Watch a Moon Occult Aldebaran This Weekend

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How about that perigee Full Moon this past weekend? Thus starts ‘Supermoon season’ for 2015, as this month’s Full Moon occurs even closer to perigee — reduction than an hour apart, in fact — on Sep 28th, with a final sum lunar obscure of a ongoing tetrad to boot. Keep an eye on Luna this week, as it crosses into a early AM sky for several pivotal dates with destiny usually before to a start of a second and final obscure deteriorate for 2015.

The prominence footprint for a Sep 5th occultation of Aldebaran by a Moon. Image credit: Occult 4.1

The prominence footprint for a Sep 5th occultation of Aldebaran by a Moon. Image credit: Occult 4.1

The large eventuality after this week is a thoroughfare of a loss gibbous Moon by a Hyades open cluster on a morning of Saturday, Sep 5th, climaxing with a thespian occultation of a splendid star Aldebaran on a same morning. This is prejudiced of a array of 49 ongoing occultations of Aldebaran by a Moon, one for any lunation fluctuating out to Sep 2018.

This weekend’s eventuality will start during moonrise underneath night skies for a northeastern United States and a Canadian Maritimes, and nearby emergence and underneath daytime skies for observers in Western Europe and Northern Africa eastward. We celebrated an occultation of Aldebaran by a Moon underneath daytime skies from Alaska behind in a late 1990s, and can demonstrate that a star is indeed manifest nearby a prong of a Moon in binoculars. A good low blue sky is pivotal to spotting +1 bulk Aldebaran in a daytime.

The perspective from London UK during 7:11 AM local. Image Credit: Starry Night Education software

The perspective from London UK during 7:11 AM local. Image Credit: Starry Night Education software

During loss phase, a splendid corner of a Moon is always leading, definition Aldebaran will accession (wink out) on a splendid prong of a 52% splendid Moon, and outlet (reappear) along a dim limb.

Here are some pivotal times for ingress/egress by plcae (all times quoted are internal and incorporate illumination saving/summer time):

Washington D.C.

Moonrise: 11:53 PM

Ingress: N/A (before Moonrise)

Egress: 12:38 AM (altitude = 8 degrees)

Boston

Moonrise: 11:22 PM

Ingress 11:57 PM (altitude = 6 degrees)

Egress: 12:41 AM (altitude = 14 degrees)

Gander, Newfoundland

Moonrise: 11:26 PM

Ingress: 1:37 AM (altitude = 20 degrees)

Egress: 2:26 AM (altitude = 28 degrees)

London

Moonrise: 11:04 PM

Ingress: 5:50 AM (altitude = 53 degrees)

Sunrise: 6:18 AM

Egress: 7:07 AM (altitude = 54 degrees)

Paris

Moonrise: 12:02 AM

Ingress: 6:53 AM (altitude = 56 degrees)

Sunrise: 7:12 AM

Egress: 8:10 AM (altitude = 57 degrees)

Occultations of splendid stars by a Moon are one of a few times besides a solar or lunar obscure when we can indeed discern a one grade per each dual and half hours orbital suit of a Moon in genuine time. The Moon moves usually a small some-more than a possess apparent hole as seen from a Earth each hour. This also sets us adult for 4 some-more excellent occultations of Aldebaran by a Moon swapping between Europe and North America on Oct 2nd, Oct 29th, Nov 26th, and Dec 23rd.

The final 4 occultations of Aldebaran by a Moon for 2015.  Image credit: Occult 4.1

The final 4 occultations of Aldebaran by a Moon for 2015. Image credit: Occult 4.1

The splendid stars Antares, Spica and Regulus also distortion along a trail of a Moon, that is prone about 5 degrees relations to a ecliptic. A array of occultations of Regulus by a Moon starts in late 2016.

Fun fact: The Moon used to mystic a splendid star Pollux in a constellation Gemini until about 2100 years ago in 117 BC. The 26,000 year cycle famous as a Precession of a Equinoxes has given carried a star out of a Moon’s path.

Observations of occultations — generally thespian grazes spied right from a corner of a trail — can be used to erect a form of a lunar limb. A step-wise ‘wink out’ of a star during an occultation can also misuse a existence of a tighten binary.

Recording an occultation of a star by a Moon is as easy as using video while sharpened a Moon. The dim prong outlet of Aldebaran will be most easier to record during a Sep 5th eventuality than a accession of a star opposite a splendid limb. we typically run video with a DLSR directly joined to a Celestron 8” SCT telescope, with WWV radio using in a credentials for a accurate audio timing of a event. Remember, a Moon will also be transiting a Hyades star cluster as well, covering and uncovering many fainter stars for observers worldwide around a same time frame.

The Last Quarter Moon contra Aldebaran and a Hyades on Sep 5th during ~5:00 UT. Image credit: Stellarium

The Last Quarter Moon contra Aldebaran and a Hyades on Sep 5th during ~5:00 UT. Image credit: Stellarium

Now for a ‘wow’ factor. The Moon is about 240,000 miles (400,000 km), or 1 1/4 light seconds distant. Aldebaran is 65 light years away, and pronounced light left a star around 1950, usually to have a light ‘rejected’ during a really final second by a hilly plateau along a lunar limb. And yet Aldebaran appears to be a member of a Hyades, it isn’t, as a open cluster sits 153 light years from Earth.

And watch that Moon, as it afterwards heads for a prejudiced solar obscure as seen from South Africa and a southern Indian Ocean on Sep 13th, and a sum lunar obscure manifest from North America and Europe on Sep 28th.

Source: Universe Today, created by David Dickinson