FW: Calipso questions

From: Derek C Breit (breit_ideas@hotmail.com)
Date: Sun Mar 15 2009 - 05:32:03 UTC

  • Next message: Greg Williams: "Audio of ISS space junk situation"

     
     So Maybe someone that does flare predictions can add these passes to their
    predictions and give me a heads up when I might see it?? I would DEFINITELY
    'go mobile' for this..
    
    
    Derek
    www.poyntsource.com/New/index.htm
     
    
    
    -----Original Message-----
    From: Gregg Hendry [mailto:gregg.hendry@gmail.com] 
    Sent: Friday, February 27, 2009 11:24 PM
    To: seesat-l@satobs.org
    Subject: Re: Calipso questions
    
    
    On Fri, Feb 27, 2009 at 10:30 AM, Paul Bridges <bridges_paul@yahoo.com>
    wrote:
    
    > Amateur/Lurker here in California. I have some Calipso passes over the 
    > next few months and would like to try to observe/photograph the green 
    > laser. I see that the laser is down for most of Mar/Apr due to a leak, 
    > but I have good passes in May. I would be appreciative if someone 
    > could clear up some of these questions...
    >
    > 1. I normally usually use Heavens-Above and HeavenSat to spot ISS, 
    > STS, and Iridiums.  Is there a better tool (using Windows) for making 
    > ground tracks?  H-Above provides little detail. SeeSat archives 
    > mention http://www-calipso.larc.nasa.gov/tools/overpass/coords, but 
    > this appears to be only historical data, and I don't know how to make 
    > a ground track from it.
    
    The best source for the laser ground track is from the web site mentioned
    (http://www-calipso.larc.nasa.gov/tools/overpass/coords).
    It usually, but not always contains up to date information.
    
    I have found the most up-to-date 1 second files by highlighting the "10
    Second Products" tab and scanning down to the "1-SIXTEEN-DAY-FILE" section.
    The first file in the list is the most current.  The latest 16 day file is
    however out of date today (2/27) but the latest 1-minute file is current.
    Hopefully the 1 second files will be updated when normal operations resume.
    
    For the last year or so the laser has been pointed 3 degrees ahead of the
    satellite's nadir which results in a laser ground track about 2000 meters
    east of the sub-satellite ground track.
    
    For plotting the satellite ground track I use an old copy of STK running on
    XP but it is easiest to rely on the NASA web site.
    
    Whatever software is used to generate the satellite's position make sure the
    output is in geodetic coordinates and not geocentric coordinates as it makes
    a difference of over 3 miles at mid-latitudes.
    
    
    > 2. I see mentions of "orbit raise" and "drag make-up maneuver". What 
    > is the difference?  Is it safe to assume they only affect timing by a 
    > few seconds and not the ground track?
    
    I think "orbit raise" and "drag make-up" are referring to the same
    operation.  The ground track of the laser is not significantly changed from
    2000 meters east of the sub-satellite track due to the maneuver but the
    sub-satellite ground track moves around over time by plus or minus 3 miles
    or more.
    
    
    > 3. Since the beam width on ground is only 70 meters, how do I fine 
    > tune or verify position?  How would I generate coordinates for use 
    > with GPS?
    
    I fine tune my position using the LIDAR ground track files from the web site
    mentioned above by plotting the 1 second points as a route on mapping
    software.  I use the National Geographic TOPO! software. I then find a
    suitable location on the map and record the coordinates in a GPS receiver.
    
    Plotting the points on GoogleEarth also works well to plan an observation.
    
    Hopefully this helps,
    Gregg Hendry
    
    
    
    > ----------------------------------------------------------------------
    > ---
    > Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:
    > http://www.satobs.org/seesat/seesatindex.html
    >
    >
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    
    
    No virus found in this incoming message.
    Checked by AVG - www.avg.com 
    Version: 8.0.237 / Virus Database: 270.11.13/2001 - Release Date: 03/14/09
    06:54:00
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Sun Mar 15 2009 - 05:35:45 UTC