by alter-ego » Sun Dec 16, 2018 5:58 am
I realized there was something up when I saw your link claiming Io as the moon rising. Sure enough I found I misinterpreted a HORIZONS parameter I used to find the Jovian moon candidates. Using the right parameter (angular separation / visibility) it's clear the link is right.
Io is the moon. Io just cleared the limb at about 21:24:30 UT on 10/29/18. The predicted separation from the limb at 21:26 UT = 3.3°, when Jupiter's apparent limb-to-limb diameter = 108°.
Considering the 10 brightest moons (J1→JX), it turns out there were two other moons that rose for Juno, but because of image timing, other field of views during the sequence, and/or too faint magnitudes, the moons weren't captured:
Ganymede rose around 21:37:30 UT
Himalia (JVI) rose around 21:30 UT
I'm glad you found that link. I didn't look hard at all as I was more interested in calculating the moon. I had high expectations for HORIZONS, and it came through in grand style.
[quote=neufer post_id=288120 time=1544853091 user_id=124483]
...
Bright/resolved Io has a magnitude of around -10.5 here:
https://www.missionjuno.swri.edu/news/io_rising
My guess is the dimmer/unresolved but still quite bright [url=https://en.wikipedia.org/wiki/Amalthea_(moon)]Amalthea[/url].
[/quote]
I realized there was something up when I saw your link claiming Io as the moon rising. Sure enough I found I misinterpreted a HORIZONS parameter I used to find the Jovian moon candidates. Using the right parameter (angular separation / visibility) it's clear the link is right. [color=#0000FF][b]Io [i]is[/i] the moon[/b][/color]. Io just cleared the limb at about 21:24:30 UT on 10/29/18. The predicted separation from the limb at 21:26 UT = 3.3°, when Jupiter's apparent limb-to-limb diameter = 108°.
Considering the 10 brightest moons (J1→JX), it turns out there were two other moons that rose for Juno, but because of image timing, other field of views during the sequence, and/or too faint magnitudes, the moons weren't captured:
Ganymede rose around 21:37:30 UT
Himalia (JVI) rose around 21:30 UT
I'm glad you found that link. I didn't look hard at all as I was more interested in calculating the moon. I had high expectations for HORIZONS, and it came through in grand style.