[Aavso-photometry] 0 Vir

[Tim Crawford]

70 Vir

Experimented this evening (Saturday) with this bright
object.  Equipment: 12” SCT, F/10 & SBIG ST-9E.  

With this object above 25 degrees altitude the most
practical solution was a Hartman style mask with one 4
inch round opening.  I was then able to do TS with the
B Filter doing 3 second integrations with the target
averaging around 45,000 ADU.  

Aside from the bright target star another major issue
is that I was only able to place the 8.6 comp star
within the same field. My FOV is around 12 x 12
ArcMin.   All other stars were undetectable at this
short of integration.  This creates a problem with
AIP4WIN solving a TS as their software seems to demand
that a check star be chosen in addition too the comp
and target… I am not aware of a workaround for this
problem (well single image will do the trick-but I
have a life).  Jim Jones informed me that MaxIM will
solve TS with only two stars.

I am concerned about Scintillation with my final
arrangement but unable to test any of the series for
the spread of variations in values (outside of a few
single image solutions) until I resolve the software
issue (not sure whether or not Canopus will solve TS
with only two stars)by trying out MaxIM.

Tim Crawford CTX
Arch Cape Observatory
OR