AAVSO Alert Notice 704 announces an urgent observation alert for the exoplanet candidate system TYC 2483-160-1 for THIS EVENING, 2020 MAY 6. Please see the notice for details and observing instructions.
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
With a mid-eclipse ephemeris at 03:00 UT and an eclipse duration of about 06h40, I expected a start of ingress around 23:40 UT because exoplanet transit lightcurves are usually symetrical.
Here in Europe, the target was very low and I just planned to see the ingress. But at first glance, I see a flat lightcurve during my whole session, from 22:18 UT to 00:26 UT
PJMO captured a light curve of the primary eclipse from about 02:23:16 UT until we stopped just before the telescope hit its altitude limits at 06:04:18 UT. Below is a rough preliminary flux LC in R @ 10 sec EXPTIMES produced real time with the images calibrated by darks only. We didn't take flats until after the run. There were 3 anomalous images that produced the three spikes.
If life doesn't get in the way, I should have a final LC uploaded to AAVSO today.
Brad Walter, WBY
The PI may want the AIJ output files in addition to the WebObs data. If they want the original images we can also upload those to an sftp site.
I noticed the RHM R filter LC was very similar in shape over the common time range spanning the minimum but offset 0,3+ (oops dropped the decimal point initially) magnitudes (fainter) from the PJMO R magnitude LC. APASS only has B and V magnitudes for this star but Gaia has observations in all of its normal filters and they transform to a value of 9.832 R mag. The PJMO R mag LC appears consistent with the R mag derived from Gaia data. and the average of 119 check star measured R magnitudes for the run was substantially less than one standard error from the R mag for the 119 check star in the VSP sequence. I have no idea what causes the offset between LCs, but the RHM LC appears consistent with V magnitudes for this star in APASS and derived from Gaia rather than R magnitudes.
I wish that we could have captured the complete egress but we were under 16 degrees altitude; the data had too much scatter to the point of occasional differential magnitude sign reversals between 11.349 R mag comp and 11.421 R mag check and the telescope was about to hit the hardwired stops.
PJMO LCs below. Mag LC uploaded to AAVSO.
Brad Walter, WBY
I managed to measure a large portion of the eclipse from the RIT Observatory in Rochester, NY, though I missed both ingress and egress. I used an "R" filter due to the large airmass -- the object was at sec(z) = 2.7 when I stopped observing around 12:30 AM. You can find a description of the observations and reductions, together with a full dataset, at
I've uploaded my measurements to the AAVSO website as well. Note that I caught the eclipsing binary YY Cnc at the southern edge of my field, and it, too, was undergoing an eclipse last night.
Good luck to the project!
I want to thank all those who participated in this observation. My summary of results for those I have heard from so far are as follows:
Brad Walter – captured eclipse approx. 40 minutes before midpoint to approx. 3 hours after
Michael Richmond – captured eclipse approx. 1.5 hours before and 1.5 hours after midpoint
Serge Bergeron – also was able to observe approx. 1.5 hours before and after midpoint; awaiting results
Claudio Lopresti – unfortunately was only able to observe prior to ingress
Emanuel Conseil – was able to observe only up to ingress.
So, because of the duration of the eclipse and time of midpoint, we were not able to get a full eclipse prior to and after egress, however, the observations of Brad, Michael and Serge should still be useful to the science team. I’d like to ask all three to continue communication with me directly via email at firstname.lastname@example.org so we can better discuss results. I will then report back to the Forum any preliminary results. I have heard via email from Brad, so if Michael and Serge could email me we can continue discussing the results and data format required to send to the PI.
Thanks again to all who participated.
Chair, AAVSO Exoplanet Section
I send Jerry an excel file of my results including both my AIJ fluxes and my VPhot magnitudes. He responded that what he needed was BJD(TDB) and flux (and I assume uncertainties). I will be sending my BVIc results to him today. I am also following up with some out-of-eclipse data if I get another clear night.