Satellite location prediction weeks away and JOTA
Everyone has been so terrific helping me understand every aspect of Satellite communications. I have another question that may really show my ignorance of this part of the hobby. Hopefully I will not be banned from ever asking another dumb question.
I will be working with a Boy Scout troop on October 20 participating with JOTA (Jamboree On The Air). Is there an easy way to predict when the various satellites and ISS will be passing overhead on October 20? It would be nice to know the times and locations for October 20 weeks ahead.
I wonder if others will be participating in JOTA by demonstrating the use of satellites.
Thanks and 73, -james W5AOO
On 2012.09.20 07:42, James Luhn wrote:
Is there an easy way to predict when the various satellites and ISS will be passing overhead on October 20? It would be nice to know the times and locations for October 20 weeks ahead.
F.E. gpredict, "Sky at glance option" p.s. software need a little tweaking for own taste, but it's great and the price is right :-)
73 Zilvis
On 09/20/2012 12:42 AM, James Luhn wrote:
I will be working with a Boy Scout troop on October 20 participating with JOTA (Jamboree On The Air). Is there an easy way to predict when the various satellites and ISS will be passing overhead on October 20? It would be nice to know the times and locations for October 20 weeks ahead.
Tracking software should be able to give you an 'ephemeris' table for each pass for the day. For example, the software I use lists FOUR passes on 20th October, for ISS. The best of these is 11:59:20 to 12:09:55 (nearly 13 minutes!). If I drill down on that pass, it lists times, AZ/EL angles, range, doppler correction, etc, from AOS (314°/0°) thru TCA (233°/40°) to LOS (157°/0°) in increments of 30-40 seconds. I would expect any halfway decent tracking software should be able to give the same sort of info.
So, tell us what software you want to use, ande maybe someone who uses that particular software can tell you how to get the ephemeris info for the particular date, QTH and satellite(s) you want.
But consider that "weeks ahead" means that you are using elements that are weeks old! (Or, they will be, weeks from now when you need to use the data.) So any ephemeris data generated "weeks ahead" should be regenerated periodically as new elements become available, so your ephemeris becomes more accurate the closer you get to the date of interest.
Predicting ISS out that far is more challenging than the other satellites as the ISS has frequent orbital maneuvers that most of the other amateur satellites do not. The significant factor affecting the other static amateur satellites is variations in orbital drag due to solar activity. ISS is much more dynamic being controlled by reboosts and occasionally maneuvered to avoid debris. Even the crew members moving around can cause subtle changes in the orbit.
Best to use ISS predicts that far ahead as a ballpark estimate instead of a pinpoint prediction.
Kenneth - N5VHO
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gus 8P6SM Sent: Thursday, September 20, 2012 12:23 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Satellite location prediction weeks away and JOTA
On 09/20/2012 12:42 AM, James Luhn wrote:
I will be working with a Boy Scout troop on October 20 participating with JOTA (Jamboree On The Air). Is there an easy way to predict when the various satellites and ISS will be passing overhead on October 20? It would be nice to know the times and locations for October 20 weeks ahead.
Tracking software should be able to give you an 'ephemeris' table for each pass for the day. For example, the software I use lists FOUR passes on 20th October, for ISS. The best of these is 11:59:20 to 12:09:55 (nearly 13 minutes!). If I drill down on that pass, it lists times, AZ/EL angles, range, doppler correction, etc, from AOS (314°/0°) thru TCA (233°/40°) to LOS (157°/0°) in increments of 30-40 seconds. I would expect any halfway decent tracking software should be able to give the same sort of info.
So, tell us what software you want to use, ande maybe someone who uses that particular software can tell you how to get the ephemeris info for the particular date, QTH and satellite(s) you want.
But consider that "weeks ahead" means that you are using elements that are weeks old! (Or, they will be, weeks from now when you need to use the data.) So any ephemeris data generated "weeks ahead" should be regenerated periodically as new elements become available, so your ephemeris becomes more accurate the closer you get to the date of interest.
That's hard to do. ISS periodically reboosts and that changes the orbit. If you use today's keps you could for example be off by several minutes or even more. If you have NOVA or SatPC32 you can do an update the week before and be close assuming no reboost.
John AG9D
Sent from my iPod
On Sep 19, 2012, at 11:42 PM, James Luhn luhn@wt.net wrote:
Everyone has been so terrific helping me understand every aspect of Satellite communications. I have another question that may really show my ignorance of this part of the hobby. Hopefully I will not be banned from ever asking another dumb question.
I will be working with a Boy Scout troop on October 20 participating with JOTA (Jamboree On The Air). Is there an easy way to predict when the various satellites and ISS will be passing overhead on October 20? It would be nice to know the times and locations for October 20 weeks ahead.
I wonder if others will be participating in JOTA by demonstrating the use of satellites.
Thanks and 73, -james W5AOO _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (5)
-
Gus 8P6SM -
James Luhn -
John -
Ransom, Kenneth G. (JSC-OC)[BARRIOS TECHNOLOGY] -
Zilvinas, LY2SS