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

2015 Observing Highlights

May 2015
  • Friday, 5/1/2015 - Mer in W thru 5/18 - Time: 20:30
    • This is the best evening apparition of Mercury in 2015. Mercury reaches greatest altitude on 5/5 when it is 11° high 45 minutes after sunset. Begin looking for Mercury around 8:30pm in late April, or around 8:45pm in mid-May. Mercury will fade in brightness as May progresses.
  • Saturday, 5/2/2015 - Io Sat/Sh Tr - Time: 23:00
    • Io will transit Jupiter from 11:02pm to 1:19am followed by its shadow which transits starting at 12:17am and is transiting when Jupiter sets.
  • Sunday, 5/3/2015 - "Flower" Moon - Time: 20:30
    • -
  • Sunday, 5/3/2015 - Io ecl reapp - Time: 23:30
    • Io will reappear from Jupiter's shadow a bit more than half the planet's diameter east of Jupiter at 11:57pm. Note: Callisto is in transit at this time about 80% of the way across Jupiter, with transit ending at 1:04am.
  • Tuesday, 5/5/2015 - Io ecl Eur - Time: 01:00
    • This is a Jovian mutual satellite event. From 1:13 to 1:19am Io, moving east to west, will partially but substantially eclipse Europa with maximum dimming of 64% at 1:16.2am. The E to W Jovian arrangement just before eclipse is:
      Gan - Jup - Eur - Io - Cal
      Larger aperture scopes at high magnification should try to view the umbral shadow on Europa's disk.
  • Tuesday, 5/5/2015 - Mn nr Sat - Time: 04:00
    • -
  • Friday, 5/8/2015 - Eur ecl reapp - Time: 22:00
    • Europa reappears from Jupiter's shadow about one planet diameter east of Jupiter at 10:20pm.
  • Saturday, 5/9/2015 - Gan ecl reapp - Time: 23:30
    • At 11:54pm Ganymede reappears from Jupiter's shadow about 1.25 planet diameters east of Jupiter.
  • Monday, 5/11/2015 - Last Qtr - Time: 03:30
    • -
  • Monday, 5/11/2015 - Io Sat/Sh Tr - Time: 20:30
    • Io will be in transit about half way across Jupiter when it becomes viewable during twilight. Io's shadow transits from 8:43 to 10:59pm, with Io ending transit at 9:43pm.
  • Tuesday, 5/12/2015 - Gan occ Io - Time: 23:00
    • This is a Jovian mutual satellite event. From 11:05 to 11:10pm Ganymede, moving east to west, will partially but substantially occult Io. The E to W Jovian arrangement just before occultation is:
      Eur - Cal - Gan/Io - Jup
      Begin observing by 10:45pm to watch Ganymede and Io approach. Those with larger aperture scopes at high magnification should look for a color contrast between the two satellite disks.
  • Saturday, 5/16/2015 - Eur ecl reapp - Time: 00:30
    • Europa reappears from Jupiter's shadow about one planet diameter east of Jupiter at 12:57am.
  • Saturday, 5/16/2015 - Ecl of Gan - Time: 24:00
    • After reappearing from behind Jupiter at 10:37pm, Ganymede will disappear into Jupiter's shadow east of the planet at 12:04am.
  • Sunday, 5/17/2015 - New Moon - Time: 21:00
    • -
  • Sunday, 5/17/2015 - Eur occ Io - Time: 21:00
    • This is a Jovian mutual satellite event. Europa, moving east to west, will partially occult Io from 9:09 to 9:13pm. The E to W Jovian arrangement just before occultation is:
      Cal - Gan - Jup - Eur/Io
      Begin observing by 8:50pm to watch Europa approach Io. Those with large aperture scopes at high magnification should look for a color difference between the disks.
  • Monday, 5/18/2015 - Io Sat/Sh Tr - Time: 21:00
    • Io transits Jupiter from 9:23 to 11:40pm followed by its shadow from 10:36pm to 12:54am.
  • Tuesday, 5/19/2015 - 5.1% Cr Mn - Time: 21:00
    • Look for a thin crescent moon 42 minutes after sunset (or at 9:00pm calculated for RFO). It will be 10° high 15° north of due west.
  • Tuesday, 5/19/2015 - Gan occ Eur - Time: 21:30
    • This is a Jovian mutual satellite event. From 9:33 to 9:40pm Ganymede, moving east to west, will almost totally occult Europa. The E to W Jovian arrangement just before occultation is:
      Cal - Gan/Eur - Jup
      Begin observing by 9:10pm to watch Ganymede and Europa approach. Those with larger aperture scopes at high magnification should look for a color contrast between the two satellite disks. Note: Io is eclipsed by Jupiter and will reappear east of Jupiter at 10:15pm.
  • Tuesday, 5/19/2015 - Io ecl reapp - Time: 22:00
    • Io will reappear from Jupiter's shadow a bit more than half the planet's diameter east of Jupiter at 10:15pm. Note: Ganymede, Europa and Callisto (in that order, west to east) will be grouped VERY close together to the east of Io.
  • Thursday, 5/21/2015 - Cr Mn nr Ven - Time: 21:00
    • -
  • Friday, 5/22/2015 - Sat opp - Time: 19:00
    • Saturn is at opposition in Libra at magnitude 0.0 and a disk size of 19". The diameter of the rings is 42" with a tilt angle of 24.4°.
  • Saturday, 5/23/2015 - Mn nr Jup - Time: 23:00
    • -
  • Sunday, 5/24/2015 - Eur Sh Tr - Time: 21:30
    • Europa's shadow will be about 70% of the way across Jupiter when it becomes visible during twilight. The shadow transit ends at 10:38pm.
  • Sunday, 5/24/2015 - Eur occ Io - Time: 23:00
    • This is a Jovian mutual satellite event. Europa, moving east to west, will partially occult Io from 11:26 to 11:30pm. The E to W Jovian arrangement just before occultation is:
      Gan - Jup - Eur/Io - Cal
      Begin observing by 11:10pm to watch Europa approach Io. Those with large aperture scopes at high magnification should look for a color difference between the disks.
  • Monday, 5/25/2015 - 1st Qtr - Time: 10:30
    • -
  • Tuesday, 5/26/2015 - Occ of 79 Leo - Time: 20:30
    • At about 8:43pm, during twilight, mag 5.4 79 Leonis will disappear behind the moon's dark limb 29° from the south cusp. Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Tuesday, 5/26/2015 - Io ecl reapp - Time: 24:00
    • Io will reappear from Jupiter's shadow a bit more than half the planet's diameter east of Jupiter at 12:10am.
  • Friday, 5/29/2015 - Io ecl Eur - Time: 21:00
    • This is a Jovian mutual satellite event. From 9:12 to 9:17pm Io, moving east to west, will partially eclipse Europa with maximum dimming of 35% at 9:14.6pm. The E to W Jovian arrangement just before eclipse is:
      Cal - Jup - Eur - Io - Gan
      Larger aperture scopes at high magnification should try to view the umbral shadow on the north edge of Europa's disk.
  • Sunday, 5/31/2015 - Eur Sh Tr - Time: 22:00
    • Europa's shadow begins transiting at 10:22pm, at which time Europa, in transit, is about 80% of the way across Jupiter. Europa ends transit at 10:55pm, and Jupiter sets with the shadow transit still in progress.

June 2015
  • Monday, 6/1/2015 - Mn nr Sat - Time: 21:00
    • -
  • Tuesday, 6/2/2015 - "Strawberry" Moon - Time: 09:30
    • -
  • Wednesday, 6/3/2015 - Dbl Sh Tr of Jup - Time: 21:30
    • Io and its shadow begin transit during late daylight/early twilight. By 21:30 Io is about 70% of the way across Jupiter, trailed by its shadow at about 25%. The arrangement at this time is: Cal - Eur - Jup - Gan. Then...
      21:58 Ganymede's shadow begins transit
      START Dbl Sh Transit
      22:05 Io's transit ends
      23:13 Io's shadow ends transit
      END Dbl Sh Transit
      By this time Jupiter's altitude is 16°. Ganymede will occult Io beginning at 24:03 but the altitude will only be 6°. Jupiter sets at 24:35 with Ganymede's shadow still in transit.
  • Friday, 6/5/2015 - Io ecl Eur - Time: 23:00
    • This is a Jovian mutual satellite event. From 11:30 to 11:36pm Io, moving east to west, will partially eclipse Europa with maximum dimming of 31% at 11:32.7pm. The E to W Jovian arrangement just before eclipse is:
      Cal - Jup - Eur - Io - Gan
      Larger aperture scopes at high magnification should try to view the umbral shadow on the north edge of Europa's disk. Note: Jupiter will be 10° high in the west during this event.
  • Tuesday, 6/9/2015 - Last Qtr - Time: 08:30
    • -
  • Tuesday, 6/9/2015 - Eur ecl reapp - Time: 22:00
    • Europa reappears from Jupiter's shadow about one planet diameter east of Jupiter at 10:06pm.
  • Wednesday, 6/10/2015 - Gan occ Io - Time: 21:30
    • This is a very challenging Jovian mutual satellite event viewable only by large aperture scopes under good conditions. From 9:56 to 10:18pm Ganymede, moving east to west, will partially but substantially occult Io. Both satellites will be transiting Jupiter near the east limb. The E to W Jovian arrangement just before occultation is:
      Eur - Jup[Io/Gan]Jup - Cal
      Begin observing before 9:30pm to watch the two satellites begin their Jovian transits, Ganymede at 9:34 and Io at 9:46pm.
  • Wednesday, 6/10/2015 - Io Sat/Sh Tr - Time: 21:30
    • This is an interesting event, with a double satellite transit accompanied by a shadow transit. Ganymede begins transit at 9:34pm, followed very closely by Io at 9:46pm. Io's shadow begins transit at 10:51pm, by which point faster Io is about 50% across Jupiter and Ganymede about 40% across. (Io's transit ends at 12:04am, moments before Jupiter sets.)
  • Thursday, 6/11/2015 - Pallas opp - Time: 18:00
    • The minor planet Pallas is at opposition in Hercules near the stars 83 and 84 Her and at a challenging magnitude 9.4. A finder's chart and repeat observations are essential for spotting.
  • Thursday, 6/11/2015 - Io ecl reapp - Time: 22:00
    • Io will reappear from Jupiter's shadow about half the planet's diameter east of Jupiter at 10:28pm
  • Tuesday, 6/16/2015 - New Moon - Time: 07:00
    • -
  • Wednesday, 6/17/2015 - 3.0% Cr Mn - Time: 21:00
    • Look for a very thin crescent moon 24 minutes after sunset (9:00pm calculated for RFO). It will be 10° high 15° north of due west.
  • Friday, 6/19/2015 - Cr Mn nr Ven - Time: 21:30
    • -
  • Saturday, 6/20/2015 - Cr Mn nr Jup - Time: 22:00
    • -
  • Sunday, 6/21/2015 - Solstice - Time: 09:30
    • The summer solstice occurs at 9:38am.
  • Monday, 6/22/2015 - Mer in E thru 7/8 - Time: 05:00
    • This is a poor morning apparition of Mercury, which reaches greatest altitude on 6/29 of only 5.5° and 21° north of due east 45 minutes before sunrise. Look for Mercury between 4:50 and 5:15am.
  • Wednesday, 6/24/2015 - 1st Qtr - Time: 04:00
    • -
  • Thursday, 6/25/2015 - Eur occ Io - Time: 23:00
    • This is a Jovian mutual satellite event. Europa, moving east to west, will partially occult Io from 9:52 to 9:56pm. The E to W Jovian arrangement just before occultation is:
      Jup - Eur/Io - Gan - Cal
      Begin observing before 9:40pm to watch Europa approach Io. Those with large aperture scopes at high magnification should look for a color difference between the disks. Note: Europa's shadow will be transiting Jupiter.
  • Sunday, 6/28/2015 - Mn nr Sat - Time: 22:30
    • -
  • Tuesday, 6/30/2015 - Ven v nr Jup - Time: 22:00
    • Jupiter will approach Venus in the western sky during late June with closest approach of less than half a degree this evening. Coincidentally, the disk size of large crescent phase Venus will be almost the same as that of Jupiter!

July 2015
  • Wednesday, 7/1/2015 - "Buck" Moon - Time: 19:30
    • -
  • Sunday, 7/5/2015 - Io occ Gan - Time: 21:00
    • This is a Jovian mutual satellite event. Io, moving east to west, will partially occult Ganymede from 9:18 to 9:20pm. There should be a noticeable color difference between the disks for large aperture scopes at high magnification. The E to W Jovian arrangement just before occultation is:
      Cal - Eur - Jup - Io/Gan
      Begin observing before 9:00pm to watch Io approach Ganymede.
  • Wednesday, 7/8/2015 - Last Qtr - Time: 13:30
    • -
  • Wednesday, 7/15/2015 - New Moon - Time: 18:30
    • -
  • Thursday, 7/23/2015 - 1st Qtr - Time: 21:00
    • -
  • Friday, 7/31/2015 - "Blue" Moon - Time: 03:30
    • -

August 2015
  • Thursday, 8/6/2015 - Last Qtr - Time: 19:00
    • -
  • Wednesday, 8/12/2015 - Perseids peak - Time: 24:00
    • Conditions are very favorable this year for the Perseid meteors. The shower is expected to peak between 11:30pm 8/12 and 2:00am 8/13, though this can vary. Rates of 100 per hour are typical. The Perseids are viewable after about 10pm or so for many days around the peak but the highest rates should be this night.
  • Friday, 8/14/2015 - New Moon - Time: 08:00
    • -
  • Wednesday, 8/19/2015 - Occ of 82 Vir - Time: 20:30
    • At about 8:34pm, during late twilight, mag 5.0 82 Virginis will disappear behind the crescent moon's dark limb 30° from the north cusp. Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Saturday, 8/22/2015 - 1st Qtr - Time: 12:30
    • -
  • Saturday, 8/29/2015 - "Sturgeon" Moon - Time: 11:30
    • -

September 2015
  • Saturday, 9/5/2015 - Last Qtr - Time: 03:00
    • -
  • Saturday, 9/12/2015 - New Moon - Time: 24:00
    • -
  • Monday, 9/21/2015 - 1st Qtr - Time: 02:00
    • -
  • Sunday, 9/27/2015 - "Harvest" Moon - Time: 20:00
    • -

October 2015
  • Friday, 10/2/2015 - Occ of 75 Tau - Time: 02:30
    • This is a double event. First, at about 2:50am a mag 6.7 double star will reappear from behind the dark limb at axis angle 213° (29° from the south cusp). A double "blink in" may be detectable. This event requires larger aperture scopes for viewing.
      Next, at about 2:54am mag 5.0 75 Tauri will reappear from behind the dark limb at axis angle 268° (84° from the south cusp).
      Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Friday, 10/2/2015 - Occ of Aldebaran - Time: 06:00
    • This is a double event viewable with any scope. Those with binoculars may wish to watch as well. First, at about 6:15am the very bright (mag 0.9) star Aldebaran (alpha Tauri) will disappear behind the moon's bright limb 50° from the south cusp.
      Next, at about 7:17am Aldebaran will reappear from behind the dark limb. This occurs almost exactly at sunrise. Those with tracking scopes can easily locate the reappearance point by tracking from the disappearance. Others may locate the reappearance point by its axis angle of 233° (or 50° from the south cusp).
      Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Saturday, 10/3/2015 - Occ of 111 Tau - Time: 01:30
    • At about 1:50am mag 5.0 111 Tauri will reappear from behind the dark limb at axis angle 253° (71° from the south cusp).
      Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Sunday, 10/4/2015 - Last Qtr - Time: 14:00
    • -
  • Monday, 10/5/2015 - Occ of lambda Gem - Time: 02:30
    • This is a double event. First, at about 2:41am mag 3.6 lambda Geminorum will disappear behind the moon's bright limb 46° from the south cusp. This event requires larger aperture scopes.
      Then, at about 3:24am the star will reappear from behind the dark limb at axis angle 212° (33° from the south cusp). Those with tracking scopes can track from the disappearance.
      Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Thursday, 10/8/2015 - Draconids peak - Time: 22:30
    • About 20 meteors per hour are expected around the peak, but outburst have been known to happen. Conditions are favorable all night until after moonrise at 4:12am on 10/9.
  • Monday, 10/12/2015 - New Moon - Time: 17:00
    • -
  • Tuesday, 10/20/2015 - 1st Qtr - Time: 13:30
    • -
  • Wednesday, 10/21/2015 - Orionids peak - Time: 24:00
    • The peak time is uncertain for this meteor shower but the morning of 10/22 after the moon sets at 1:45am is the best time for meteor watching. Rates of about 15 per hour are expected.
  • Tuesday, 10/27/2015 - "Hunter's" Moon - Time: 05:00

November 2015
  • Tuesday, 11/3/2015 - Last Qtr - Time: 04:30
    • -
  • Wednesday, 11/11/2015 - New Moon - Time: 10:00
    • -
  • Tuesday, 11/17/2015 - Leonids peak - Time: 20:00
    • Conditions are very good for Leonid meteor observing this year, though the rate is expected to be on the low side with about 15 to 20 meteors per hour at peak. The meteors are viewable starting around 11:30pm and the morning of 11/18 will be moonless.
  • Wednesday, 11/18/2015 - 1st Qtr - Time: 22:30
    • -
  • Wednesday, 11/25/2015 - "Beaver" Moon - Time: 14:30

December 2015
  • Wednesday, 12/2/2015 - Last Qtr - Time: 23:30
    • -
  • Monday, 12/7/2015 - Occ of Venus - Time: 07:30
    • This is a daylight double event viewable with any scope. Those with binoculars may wish to watch as well. First, at about 7:15am very bright Venus will disappear behind the crescent moon's bright limb 84° from the south cusp.
      Next, at about 9:37am Venus will reappear from behind the dark limb at axis angle 273° (88° from the north cusp).
      Both the disappearance and reappearance will take about 27 seconds due to the size of Venus's disk at 17" and 69% gibbous phase.
      Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Friday, 12/11/2015 - New Moon - Time: 02:30
    • -
  • Monday, 12/14/2015 - Geminids peak - Time: 10:00
    • This consistently strong shower with about 120 meteors per hour is best viewed on the night of 12/13-14 this year. The shower is viewable all night, which is from about 6:30pm until 6am. The 12/14 10am peak prediction time is uncertain; it could occur any time from 5:30pm on 12/13 to 3pm on 12/14.
  • Friday, 12/18/2015 - 1st Qtr - Time: 07:00
    • -
  • Monday, 12/21/2015 - Occ of ZC454 - Time: 22:30
    • At about 10:56pm the mag 5.6 star ZC454 will disappear behind the dark limb 57° from the north cusp. Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.
  • Friday, 12/25/2015 - "Cold" Moon - Time: 03:00
    • -
  • Wednesday, 12/30/2015 - Occ of 48 Leo - Time: 01:30
    • At about 1:53am mag 5.1 48 Leonis will reappear from behind the dark limb at axis angle 259° (79° from the south cusp). This is an extreme close equal double so a double "blink in" might be detectable. Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.

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