AAVSO’s VPhot tool. If you become serious about studying variable stars you are encouraged to join AAVSO and enjoy the benefits of membership.