V1396 Cyg

[Dr Andrew Smith]

I have been monitoring V1396 Cyg for flares but as of the 22-08-2020 I have been getting a step down in brightness of about 5%.

The points are 12 to 13 sec apart (10s exposure) and are rough photometry on the Zero order spectra from my Ultra Low Res Spectrograph. The photometry before 22nd did not show a step which has reoccurred on 23, 25 and 26 (no data on 24th).  The timing has been +/- 15min or so with no trend. The graphs show the data for 22nd. The companion stars are offset. 

The observatory reports no events at the timing of the step and checking other stars in the field show no changes other than the shift on the meridian flip and drift with air mass.

Any comments or advice would be welcome.

Regards Andrew

Attachments:

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   V1396-Cyg-22-08-2020.png
   

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   V1396-Cyg-22-08-2020-1.png
   

[Robin Leadbeater]

Looks like it is flickering for a few minutes when it drops. Drifting over a hot/cold pixel perhaps ?

Robin

[James Screech]

I’ve had similar steps in time series photometry with a newtonian at meridian flip. I think they were caused by the main mirror moving in it’s cell as the weight shifted.

[Dr Andrew Smith]

Good spot Robin,  there was a warm pixel that was moving out of the photometry aperture.  

Thanks Andrew

[Dr Andrew Smith]

Not too much of an issue for me as I am not doing serious photometry. Just using it to spot flares. I then calibrate the relevant images and extract the spectra. Thanks for the comment though.

Regards Andrew 

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