Re: Obs formats, Mag. estimates - Was: ISS, IR-35, IR-47 1.VIII.2000 Berlin City

From: Bjoern Gimle (b_gimle@algonet.se)
Date: Thu Aug 10 2000 - 03:37:52 PDT

  • Next message: Mike Waterman: "Re: Obs formats"

    >
    > How to decode these often seen professional observation
    > reports (a lot of numbers) ?
    
    Mike Waterman, David Brierley and other UK observers use a
    format with a descriptive heading (RA in hours, minutes+decimals,
    Dec in degress+decimals or degrees, minutes+decimals, Epoch 2000.0?)
    
    YATELEY(WATERMAN)ENGLAND
    IntlId SiteYYMMDDHHMMSSss  Sss  TCHHMMmm   DDddd  Ddd E             MMm
    99057GB211500050121190931  020  13155279  +2639   007 5             +65
    
    IntlId SiteYYMMDDHHMMSSss  Sss  TCHHMMmm   DDMMm   Mm E
    7711201267500071823101708  010  12165600  +15236   15 5
    
    Russell Eberst uses:
    2420 0008 0.211 1204
    05
    9903702 213010.21 204336+303212 7.0 7.0 0 S
    
    which I (empirically) decode as:
    Site YYMM xxxxx xxxx
    DD
    IntlId  HHMMSS.ss HHMMSS DDMMSS M.m M.m x F   (RA,Dec 1950.0)
    
    Rainer Kracht often shows observations in the analysis format for
    ftp://ftp.fc.net/pub/users/mikem/elcor.zip or
    ftp://ftp.fc.net/pub/users/mikem/fitelem.zip
    
    Most others use the IOD format produced and described by:
    ftp://ftp.fc.net/pub/users/mikem/obsentry.zip
    
    > How to estimate IRIDIUM brightnesses without anything
    > for comparisation?
    >
    I haven't used it yet, but Mike Waterman mentioned a method in
    http://www2.satellite.eu.org/seesat/Mar-2000/0220.html
    (http://www2.satellite.eu.org/seesat/Mar-2000/0250.html)
    
    If I think and compute correctly, a highly reflective ball with
    diameter d, held with its surface at a distance D from the eye,
    at angle v from the object observed, would increase its magnitude
    by 5 * Log10 ( Di/d ) - 2.5 * Log10 ( cos ( 90 - v/2 ) )
    
    E.g. a 4 cm ball at arms length (54 cm) from the eye, 90 degrees
    from the object watched as reflection, is 6.03 magnitudes fainter.
    
    Near 180 degrees (impractical for comparisons) this is 5.65 magnitudes.
    This is also the effect of a watching straight through negative lens
    with -2 cm focal length (or a 2 cm positive lens held at 58 cm).
    
    
    -- b_gimle@algonet.se (home)  http://www.algonet.se/~b_gimle --
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