[vsnet-chat 1730] Photometric Accuracy

[aah@nofs.navy.mil]

Stan Walker asked how accurate his photometry should be
with a CCD system.  While I suggested one percent is
a good number to strive towards, and that published
CCD photometry has been as good as a few millimag, I
wanted to remind observers that I placed on our anon
ftp site light curves for the delta-Scuti star CY Aqr
a few months ago.  This field is not particularly
well suited for our 1.0-m telescope, with only one
real comparison star in the 11arcmin field of view.
In addition, I only observed the field during non-photometric
weather.  However, the light curve precision is
better than 0.01mag; any amateur with a 10cm or
larger telescope should be able to duplicate these
light curves (though with poorer time resolution).  See them at
     http://ftp.nofs.navy.mil/pub/outgoing/aah/photom
Other photometry by amateurs of this star is linked on
Doug Welch's homepage.

Light curves of some of the FASTT variables, taken with
amateur systems and demonstrating 0.01-0.02mag
accuracy, can be found under /aah/fastt1/*.gif.
One or two percent differential photometry is not difficult.
Going to the millimag range with a CCD is about like a
visual observer reaching the 0.1mag precision goal;
obtainable if you pay attention to the details.
Arne

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp