The Moon dances through Taurus and the Hyades Tuesday night

tau-hyades-occultation-1-14-oct-16In spite of the media hubbub over the Harvest “Supermoon”, in my estimation a much more interesting celestial event, a lunar occultation of the bright star Aldebaran in constellation Taurus will take place on the night of October 18-19, Tuesday night into Wednesday morning.

This occultation is one of a series which will continue through September, 2018 and this week’s event will favor observers across North America.

Aldebaran’s disappearance and reappearance behind the 86% sunlit waning gibbous Moon will culminate a four hour series of occultations of stars in the Hyades asterism.

The most interesting observations will be along the “graze line” stretching across a northeast to southwest path from Labrador through Minneapolis, Denver, just south of Las Vegas and on to Los Angeles.

On this graze line the star will appear to skip along Luna’s north limb flickering in and out as lunar mountains and valleys pass in front of it.

Observing these occultations will require a telescope as the Moon’s bright limb overtakes the stars, binoculars will be adequate for observing the reappearances.

The lead graphic above, which I prepared using Stellarium, shows a relatively “tight shot”, 3 degree field of view, of the Moon, Hyades and Aldebaran at 0200 UT, or 10:00 pm EDT, at New Albany, IN Tuesday evening, October 18. This will be low on the eastern horizon about 5 minutes before the disappearances of 01 and 02 TAU.


To help orient you these graphics show a much wider view above the eastern horizon at approximately 10:45 pm EDT on Tuesday evening.


The second graphic shows constellation lines for orientation.

For detailed timings see the International Occultation Timing Association IOTA link. More information on the Graze line is here.

See the Sky and Telescope article here.

Unfortunately the weather forecast for the Louisville area is calling for clouds. I have included timings for the brightest stars as seen from the Louisville area below. Aldebaran and the Moon will be at an elevation of 45 degrees on a bearing of azimuth 106 degrees at the moment of disappearance.

01 TAU 10:04:xx D/10:57:17 R
02 TAU 10:05:14 D/10:58:36 R
HIP21029-SAO93975 11:03:47 D/11:44:28 R
Aldebaran (A Tau) 1:28:08 am D/2:26:46 am R