February Moon at Ascending Node, a Penumbral Lunar Eclipse, and a Comet!

11feb-ascending-node   Saturday February 11th the full Moon will be crossing the plane of the ecliptic moving north relative to the ecliptic. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic. The ecliptic is actually the Earth’s orbit and the Moon’s orbit is inclined about 6o from the ecliptic, so there are two node intersections, the ascending and descending nodes.
   When a node crossing happens near the time of a full or new Moon there is a chance for an eclipse. The closer the two times are to each other the more centered the Moon will be with respect to the Sun for a total eclipse, or more centered such that the Moon passes through the inner and darker umbral shadow.
   That is the situation for this weekend with full Moon at 0:33 UT Saturday January 11th (6:30 pm CST Friday January 10th), and the node crossing at 19:50 UT (1:50 pm CST) Saturday. This time, due to the nearly 20 hour difference the Moon’s orbital path will take it across the Earth’s fainter outer, the penumbra. A penumbral lunar eclipse is not that easily noticeable because the bright reflected light from the Moon is not dimmed that much as the Moon passes through the penumbra.

   Click here to go to the Hermit Eclipse web site for more information about this eclipse.

   Adding to the viewing there is a good chance Comet 45P/Honda-Mrkos-Pajdusakova, aka the “Green Comet”, will be bright enough to be seen with binoculars over the next several evenings. On the 11th the comet will be at its closest to the Earth and may be brighter than 4th magnitude. Unfortunately the Moon’s reflected light will brighten the sky making it that much more challenging to see the comet. Click here to read an article about the comet at the EarthSky web site.

   Does our Moon actually go around the Earth as many graphics show? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Full Moon – Spoiler Alert!

   Wednesday December 14th the Moon will be at its full phase and while pleasing to observe the reflected light from the Moon plus any local light pollution spoils the night sky as either one or both brightens the night sky making it difficult to impossible to see much of anything except the very brightest of celestial objects. What this brighter sky means in terms of December 14th is that the nearby open star cluster M-35 will not be seen, nor will the Geminids Meteor Shower with a radiant near the Moon and which peaks on the 14th.
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

November Perigee, and Full Moon

14nov-perigee_moon   The Moon reaches perigee, (minimum distance from Earth), this month on Monday November 14th. At that time the Moon will more or less be at a distance of 27.95 Earth diameters (356,509 km or 221,524 miles) from the Earth.
   The Moon reaches perigee Monday at 11:30 UT (5:30 am CST) and this is about 2 hours before it will be at full Moon phase at 13:52 UT, (7:52 am CST November 14th). Since the full Moon is this close to its closest to the Earth for this orbit the full Moon could be considered one of the ‘Super Moons’ this year. In fact this is the closest one for this year and according to records the closest full Moon in the past 30 years.
full-moons2016-ani
   This animated graphic shows the full Moons of 2016. Are you able to see a difference in the sizes?

   Read more about the idea of a super Moon or super mini-Moon in a previous posting.

   Does our Moon actually go around the Earth as the first graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth.
   Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)
   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   On the day of the lunar perigee the full Moon rises at around sunset local time and is setting at sunrise the following morning.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

October Moon at Perigee

16oct-perigee_moon   The Moon reaches perigee, (minimum distance from Earth), this month on Sunday October 16th. At that time the Moon will more or less be at a distance of 28.05 Earth diameters (357,861 km or 222,364 miles) from the Earth.
   The Moon reaches perigee Sunday at 23:47 UT (6:47 pm CDT) and this is less than 20 hours after it was at full Moon phase also on Sunday but at 4:23 UT, (11:23 pm CDT October 15th). Since the full Moon is this close to its closest to the Earth for this orbit the full Moon could be considered one of the ‘Super Moons’ this year.
   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

   On the day of the lunar perigee the 16-day old just past full waning gibbous Moon rises at around sunset local time and is over the southwest horizon at sunrise the following morning. Two of the Dwarf planets, Eris and Ceres are near the Moon but due to their respective apparent magnitudes (Ceres 7.0; Eris 18.6) and the bright reflected light from the Moon the two are all but invisible. Interestingly these two represent two similar but very different types of Dwarf Planets – Ceres is within the main asteroid belt at a distance of 1.9 AU (176,616,033 miles; 284,235,954 km) while Eris is in the outer regions of the solar system at a distance of 95 AU (8,830,801,690 miles; 14,211,797,715 km) from the Earth.
   
   
   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Full Moon – Penumbral Eclipse


   Friday September 16th the full Moon, just one day after it was at descending node, passes through the Earth’s outer shadow. This sets up what is called a penumbral lunar eclipse, and during a penumbral eclipse the change in the brightness of the Moon does not decrease enough so that the eclipse is usually noticed. This eclipse will be visible across the continental United States.     The Earth has two distinct shadows, an inner and much darker umbra, and the outer and fainter penumbra as this graphic shows.
    For additional information about this or other eclipses go to the Hermit Eclipse web site.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Moon Passes Mars and Saturn

   This weekend the Moon will pass by the planets Mars and Saturn, both of which are located near the reddish star Antares in Scorpius the Scorpion. The Moon reaches its full phase on Saturday and while it is within a few degrees from Mars the planet Mars will be at opposition. The next evening, Sunday May 22nd the Moon, now at waning gibbous phase, will have moved further east and will be within a few degrees from Saturn.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Penumbral Lunar Eclipse

penumbral-eclipse-ani
   At 9:39 UT (4:39 am CDT) Wednesday March 23rd the full Moon will start passing through the Earth’s shadow setting up the condition for a lunar eclipse. Approximately 24 hours previously the Moon was at its ascending node but since the time for full Moon was about 24 hours after the node crossing the Moon will only pass through the Earth’s fainter outer shadow, the penumbra.
   A penumbral eclipse is not nearly as easily seen nor as spectacular as a partial or total lunar eclipse when the Moon passes through the darker inner shadow – the umbra. The fainter outer shadow, the penumbra, barely darkens the appearance of the full Moon.
   That’s Jupiter just to the left from the Moon.
   Learn more about this eclipse from the Hermit Eclipse web site.

   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.