Closed glenenglishgithub closed 4 years ago
glenenglishgithub
commented
5 years ago Got it ! yes had to uninstall the repository version 2.8 that was installed using setup.py by reinstalling and generating the file list, and then de-stalling. I really need to learn about virtual environments .
Ok that ran. Yep I agree with the error. When varying time, it isn't a simple time error judging from what happens to the numbers.
brandon-rhodes
commented
4 years ago Coming back to this old issue, I'm happy to report that the most recent release of Skyfield includes support for Moon orientation:
https://rhodesmill.org/skyfield/planetary.html
If I'm correct, an interested party can ask for the alt/az of the Earth when viewed from the 0° / 0° latitude longitude on the Moon to find out how many degrees the Moon is librated from our point of view. Or they could even ask about the libration angle as viewed from a specific spot on the Earth!
So I'll go ahead and close this as complete. Feel free to open a new issue in the future, though, if there's specific data you find you can't generated from Skyfield with respect to Moon orientation.
glenenglishgithub
commented
4 years ago Hi Brandon
fantastic, cheers. The librartion information will be well received and form a chunk of new moon tracking software for EME (earth-moon-earth) amateur radio comms.
BTW , as a result of the knowledge based on discussions with your group, and the resultant tracking questions resolved the world record on moonbounce comms was broken last year - Europe was on the setting moon that was on the horizon at the mid point of the contact- (easy to track the moon down to the horizon on moon noise with a big dish), and in New Zealand end - rising moon- the moon wasnt even visible for good deal of the 5-10 minutes taken to complete the contact- that is the moon was below the (optical) horizon and also there was a cloud bank on the horiozn (over ocean) ....so the tracking information was computed, and lined up and fingers crossed- and it all worked.
A pair of Ublox M8T RTK GPS receivers ~ 10 meters apart was used to compute the azimuth to within 0.1 deg....and the dish was lined up on that bearing and then hoped the calcs were correct...
regards
glen english
On 2/02/2020 1:48 am, Brandon Rhodes wrote:
Coming back to this old issue, I'm happy to report that the most recent release of Skyfield includes support for Moon orientation:
https://rhodesmill.org/skyfield/planetary.html
If I'm correct, an interested party can ask for the alt/az of the Earth when viewed from the 0° / 0° latitude longitude on the Moon to find out how many degrees the Moon is librated from our point of view. Or they could even ask about the libration angle as viewed from a specific spot on the Earth!
So I'll go ahead and close this as complete. Feel free to open a new issue in the future, though, if there's specific data you find you can't generated from Skyfield with respect to Moon orientation.
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/brandon-rhodes/pyephem/issues/155?email_source=notifications&email_token=AGBJLNEKAVQULZMO37V5Q73RAWDS7A5CNFSM4FYBZMJKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEKQ6YWA#issuecomment-581037144, or unsubscribe https://github.com/notifications/unsubscribe-auth/AGBJLNDQONYXJNRXHTNYKF3RAWDS7ANCNFSM4FYBZMJA.
-- Glen English RF Communications and Electronics Engineer
CORTEX RF & Pacific Media Technologies Pty Ltd
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia. au mobile : +61 (0)418 975077
brandon-rhodes
commented
4 years ago That's AMAZING! After so much hard work, that it would come down to aiming the antennas and then having to just wait and see if the link appeared. What a success.
Is there a write-up telling the full story of the effort, by any chance?
glenenglishgithub
commented
4 years ago Sure
here you go.. gee it was a while ago now.
attached
I have also dumped them on a a web server, they might appear here :
www.cortexrf.com.au/diffGPS.pdf
www.cortexrf.com.au/WW10gig.pdf
On 2/02/2020 8:18 am, Brandon Rhodes wrote:
That's AMAZING! After so much hard work, that it would come down to aiming the antennas and then having to just wait and see if the link appeared. What a success.
Is there a write-up telling the full story of the effort, by any chance?
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/brandon-rhodes/pyephem/issues/155?email_source=notifications&email_token=AGBJLNAJ2B23QTEKYLVATKDRAXRLHA5CNFSM4FYBZMJKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEKRG4QQ#issuecomment-581070402, or unsubscribe https://github.com/notifications/unsubscribe-auth/AGBJLNBOHULW65GG5QTDCVDRAXRLHANCNFSM4FYBZMJA.
-- Glen English RF Communications and Electronics Engineer
CORTEX RF & Pacific Media Technologies Pty Ltd
ABN 40 075 532 008
PO Box 5231 Lyneham ACT 2602, Australia. au mobile : +61 (0)418 975077
brandon-rhodes
commented
4 years ago I was able to read both documents, thanks!
I found predicted moonrise times to be very early (2-3 minutes) compared to observations for negative horizons. In this case, altitude was 1270 m which has an ocean horizon ~ -1.14 deg. This was for 1013 Pa and 14 deg C.
I picked out the refract.c and ran refract.c alone and found that at -1.14deg Ta, refraction of 0.9 deg was being applied, resulting in *aa being set to ~ -2.04 deg ! Is this refraction calc invalid for negative horizons ? I see there are a few methods around.
I modified refract.c so that the refraction correction would never exceed 34/60 and now the moonrise times are very close (seconds!) with exception of a moon elevation question I posted on stackoverflow.
Great software Brandon, nice work. I am using it for very low angle ham radio moonbounce calculations for world records where the elevation of the moon is about 0.5 deg at each end , IE working at the antipodes, there is only a few minutes to make the communication.
regards glen english Canberra, Australia.