If you have a CCD or CMOS camera designed for astroimaging, or a DSLR camera attached to your telescope, you can perform photometry of variable stars.
Using the naked eye, binoculars or telescopes, the variable star and nearby non-variable stars of known brightness are observed, and the brightness of the variable star, at a particular time, is estimated by comparing it with the appearance of these adjacent comparison stars.
A novel method of digital single lens reflex (DSLR) photometry is described. It derives non-transformed instrumental magnitudes from white light (green, blue, and red channels of the DSLR sensor combined), and is assessed by comparing the results with non-transformed instrumental magnitudes from the green channel alone, and with green channel magnitudes transformed to the Johnson V standard.
The high amplitude δ Scuti star AD Canis Minoris was studied by photoelectric photometry (PEP) during one night in February 2011 and by digital single lens reflex (DSLR) photometry during seven nights in January and February 2016.
Digital Single Lens Reflex (DSLR) photometry of the high amplitude δ Scuti stars V1338 Centauri, V1430 Scorpii, and V1307 Scorpii was taken during the southern autumn and winter of 2015.
The δ Scuti star ZZ Microscopii (HD 199757) was studied by photoelectric photometry (PEP) on three nights in 2008 and by DSLR photometry on three nights in 2014.
DSLR photometry of the δ Scuti star EQ Eridani (HD 28665) was undertaken on six nights between 2 November and 8 December 2013.
Methods are described for the construction and analysis of O–C (observed minus computed) diagrams and for the determination of light elements (ephemerides) of variable stars and the standard errors of the elements.
V393 Carinae is a 7th magnitude δ Scuti star which has a principal period of 0.1413 d and an amplitude of 0.2 magnitude in V.
Photoelectric and DSLR photometry of the monoperiodic high amplitude δ Scuti star RS Gruis yielded 16 times of maximum determined by the author from 2007 to 2013.