Greetings from RFO (www.rfo.org), May is a somewhat "quiet" month this year except for the opposition of the always awesome Jupiter, now at its full glory. Venus is bright and prominent in the west. Mars and Saturn are growing more prominent in the morning skies with Mars starting to rise before midnight this month. The moon has nice pairings with most of these planets and also occults a couple of bright stars.
MAY ASTRONOMY EVENTS TO WATCH FOR - Note: All times are local Pacific Time and calculated for the RFO site.
* Use the "What's Up in the Night Sky" link on our website for additional events and details.
Moon - The moon is near Saturn around 4:30 am on 5/4. The moon is near Mars around 2 am on 5/6. Last Quarter is on the evening of 5/7. New Moon is on the morning of 5/15. A thin 4.0% crescent moon is in the west after sunset on 5/16. The crescent moon is near Venus around 9 pm on 5/17. The moon will occult the star 20 Cancri on the night of 5/19 (see below). The first quarter moon is very near the bright blue star Regulus in Leo around 9 pm on 5/21 (use binoculars to appreciate the color). The moon will occult the star 7 Virginis on the evening of 5/23 (see below). The moon is near Jupiter around midnight on the night of 5/26. The "Flower" full moon is on the morning of 5/29. The moon is very near Saturn around midnight on evening of 5/31. [Note: Early in the month there are two bright star reappearance occultations. These are more challenging to observe. Details are on our website(*).
Mercury - Mercury finishes up an extremely poor morning apparition early in the month and is essentially not viewable this month.
Venus - Venus is now very prominent in the evening sky, setting around 11 pm. It is near red-orange Alebaran and the Hyades star cluster early in the month (use binoculars). The crescent moon joins Venus on the evening of 5/17.
Mars - Mars moves from Sagittarius to Capricornus mid-month, when it will be rising around 1 am. It is now quite bright and growing brighter, reaching magnitude -1.2 by month-end. The Moon is near Mars around 2 am on 5/6.
Jupiter - Jupiter, in Libra, is at opposition on the evening of 5/8, reaching magnitude -2.5 and a disk diameter of 43.8". A planet is nearest Earth around opposition so this is when it is biggest and brightest for observing. Jovian satellite events are now readily observable with especially interesting events occurring just before and after opposition. Details on all of these are on our website(*). The moon is near Jupiter on the night of 5/26-27.
Saturn - Saturn, retrograde in Sagittarius, rises around 11:30 pm mid-month. The moon is nearby around 4:30 am on 5/4. Being so far south, Saturn stays relatively low in the southern sky. The moon again joins Saturn, this time very near, around midnight on the evening of 5/31.
Occultation of 20 Cancri - At about 11:30 pm on 5/19 the magnitude 5.9 star 20 Cnc will disappear behind the moon's dark limb 70° from the north cusp. (Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.)
Occultation of 7 Virginis - At about 8:44 pm on 5/23 the magnitude 5.4 star 7 Vir will disappear behind the moon's dark limb 78° from the south cusp. (Calculated using Occult4 for the RFO site. Details will differ as distance from RFO increases.)
TIME SEQUENCE SUMMARY OF EVENTS: Capitalized items refer to the sections above.
5/04 - MOON near SATURN
5/06 - MOON near MARS
5/07 - Last Quarter MOON
5/08 - JUPITER at opposition
5/15 - New MOON
5/16 - 4% Crescent MOON in west
5/17 - Crescent MOON near VENUS
5/19 - OCCULTATION OF 20 CANCRI
5/21 - First Quarter MOON
5/21 - MOON very near Regulus
5/23 - OCCULTATION OF 7 VIRGINIS
5/26 - MOON near JUPITER
5/29 - "Flower" Full MOON
5/31 - MOON very near SATURN