Sv: How to help newbies?

Bjorn Gimle (bjorn.gimle@online.dextel.se)
02 Aug 1995 13:34:46 GMT

To: seesat-l@iris01.plasma.mpe-garching.mpg.de
>Subject: How to help newbies?
>To: dk058@cleveland.Freenet.Edu (Walter Nissen)
>Subject  Visual Observing of Satellites
>To  markus@interaccess.com, jjmalley@maui.netwave.net
 
> Any comments about the adequacy of the response below?
 
 
>Date  Fri Jul 28 22:03:53 1995
>From  dk058@cleveland.Freenet.Edu (Walter Nissen)
 
> From: markus@interaccess.com (mark haas)
> Newsgroups: sci.astro.amateur
> Subject: SATALITE VIEWING
> Date: Mon Jul 24 01:34:54 1995
 
> I AM INTERESTED IN IDENTIFYING SOME OF THE SATALITES THAT PASS OVER
> ON A GIVEN EVENING. WHATs a good PROGRAM TO USE TO PLOT ELEMENT DATA?
> THANKS..
 
 
> From: jjmalley@maui.netwave.net (John J. Malley)
> Newsgroups: sci.astro.amateur
> Subject: Tracking satellites
> Date: Thu Jul 27 23:33:29 1995
....
> What types of things affect their visibility?  Altitude? Their color???  
> Any help would be appreciated. I'm getting tired of plotting these
> things on the computer and not being able to spot them!
...
> John
----------------------------------------------------------------------------

I think some aspects are missing from Walter's reply :

1) What types of things affect their visibility?....
Purpose of observing and "prediction":
2) WHATs a good PROGRAM TO USE TO PLOT....
3) Identify satellites "accidentally" spotted.
4) Plan observations of a few satellites well.
5) Find ANY satellite.
6) Find satellites of a particular class.
7) Find as many satellites as possible.
8) Identify satellites that have recently become visible and you
   haven't seen in a long time, or that are newly launched.
.... and hundreds of other flavours of interest !

1) Many satellites are not the regular diffuse spheres that programs
   predicting magnitudes assume. If it is stabilized, or rotating very
   slowly, and irregular (even cylindrical), it can be many magnitudes
   fainter than average where you are trying to find it. Or, it can 
   shine with bright flashes from solar panels, sometimes lasting
   many seconds....

2) 3) 4) Can be very tedious with a text-only program like QuickSat
   and most others. A graphic program, like SkyMap 5.9 by Rob 
   Matson, saves a lot of time and effort, and increases accuracy.
   Skymap 5.9 identifies earth shadow (more accurately than QuickSat,
   which only prints the height in km. above the shadow, and optionally
   omits points below it), plotting the penumbral part of the tracks in
   a different colour, and another colour for the part where magnitude
   is fainter than the selected limit. And it displays the magnitude 
   value at points along the track. The plot can be recorded on a file,
   and sent to a HP plotter or compatible printer, or output to almost
   any kind of output device and EGA/VGA screens, PCX and PostScript
   files by utility programs. These give much better accuracy than
   screen dumps.

5) 7) 8) QuickSat, SkyMap and most other programs can be used for this.
   Since version 5.9, the text form of SkyMap output includes the 
   maximum magnitude for each pass and the satellite name. As in earlier
   versions, the positions and times of selected minimum elevation (or
   shadow entry/exit) and maximum elevation of each pass, is on the
   same line. And the screen/plots are useful, as described above.

6) This is my main use of QuickSat. By maintaining my own copy of the
   "intrinsic magnitudes" file as a "reference file", I set the flag
   character in column 7 to indicate my classes of interest, and can
   very easily get predictions for only the satellites of interest.
   I indicate satellites near decay, classified satellites, those
   in the Belgian Working Group's Determination-of-Rotation-Axes
   project, and their "Flash" project, fragments, and those that
   are currently of no interest to me, like the attached MIR objects,
   stable objects, and of course decayed objects. This way I don't
   have to edit each TLE file I acquire, or the predictions I produce.

   You may have a large number of widely differing criteria, but no
   more than five at a time can be selected by QuickSat.

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Bjorn_gimle@lector.kth.se == bjorn.gimle@duesenberg.se ==
== bjorn.gimle@online.dextel.se ;  59.22371 N, 18.22857 E
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