AstroEvent(s): Hunting the Lunar V & More.

An uber-thin crescent from September 2011.

Take heart, residents of the northern hemisphere; Fall and hopefully cooler climes and darker nights are almost upon us. Growing up in northern Maine, autumn was always our favorite season of the year. It’s the season without the aggravations of all the others; lacking the chill of winter, the mud of spring and the bugs of summer, Fall is the best. If we ever find an exoplanet with a climate that resembles a perpetual New England Fall, I propose that a multi-generational ark be constructed immediately…

But I digress. This equinox week provides an occultation grab bag, as well as your chance to locate a unique lunar feature.

The Moon+Planets looking west at dusk on the evening of the 18th. (all simulations created by the author using Starry Night and Paint).

First up, the 3-day old crescent Moon will join the ever changing trio of Saturn, Spica and Mars in the dusk skies. The Moon occults Spica on the 18^th as seen from Antarctica ~03:00 UTC, & proceeds to occult the planet Mars on the 19^th ~22:00 for observers in South America. As was the case for the Jupiter occultation last week, the rest of us will see a close (less than 1 degree) pass.

Next up: Trans-Neptunian Object 2000 PD30 occults an 8^th magnitude star in the constellation Aquarius on September 20^th around 6:38 UTC. Although the central path of the occultation crosses Bolivia & Peru in South America across the Pacific to New Zealand towards twilight, it should be noted that the uncertainties of the path of such a distant event is larger than the diameter of the Earth itself… it may be worth your while if you’re based in the southern United States to train your scope on the star at the time of the occultation and watch. Occultations by TNOs are rare phenomena!

Uranus on closest approach to 44 Piscium at 14:00 UTC on September 23rd.

Meanwhile, in the constellation Pisces near the Cetus border, the planet Uranus passes less than 1’ from the +5.75 magnitude star 44 Piscium on September 22^nd. In fact, Uranus is about the same brightness, making the pair appear as a wide colored double in the eyepiece of a telescope. This is one of the closer planet-star conjunctions of 2012. Uranus will appear as it always does, with a tiny blue-green disk 3.7” across. Uranus reaches opposition on September 29th and around such time it may just be possible to spot its elusive moons (See the addendum at the end of this post). 44 Piscium can also occasionally be occulted by the Moon (which can also pass into the non-zodiacal constellation of Cetus nearby) And even more rarely, by a planet, as last occurred on March 1931 by Mercury and will next occur on February 24^th, 2055 featuring the planet Venus.

Uranus & 44 Piscium; a wide field view.

The coordinates for 44 Piscium are as follows;

Right Ascension: 00 Hours 25’ 24”

Declination: +01° 56’ 23”

And don’t forget that Equinox on September 22 occurring at 14:49 UTC. This ushers in the start of Fall in the northern hemisphere and the beginning of Spring in the southern. And like its counterpart 6 months ago, it’s the earliest occurring since 1896, but will be beaten out for that record next leap year on 2016 by 28 minutes.

Finally, on to the tagline and title object of this week’s post… hey, it was worth the wait and the read, right? The 1^st Quarter Moon occurs this weekend on Saturday, September 22^nd at 15:41EDT/19:41 UTC. Right around that time is traditionally an excellent time to observe the Moon, as several features in the lunar highlands stand out in stark contrast against the terminator. Fans of the space will by now be seasoned veterans of spotting the Lunar X, but did you know that there’s another letter shaped feature visible at the same time? Dubbed the Lunar V, the confluence of two distinctive ridges between the Sinus Medii and Mare Vaporum, this feature is visible around First and Last Quarter. In fact, it’s possible to catch the Lunar X and V in the same image! Any other lunar letters/Roman numerals out there a waiting to be discovered? Send ‘em in, we may just do a dedicated “Lunar Alphabet” post if warranted!

And finally… the best elongations and positions for said Uranian Moons are as follows;

Created by Ed Kotapish using NASA’s PDS Rings Node.