Archive
02/20/2015 – Ephemeris – The Moon joins Venus and Mars in the west tonight
Ephemeris for Friday, February 20th. The sun will rise at 7:35. It’ll be up for 10 hours and 42 minutes, setting at 6:17. The moon, 2 days past new, will set at 8:49 this evening.
Tonight the two day old moon will be seen in the west in a tight triangle with Venus and Mars. They will become visible about 7 o’clock. The planets will be to the left of the Moon with much dimmer Mars above Venus. The formation is tight enough that the motion of the moon will be evident between 7 and when the Moon sets at 8:49. The moon moves its own diameter in about an hour. The moon will also exhibit earthshine, the reflection of the bright earth in the moon’s sky on the night side of the Moon itself. The earthshine lit part of the moon shows a ghostly man in the moon image we are familiar with at full moon. This earthshine is visible on the Moon for a few days before new moon to a few days after new moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Views of the Venus, Mars, Moon grouping from three locations.
Appearance of the grouping from northern Michigan, US
Venus and Mars with the Moon at 7 p.m. EST on February 20, 2015. This is for northern Michigan. Created using Stellarium.
Appearance of the grouping from Los Angeles, CA
Venus and Mars with the Moon at 8 p.m. PST on February 20, 2015. This is for Los Angeles, CA. Created using Stellarium.
Appearance of the grouping from London, UK
Venus and Mars with the Moon at 20:28 GMT on February 20, 2015. This is for London, UK. Created using Stellarium.
02/19/2015 – Ephemeris – What’s a conjunction?
Ephemeris for Thursday, February 19th. The sun will rise at 7:37. It’ll be up for 10 hours and 39 minutes, setting at 6:16. The moon, 1 day past new, will set at 7:32 this evening.
Saturday night* Venus will be in conjunction with Mars. To me the best sight will be tomorrow night when the thin crescent moon will join the two planets in a very picturesque triangle. Conjunctions are terms shared between astronomers and astrologers and why shouldn’t they be, astrology is, in my opinion, astronomy’s illegitimate parent. To astronomers conjunctions are when two solar system objects are directly north and south of each other (the same right ascension). Astrologers have the conjunction on the same date, but most will say it’s occurring in Aries. Astronomers in the other hand can see that the two planets are now seen against the stars of western Pisces. Most astrologers don’t recognize the precession of the earth’s axis, it’s 26,000 year wobble in their calculations.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
* As reported in the radio program it was Sunday. However the two planets appear closest Saturday night. 7 p.m. EST ( UT – 5 hr) on the 21st is actually 0 hr UT on the 22nd (Sunday).
Addendum
Venus and Mars in conjunction at 7 p.m. EST February 21, 2015. Created using Stellarium.
The big picture: In a conjunction planets simply happen to appear along a line of sight from the Earth. They have nothing to do with each other. This is the location of the planets Earth, Venus and Mars on February 22, 2015. Created using Celestia.
Below see the shift of the vernal equinox or first point of Aries, as it’s sometimes called has shifted from 150 CE in Ptolemy’s day to today.
The vernal equinox in 150 CE. Note that Aries to the left. The Sun travels on the ecliptic line (The diagonal line) from right to left. Created using Cartes du Ciel (Sky Charts).
The vernal equinox today, in 2015 CE. Note that Aries has slid off to the left. The Sun travels on the ecliptic line (The diagonal line) from right to left. Created using Cartes du Ciel (Sky Charts).
02/18/2015 – Ephemeris – Wednesday is bright planet day (or night) on Ephemeris
Ephemeris for Ash Wednesday, Wednesday, February 18th. The sun will rise at 7:38. It’ll be up for 10 hours and 36 minutes, setting at 6:15. The moon is new today, and won’t be visible.
Lets take a look at the bright planets and a fading binocular comet for this week. Brilliant Venus is in the west-southwest by 7 p.m. It will set at 8:37 p.m. It’s nearing Mars which appears above and left of it. They will be at their closest on the 22nd. The Red Planet will set tonight at 8:45 p.m. Jupiter will appear In the southeastern sky in the evening. It will be up all night, and will set at 7:14 a.m. It’s near the sickle-shaped head of Leo the lion, and it’s the brightest star-like object in the sky. Early risers will be able to spot Saturn which will rise in the east-southeast at 2:15 a.m. Comet Lovejoy, visible in binoculars, is about half way from the star at the end of Andromeda, called Almaak and the “W” of Cassiopeia.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus and Mars low in the west after sunset. This is 7 p.m., February 18, 2015. Created using Stellarium.
Venus, Mars and the moon on Friday night at 7 p.m. (2/20/15). Created using Stellarium.
Jupiter with the winter constellations at 9 p.m., February 18, 2015. Created using Stellarium.
Jupiter and it’s moons at 9 p.m. February 18, 2015. Note that at this time the Great Red Spot is on the face if Jupiter. Created using Cartes du Ciel (Sky Charts).
The track of Comet 2014 Q2 (Lovejoy) from 2/18/15 to 02/24/15 which will appear high in the west at 9 p.m. On the 20th the comet will pass near M76, a 10th magnitude planetary nebula. It will be much dimmer than the comet. Created using Cartes du Ceil (Sky Charts).
Looking southward at 6 a.m. February 19, 2015 to a preview of the constellations of summer with Saturn in the south and Jupiter setting in the west. Click to enlarge.
What Saturn and its moons might appear like in a telescope at 6 a.m., February 19, 2015. Small telescopes will show only the moon Titan. Created using Cartes du Ceil (Sky Charts).
02/17/2015 – Ephemeris – There are no unicorns except in the heavens
Ephemeris for Fat Tuesday, Tuesday, February 17th. The sun will rise at 7:40. It’ll be up for 10 hours and 33 minutes, setting at 6:13. The moon, 1 day before new, will rise at 7:07 tomorrow morning.
Among all the constellations in the sky of animals real and mythical, there is also a unicorn. It’s called Monoceros, and inhabits the southeastern sky at 9 p.m. bounded by Orion on the right, Canis Major, the great dog below and Canis Minor, the little dog to the left. Unfortunately for observers without optical aid Monoceros, though large, is devoid of any but the faintest stars. Maybe that’s why no one sees unicorns anymore. It has many faint stars because the Milky Way runs through it. To the telescope it is a feast of faint nebulae or clouds of gas and dust, the birth place of stars, including the red rose of the Rosette Nebula, and the strange and tiny Hubble’s Variable Nebula. It contains no bright stars, but it has wonders for the telescope.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellation Monoceros the unicorn. Created using Cartes du Ciel (Sky Charts). Click to enlarge.
Can you see a unicorn here? Me neither.
One thing I didn’t mention in the program is the star labeled β. It is a triple star in telescopes.
Universe Today has a great post on Monoceros by Tammy Plotner, who by sad coincidence passed away a few days ago.
02/16/2015 – Ephemeris – The Winter Circle
Feb 16. This is Bob Moler with Ephemeris for President’s Day, Monday, February 16th. The sun will rise at 7:42. It’ll be up for 10 hours and 30 minutes, setting at 6:12. The moon, 2 days before new, will rise at 6:25 tomorrow morning.
The winter skies are blessed with more first magnitude stars than any other season. That’s a full one-third of the total are seen is a relatively small area. Six of these stars lie in a large circle centered on the seventh. This circle is up at 9 p.m. Starting high overhead is Capella in Auriga the charioteer. Moving down clockwise is Aldebaran in the face of Taurus the Bull. Then down to Orion’s knee we find Rigel. Down and left is the brightest star of all Sirius the Dog Star in Canis Major, lowest of these stars in the south-southeast. Moving up and left is Procyon in Canis Minor, Above Procyon is Pollux in Gemini the twins. All these are centered on Betelgeuse the bright red star in Orion’s shoulder.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Winter Circle of 1st magnitude stars
02/13/2015 – Ephemeris – The stars Castor and Pollux
Ephemeris for Friday, February 13th. The sun will rise at 7:46. It’ll be up for 10 hours and 21 minutes, setting at 6:08. The moon, 2 days past last quarter, will rise at 3:51 tomorrow morning.
At 9 p.m. the constellation of Gemini the twins will be seen high in the southeast. The namesake stars of the two lads are the two bright stars at the top of the constellation. Pollux the pugilist, or boxer, is the lower of the two, while Castor, the horseman, is the other star, or rather a six star system. In telescopes two close stars may be seen each is a spectroscopic binary, meaning the lines of two stars can be seen in the spectrum. A faint nearby spectroscopic binary also belongs. Pollux, though a single star, does have at least one planet, one over twice the mass of Jupiter orbiting the star at a distance somewhat greater than Mars is from the sun. Pollux is 34 light years away while Castor is 50 light years away. Not too far away as stars go.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Gemini with the stars Castor and Pollux. Created using Stellarium.
02/12/2015 – Ephemeris – The brilliant blue star in Orion: Rigel
Ephemeris for Thursday, February 12th. The sun will rise at 7:47. It’ll be up for 10 hours and 18 minutes, setting at 6:06. The moon, 1 day past last quarter, will rise at 2:52 tomorrow morning.
Two days ago I talked about the star Betelgeuse the bright red star in the top left of Orion’s upright rectangle. Orion is seen in the south at 9 in the evening. The blue-white star in Orion’s opposite corner is usually brighter. It is Rigel whose longer Arabic name of which Rigel is the first part means Left Leg of the Giant. Rigel is a giant itself, actually a super giant star, which is more a measure of its mass than its size, that of 21 solar masses. Its surface temperature is more than twice as hot as the sun. It is 120 thousand times as bright as the sun and 78 times its diameter. Its distance is around 860 light years. Those with telescopes might be able to spot a close companion star to Rigel, just at the edge of the bright arc light image of Rigel itself.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion upright and due south. Created using Stellarium.
Rigel with its companion star as photographed through a telescope. No attribution. Source: http://washedoutastronomy.com/content/urban-orion?page=1
02/11/2015 – Ephemeris – Wednesday is bright planet day around here
Ephemeris for Wednesday, February 11th. The sun will rise at 7:49. It’ll be up for 10 hours and 16 minutes, setting at 6:05. The moon, at last quarter today, will rise at 1:52 tomorrow morning.
Lets take a look at the bright planets and a binocular comet for this week. Brilliant Venus is in the west-southwest by 7 p.m. It will set at 8:19 p.m. Mars appears above and left of Venus in the southwest. Venus is approaching Mars and they will be at their closest on the 22nd. The Red Planet will set tonight at 8:44 p.m. Jupiter will appear In the southeastern sky in the evening. It will be up all night, and will set just before sunrise. It’s near the sickle-shaped head of Leo the lion, and it’s the brightest star-like object in the sky. Early risers will be able to spot Saturn which will rise in the east-southeast at 2:41a.m. Comet Lovejoy, visible in binoculars, is about the width of a binocular field to the right of the star at the end of Andromeda, called Almaak.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus and Mars low in the west at 7 p.m. on February 11, 2015. The crescent moon will be seen with the two planets on the evening of the 20th, and they will be in conjunction on the 22nd. Created using Stellarium.
Jupiter and the bright winter stars at 9 p.m. on February 11, 2015. Created using Stellarium.
Jupiter and its moons as they might appear in a telescope tonight. Created using Cartes du Ceil (Sky Charts).
The Moon will appear near Saturn at 6 a.m. February 12, 2015. Created using Stellarium.
The Moon as it might appear in binoculars at 6 a.m. on February 12, 2015. Created using Stellarium.
What Saturn and its moons might appear like in a telescope at 6 a.m., February 12, 2015. Small telescopes will show only the moon Titan. Created using Cartes du Ceil (Sky Charts).
The track of Comet 2014 Q2 (Lovejoy) from 2/11/15 to 02/17/15 which will appear high in the west at 9 p.m. Toward the end of the period the comet will pass near M76, a 10th magnitude planetary nebula. It will be much dimmer than the comet. Created using Cartes du Ceil (Sky Charts).
02/10/2015 – Ephemeris – Orion’s bright red star, Betelgeuse
Ephemeris for Tuesday, February 10th. The sun will rise at 7:50. It’ll be up for 10 hours and 13 minutes, setting at 6:03. The moon, 1 day before last quarter, will rise at 12:51 tomorrow morning.
The bright red star in constellation Orion’s shoulder is Betelgeuse, and its now thought to be about 640 light years away give or take a couple of hundred light years*. The name Betelgeuse means “Armpit of the central one” in Arabic. Orion is seen in the south at 9 in the evening. Even at Betelgeuse’ great distance it’s the star whose surface is easiest seen, after the sun of course. That’s because it’s so big. As large around as the size of the orbit of Jupiter. Betelgeuse is losing mass in a huge cloud around it. It is a massive star in the late stages of its life even though it’s only 7 million years old. Some astronomers speculate that it will explode in a massive supernova within the next million years.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Update
* I’m being a bit facetious here. See the addendum, and also by coincidence a post from EarthSky today How far is Betelgeuse?
Addendum
Orion upright and due south. Created using Stellarium.
Our estimates of the size, mass and luminosity of Betelgeuse depend on knowing its distance. The distance is not well-known because Betelgeuse is a single star, it is not a binary for which can be applied Newton’s laws to calculate these values. Therefore these values in the broadcast program, where I have 59 seconds total, appear more certain than they really are. Wait for Thursday’s program when I cover Rigel and see how close the values are between the two. But Rigel appears to be a different star altogether. Somebody’s wrong.
“This artist’s impression shows the supergiant star Betelgeuse as it was revealed thanks to different state-of-the-art techniques on ESO’s Very Large Telescope, which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate. The scale in units of the radius of Betelgeuse as well as a comparison with the Solar System is also provided.” Credit: ESO/L. Calçada (ESO is the European Southern Observatory)
02/09/2015 – Ephemeris – How to find the constellation of Cancer the crab
Ephemeris for Monday, February 9th. The sun will rise at 7:52. It’ll be up for 10 hours and 10 minutes, setting at 6:02. The moon, 2 days before last quarter, will rise at 11:51 this evening.
A small, dim member of the zodiac is Cancer the crab. It’s dim stars make to my eyes and upside down letter Y. It lies between Gemini to the upper right and Leo to the lower left, especially as it is still rising in the southeastern sky at 9 p.m. Right now the bright planet Jupiter is about half way between it and Leo. It does have a relatively bright fuzzy object to the naked eye amongst it’s stars, positioned roughly in the center. It was discovered as a fuzzy spot before the invention of the telescope and called Praesepe, the manger. With the invention of the telescope it was discovered to be a loose group of stars in an open or galactic star cluster. This easy binocular object is best known now as the Beehive cluster or M44.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The zodiacal constellation Cancer with Jupiter nearby in the southeast at 9 p.m. February 9, 2015. Created using Cartes du Ceil (Sky Charts).
The Beehive star cluster, M44. Its ancient name was the Praesepe or manger when glimpsed by the naked eye. Created using Cartes du Ciel (Sky Charts).
M44 is a young star cluster, perhaps 600-700 million years old and only 577 light years away. It is an open or galactic star cluster. It only appears outside the band of the Milky Way because it’s close to us. The same cannot be said for M67.
Finder Chart for open cluster M67, found just west of α Cancri, or Acubens. Created using Cartes du Ceil (Sky Charts).
M67 is a fuzzy spot in binoculars but really shows its beauty in telescopes. M67 is pretty old for an open star cluster, one of the oldest known, at about the age of the Sun or a bit younger. It’s nearly 3,000 light years away, so it really is out of the plane of the galaxy.
