April 2015 lunar eclipse explained

Type:total
Date:4 April 2015
Gamma:0.4460
Magnitude:1.0008
Saros Ser:132
Saros No:30 of 71
Totality:4 minutes, 43 seconds
Partiality:209 minutes, 1 seconds
Penumbral:357 minutes, 31 seconds
P1:09:01:27
U1:10:15:45
U2:11:57:54
Greatest:12:00:15
U3:12:02:37
U4:13:44:46
P4:14:58:58
Previous:October 2014
Next:September 2015

A total lunar eclipse took place on 4 April 2015. It is the former of two total lunar eclipses in 2015, and the third in a tetrad (four total lunar eclipses in series). Other eclipses in the tetrad are those of 15 April 2014, 8 October 2014, and 28 September 2015.

This is the 30th member of Lunar Saros 132, and the first total eclipse. The previous event was the March 1997 lunar eclipse, being slightly partial.

Duration

Totality lasted only 4 minutes and 43 seconds,[1] making it the shortest lunar totality in almost five centuries since 17 October 1529 (which lasted 1 minute and 42 seconds). It was claimed by some that due to the oblateness of the Earth, it may have actually just been a partial eclipse.[2] It was the sixth total lunar eclipse out of nine with totality under 5 minutes in a five millennium period between 2,000 BC and 3,000 AD. The eclipsed moon was 12.9% smaller in apparent diameter than the supermoon September 2015 lunar eclipse, measured as 29.66' and 33.47' in diameter from the center of the Earth. It occurred 3 days past apogee at 29.42'.

Visibility

The eclipse was visible across the Pacific, including all of Australia and New Zealand. It was visible near sunrise for North America, and after sunset for eastern Asia including India.

Background

See main article: Lunar eclipse. A lunar eclipse occurs when the Moon passes within Earth's umbra (shadow). As the eclipse begins, Earth's shadow first darkens the Moon slightly. Then, the shadow begins to "cover" part of the Moon, turning it a dark red-brown color (typically - the color can vary based on atmospheric conditions). The Moon appears to be reddish because of Rayleigh scattering (the same effect that causes sunsets to appear reddish) and the refraction of that light by Earth's atmosphere into its umbra.[3]

The following simulation shows the approximate appearance of the Moon passing through Earth's shadow. The Moon's brightness is exaggerated within the umbral shadow. The southern portion of the Moon will be closest to the center of the shadow, making it darkest, and most red in appearance.

Timing

Local times of contacts
Time Zone
adjustments from
UTC
+8h+11h+13h-10h-8h-7h-6h-5h-4h
AWSTAEDTNZDTHSTAKDTPDTMDTCDTEDT
EventEvening April 4Morning April 4
P1Penumbral beginsN/A†8:01 pm10:01 pm11:01 pm1:01 am2:01 am3:01 am4:01 am5:01 am
U1Partial begins6:16 pm9:16 pm11:16 pm12:16 am2:16 am3:16 am4:16 am5:16 am6:16 am
U2Total begins7:58 pm10:58 pm12:58 am1:58 am3:58 am4:58 am5:58 am6:58 amSet
Greatest eclipse8:00 pm11:00 pm1:00 am2:00 am4:00 am5:00 am6:00 am7:00 amSet
U3Total ends8:03 pm11:03 pm1:03 am2:03 am4:03 am5:03 am6:03 amSetSet
U4Partial ends9:45 pm12:45 am2:45 am3:45 am5:45 amSetSetSetSet
P4Penumbral ends10:59 pm1:59 am3:59 am3:59 am5:59 amSetSetSetSet
† The Moon was not visible during this part of the eclipse in this time zone.

Related eclipses

Eclipses of 2015

Half-Saros cycle

A lunar eclipse will be preceded and followed by solar eclipses by 9 years and 5.5 days (a half saros).[4] This lunar eclipse is related to two total solar eclipses of solar saros 139.

Lunar year series

The eclipse is the one of four lunar eclipses in a short-lived series at the ascending node of the Moon's orbit.

The lunar year series repeats after 12 lunations, or 354 days (shifting back about 10 days in sequential years). Because of the date shift, the Earth's shadow will be about 11 degrees west in sequential events.

Tzolkinex

See also

External links

Notes and References

  1. Web site: Espenak . Fred . Total Lunar Eclipse of 2015 Apr 04 . NASA's GSFC.
  2. News: The Lunar Eclipse Wasn't Total After All?!. Sky & Telescope . 6 April 2015.
  3. Web site: Visual Appearance of Lunar Eclipses. NASA. Fred Espenak and Jean Meeus. April 13, 2014.
  4. Mathematical Astronomy Morsels, Jean Meeus, p.110, Chapter 18, The half-saros