Cepheid Images needed for photometry & period determination

American Association of Variable Star Observers (AAVSO)
Wed, 11/09/2022 - 11:08

I'm working on a school project and I have to determine periods of different types of variable stars in order to calculate the distance. For this reason I am looking for images of different variables stars like Cepheids and eclipsing binaries. A data set with at least two visible visible peaks is needed and the more images you have the better! All kind of Cepheids are welcome, stars like RR-Lyrae-type, Mira-type, long period/short period, delta-scuti-stars.

I'm really thankful for any data set you are able to provide.

Generally, data for a given…

Generally, data for a given star is not so "dense" as to provide a nicely graphable period from just a couple periods. We may only have data every week or more for a given star. That said, for long observed stars VStar can get you a period or range of possible periods. 

1) Use VStar to examine data for a star. use VStar to find best fit period. Verify in VStar by doing phase plot.

For instance, for CG Cas, the Vstar plot looks pretty sparse. but by doing FFT analysis it comes up with a suggested period. Do finer scale analysis around that suggested period to come up with a more accurate period. Use VStar to do phase plot on that period to see if curve is reasonable.

Do you want some suggestions of stars to do this with??

Also, and this may be "cheating" for your project, you can look up a cepheid in VSX and if the period is known it will tell you what it is.





American Association of Variable Star Observers (AAVSO)
Images or magnitudes?

Pavithiran -- Would data already in the form of magnitudes be of use to you, or do you need images?  Magnitudes that can be used in period searches are more easily available than unreduced images, not only from the AAVSO database but from sources such as ASAS-SN. -- Horace Smith


American Association of Variable Star Observers (AAVSO)
Delta Scuti or Beta Cephei

I think your best bet in the this case is going to be either a delta Scuti or beta Cep where you can get a couple cycles in one night.  I would also suggest having a couple nights with some separation to provide a longer baseline.  You could then mix in archival data from AAVSO, TESS, ASSN, etc.  A couple questions:

1) This would likely be a fairly large set of data.  So, how could it be transferred?

2) Would you want raw data frames or ones that have already been processed with Zeros, Darks, and Flats?

Eric Hintz

American Association of Variable Star Observers (AAVSO)
Hello EricDelta Scuti or…

Hello Eric
Delta Scuti or Beta Cephei data would be awesome! I usually do data transformation via "mega.io upload" or "google storage" and then send download links of the data sets. Preferably I would need processed images. If you are able to provide me with such data, I would be really grateful!