October 22, 2017

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 18th as seen from Antarctica ~03:00 UTC, & proceeds to occult the planet Mars on the 19th ~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 8th magnitude star in the constellation Aquarius on September 20th 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 22nd. 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 24th, 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 1st Quarter Moon occurs this weekend on Saturday, September 22nd 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.

ELONGATIONS OF THE URANIAN MOONS 2012

DATES AND TIMES IN UT

SEP 12

UMBRIEL 0443 E

ARIEL   1423 E

SEP 13

ARIEL   2038 W

SEP 14

UMBRIEL 0628 W

TITANIA 1518 E

SEP 15

ARIEL   0253 E

SEP 16

UMBRIEL 0813 E

ARIEL   0908 W

OBERON  1053 E

SEP 17

ARIEL   1523 E

SEP 18

UMBRIEL 0953 W

ARIEL   2138 W

TITANIA 2333 W

SEP 20

ARIEL   0353 E

UMBRIEL 1138 E

SEP 21

ARIEL   1008 W

SEP 22

UMBRIEL 1323 W

ARIEL   1618 E

SEP 23

OBERON  0428 W

TITANIA 0818 E

ARIEL   2233 W

SEP 24

UMBRIEL 1508 E

SEP 25

ARIEL   0448 E

SEP 26

ARIEL   1103 W

UMBRIEL 1648 W

SEP 27

TITANIA 1633 W

ARIEL   1718 E

SEP 28

UMBRIEL 1833 E

ARIEL   2333 W

SEP 29

OBERON  2208 E

SEP 30

ARIEL   0548 E

UMBRIEL 2018 W

OCT 01

ARIEL   1203 W

OCT 02

TITANIA 0113 E

ARIEL   1818 E

UMBRIEL 2203 E

OCT 04

ARIEL   0033 W

UMBRIEL 2348 W

OCT 05

ARIEL   0648 E

OCT 06

TITANIA 0933 W

ARIEL   1303 W

OBERON  1543 W

OCT 07

UMBRIEL 0133 E

ARIEL   1918 E

OCT 09

ARIEL   0133 W

UMBRIEL 0313 W

Oct 10 2012

ARIEL 0748 E

TITANIA 1813 E

OCT 11

UMBRIEL 0458 E

ARIEL 1403 W

Trackbacks

  1. [...] in the constellation Pisces on September 29th. Fans of this space will recall our handy finder chart to spotting those elusive Uranian moons… break out the Shakespeare, as all of these worldlets are [...]

  2. [...] northward, the Lunar V feature in the Mare Vaporum is also sometimes prominent around the same time as the Lunar X, and it's [...]

Speak Your Mind

*