[Aavso-photometry] Re: 70 Vir + Help Needed for This and two other Targets

[Tim Crawford]

Last night I had great success on this target with a B
Filter (under same system, V filter should work out at
about half the integration time or so).

I have a 12 inch SCT for which I made a new mask with
just a 3.5 inch opening (I used one of the commercial
harding style masks) and made the actual opening out
of thin cardboard (sprayed black) over the hole
enlarged in the original metal mask which was hard to
get fully round... much easier to cut cardboard round
(although, I must confess that I had my bride cut the
hole out).  It should be not big deal to make a mask
out of cardboard to fit the whole of the diameter of
your larger scope... just watch the central
obstruciton if a SCT and the edge of the corrector
plate or opening.

I took 60 second integrations on a slightly defocus-ed
field and was getting counts of 20,000 or so (at 44
degrees altitude) for the 8.6 comp star without over
saturation of the Target. 

We need some more folks participating on this target
for the next three nights...

And the same thing goes for tau Boo and HD 162020...
check out the Campaign page for further details on all
of these targets.

Tim Crawford CTX
Arch Cape Observatory