RFO

What's Up in the Night Sky

Here's a month-by-month listing of astronomical predictions for the year, compiled by
Jack Welch, RFO astronomy instructor.

 

Abbreviations

Astr Twi - Astronomical Twilight
Civ Twi - Civil Twilight
Cr - Crescent
Dbl Tr - Double Tansit
Ex - Exit
Gr El - Greatest Elongation
Jup - Jupiter
Mer - Mercury
Min - Minimum
Naut Twi - Nautical Twilight
Nr - Near
Occ - Occultation
Opp - Opposition
Reap - Reappear
Qtr - Quarter
Sat - Saturn
Sh - Shadow
Stat - Stationary
V Nr - Very Near
Ven - Venus
Zod Lt - Zodiacal Light

 

Observing

2014 Observing Highlights

December 2014
  • Friday, 12/5/2014 - Cal occ Eur - Time: 23:00
    • This is a Jovian mutual satellite event. From 11:03 to 11:51pm Callisto, moving east to west, will partially occult Europa. The E to W Jovian arrangement just before occultation is:
      Gan - Jup - Io - Cal/Eur
      Jupiter will be 11° high in the ENE (calculated for the RFO site) at the start of this event. Both Callisto and Europa are moving E to W so the occultation lasts a long time, with Jupiter 20° high by the end of occultation. Separation of the two satellites will occur slowly as Jupiter rises higher.
  • Saturday, 12/6/2014 - "Cold" Moon - Time: 04:30
  • Sunday, 12/7/2014 - Algol min - Time: 03:30
    • Algol minimum is at 3:29am.
  • Monday, 12/8/2014 - Occ of lambda Gem - Time: 20:30
    • At about 8:38pm mag 3.6 lambda Geminorum, an extreme close double, will reappear from behind the dark limb of the 92% moon at axis angle of 236° of 47° from the south cusp. The moon will be 14° high in the east. Calculated with Occult4 for the RFO site. Details will vary as distance from RFO increases.
  • Wednesday, 12/10/2014 - Algol min - Time: 00:30
    • Algol minimum is at 12:18am.
  • Friday, 12/12/2014 - Algol min - Time: 21:00
    • Algol minimum is at 9:07pm.
  • Saturday, 12/13/2014 - Geminid Meteors - Time: 22:00
    • Consistently one of the year's best meteor showers, more than 100 per hour are possible near the peak, which might occur any time from 11am 12/13 to 9am 12/14. Best local observing window is 7:30pm to midnight on 12/13. (There is also a possibility of a second peak on the morning of 12/15. Best local window for this is 7:30pm 12/14 to 1am 12/15.)
  • Sunday, 12/14/2014 - Last Qtr - Time: 05:00
    • -
  • Monday, 12/15/2014 - Dbl Sh Tr / Dbl Tr of Jup - Time: 22:00
    • Europa's shadow will be in transit when Jupiter rises at about 9:30pm. Jupiter will be 9° high when the next event occurs and rise higher thereafter:
      10:12p Sh Tr Beg Io - Start Dbl Sh Tr
      10:18p Tr Beg Europa
      11:02p Sh Tr End Europa - End Dbl Sh Tr
      11:15p Tr Beg Io - Start Dbl Tr
      12:29a Sh Tr End Io
      01:12a Tr End Europa - End Dbl Tr
      01:32a Tr End Io
  • Tuesday, 12/16/2014 - Eur occ Io - Time: 02:00
    • This is a Jovian mutual satellite event. From 2:36 to 3:04am Europa, moving east to west, will partially occult Io, which is moving even more quickly E to W such that it will be Io that appears to approach and then separate (from behind Europa). The E to W Jovian arrangement just before occultation is:
      Cal - Jup - Io/Eur - Gan
      Starting at 10:12pm on 12/15 both of these satellites are involved in shadow and satellite double transits of Jupiter's disk. So you may wish to start observing during the transits, but should start watching by about 1:40am in any case.
  • Wednesday, 12/17/2014 - Eur occ Gan - Time: 21:30
    • This is a Jovian mutual satellite event. From 9:34 to 10:20pm Europa, moving west to east, will partially occult Ganymede, which is moving even more slowly W to E. The E to W Jovian arrangement just before occultation is:
      Cal - Gan/Eur - Jup - Io
      Jupiter is only 3° high in the ENE at 9:34pm (calculated for the RFO site) but will reach 12° of altitude by the end of the occultation.
  • Friday, 12/19/2014 - Eur occ Io - Time: 21:30
    • This is a Jovian mutual satellite event. From 9:32 to 9:52pm Europa, moving east to west, will partially occult Io. The E to W Jovian arrangement just before occultation is:
      Cal - Gan - Jup - Eur/Io
      While partial, this is nearly an annular occultation with maximum combined light dimming of 39%. The altitude of Jupiter is only 4° at the start and 8° at the end of the occultation (calculated for the RFO site) so this event will be challenging to observe.
  • Sunday, 12/21/2014 - Cal ecl Io - Time: 03:30
    • This is a Jovian mutual satellite event. From 3:50 to 4:12am Io, moving east to west, will move through Callisto's shadow for an annular eclipse of Io. The E to W Jovian arrangement just before eclipse is:
      Cal - Io - Gan - Jup - Eur
      And Ganymede's shadow will be in transit of Jupiter. Maximum eclipse is at 4:01 with 38% dimming of Io. Those with large aperture scopes should try to view Callisto's shadow on Io using high magnification.
  • Sunday, 12/21/2014 - Solstice - Time: 09:00
    • The Winter Solstice occurs at 3:03pm PST.
  • Sunday, 12/21/2014 - New Moon - Time: 17:30
    • -
  • Monday, 12/22/2014 - 1.5% Cr Mn nr Ven - Time: 17:00
    • An ultra-thin 1.5% crescent moon is 9° high 31° south of due west at 5:15pm. Venus is 3° lower and slightly to the south (left). Use binoculars.
  • Monday, 12/22/2014 - Dbl Sh Tr / Dbl Tr of Jup - Time: 22:30
    • This is a very interesting event. Europa's and Io's shadows will transit Jupiter's disk, as will Europa and Io themselves. And during this transit, Europa will occult Io (see separate entry). The sequence of events:
      10:44p Eur ShTr Start
      12:05a Io ShTr Start - Start Dbl Sh Tr
      12:42a Eur Tr Start
      01:03a Io Tr Start - Start Dbl Tr
      01:38a Eur ShTr End - End Dbl Sh Tr
      02:22a Io ShTr End
      03:19a Io Tr End - End Dbl Tr
      03:36a Eur Tr End
  • Tuesday, 12/23/2014 - Eur occ Io - Time: 02:00
    • This is a Jovian mutual satellite event. From 2:10 to 2:21am Europa, moving east to west, will partially occult Io, which is moving east to west more quickly than Europa such that Io will pass behind Europa. Also, Europa and Io will be transiting the disk of Jupiter during this event (see separate entry for the double transit). The E to W Jovian arrangement just before occultation is:
      Jup[Io/Eur]Jup - Cal - Gan
  • Tuesday, 12/23/2014 - Eur ecl Gan - Time: 22:00
    • This is a Jovian mutual satellite event. From 10:24 to 10:45pm Europa, moving east to west, will eclipse Ganymede. This is an annular eclipse with the umbral portion from 10:27 to 10:42pm. The E to W Jovian arrangement just before eclipse is:
      Jup - Eur - Gan - Cal (Io is occulted by Jupiter)
      Maximum eclipse is at 10:35 with 37% dimming of Ganymede. Those with large aperture scopes should try to view Europa's shadow on Ganymede using high magnification.
  • Wednesday, 12/24/2014 - Occ of 8 Aqr - Time: 18:00
    • At about 6:23pm mag 6.6 8 Aquarii will disappear behind the crescent moon's dark limb 71° from the south cusp. Calculated with Occult4 for the RFO site. Details will vary as distance from RFO increases.
  • Thursday, 12/25/2014 - Eur ecl Gan - Time: 01:00
    • This is a Jovian mutual satellite event. From 1:19 to 2:41am Europa, moving west to east, will eclipse Ganymede, which is moving west to east more slowly making this a long lasting event. This is a partial (though nearly annular) eclipse with the umbral portion from 1:28 to 2:32am. The E to W Jovian arrangement just before eclipse is:
      Eur - Gan - Jup - Io - Cal
      Maximum eclipse is at 2:00 with 29% dimming of Ganymede. Those with large aperture scopes should try to view Europa's shadow on Ganymede using high magnification.
  • Friday, 12/26/2014 - Eur occ Io - Time: 24:00
    • This is a Jovian mutual satellite event. From 12:22 to 12:35am (12/27) Europa, moving east to west, will partially occult Io. The E to W Jovian arrangement just before occultation is:
      Gan - Jup - Eur/Io - Cal
      Begin observing by 11:40pm to view Europa approaching Io.
  • Saturday, 12/27/2014 - Algol min - Time: 05:00
    • Algol minimum is at 5:13am.
  • Saturday, 12/27/2014 - Gan occ Io - Time: 23:30
    • This is a Jovian mutual satellite event. From 11:39 to 11:37pm Ganymede, moving east to west, will partially (nearly totally) occult Io. The E to W Jovian arrangement just before occultation is:
      Gan/Io - Jup - Eur - Cal
      Begin observing by 11:00pm to view Europa approaching Io.
  • Sunday, 12/28/2014 - 1st Qtr - Time: 10:30
    • -
  • Sunday, 12/28/2014 - Gan occ Io - Time: 21:00
    • This is a Jovian mutual satellite event. From 9:24 to 9:34pm Ganymede, moving east to west, will partially occult Io. The E to W Jovian arrangement just before occultation is:
      Eur - Jup - Gan/Io - Cal
      Jupiter's altitude in the ENE at 9:24pm is 10°, but try to start observing as early as possible.
  • Tuesday, 12/30/2014 - Occ of Torcularis Septentrionalis - Time: 00:30
    • At about 12:35am the mag 4.3 beautifully named star Torcularis Septentrionalis (omicron Piscium) will disappear behind the moon's dark limb 39° from the south cusp. Calculated with Occult4 for the RFO site. Details will vary as distance from RFO increases.
  • Tuesday, 12/30/2014 - Algol min - Time: 02:00
    • Algol minimum is at 2:03am.
  • Tuesday, 12/30/2014 - Occ of 31 Ari - Time: 23:30
    • At about 11:31pm the mag 5.6 extreme close equal double star 31 Arietis will disappear behind the moon's dark limb 23° from the south cusp. This event requires a larger aperture scope. Calculated with Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Wednesday, 12/31/2014 - Eur ecl Gan - Time: 02:30
    • This is a Jovian mutual satellite event. From 2:45 to 3:12am Ganymede, moving west to east, will pass through Europa's shadow. This is an annular eclipse with the umbral portion from 2:49 to 3:08am. The E to W Jovian arrangement just before eclipse is:
      Cal - Io - Jup - Eur - Gan
      Maximum eclipse is at 2:00 with 29% dimming of Ganymede. Those with large aperture scopes should try to view Europa's shadow on Ganymede using high magnification.

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