I will come up with an I band magnitude for the comp as soon as I can.
Tom
Ben Taylor's 1986 paper, TRANSFORMATION EQUATIONS AND OTHER AIDS FOR VRI PHOTOMETRY, ApJS, provides R-I for both the comparison and check stars.
Comp HD58207/HR2821 R-I = 0.471
Check HD60522/HR2905 R-I = 0.850
Using the VSP Rc magnitudes yields comparison I = 2.796
check I = 2.337
Taylor also provides V-R for the check star as 0.860. This is reasonably close to the VSP value of 0.873, which has a very large uncertainty.
A note to CCD observers (e.g. the AAVSOnet BSM systems), the nearby red star HD 61911 is a tempting comparison but I will note that it shows variability at the ~1% level in previous TESS data. Since TESS will observe it simultaneously with sigma Gem, it might be possible to correct for its variability but I wanted to make people aware of it. HD 63138, about a degree to the east, looks much more stable if you can get it in your FoV.
CCD observers have been using 000-BPS-000 (HD 61911) as a comparison. The Variable Star Plotter has a new message about this star: "HD 61911 - SRS+ORG - V= 7.70 - 7.74. ONLY FOR VISUAL USE."
This is presumably due to the VSD cleanup.
Tom
Elizabeth:
Are the TESS observations completed? Is the campaign concluded as per schedule?
Ken
Thanks for asking, Ken. I asked Shashank about the status of the campaign earlier this week and expect to hear from him shortly. He or I will post here as soon as possible.
Good observing,
Elizabeth
Alert Notice 837 announces an observing campaign on the bright RS CVn variable sigma (sig) Gem. For details and observing instructions (campaign is best suited to PEP but CCD/CMOS may be possible), please see the notice.
There is a thread for this campaign under the following AAVSO forum:
- Campaigns and Observing Reports: https://www.aavso.org/sigma-gem-campaign
Please subscribe to this thread if you are participating in the campaign so you can be updated, ask questions, and join in the discussion!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ