[vsnet-alert 23883] Re: Wils_SDSSJ162520.29+120308.7

[Denis Denisenko d.v.denisenko@gmail.com via vsnet-alert]

If you have a 30+cm scope with the CCD field of view larger than 32 arc min
along RA axis, you can "shoot two birds with one shot" here. There is
another unusual CV in Hercules well worth monitoring - SDSS
J162322.23+121334.0 (see [vsnet-alert 23381] from July 2019).

This variable is in the very rare evolution stage. It was hibernating below
20m on all Palomar plates in 1982-1997, has "turned on" in July 2000 as a
nova-like variable spending 90 per cent of time at 17m, but since 2017 it
started to produce superoutbursts stable as a clock every 51 days without
normal outbursts between them! The orbital period is yet unknown, so the
goal is to catch the next superoutburst and to involve "big calibers" for
the time series.

SDSS J162322.23+121334.0 historical light curve:
http://scan.sai.msu.ru/~denis/J162322+121333-DSS-NEAT.gif

Now back to Wils_SDSSJ162520.29+120308.7.

SDSS spectrum shows the large contribution from the secondary component:
http://scan.sai.msu.ru/~denis/J1625+1203-spectrum.jpg (note the 5577 AA
airglow line removed in processing).

ZTF DR2 light curve: http://scan.sai.msu.ru/~denis/J1625+1203-ZTF-DR2-LC.gif

Catalina Sky Survey light curve:
http://scan.sai.msu.ru/~denis/J162520.3+120308-CRTS_LC.gif (note the low
state at around 19.5m with no outbursts and high state at 18m with rather
frequent outbursts to 13m).

The mid-point between two stars is:
16 24 21.27 +12 08 21.4
Both variables are 15.34' from this point.

Don't try this with Open University's COAST telescope. If somebody has one
of this stars in his request list at telescope.org, let me know privately
and I will take on the other to avoid duplication of efforts.

Denis Denisenko