Our Moon does not follow a path with the Earth around the Sun that is parallel with the Earth’s orbit, the ecliptic. The Moon is tilted or inclined by approximately 5.14o from the Earth’s orbital path meaning that there are places where the Moon’s orbital path intersects or crosses the Earth’s orbital path, the ecliptic. At up to 3 times each month the Moon will cross the ecliptic moving south or north in what is called a node crossing – one ascending and the other descending.
However with regard to the celestial equator, an extension of the Earth’s equator into space, the maximum declination for our Moon, as measured from the celestial equator, could be as much as about 28.64o either north or south based on the Earth’s axial tilt of 23.5o plus the Moon’s inclination angle 5.14o (23.5 + 5.14 = 28.64o).
This month our Moon reaches a maximum northernmost declination of 25.3o on Monday March 22nd.
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.
Friday evening March 19th look for the 6.7-day old waxing crescent Moon to be about 3o from the ‘Red Planet’ Mars, and about 5-6o from the reddish star Aldebaran in Taurus the Bull. All three should just barely fit within the field of view of 7×50 binoculars.
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.
Apogee – Descending Node – Conjunction with the Pleiades
Apogee Moon
Our Moon reaches apogee, (furthest from Earth), for this orbit, on Thursday March 18th. For this apogee the 6.6-day old waxing crescent Moon will be at a distance of 31.77 Earth diameters, 251,841 miles (405,300 km) from the Earth.
Descending Node
The 6.6-day old waxing crescent Moon crosses the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
Conjunction with the Pleiades
The apogee Moon, at nearly first quarter phase, will be above the western horizon and will be within a few degrees from the open star cluster the Pleiades. This should make for a good view with binoculars.
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*
*Click here to read my Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)
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.
Tuesday and Wednesday mornings, March 9th and 10th, the thin waning crescent Moon wil be passing by the planets Saturn. Jupiter, and the inner planet Mercury. On the 9th the 26-day old waning crescent Moon will be about 3-4o from Saturn and on the 10th the 28-day old Moon will be about 4-5o and about 6-7o from Mercury.
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.
On Saturday March 6th Mercury, the innermost planet, will reach its orbital position known as greatest western elongation at 27.3o. At that moment Mercury, the Sun, and the Earth, would be arranged in something close to approximating a right angle as this graphic shows. Even though it sounds confusing, at western elongation for either Mercury or Venus the inner planet will be to the right of the Sun as we view them, meaning that at western elongation an inner planet rises in the east before the Sun rises. And at eastern elongation with the inner planet on the left side of the Sun the inner planet follows the Sun across the sky setting after the Sun sets.
From our perspective the orbits of Mercury and Venus appear to move from one side of the Sun to the other – out to the left (east) from the Sun to eastern elongation, then reverse and move westward (inferior conjunction) between the Earth and the Sun to western elongation. From there the inner planet moves eastward going behind the Sun (superior conjunction) and eventually reappearing on the eastern side of the Sun for an eastern elongation. Repeat over and over – do not stop!
Mercury is currently visible in the morning skies before the Sun rises. This inner planet is steadily moving past Jupiter after having passed by Saturn last week.
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.
Friday March 5th the 22-day old last quarter Moon crosses the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
On the date of the descending node the 22-day old last quarter Moon will be over the southern horizon at sunrise local time, and about 3-4o from the reddish star Antares in Scorpius the Scorpion.
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.
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Whoops!! I did tis way too early!!! The Moon is actually at perigee Not apogee.
Our Moon reaches perigee, (closest to Earth), for this orbit, on Monday March 1st. For this perigee the 18.25-day old waning gibbous Moon will be at a distance of 28.64 Earth diameters, 227,049 miles (365,400 km) from the Earth.
On the date of the perigee Moon the waning gibbous Moon will rise around mid-evening local time. Interestingly, as it rises, the Moon will be part of the mnemonic: “Follow the arc to Arcturus and then speed to Spica.”
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*
*Click here to read my Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)
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.
Also Follow me and other great resources at Feedspot.
Over the next few evenings the waxing gibbous Moon will move eastward passing by the open star cluster known as the Beehive Cluster this evening and then in a couple of days, as a full Moon, will be close to the heart of Leo the Lion the star Regulus.
While the Moon may be close to the open star cluster the waxing gibbous Moon with its considerably greater apparent magnitude will outshine the star cluster making it not visible. Wait a few days and then aim your binoculars or low power eyepiece for a better view.
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.
Tuesday evening February 23rd the 12-day old waxing gibbous Moon will be about 2o from Pollux, one of the two ‘Twin’ stars of the constellation Gemini the Twins. The other brother is Castor, which is about 6o away from 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.
