Return to Home Page
Date: Mon, 2 Sep 2002 15:53:08 +0200 (CEST) From: Rudolf Novak <rudolfn@hvezdarna.d-net.cz> Subject: [vsnet-campaign-ccd-discussion 0] Re: [vsnet-chat 5473] (fwd) Assistance Needed with Light Curve of V1432 Aql Dear all, according to the topic of uncertainty. Most observers reports their error (sigma) as simple estimate of the uncertainty given by photometric software they use which is (in my opinion) only the estimate of noise in the radius used for photometry around one star. More exact result could be done when you determine sigma for whole run - optimal way is to create artificial star (combining several bright stars in the field) and use this for differential photometry. When you plot a histogram of such a run, you should got mean and sigma more precisely. And also don't forget that sigma for variable is different on different phases ;) I experimented with this in my bc. theses and got quite interresting results. I know this is trivia but I see quite often observers reporting 0.01mag error of photometry which is imho only the estimate made from one CCD image and tells you only some info if the point is not bad (weight of the measurement used for further statistics...) Enjoy your variable stars research ;) Rudolf P.S. I saw combined light curve. Interresting. I tried to do something like this with my runs on UX UMa and profile of minimum was changing mostly on each run... These targets could be destroyed ;) > PS I would rather refer to an uncertainty of 0.03 magnitude (not an > error), although it probably only includes the standard deviation of the > noise (K-C), not?
Return to the Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
