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AAVSOnet telescopes in New Mexico have made two observations of ER UMa this week marking the start of this star’s observing season. As noted above, the next superoutburst may be around Oct 1 but could be later by a week or so as ER Uma does appear to vary its super cycle period between 45 and 55 days.
For UK observers, the star is very low in the north by north west sky in the evening. In the unsociable early morning, it does rise about 30 degrees above the horizon before dawn.
More details on ER UMa were presented in VSS Circular 188.
Nick, I’m pleased to see your results in the BAA database as neither SLOOH or AAVSOnet have delivered results for last night. Slooh had it at CV 14.9 at UTC 2021/09/06 00:10:23. Looks like the superoutburst is under way and it was around the time expected. Normally they last for about 10 days. Stewart
IX Dra has a superoutburst period of around 60 days – give or take a day. This means the next superoutburst is likely to be around September 5 -7th. The most recent magnitude I have is around 17.7 CV (on 2459456.5 Aug 30) using SLOOH Canary 2. Further observations to capture the start of the superoutburst would be welcome.
Got a series of seven 60 s images from iTEL 18 in Spain last night 2459431.46 . Airmass of about 1.016.
All seven are around 11.47 V mag using Vphot and AAVSO comp stars.
This is a bit of a fade over the last 2 days.
Stewart
I am occasionally contributing to the present campaign on CG Dra with a V filter on iTEL 18 in Spain. Many of the results are being gathered using the CV method.
What systematic differences do we expect between the two?
Stewart
The good news is that iTEL are forgiving of my mistakes in setting up runs. They have refunded my account which I think is very good of them.
I thought I would give this bright nova a try with iTEL 18 (300 mm) in Spain. Even with only a 5 sec exposure the images were saturating. Then all iTEL images are charged as if they were 60 sec exposures – not economical.
So I will stick to fainter objects unless someone can point out a workaround.
Stewart
Nick, These two observations constrain the start of the superoutburst rather well giving a super outburst period of about 59 days. This is in line with recent periods. IX Dra does seem to be fairly consistent. Until the next time of course.
Cheers
Stewart
iTEL 18 and Vphot gave CG Dra at 16.71 very early this morning.
Check star 147 (14.674 ) estimated at 14.679. Airmass 1.04.
Stewart
IX Dra has been observed by AAVSOnet New Mexico scope, in combination with Vphot, as follows.
2021/07/09 03:45 14.57 V
2021/07/10 04:44 14.7 V
These are values consistent with a superoutburst. There has been a week of no observations so the start of the outburst is not yet clear.
Stewart
iTEL 18 and Vphot report CG Dra, 2459405.55119, 16.693 V filter
So a short outburst that I have just missed. Still all results are useful. iTEL subscription get refreshed on the 12th so will try again.
Stewart
Tim, At the MAST site there is one 27 day photometry measurement for RX And in the TESS data. this record suggests there may be a period of 0.21 days. However there seems to be a lot of short term variation that makes pulling out the 0.21 period really difficult.
MAST is at STScI | Mikulski Archive for Space Telescopes (MAST) Portal
type in “rx and” into the “and enter target” box and hit RETURN. Click on the uppermost “Timeseries Viewer” icon in the second row down. Up pops the photometry record which you can zoom into.
Stewart
Using iTEL 18 (Spain), Vphot gave a V filter mag of 16.86 ( three 300s images stacked) this morning. Stewart
The present superoutburst seems to have been recorded first by Graeme Coates and Tim Haymes on the evening of the 23rd June. This translates to a superoutburst period of 51 +-1 day which is right in the middle of the range of values from 45 to 55 days discussed in VSSC188.
Thanks again to Graeme and Tim and all other contributors.
This target is now really difficult and June has previously marked the end of the observing season. In October the whole cycle begins again with a possible superoutburst around Oct 1. Can this one be observed?
Stewart
I used iTEL 18 last night to get a time series. VPhot reports the V filter magnitude dropping from 13.15 to 13.3 over 13 minutes. The variation may be related to the orbital period of 90 min or the change in skyglow in the dusk sky. Going to repeat tonight but starting a bit later. Stewart
Ken Menzies (AAVSO) has helped me upload images with the clear filter as CV into the AAVSO database. All fit with the existing results from other observers so I seem to have done it right. Stewart
Definitely in outburst and possibly this will trigger the superoutburst. The last superoutburst was recorded, at its brightest at 12.2 visual, by OJR (AAVSO) on 2459339. So we are ~50 days later right now. Could well brighten over the next day or two.
Stewart
ER Uma was at quite dim last night at 15.0 V mag. It is also approaching time for the next superoutburst as the last one started around JD 2459338. With a super outburst period of 55 +_ 5 days, this minimum may be the last before a normal outburst triggers the superoutburst. A few extra observations in the next 5 days could capture the event nicely.
Thanks in advance.
Stewart
