APPARENT PATHS OF THE PLANETS
CELESTIA excels at showing us the "apparent" paths of the planets, that is, their paths through our skies as seen from Earth. This month, Mars and Saturn are in retrograde motion; they're "moving backwards" (from our earthly perspective)!
Run these links as often as you like. And remember: you can use the J, K and L keys respectively to reverse, slow down and speed up time in CELESTIA.
MARS: 2010 Feb
At opposition in late January, Mars continues its retrograde motion in Cancer throughout the entire month of February. The following links let you see Mars's entire retrograde loop of 2009-2010. (1.6.x) (1.4.1)
JUPITER: 2010 Feb
(and 3 other planets too!)
Jupiter moves slowly through Aquarius in February and is overtaken by Venus and the Sun. The latter, of course, means that Jupiter is in conjunction, which occurs late in the 10th hour on Feb 28. (1.6.x) (1.4.1)
The immediately preceding links turn out to be rather fortituitous for us, as they also show essentially all of February's motions of Venus, Uranus (in Pisces) and Neptune (in Capricornus)! By the way, Neptune is in conjunction in the middle of the 23rd hour of Feb 14, as the links also confirm.
SATURN: 2010 Feb
Nearing its opposition on March 22, Saturn continues its retrograde motion in Virgo throughout the entire month of February. The following links let you see Saturn's entire (though smallish) retrograde loop of 2010. (1.6.x) (1.4.1)
APPARENT PATH OF THE SUN: 2010 Feb
Here are the Sun's positions along the Ecliptic at 00:00 UTC on the days shown.
The slightly curved lines above and below the Ecliptic show the extent of the Zodiac, which you may download from our Bonuses page and add to any version of CELESTIA. Note that the curve in the Zodiac lines is the result of CELESTIA's rendering in perspective.
W A R N I N G ! It is never safe to look directly at the real Sun with the naked eye! Moreover, looking at it through a telescope or binoculars—even for an instant—can cause permanent blindness! NEVER DO IT! Consult the professionals at your local planetarium or observatory to learn how you can safely "observe" the Sun and any SOLAR eclipse!
Of course, you can safely view CELESTIA's depiction of the Sun's apparent path in the sky in February. Here are the links: (1.6.x) (1.4.1). Note that versions 1.6.x and 1.4.1 differ in the way their "follow" and "lock" features work. If you "follow" Earth and then "lock" the Sun to it, versions 1.6.x and 1.4.1 respectively maintain the "attitudes" of the Ecliptic and the the Celestial Equator. This means that the Ecliptic remains "level" when you run the first link, but begins to tilt when you run the second! Differences like this will be discussed on our Help page.
HALF OF EARTH IN SUNLIGHT & DARKNESS
During your voyages in CELESTIA, would you like to be able to position yourself directly over the center of the half of Earth in sunlight or the half in darkness at any time this month? On our Tips page, you'll find that it's quite easy to do so! If you're any kind of sky watcher at all, you probably know just how helpful this can be!
PHASES OF THE MOON: 2010 Feb
In UTC per CELESTIA 1.6.x (& 1.4.1):
3rd Qtr: Feb 5, 23:49 (23:50). New: Feb 14, 2:52 (2:53).
1st Qtr: Feb 22, 0:43 (0:44). Full: Feb 28, 16:38 (16:39).
NOTE: New, 1st Quarter, Full and 3rd Quarter Moons respectively are defined to occur when the Geocentric Ecliptic Longitudes of the Moon and the Sun differ by 0°, 90°, 180° and 270°.
Produced with our "Moon Phase Calendar" script. The numbers of the days of the month were added with an image-editing program.
LUNAR PERIGEE & APOGEE: 2010 Feb
Per CELESTIA 1.6.x (and 1.4.1):
Apogee: Feb 13 2:07 (2:08) UTC; 406,544 km.
Perigee: Feb 27 21:25 (21:24) UTC; 357,830 km.
Determined by our "Earth-Moon Distance" and "Moon's Apparent Path" scripts.
The lunar apogees and perigees of this month and last—which we always give as the distances between Earth's and the Moon's centers—illustrate how irregular the lunar orbit is. From 1500-2500 CE, the Moon's apogee averages about 405,400 km, varying from about 404,050 km to its extreme high of about 406,720 km. The Moon's perigee is considerably more variable, averaging about 363,400 km and varying from about 370,350 km to its extreme low of about 356,370 km!
Extreme apogees and perigees occur mostly due to the Sun's pull on the Moon and tend to happen during the winter months, when the Earth is closest (yes, closest!) to the Sun. Extreme apogees tend to happen when the Moon is New, because the Sun pulls it "away from" the Earth, while extreme perigees tend to happen when the Moon is Full, because the Sun pulls it "toward" the Earth.
This explains why 2010's February and January apogee and perigee distances respectively are fairly near their highest and lowest possible values. First, the time of year is right. Second, the apogees and perigees for these months occur only a day or two from New and Full Moons respectively.
LUNAR ANALEMMA: 2010 Feb
Here is the lunar analemma, generated by the Moon's positions relative to the mean lunar orbit and the Ecliptic at 0:00 UTC every day of February.
This phenomenon can be observed using our "Moon's Apparent Path" script. Care to guess what the lunar analemma will look like next month?
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Various astronomical "shadow events" occur throughout the Solar System! This month's more interesting ones are featured here.
Here we highlight (and set up) the most awe-inspiring eclipses taking place in our Solar System, so that all you need to do is click on their links. Don't forget that you can generate lists of Earth's, Jupiter's, Saturn's, Uranus's, Neptune's and even Pluto's eclipses, using CELESTIA's own built-in "Eclipse Finder." You'll find it in the program's menu under "Navigation".
All events listed below are displayed as if viewed from Earth, their magnifications shown in parentheses at the lower right of CELESTIA's window. Events involving more than one moon are often cyclical, so usually only the first example is given, and then the period of the cycle.
As depicted in CELESTIA, here are highlights of the 29 solar eclipses that Io, Europa, Ganymede and Callisto—the "Galilean" moons of Jupiter—produce in February. While simultaneous solar eclipses are fairly common on Jupiter, this month no two Galileans cast their shadows onto the planet at the same time. Included are a few examples of the Galilean moons moving into Jupiter's shadow, i.e. being eclipsed by Jupiter.
While CELESTIA 1.6.x shows the shadows of Titan, Rhea, Iapetus, Dione and Tethys, version 1.4.1 displays only the shadows of Titan, Rhea & Iapetus. So, 1.6.x and 1.4.1 respectively show 32 and 8 solar eclipses on Saturn in February. The highlights are as follows:
URANUS, NEPTUNE & Dwarf Planet PLUTO
Neither Uranus nor Neptune will experience eclipses for decades. Dwarf planet Pluto will experience no eclipses by Charon for about a century!
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