Occultation of Mercury: October 28, 2011

The third and final occultation of 2011, Mercury's occultation this October 28, 2011 will be an astronomical treat for those in Australia, New Zealand, & southern Oceania. Although it was a true fact that each of these occultations this year (2011) were poor to view, 2012 brings yet another smorgasbord of events, as listed at the end of this article.

"It will be observable after sunset from French Polynesia," the Transits Page writes in correspondence of the event. From there, the whole southern Oceanic hemisphere, centered in Australia & New Zealand, will see Mercury occult, right through the center of the Moon. This is a "central one," referring that Mercury will pass through the center of the Moon. Basic information is below.

Greatest Occultation = 2011-Oct-28 02:11:32 TT

Occulted Planet = Mercury

Occultation Series = 7560

Member = 1 of 1

Elongation from Sun = 18° E

Moon illuminated fraction = 2 %

Lunar Magnitude = -5.9

Planetary Magnitude = -0.3

Gamma = -0.21966

Gr. Longitude = 158° 31.4' E

Gr. Latitude = 32° 43.0' S

Gr. Duration = 94m 10.3s

ΔT = 66.64s

Credit: the Transits Page

This occultation occurs in the 7560 series (similar to the Saros of eclipses), and will be the best to view. Mars' Tahitian occultation in July, and Venus' Mediterranean occultation in June both occurred with poor lunar conditions, but the moon will only be two percent illuminated this time! Mercury will pass swiftly - starting on the 27th of October at 23:56 UT and ending on the 28th at 04:24 UT - four hours and twenty-eight minutes total. Below is a picture of Mercury's entrance and exit passage at the green dot in the above picture (in between Australia and New Zealand).

Credit: Transits Page

Local Circumstances—Greatest Occutation

Longitude = 160° 42' 51" E

Latitude =  32° 08' 34" S

Elevation = 0m.

Greatest Occultation = 2011-Oct-28 02:16:20.4 UT

Altitude =  77.8°

Azimuth = 353.7°

  

            Calendar Date and Time          Planet           Sun     Limb

                Universal Time         Azi    Alt    PA      Alt      PA

Ingress    2011-Oct-28 01:29:10.9 d   39.2°  74.8°  102.4°   69.7°  290.8°

Egress     2011-Oct-28 03:03:56.2 b  311.7°  72.9°  287.7°   56.0°  290.4°

Duration    94m 45.3s

Mercury's occultation is hoped to be great - so watch the Moon, if you live in the area of occultation!

The Moon Occults Pi Sagittarii August 10

On August the 10, 2011, the 92% illuminated moon will occult the star Pi Sagittarii, respectively in the constellation of Sagittarius. Shining in the heavens at magnitude 2.88, Pi Sagittarii will occult for the eastern half of North America, so keep your hopes that no clouds or rain will block your view from this magnificent occultation! Although it is rather too bad that the moon is as bright as it is, remember how nice the new moon was for the occultation of Mars last July 27, nevertheless, this occultation should still be good despite the moon!

Pi Sagittarii occulted this past February 28, 2011 over Madagascar and the Indian ocean if you recall, and on June 17, 2011 it occulted over the USA. Finally, The moon has found its way back to this luminous threesome. π Sagittarii is 440 light years away and is a collection of three stars, although too far to distinguish by a telescope. Peculiar to note, π Sgr has a number of names, including Albaldah, 41 Sagittarii, HR 7264, HD 178524, SAO 187756, HIP 94141, and CCDM 19098-2101.

Visibility map for occultation.

Because this star system has three components, it may dim due to eclipsing, so watch out for this. Starting over the Midwest US around 8:30 pm (CDT), the occultation will be seen throughout eastern America and some of Canada; ending at 10:30 EDT in Maine. Although the disappearance (the part everyone looks forward of seeing) has a smaller field of view than the reappearance, mind you that both events will be extremely hard to distinguish due to the moon's glow. "It's also very hard to make sure that you're looking at exactly the right place and time to see the star reappear," Sky&Telescope writes.

Upcoming Occultations:
16 Aug - Occultation of κ Psc - 5.0m - w Canada, w USA, Alaska, Hawaii
21 Aug - Occultation of δ Ari - 4.4m - USA, Canada
22 Aug - Occultation of 37 Tau - 3.0m - USA, Central America, n So America, Caribbeans