I don’t see why you couldn’t

Forums Variable Stars Measuring variable stars with a DSLR I don’t see why you couldn’t

James Screech

I don’t see why you couldn’t use the calibration in Nebulosity and then do photometry in Iris, though I’ve never used Iris myself. Below are details of the hardware, software and workflow that I use.

Canon 500D (modified) with red dot finder mounted on the hot shoe
Bahtinov mask
Canon 200mm f2.8 lens
Celestron SE4 alt/az mount
Bracket made from a binocular L mount and dovetail bar (to connect lens collar to mount)

Nebulosity 4 (demo)

Capture workflow:
Perform two star alignment of mount using APT’s liveview feature with crosshairs on.
Manually focus lens using mask using 1 – 2 sec exposures,I find APT’s bahtinov aid doesn’t work very well, so just look at the images on screen.
Capture 20 flats (same ISO as required for variable)
Capture 20 darks (same ISO and exposure as required for variable)
Use APT’s Goto++ feature to get within 100 pixels of the target star
Use APT to capture images

I have previously ascertained the correct ISO/exposure for a variety of star magnitude ranges so as not to saturate the variable or comparison stars.
APT’s Goto++ is a great way to centre an object and saves a log of time.

Processing workflow:
Use Fitswork in batch mode to extract 3 colour planes into individual fits files for flats, darks and lights.
Delete the red and blue files as they of no use.
Use Nebulosity demo to preview the files and rename/delete those that have excess trailing or cloud, so these files are not used for photometry.
In AIP4Win setup basic calibration (darks and flats).
Use AIP4Win MIPT to analysis images (calibrating at the same time).
Import the AIP4Win data file into the BAA VSS spreadsheet to produce BAA database submission format files.
As well as submitting the photoemtry to the BAA VSS I also measure the timeings of minimums (using software I have written) and submit the times to the Krakow University database.

I have previously determined the read noise and gain of the ISO settings I use as these are needed by AIP4Win
I have a small utility to calculate the heliocentric offset, again used in AIP4Win.
Personally I don’t think much of AIP4Win and only use it so that I can use the VSS spreadsheet. It contains a lot of bugs and the author is not interested in fixing them.
For comparison stars I use the AAVSO VSP to produce charts and tables of suitable stars.

The above works for me, I’m sure a lot of other software and workflows will also work. Good luck if you decide to give it a try and feel free to ask if you wat any help / advise.