Re: planscan: Computing optimal directions for performing a plane scan

From: Greg Roberts via Seesat-l <>
Date: Tue, 16 Feb 2016 07:24:25 +0200
Morning Cees and readers

Thanks for your reply.

A valid point re the scan altitude - did not think of that :-(((

Meanwhile I have tried your program with success and a few comments - 
last time I will worry you this time!

Could you include the option to set the time increment between 
predictions. I
would appreciate something finer than 1 minute - say 30 seconds but that 
is not
critical. Also give azimuth and elevation to one more decimal place. If 
you run
out of space for a single line prediction magnitude could be given to 1 
place and, relying on memory, range could be to nearest kilometer. Again not
serious but should give me a smoother scan .

There is no need to go into command prompt mode in windows. In windows
go to the relevant directory - say PLANESCAN and create a file called 
Using one of the editors in windows populate this file with the command line
scan data and when done save as SCAN.BAT.  Keep the original SCAN.BAK 
for next
time when you type in new data . Click on SCAN.BAT and the program will
execute and give you your SCAN.TXT.    Now one could do multiple scans 
a single BAT file with a command line for each satellite except that one 
need to change the output file SCAN.TXT.  One could do this with the BAT 
ut easier in the original PLANSCAN.EXE.  Could you not perhaps change 
the file
SCAN.TXT  say 28888.TXT when doing a scan for say satellite 28888. You have
the number already in your command line so this should be easy.

So when you run a multi-object SCAN.BAT you will end with several *****.TXT
files and when the time comes to observe choose which best suits conditions
time etc.

I think that is all I have to say - Ive virtually finished the program 
to convert your
output to the format and data I need for my CoSaTrak program and hope to
try it out in the next day or so - your program is much simpler to use - 
so quicker -
than mine and I am looking forward to using it.

Many thanks

On 2/16/2016 12:39 AM, C. Bassa wrote:
> Hi Greg,
> On Mon, Feb 15, 2016 at 7:42 AM, Greg Roberts via Seesat-l
> <> wrote:
>> I am still a little puzzled why you need to specify the altitude of the
>> satellite. You are using TLE's and either computing shadow entry or
>> exit points or maximum brightness so you must be using the altititude
>> given by the elements so why is there a need to specify the altitude?
>> (to be honest I am being a little lazy here as I am trying to avoid
>> having to use a prediction to get an idea of the altitude to enter in
>> the command line.
> The reason I ask the user to specify it is to force them to think
> about what they are doing. For most objects in circular orbits the
> mean altitude should be used, but for objects in eccentric LEO orbits
> they will have to make a conscious choice. Consider trying to recover
> the KH USA 224 in the coming spring after it has not been seen for at
> least 7 months. We can expect it is still in its 270x1010 km orbit,
> but we don't know if the argument of perigee is still correct. Most
> likely it will have maneuvered and changed this. For this object it
> wouldn't make much sense to search at the 640 km mean altitude.
> Instead, the best strategy is to first perform plane searches on the
> higher orbital altitudes where the object first becomes sunlit, and as
> the season continues continue scanning lower and lower altitudes until
> it is recovered.
> However, I agree that for most cases the mean altitude will suffice.
> I'll implement this in the next version.
> Regards,
>      Cees

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