Two Questions From A New Observer - First Light Curve

American Association of Variable Star Observers (AAVSO)
Fri, 11/03/2023 - 02:36

Hello All,

Question 1: How can we share image and spreadsheet data? The upload links are greyed out for security (so I understand). How can we get feedback on work?

Question 2: Where is it possible to get ephemeris data for more than a month ago? The VSI is limited to the beginning of the month. I haven't had any luck with the Light Curve Generator.

I constructed my first light curve (SW Lac JD: 2460238.716829 to 2460238.878495 - 230 frames of 50s with a V filter). The curve is constructed with AstroImageJ with both calibrated and uncalibrated frames - separately - (to test one against the other and gauge annulus). The curve is fairly dramatic over the 3.88 hours of patrol. The period of SW Lac is ~ 7 hours.

I'm looking to see that I'm on the right track. I also don't fully understand transformation. I've read the mono imaging manual, but I don't really understand the threshold for transformation.

Thanks for any help on this.

Best -


American Association of Variable Star Observers (AAVSO)
Use VPHOT to define your…

Use VPHOT to define your telescope .

Upload your images into VPHOT

Use VPHOT to create valid sequence with Target star, Comps and Check star, you can then apply the sequence to a group of images (same target, same time frame, mix of UBVRI filters)

Then run Transform Generator program mentioned above supplying Telescope and exported Time Series images.

TG can export a file to apply to your Telescope which contains the Coefficients.

Not a simple process in my opinion. Perhaps you can accomplish some of the steps above.

I took two online course offered by AAVSO - CCD Photometry, Parts 1 & 2  &  Photometry Using VPhot. I needed these courses to understand the processes outlined above.

Courses can be found here -

Tony the Transform Generator (windows) executable can be found at the following link -