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Re: [vsnet-chat 5995] CCD-V Vs visual observations (Slightly shortened the message subject :-) Dear Richard, > I am very sorry, but the values are not invariably zero. These > values may be optionally entered by the observer: > > 1) time zone correction > 2) computer clock error correction > 3) heliocentric correction. I put different weights on them. Computer clock correction is purely observational, and we assume that the observers adequately correct them (usually there is no way to check after everything is done). Time-zone correction is a serious source of errors, and when I notice inconsistensies, I ask to check this possibility first of all. I wonder if there is a better validation method for observer's selection of time-zone values. Heliocentric corrections are purely mathematical ones, and when needed, one can basically introduce a routine to automatically compute them. But this correction is rather complex, and is a frequent cause of errors; it is best to avoid correction on the observer's side, unless the observer is going to analyze/publish the data by himself/herself. We ask everyone on this lists to set "invariable zero" for heliocentric corrections when using AIP for Windows. > However, please note that all of the original information from > the image is reproduced in the data record. The date and time > are preserved, and are not altered in the calculation of the > Julian Day. This means that you can independently compute > the Julian Day when you use the data. Okay, this is a nice feature. However, would there be a special reason to calculate JDs to 10^(-8) d (about 1 ms)? Regards, Taichi Kato
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