Sunday night's lunar eclipse is quite rare

Posted at 10:24 PM, Sep 27, 2015
and last updated 2015-09-28 00:24:09-04

Sunday’s lunar eclipse was a rare one. This type of eclipse has not happened in 33 years, and will not happen again for another 18.

We have full moons every calendar month; that is not rare. But an eclipse of that full moon can happen once, maybe twice, per year. So now we are ratcheting up the rarity.

Let’s take it up another level. 

What makes this such a unique event is that it is an eclipse that will coincide with the “Supermoon”. (While I am not a big fan of the term, it is so called because of an article in 1979 from an astrologer (not an astronomer) that called the perigee of the moon a Supermoon.)

The actual astronomical interest here is that the moon is at its perigee, or closest point to the earth in its orbit. 

The moon’s orbit isn’t a perfect circle. So, in its egg-like orbit, the moon was closest to earth on Sunday. By being a bit closer, the moon appears technically 14% larger. However, how many of us can tell if it is a small percentage bigger than any other time? I can’t.

What you will actually see is the eclipse. In addition to being a bit egg-shaped, the Moon’s orbit is tilted as it spins around us. There are particular moments in Earth’s orbit around the sun when the moon will pass through the earth’s shadow, thus making an eclipse. Again, this may happen once or twice a year.

Here is the timeline of the eclipse:

  • Eclipse begins at 6:11 p.m.
  • In Denver, the moon will begin to rise above the eastern horizon at 6:44 p.m.
  • Partial eclipse begins at 7:07 p.m.
  • Full eclipse at 8:47 p.m.
  • Partial eclipse ends at 10:27 p.m.
  • Eclipse ends at 11:22 p.m.

This is a great animation of what happens between the earth and the moon during this Supermoon eclipse:

The bottom line is we had a rare event on Sunday.

The next lunar eclipse will be in March 2016, but the next time we have an eclipse and the perigee of the moon will be in 18 years.

NASA will be streaming the eclipse online below: 

Matt Makens is looking forward to your photos and videos of the eclipse. Please share with him on facebook and twitter.