Hi Folks,
We've been asking users to NOT use AO-91 when it is in eclipse. I've gotten some questions about this, which is great. Here is a bit of info that is more operational than analytical!
The best way to know if a satellite is in eclipse is to use software. I use SatPC32 and it shows when a satellite is in sunlight and when it's in the dark (eclipse). Remember, you can download a demo version limited only by having to enter your info/lat/long each time you start the program. Surely many other programs indicate eclipse/sunlight as well, but since I don't use them, I can't say for sure. Maybe there is a list somewhere, or maybe we can build a list here! (PREDICT does, Gpredict probably does, as I would guess Macdoppler as well?) There is also a program called ILLUM by DK3WN that is really superb for long term calculations. Others can chime in (please!) if you know of a program that shows sunlight/eclipse for a satellite.
This is far from perfect, but a good "rule of thumb" for AO-91--if you're in the continental US/Hawaii, and if it's dark outside, the satellite is in eclipse so please don't use it during evening passes. When it's daytime/daylight at your QTH, then AO-91 is in sunlight and it's OK to use. This appears to hold true for AO-91 pretty much of the year due to its orbit. If you live at a very northern latitude, things get more interesting ;)
If a satellite seems to linger along the terminator line (day/night line), you're really going to need software to tell you!
Thanks for your help and cooperation.
Hope that helps...
73,
A quick way to see if satellite is sunlit could be:
http://amsat.org.ar/pass?satx=ao-91 shows passes for your location in local time.
if satellite is sunlit shows a sun icon close to the satellite name top right .
73, lu7abf. Pedro
On 12/22/20, Mark Hammond marklhammond@gmail.com wrote:
On 12/23/20 12:12 AM, Mark Hammond wrote:
I can answer this for gpredict
In gpredict, the 'show next pass' or 'show future passes' will have a column 'Vis'. Somehow this column can hide in the righthand side of the prediction window so resize it horizontally.
The values important for this discussion are 'D' for 'daylight', 'E' for 'eclipsed'. A full pass can have both D and E, so if you see that select that pass to get the complete answer.
Koos PE4KH
MacDoppler has several ways: The actual satellite sphere (which is artificially larger than scale for practical reasons) is grey when it is in eclipse - no sunshine. When it is illuminated by the sun and not eclipsed by the earth the satellite is shown as yellow. There is also a column named Eclipse which will display Sun if the satellite is illuminated by the Sun, else Drk.
-Kevin (KK4YEL)
G0KLA Track will show you visually which satellites are in sun vs eclipse if you click the little sun icon. You can see all your selected satellites for the next 2 days. It is very low overhead so I just run it in parallel with the program I am using to steer the antenna. It is best used as a forecast of upcoming passes rather than as a view of a pass in progress. There is an example of the sun/eclipse view on this page: https://www.g0kla.com/klatrack/index.php
73 Chris
On Wed, Dec 23, 2020 at 6:50 AM kk4yel@gmail.com wrote:
Gosatwatch for the iPhone/ iPad makes it very easy for you to see, either on the world map, the sky view. or pass prediction graph whether it’s eclipse or not. It’s fun when showing people invisible I SS pass and girl it’s going to disappear in about 10 seconds and yes it does.
Sent from my iPhone
I have used SatSat which also is an app for the iphone. Works well and assuming it's day the satellite is not in night because the time(s) are set to your QTH or rove location
John N7AMEEverett WA
Faith is confidence in what we hope for and assurance about what we do not see.
On Friday, December 25, 2020, 10:38:51 AM PST, Tom Schuessler via AMSAT-BB amsat-bb@amsat.org wrote:
Gosatwatch for the iPhone/ iPad makes it very easy for you to see, either on the world map, the sky view. or pass prediction graph whether it’s eclipse or not. It’s fun when showing people invisible I SS pass and girl it’s going to disappear in about 10 seconds and yes it does.
Sent from my iPhone
On Dec 25, 2020, at 10:35, Chris Thompson chrisethompson@gmail.com wrote:
G0KLA Track will show you visually which satellites are in sun vs eclipse if you click the little sun icon. You can see all your selected satellites for the next 2 days. It is very low overhead so I just run it in parallel with the program I am using to steer the antenna. It is best used as a forecast of upcoming passes rather than as a view of a pass in progress. There is an example of the sun/eclipse view on this page: https://www.g0kla.com/klatrack/index.php 73Chris On Wed, Dec 23, 2020 at 6:50 AM kk4yel@gmail.com wrote:
MacDoppler has several ways: The actual satellite sphere (which is artificially larger than scale for practical reasons) is grey when it is in eclipse - no sunshine. When it is illuminated by the sun and not eclipsed by the earth the satellite is shown as yellow. There is also a column named Eclipse which will display Sun if the satellite is illuminated by the Sun, else Drk.
-Kevin (KK4YEL)
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Hi all,
Koos created an initial wiki page on the sats.wikidot.com wiki with this info. I just added all the other programs mentioned in this thread to the page.
http://sats.wikidot.com/how-do-i-check-whether-ao-91-or-another-satellite-is...
I also found a way to see if a sat is in eclipse with Heavens-Above Pro (Android). I added that to the page as well. For reference here are the steps:
Select a satellite by searching for it or finding it under "Radio Satellites" Select the "ORBIT" tab You can see the sunline on the world map and the part that is dark. Make sure the satellite is not in the dark part.
73, John Brier KG4AKV
On Fri, Dec 25, 2020 at 1:39 PM Tom Schuessler via AMSAT-BB amsat-bb@amsat.org wrote:
participants (8)
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Chris Thompson
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John Brier
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johnv@frontier.com
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kk4yel@gmail.com
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Koos van den Hout
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Mark Hammond
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Pedro Converso
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Tom Schuessler