Re: Successful ISS solar transit obs

From: Kevin Fetter (kevin_fetter@hotmail.com)
Date: Mon Apr 22 2002 - 19:08:38 EDT

  • Next message: Robin R. Wier: "Re: Successful ISS solar transit obs"

    Rob Wrote
    
    The next challenge is for someone to observe a silhouette
    transit of ISS across a full (or nearly full) moon.  I don't
    believe anyone has done this yet.  At least in this case
    there's no danger of retinal damage.
    
    It's been done!
    
    Using a prediction by me, Vance Petriew of the regina centre of the royal 
    astronomical society of canada ( RASC ) observed the iss going across the 
    full moon using his 20 ince telescope. He observed it on Mar 29 around 
    3:53:43 UTC plus or minus a few seconds :)
    
    Here is what he wrote , sorry for the long post.
    
    It was pretty cool!!!  Man it moves quick!  The "blink and you'll miss it" 
    statement definitely holds true.
    
    I started setting up the 20" Obsession in front of my garage about 20 
    minutes ahead of time.  There were some small cumulus clouds floating across 
    the sky but nothing too serious.  As I was assembling the scope, there must 
    have been a dozen vehicles pass by.  I was beginning to think that that 60 
    lb piece of glass was some kind of vehicle magnet.  I guess everyone picked 
    9:40 PM to be heading somewhere because our street is never that busy.
    
    By 9:45 PM I had the light shroud on and did a quick collimation.  I headed 
    back to the garage and grabbed the Telrad and noticed that a car had come to 
    a stop just past the telescope.  I proceeded over to the telescope as they 
    were backing up.  I looked at my watch.  9:48 PM.  I thought to myself 
    "Maybe they're just wondering what this big thing was on the street and will 
    move on".  As I fumbled to put the Telrad on the scope, I heard a voice from 
    the car ask "Excuse me?".
    
    Thoughts poured through my head.  "Should I help these people and risk 
    missing the ISS?  Every second is crucial."  I decided to walk over to the 
    car.  They wanted to know how to find a particular street.  Since I can 
    never remember street names on the best of days, I told them to turn right 
    and then left and keep looking.  They were happy with that answer and I was 
    happy since there was still time left on the clock.
    
    I walked back to the scope, put on the Telrad and inserted the eyepiece.  
    Not knowing what to expect, I chose my 31 mm Nagler at 80x so I could see 
    the whole moon.  I checked my watch.  9:51 PM.  I swung to the scope over to 
    the moon only to find it covered in a thick haze.  It looked like it could 
    clear out so I decided to watch the moon through the haze anyway.  As I had 
    my eye glued to the eyepiece, I kept getting this urge to check my watch to 
    see how much time was left.  I resisted the temptation and stared at the 
    moon trying not to blink.  Now, for anyone that's ever looked at the full 
    moon through a full aperture 20" scope, staring at the moon is like looking 
    down the end of a Mag-Lite!  Those photons almost hurt!  This was one time I 
    was happy to have a little haze.  Luckily, I could see the craters start to 
    appear as the haze appeared to thin.
    
    After what seemed like a very long time, THERE IT WAS!  It was much smaller 
    than I was expecting at 80x.  A small, detailed speck in the eyepiece.  The 
    speck looked like a 'T' with a lobe on the bottom of it.  The top of the 'T' 
    had some small light gaps in it which reminded me of a solar panel mounted 
    to a truss.  Because it was moving so quickly, my eye was not able to pick 
    up the movement of it until it crossed the meridian.  So realistically, you 
    only get about 1/2 second to pick up details.  From my vantage point, the 
    ISS crossed about 1/3 of the way between the moon's equator and the north 
    pole.  Very cool!
    
    So what would I do differently?  I'd choose as much magnification as I could 
    (160x for me) while still maintaining a 30' field of view.  Since the moon 
    was still low in the sky, the ISS would have been much smaller than if it 
    were directly overhead.  In my case, I think it would have been hard to see 
    at anything less than 50x.  Next time, I'd also check my watch with my good 
    eye rather than the blind one :o)
    
    Thanks again, Kevin!
    
    Vance Petriew
    Regina Centre
    
    His the one who discovered comet petriew last year.
    
    
    Kevin
    
    _________________________________________________________________
    MSN Photos is the easiest way to share and print your photos: 
    http://photos.msn.com/support/worldwide.aspx
    
    -----------------------------------------------------------------
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org
    http://www.satellite.eu.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Mon Apr 22 2002 - 19:12:52 EDT