Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 01/03/2023 - 19:31
AAVSO Alert Notice 807 reports on the dwarf nova outburst of the old nova GK Per (N Per 1901). Please see the notice for details and observing instructions.
There are threads for this outburst of GK Per under the following AAVSO forums:
- Cataclysmic Variables: https://www.aavso.org/gk-per-brightening-2022-01
- Time Sensitive Alerts: https://www.aavso.org/gk-per-brightening-2022
Please subscribe to these threads if you are observing GK Per so you can be updated. Join in the discussion or ask questions there!
Many thanks, and Good observing,
Elizabeth O. Waagen, AAVSO HQ
I'm posting this as a matter of interest. These were observations of GK per carried out by two observers at the same time ( by chance, not by design), one in England and the other in Spain. We thought it showed a remarkably close match. The time span is about one hour. Independently, we both thought that the erratic nature of the light curve might mean some problem with our observations or methods but it appears that they are correct. I quickly put the graph together in excel so the y axis is upside down from the way we usually plot magnitude. The observations have been posted in WebObs in the usual way.
https://www.aavso.org/sites/default/files/users/user64110/gk%20per%20comparison.jpg
FYI, You can check a box to invert the y-axis in excel. Google "invert axis in excel" to find out how.
Jim DeYoung (DEY)
Good job woodblock.
On this occasion, also casual, it was an almost perfect relay! hahahaha
https://www.aavso.org/LCGv2/static.htm?DateFormat=Julian&RequestedBands=V,TG&Grid=true&view=api.delim&ident=gk%20per&fromjd=2459968.29&tojd=2459968.40&delimiter=@@@
Jesús De Mula (DJEI)
Yes it looks good. No stacking this time and I shortened the exposure and increased the gain as you suggested.
Just a quick question. Do you usually use multiple reference stars? That is to say an Ensemble?
Thanks
Steve
Yes, that's how ASTAP works (ensemble). Although the analysis also asks for a comparison and a check as a reference for the report. I always choose: 000-BBG-055 and 00-BJW-692.
Each light with 20 sg at 400ISO, within the linearity of the camera, so as not to drop below the average SNR of 50. Obviously working only with the G channel.
Jesús