[Aavso-photometry] GJ436 transit (maybe)

[Arne Henden]

All data is worth reporting.  If you spent the time taking the data and
reducing it, then send it in.  This is especially true if you've done a
good job of estimating your errors.

On the other hand is the question about whether you should start taking
data in the first place on a given night.  I've done a lot of photometry under
a variety of conditions, and while you can get rid of a *lot* of the effects
of clouds with ensemble techniques, you still do have differences across
a frame because clouds are not uniform.  I usually see a 2-3mag extinction
for a field result in photometry with 0.02mag errors - a great reduction,
but not good enough for this specific project.  So my advice:  unless
conditions are pretty good (say light cirrus, or some sort of uniform
haze), it is probably best to work on something else than to try and
resolve a 7mmag transit.

The one saving grace is that the star is bright, so a bright moon really
doesn't impact your results.  It always seems that full moon nights
are clear - so make use of those nights!
Arne

On Thu, Feb 14, 2008 at 7:53 PM, Jim Roe <jroe at jamesroe.com> wrote:
>
>
>  Shawn Dvorak wrote:
>  > It's not pretty, but if you squint and look at just the right angle you
>  > might convince yourself that last night's exoplanet transit is visible
>  > in my data.  According to Alert Notice 370 the transit was predicted to
>  > occur between JD 54510.78 and 54510.82.
>
>  I got some pretty decent images up until JD54510.77 before the clouds
>  really started obscuring the field.  I actually imaged for another half
>  hour but the S/N fell too much - I through out all worse than 500 on the
>  target.  I couldn't see any sort of dip - but then I may have been too
>  early.
>
>  Is there any value in this data?  Is it worth reporting?
>
>  Jim Roe [ROE]
>  Wentzville, Missouri
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