RE: Satellite lunar transit

From: Anthony Ayiomamitis (
Date: Thu Aug 23 2001 - 04:52:54 PDT

  • Next message: Robert G Fenske Jr: "Re: Flashing satellites."

    Bruno Tilger wrote:
    > Hi Rob and list,
    > >Large solar observatories, like the one at Big Bear Lake, CA, regularly
    > >observe solar transit events.  They probably even have recordings
    > >of some of them.  Most transits are by birds, mylar balloons or
    > >airplanes, but some are satellites.  However, since it's not their
    > >area of interest, they're not likely to go out of their way to
    > >publish or even document such events.
    > Sure. There are probably more than two dozen observatories around the
    > globe which monitor the Sun constantly. Transits of birds, balloons,
    Hi Bruno,
         You can also add a madman in Greece who also constantly monitors
    the sun (and moon) daily for transits ...
    > satellites or other objects are of no scientific interest whatsoever.
    > >When you say solar transits are much more likely to be observed
    > >than lunar transits, but then go on to say there have only been
    > >two "verifiable" solar transit observations, you imply that
    > >there must be no "verifiable" record of a lunar transit.  I
    > >guess I would ask, "verifiable" by what standard?  Few people
    > >regularly record video or still photography of such events.  But
    > >if you have multiple, experienced witnesses to the same event,
    > >I'd say that's sufficient.
    > I am sure such observations have been made but they haven't been
    > reported in a forum like SEESAT-L. A scientist who makes a discovery
    > but doesn't publish it isn't credited for it.
    > As regards "verifiable" I would say any witnesses and testimonies
    > that would stand up in court qualify as verifiable. The best proof
    > is a photo or a video if it comes from a trustworthy person. Who
    > is trustworthy? Everybody who does not falsify evidence intentionally
    > (very easy nowadays) or who unwittingly is fooling himself and others.
    > The latter are the more dangerous. I remember a report in SEESAT-L
    > by someone who saw Mir against the Moon from Hawaii when Mir wasn't
    > even above the horizon. Somebody else reported in SEESAT-L that he
    > saw Mir sailing slowly across the lunar disc with antennas, booms
    > and solar panels clearly discernible. In both cases people were
    > honestly convinced they had seen what they reported.
    > >By that standard, sunlit satellite lunar transits have certainly
    > >been observed more than twice.  A group in California observed
    > >a Mir transit of the moon several years back which I have reported
    > >here more than once.  I consider that observation solid, and I
    > >believe they were the first.  They may even have recorded video.
    > I am not questioning sunlit satellite transits which are fairly
    > easy. I have seen one of Mir myself. But am not aware of an
         Sunlits transits are pretty cool ... I remember seeing one about a
    month ago as it crossed the lunar surface (as predicted by Rob's SkyMap)
    and it was a real experience!  Even 10 seconds before the actual
    transit, it was "obvious" that the satellite was headed for the moon.
    Furthermore, they are fairly easy as you suggest as well as fairly
    common. With a full moon, I easily get something like 6-10 predictions
    for a 4-day interval.
    > observation of a *dark* satellite transit. Actually, there may
    > have been one by a SEESATTER a couple of years ago, but the object
    > could not be identified (using Mike McCants' ALLDAT.TLE).
        For something like this to be captured, something like a video
    camera or CCD in continuous shooting mode is mandatory. Given that these
    transits are 1 to 1.5 seconds in duration (assuming they bisect the
    solar/lunar disk), there is no time to time it just right with a shutter
    release cable and single photo.
    > >Optically, that shouldn't be any tougher than observing a silouette
    > >solar transit.  From an equipment standpoint it's actually easier,
    > >since you don't need a solar filter.  With a mobile telescope, GPS
    > >and the desire, I doubt one would need to drive more than 100 miles
    > >to observe such an event any month around full moon that clear
    > >skies permit.
    > Fully agreed. I have written a program which shows graphically where
    > on Earth ISS casts a lunar or solar "shadow". With rare exceptions,
        Now you caught my attention!  Can I inquire if it is Windows-based,
    if it is available for use by others etc?  Such transits are something I
    check daily with Rob's SkyMap software and I would love to see something
    that would identify a footprint ... I am looking to get a rich-field
    refractor which is much more portable and probably as useful for such an
    exercise. With my existing OTA, I must use a focal reducer to fit the
    solar/lunar disk nicely across a 35mm frame. With an 80 or 90mm
    rich-field refractor, I would expect to be able to do something similar
    with a low-power eyepiece and eyepiece projection while certainly being
    much easier to lug around looking for such transits within "commuting"
    distance. As much as I love and cherish my 14" SCT, there is no way I
    would consider lugging it around chasing transits.
    > there is always such a shadow, but it may be in the Antarctic or in
    > the middle of an ocean. But often enough it falls on land. Usually,
    > there are several consecutive passes separated by a day or a couple
        I wish I had this luck (multiple passes) with my ISS solar transit
    opportunity a couple of weeks ago which fazed into nothing thanks to
    very strong winds at precisely the few minutes!
    > of days. 100 miles, or in my case 100 km, are often sufficient to
    > be right on the centerline. The big and uncontrollable unknown is the
    > weather. This has spoiled more than one transit observation (there
    > is at least one SEESATTER (AA) who will confirm).
        To make matters worse, this is something I have been after for a
    very long time and which I have been checking religiously! One other
    similar opportunity disappeared about two days before the actual
    predicted transit date/time due to a Shuttle (?) mission.
        Anyway, the daily battle does continue for yet another crack at a
    solar/lunar transit by the ISS (with or without the Shuttle).
    > Bruno
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    >    * Next message: Rod Sladen: "Re: Iridium 5 moved to non-operational
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    >    * Previous message: Matson, Robert: "RE: Satellite lunar transit"
    >    * Maybe in reply to: Bruno Tilgner: "Satellite lunar transit"
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