Some Interesting Astronomical Events for the Naked Eye During Jan – March 2018

For a monthly sky map please head here.

The first trimester of 2018 begins with a full moon on Jan 2nd . It is also the supermoon, a popular and relatively new term to indicate that the full moon phase nearly coincides with lunar Perigee (i.e., when the moon is closest to the earth). On this occasion the moon appears about 14% larger in diameter and 30% brighter than it is at apogee (when it would be farthest away). India can also witness the totality phase of the total lunar eclipse of Jan 31, 2018. Venus, which was the morning planet last year will now reappear above the western horizon in the evening. On 9th Jan, it is at superior conjunction with the Sun, that is, it is right behind it. By about mid-February it can easily be spotted above the western horizon soon after sunset.

The path of Venus along with its phases is shown in the diagram. The positions of Venus are plotted for about 40 minutes after the local sunset. This is reasonably accurate for any place in India. For the purpose of scale, on 25th Feb, Venus will be seen about 8 degrees above the horizon and on 25th of June it will about 42 degrees above the horizon 40 minutes after the sunset.

On 25th Feb the angular diameter of Venus would be about 10 seconds of arc, which increases later to 48 seconds of arc. Even a small telescope of 5 cm primary lens can show you the phases of Venus at this time.

Earth is at Perihelion (closest to the sun) on Jan 3rd at 11:29. It will be 147 million km or 0.9833 astronomical units from the sun. Sun’s angular diameter would be 32° 31.89″

Vernal equinox takes place on 20 March at 21:45. On this day the duration of Day and Night is supposed to same. The word is derived from the Latin aequinoctium, from aequus (equal) and nox (night). However, this is not actually correct and one can verify this from the sunrise and sunset time for different latitudes. Please do visit this page for more information.

Tracking the Moon

Tracking the Moon’s phases is important since, close to the New Moon, one can enjoy dark starry nights. On the quarter moon day the Moon is nearly over head at sunset (first quarter) or sunrise (last quarter).

Phases
New Moon : | Jan 17 07:47 | Feb 16 02:35 | Mar 17 18:42
First Quarter : | Jan 25 03:50 | Feb 23 12:39 | Mar 24 21:05
Full Moon : Jan 02 07:54 | Jan 31 18:57 | Mar 02 06:21 | Mar 31 18:07
Last Quarter : Jan 09 03:55 | Feb 07 21:24 | Mar 09 16:50 |

Lunar Perigee and Apogee

Perigee (closest to earth) Apogee (farthest from earth)
Date time distance Date time distance
Jan 02 03:24 356600 km Jan 15 07:39 406500 km
Jan 30 15:24 359000 km Feb 11 19:46 405700 km
Feb 27 20:18 363900 km Mar 11 14:43 404700 km
Mar 26 22:47 369100 km

Eclipses

This trimester has two eclipses:

Jan 31 Total Lunar Eclipse: This eclipse will be partially visible from India, but the entry of Moon into the penumbral shadow would be missed. Rest of the eclipse would be visible. For Mumbai, the Sun would set at 18:31 just as the Moon rises. Whereas for Kolkata, the Moon rises at 17:17 as the it enters the umbra and the sunset is at 17:24.

Circumstances of the Eclipse
Moon enters penumbra: 16:19:28
Moon enters umbra: 17:17:50
Start of totality: 18:21:06
Maximum eclipse: 18:59:33
End of totality: 19:37:59
Moon leaves umbra: 20:41:15
Moon leaves penumbra: 21:39:41

Duration of total phase: 1h 16m 53s
Duration of umbral phase: 3h 23m 25s
Duration of penumbral phase: 5h 20m 14s

Feb 16 Partial Solar Eclipse: this eclipse is not visible from India. Some may remember that the first total solar eclipse of the last century that was seen from India took place on Feb 16, 1980. It was a major astronomical event for astronomers (professional as well as for amateurs) and for general public.

Blue Moon

The popular folklore has it that when there is a second Full Moon in a month then it is called Blue Moon. We have a blue moon on 31st Jan (on the eclipse day) and on 31st March.

The moon may not necessarily look blue on this day. However, there have been observations of the Moon that looked blue in colour when it was seen through the dense smoke of wildfire.

A list of some other astronomical events for your calendar

January 2018
Date Day Time Phenomenon
2 Tu 01:29 Mercury Elongation: 22.7° W
7 Su 06:09 Mars-Jupiter: 0.2° N
9 Tu 11:46 Venus Superior Conj. (right behind the Sun)
11 Th 11:29 Moon-Jupiter: 4.7° S
13 Sa 13:30 Mercury-Saturn: 0.7° N
15 Mo 07:43 Moon-Saturn: 2.9° S
27 Sa 15:39 Moon-Aldebaran (Rohini): 0.7° S
29 Mo 17:02 Moon-Regulus North Dec.:20° N
February 2018
Date Day Time Phenomenon
1 Th 23:54 Moon-Regulus (Magha): 0.9° S
8 Th 01:17 Moon-Jupiter: 4.7° S
09 Tu 10:42 Moon-Mars: 4.8° S
11 Th 20:16 Moon-Saturn: 2.7° S
11 Th 22:16 Mars-Antares (Jyestha): 5.1° N
23 Fr 22:37 Moon-Aldebaran (Rohini): 0.7° S
March 2018
Date Day Time Phenomenon
1 Th 10:39 Moon-Regulus (Magha): 0.9° S
4 Su 11:11 Moon-Venus: 1.1° N
07 We 12:27 Moon-Jupiter: 4.4° S
10 Sa 06:07 Moon-Mars: 4.2° S
11 Su 08:07 Mars-Saturn: 2.5° S
15 Th 20:29 Mercury Elongation:18.4° E
19 Mo 00:37 Moon-Venus: 3.9° N
19 Mo 13:21 Mercury-Venus: 3.8° N
23 Fr 04:03 Moon-Aldebaran (Rohini): 0.9° S
28 We 19:08 Mars-Regulus (Magha): 1° S
For a monthly sky map please head here.