September provides various fascinating lunar occultation occasions worldwide.
Chances are high, there’s one close to you this month. The Moon is actually busy in September, as its passage covers up (occults) a number of celestial objects worldwide. If skies are clear, it’s possible you’ll simply get an opportunity to see certainly one of these occasions listed beneath, because the Moon blocks out a star, planet or star cluster.
You might effectively have seen photographs from final month’s lunar occultation of Saturn from observers throughout the UK and western Europe. The Moon occults Saturn 10 instances in 2024—as soon as for each lunation go. The slowest transferring of the bare eye planets, Saturn makes a very good repeated goal for the Moon. The rings are headed in the direction of edge-on in 2025, making for an interesting view because it peeks out from behind the lunar limb.
Why Occultations
Occultations happen in cycles, because the Moon journeys on its month-to-month trek 5 levels above and beneath the ecliptic aircraft. Within the present epoch, the Moon can occult 4 +1st magnitude stars: Aldebaran, Regulus, and (as is ongoing in 2024) Antares and Spica. The Moon strikes its personal diameter (30’ or half a level) as soon as each hour, and the darkish limb leads the way in which when it’s waxing, and trails when it’s waning. Darkish limb ingresses may be particularly dramatic.
The Moon can be using excessive within the sky in 2024, as we head in the direction of a bi-decadal Main Lunar Standstill subsequent 12 months in 2025.
An Occultation, Transit… or Eclipse?
Like eclipses, successive occultations in a cycle transfer westward by about 120 levels of longitude. Plenty of observational astronomy is not more than watching one factor go in entrance of one other, and seeing what occurs: occultations, transits and eclipses are comparable methods to specific the what is actually the identical factor. Double star companions, profiles of asteroids, and diameters of tiny stellar sources have revealed themselves throughout occultations.
Occultations in September
All thrilling stuff, to make sure. Right here’s our rundown on what’s in retailer for lunar occultations in September worldwide:
First up, the 5% illuminated waxing crescent Moon occults Venus on September 5th, centered on 10:16 Common Time (UT). Maybe, just a few penguins and some windswept distant analysis stations in Antarctica will witness to this daytime occasion. The remainder of us might be handled to a really shut pairing of the 2 at nightfall.
Subsequent, the ten% illuminated, waxing crescent occults the +1st magnitude star Spica (Alpha Virginis) for central Africa on the night of September 6th centered on 17:04 UT. Enjoyable reality: situated 250 light-years distant, Spica is a detailed candidate (together with Betelgeuse) for a close-by galactic supernova.
4 days in a while September 10th, the 43% illuminated, waxing crescent Moon occults the +1st magnitude star Antares (Alpha Scorpii) for western Australia centered on 13:09 UT. We caught an identical occasion again in 2009.
Searching for Saturn
Simply previous mid-month on September 17th, the 99.2% illuminated, waxing gibbous Moon occults Saturn for western North America, centered on 10:22 UT within the early morning hours. Northeastern Australia and the close by Pacific island area sees the occasion transpire within the night. That is simply 9 days after Saturn will attain opposition for 2024 on the 8th. The occultation happens 16 hours previous to Full Moon and the partial lunar eclipse on the 17th-18th. This eclipse favors the Americas, Africa and Europe. Saturn spans 19” in the course of the occasion, and can take about 40 seconds to vanish and reappear from behind the Moon.
Simply 5 hours after the eclipse on the 18th, the Moon occults Neptune, additionally for North America. A troublesome catch, as faint +eighth magnitude Neptune solely spans 2.4”, however a problem none the much less. Neptune reaches opposition simply 3 days later for 2024 on September 21st.
Lastly, the 75% illuminated, waning gibbous Moon occults the well-known open star cluster Messier 45 (also referred to as the Seven Sisters or the Pleiades) for North America on September 22nd. The Moon visits the cluster as soon as each lunation for the rest of this present decade.
The Worldwide Occultation Timing Affiliation (IOTA) maintains pages for stellar and planetary lunar occultations in 2024. These embody ingress/egress instances for choose websites.
Observing Occultations
Observing an occultation of a vivid star or planet by the Moon is as straightforward as watching on the appointed time. Binoculars or a small telescope will definitely enhance the view. Imaging or recording can, nevertheless, be a difficult affair—particularly if the dazzling Moon is close to Full.
“Right here in London we have been fortunate sufficient to catch an occultation of Mars by the Moon a number of years in the past, so I used to be excited to see that there can be a fairly favorable occultation of Saturn seen in the direction of the tip of August this 12 months,” astrophotographer Roger Hutchinson advised Universe In the present day. “Imaging occasions like this the place the principle topics have such an enormous distinction in brightness requires the seize of a number of photographs at totally different exposures, these then being composited to file the occasion kind of as the attention sees it. Transits, occultations and eclipses deliver house the fixed movement of our photo voltaic system and are all the time wonderful occasions to witness and seize. Can’t wait ‘til the subsequent one!”
Don’t miss certainly one of these spectacular celestial occasions, coming to a sky close to you.
