Re: PPAS reports of Flaring Geosats

From: Bram Dorreman (
Date: Wed Oct 24 2007 - 18:53:36 EDT

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    Dear Brad,
    You wrote:
    > I have received a few private communications regarding my PPAS reports on
    > flaring geosats. They have brought up several good points:
    > 1. My reports do not lend themselves well to the derivation of phase angle /
    > etc because they are not positional nor at shadow entry.
    > 2. They do not quantitatively aid in predicting where to find flares
    > opposite the shadow edge or "purple dot" position.
    > 3. They don't represent the visual appearance (they aren't really steady,
    > overall) and I would add that my annotation of FGS (flaring geosats) will be
    > lost in the PPAS reports.
    > My responses:
    > 1. This is true, and can't be rectified. However, all of the objects have
    > Space-Track or classfd.tle tle's.
    > 2. The reports were intended to be qualitative, hopefully a catalyst for
    > future observers. My first experience with these objects was astonishing and
    > I was unprepared for the number, ease, and beauty of these objects. I am
    > posting reports so that others (and future readers) will be ready to see
    > what I have seen, using other resources of course, in parallel.
    > 3. I hope that either a PPAS observing code is added or a definitive
    > judgment can be made to use a more appropriate code than "S" with the
    > soon-to-be forgotten FGS note. Any thoughts?
    As PPAS observation collector
    and observational contributor from the early years on
    and one of the contributors to the PPAS setup
    I like to add my opinion about geosat flare reporting.
    These kind of observations have nothing to do with tumbling objects
    and therefore I do not intend them to add to the PPAS database.
    The primary intention of the PPAS observations is to obtain a collection
    of flash observations ideally evenly spread in time.
    The data in the PPAS database can be used
    and is used
    to follow the evolution of the flash period
    and to find (partly afterwards) unexpected phenomena such as accelerations
    (decreases of the flash period).
    In this way I have reluctantly add observations of "Steady" objects.
    This was already discussed in our own BWGS years ago.
    If an object was a flasher before it is useful to check so now and then
    because getting a variable brightness due to tumbling might (re)appear.
    It would be nice if we should concentrate on really variable objects,
    as there are so many.
    Rocket bodies are nicer than payloads because they have "simple" shapes.
    This does not mean that I do not appreciate the reception of Steady objects
    and geosat flaring objects. About the last mentioned, these kind of
    observations are interesting in itself (or themselves(?)).
    This year I spent two nights exclusively to geosat flaring, but have
    yet to process my written en voice recorded comments. I can tell you
    that from my location I saw several times the constallation Whale
    (Cetus) with "extra stars" north of the stars theta and zeta.
    May be we can start another database of geosat flaring observations and
    discuss what should be reported in it on this SeeSat forum.
    My suggestions to this forum are the reporting of:
    - catalog number and/or international designation of (pseudo) geosat
    - location of observer (either COSPAR id or observer's initials)
    - UT date of observation(s)
    - estimated UT of max brightness before immersion (shadow entry)
    - estimated UT of max brightness after emersion (shadow exit)
    - estimated UT of max brightness when no shadow entry and exit took place.
    (Read max (stellar) magnitude for max brightness.
    I assume that those UT's can not be more accurate than about 1 minute.
    May be I am too pessimistic.)
    - color of the maximum
    - used optical equipment
    - estimated duration of the flare (find a definition for this)
    - any verbose comment
    May be it is also intersting to report in which way you observed.
    To make this clear I describe two examples:
    On my first night I looked at the predictions to see what I should find.
    On the second night I looked and identified afterwards. Latter method is
    more difficult as I "found" several objects twice or even three times with
    different stellar magnitudes.
    I suppose it is possible to find observations of previous years
    by searching the SeeSat-L archive.
    Best regards and hoping we find a nice solution for our geosat flaring
    Bram Dorreman.
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