Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 05/30/2013 - 02:11
I was just using Seqplot to examine all sources of field photometry for KT Eri. Data from W30 and SRO50 is not showing up in the results even though the boxes are checked. Only data from BSM and APASS are shown. This was the case back in January when I mentioned this subject on the Photometry forum. I was told W30 and SRO50 data would be added back to the Seqplot database when APASS DR7 was released. I'd appreciate it if someone could do this as I have some photometry of KT Eri I'd like to submit, but I need to sort out some sequence issues first.
Thanks,
Bob
Hi Bob,
Thanks for the reminder about that. The data were taken out when we rebuilt the database last year in order to accomodate APASS data. We will work on getting them back in now (it will probably be some time next week since Arne is away) and will post something here when it is done.
Regards,
Sara
Thanks Sara.
Bob
I was wondering if anyone at HQ has been able to restore the W30 and SRO data in the SeqPlot database?
Thanks,
Bob
Hi Bob,
Sorry for the delay in getting this done, but the W30 and SRO data are once again available for use in SeqPlot.
I hope it helps with your project.
Best regards,
Sara
Thanks Sara!
Bob
Sara,
For the KT Eri field, I see plenty of W30 photometry but none from SRO50. I recall that Arne mentioned that there was some photometry from SRO50 for this field. If you could ask him about this I would appreciate it.
Thanks,
Bob
Hi Bob,
From Sonoita, we have data on KT Eri (Nova Eri 2009, Nov 2009) for the nights of: 100124, 100126, 100127, 100130, 100206, 100208, and 100209, during the outburst. None of those nights were considered photometric, and so while we have good differential photometry, we don't have any calibration from SRO. Sorry if I misled you!
Arne
Arne,
O.K. I understand now. Was the W30 data taken on photometric nights? How many nights? I seem to recall that you mentioned there were 2 - 3 nights of W30 data on the KT Eri field, but the Seqplot database now shows 8 nights for most stars. The W30 data is 0.07 mag brighter than APASS. Was hoping a third set of data on this field would help me decide which was better, APASS or W30.
Bob
Hi Bob,
All data in Seqplot was taken on photometric nights. In some circumstances, a specific field may have a bad observation, due to trailed images, high airmass, passing cloud that didn't impact the standard-star observerations, etc. In most cases, those bad observations have been removed, but this is a manual step and I can miss an observation now and then.
In the case of KT Eri, W30 observed on 8 photometric nights, and looking at the data, it has reasonable error, around 0.02mag from 11.5<V<15.5 and then increasing to 0.1mag by mag17. The APASS measures for this field are 0.07mag fainter than W30, but they also have larger than normal photometric errors (also 0.07mag; probably one of the 4 nights needs to be discarded). Within their errors, these two datasets agree. However, W30 is a better choice in this case, both because of the larger number of nights, as well as true Rc/Ic measures.
Arne