Archive
02/14/2017 – Ephemeris – Is the Moon waxing or waning?
Ephemeris for St Valentine’s Day, Tuesday, February 14th. The Sun will rise at 7:43. It’ll be up for 10 hours and 26 minutes, setting at 6:10. The Moon, half way from full to last quarter, will rise at 10:18 this evening.
This morning the waning gibbous moon will be a way to the right of the bright planet Jupiter which is in the southwest at 7 a.m. Tomorrow morning the Moon will appear above and right of Jupiter. My granddaughter is taking earth science in school now and is confused about when the Moon is waxing or waning. If it’s waxing it is getting fuller each night. If waning the Moon’s phase is getting thinner each night. But I told her that if you can see the Moon in the evening it’s waxing, and if you can see the Moon in the morning it’s waning. It works except around full Moon where you’d need a calendar for the full moon date or if it rises before or after sunset.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A graphic explaining the Moon’s position with respect to the Earth and Sun (which is off the diagram to the right). The Moon orbits the Earth in a counterclockwise direction. Credit NASA/Bill Dunford.
02/13/2017 – Ephemeris – The brightest night-time star has a tiny stellar companion
Ephemeris for Monday, February 13th. The Sun will rise at 7:45. It’ll be up for 10 hours and 23 minutes, setting at 6:08. The Moon, 3 days past full, will rise at 9:16 this evening.
Sirius is the brightest night-time star and is located in the south at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius last week. But there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. It’s Sirius B, nicknamed the Pup, alluding to Sirius’ Dog Star title. The tiny star was suspected as far back as 1834 due to Sirius’ wavy path in the sky against the more distant stars. Sirius is only 8 light years away. Sirius A and the Pup have 50 year orbits of each other. The star was first seen by Alvan Clark in 1862 while testing a new telescope. The Pup was the first of a new class of stars to be discovered, white dwarfs. The Pup is about the size of the Earth, with the mass of our Sun; its out of fuel and slowly collapsing.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Sirius A & B’s path in the sky showing the wobble that betrayed the Pup’s presence. Credit Mike Guidry, University of Tennessee.
Sirius A and B (near the diffraction spike to the lower left), A Hubble Space Telescope photograph. Credit NASA, ESA.
Orion’s Belt points to Sirius. Created using Stellarium.
07/10/2017 – Ephemeris – There’s a penumbral eclipse of the Moon tonight
Ephemeris for Friday, February 10th. The Sun will rise at 7:49. It’ll be up for 10 hours and 15 minutes, setting at 6:04. The Moon, at full today, will rise at 5:58 this evening.
This evening there will be a penumbral eclipse of the moon, which will reach its peak at 7:45 p.m. The moon, on its left side will be slightly darkened as the Moon passes through the Earth’s partial outer shadow where the Sun is only partially blocked by the Earth. Only the left side of he Moon will show the effect, which is best seen wearing sunglasses to reduce the Moon’s glare. The Northwestern Michigan College’s Rogers Observatory will be open to view the event from 6:45 to 8:45 p.m. but only if it’s clear. This event does not require a telescope to appreciate, but it might be nice to view it with others. The observatory is located south of Traverse City on Birmley Road between Keystone and Garfield roads.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
How lunar eclipses occur. For this eclipse the Moon will miss the umbra but will penetrate the deep into the penumbra. Credit NASA/Fred Espenak.
Diagram of the penumbral lunar eclipse on the evening of February 10, 2016 for the Eastern time zone. Diagram adapted from Fred Espenak, NASA GSFC.
This is the maximum of the February 10th penumbral lunar eclipse. The Moon will appear to move diagonally down to the left. It is shown at maximum eclipse at 7:45 p.m. (0:45 UT February 11). The diagram is oriented for viewing from northern Michigan. Created using Cartes du Ciel.
NASA’s pdf page on this eclipse: https://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2017Feb11N.pdf
02/09/2017 – Ephemeris – Tomorrow’s penumbral eclipse of the Moon
Ephemeris for Thursday, February 9th. The Sun will rise at 7:50. It’ll be up for 10 hours and 12 minutes, setting at 6:03. The Moon, 1 day before full, will set at 7:28 tomorrow morning.
Tomorrow evening, clouds willing, we see an odd partial eclipse of the Moon called a penumbral lunar eclipse. What is a penumbra? It’s the fuzzy outer part of a shadow that’s cast when the light source isn’t a pin point. Look at your shadow in the sunlight, especially that of your head. The outline isn’t sharp. That outer fuzziness of the shadow is your penumbra where the Sun isn’t completely blocked., while the dark inner shadow is the umbra, where the Sun is completely blocked by your head. Tomorrow evening the eclipse will actually start before the Moon rises. The Moon should appear pretty much normal until it passes deep into the penumbra of the Earth’s shadow. Deepest penetration will occur at 7:45 pm. Where the upper left part of the Moon will appear dimmer than the rest of it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Diagram of the penumbral lunar eclipse on the evening of February 10, 2016 for the Eastern time zone. Diagram adapted from Fred Espenak, NASA GSFC.
P1 is the first contact with the shadow and P4 the last. Nothing will be noticed at these times. Only when closest to the greatest eclipse will the part of the moon nearest the inner shadow will show darkening.
Only from the lighter parts of the map will the eclipse be visible. Diagram from Fred Espenak, NASA GSFC.
02/08/2017 – Ephemeris – Four bright planets are visible, two each in the evening and morning
Ephemeris for Wednesday, February 8th. The Sun will rise at 7:52. It’ll be up for 10 hours and 9 minutes, setting at 6:01. The Moon, 2 days before full, will set at 6:44 tomorrow morning.
Let’s check out the bright planets for this week. Saturn can be glimpsed this morning in the southeast at 7 a.m. It will rise tomorrow at 4:35 a.m. in the east-southeast. Jupiter can be seen in the south-southwest this morning above the star Spica in Virgo. Jupiter will rise tonight at 11:19 p.m. Venus and Mars are in the evening sky. At 7 p.m. these planets will be seen in the west-southwestern sky. Venus is unmistakable as the brilliant evening star, Mars will be left and above it and much dimmer. Mars will set at 10:14. Venus itself will set at 9:52 p.m. Venus exhibits a dazzling fat crescent in small telescopes now, but a month from now as it gets closer to Earth the thinning crescent will be big enough to be seen in binoculars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus and Mars in the evening twilight of about an hour after sunset. 7 p.m. February 8, 2017. Venus is now drawing away from Mars as it heads toward the Sun faster than Mars. Their apparent paths won’t cross again until October in the October sky. Created using Stellarium.
Venus as it might appear in a telescope tonight February 8, 2017. I processed the image to overexpose it as it would appear in a telescope. Created using Stellarium.
What the Moon might look like in binoculars tonight at 7 p.m. February 8, 2017. Created using Stellarium.
Jupiter in the south above the star Spica with Saturn the southeast at 7 a.m. this morning, February 9, 2017. Created using Stellarium.
Jupiter and its moon in a compact arrangement as they might appear in telescopes this morning at 7 a.m. February 8, 2017. Created using Stellarium.
Saturn and its brightest moons as they might appear in telescopes this morning at 7 a.m. February 8, 2017. Created using Cartes du Ciel (Sky Charts).
The planets and Moon at sunset and sunrise of a single night starting with sunset on the right on February 8, 2017. The night ends on the left with sunrise on February 9. Click on image to enlarge. Created using my LookingUp program.
02/07/2017 – Ephemeris – Sirius: an important star in history
Ephemeris for Tuesday, February 7th. The Sun will rise at 7:53. It’ll be up for 10 hours and 6 minutes, setting at 6:00. The Moon, 3 days before full, will set at 5:53 tomorrow morning.
The brightest star-like object in the evening sky is Sirius, also known as the Dog Star. It also is the brightest night-time star in our skies period. Tonight at 9 p.m. it’s located in the southeastern sky. The Dog Star name comes from its position at the heart of the constellation Canis Major, the great dog of Orion the hunter. The three stars of Orion’s belt tilt to the southeast and point to Sirius. The name Sirius means ‘Dazzling One’, a reference to its great brilliance and twinkling. Its Egyptian name was Sothis, and its appearance in the dawn skies in late June signaled the flooding of the Nile, and the beginning of the Egyptian agricultural year. Sirius owes much of its brightness to the fact that it lies quite close to us, only about 8 light years away.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A simulation of the heliacal rising of Sothis (Sirius) with the Egyptian Pyramids circa 2000 BC. Note that Sirius is just visible to the right of the nearest Pyramid. Created using Stellarium and GIMP.
A heliacal rising is the first appearance of a star or planet in the morning after disappearing weeks or months before in the evening twilight.
02/06/2017 – Ephemeris – The Moon is at perigee today
Ephemeris for Monday, February 6th. The Sun will rise at 7:54. It’ll be up for 10 hours and 4 minutes, setting at 5:58. The Moon, 3 days past first quarter, will set at 4:56 tomorrow morning.
At 9 this morning the Moon will be at perigee, the closest it gets to the Earth in its current orbit of the Earth. Had the Moon been full it would be called a super-moon. The Moon isn’t just orbiting the Earth, but it is also pushed around by the Sun, which has a greater hold on he Moon than the Earth, but also by Jupiter and Venus, plus all the other objects in the solar system to a far lesser degree. You are not going to see it rise this afternoon at 1:48, so the big Moon on the horizon optical illusion doesn’t come into play. It will appear its highest at 9:21 this evening, some 63 degrees above the horizon. By then it will be some 3500 miles or so closer than when it’s on the horizon, because we’re on the Moon facing side of the Earth. Look up, there the Moon doesn’t really look very big at all, does it?
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon and the stars tonight at 9:21 p.m. Don’t be fooled by the size of the Moon. Here it appears 4 times its actual diameter, and 16 times its area in this image. It actually appears really small. But it will appear a lot bigger when it sets due to the horizon illusion. Created using Stellarium.
02/03/2017 – Ephemeris – Star Quiz tonight, the college kids vs the old star guys
Ephemeris for Friday, February 3rd. The Sun will rise at 7:58. It’ll be up for 9 hours and 56 minutes, setting at 5:54. The Moon, at first quarter today, will set at 1:35 tomorrow morning.
A Star Bowl quiz will be held this evening between the NMC Astronomy Club and members of the NMC astronomy class and the Grand Traverse Astronomical Society at this evening’s meeting of the society at 8 p.m. at Northwestern Michigan College’s Rogers Observatory. The society will accept anyone to help us. These NMC students are smart. After the Star Bowl there will be a viewing night starting at 9 p.m. On tap if its clear will be the Moon. Orion and its great nebula, a star nursery only 1400 light years away will be a wonderful sight with its clouds and wisps of gas and dust illuminated by a clutch of hot baby stars. The Observatory is located south of Traverse City on Birmley Road off either Garfield or Keystone roads.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
02/02/2017 – Ephemeris – Can you see the rabbit on the Moon?
Ephemeris for Ground Hog Day, Thursday, February 2nd. The Sun will rise at 7:59. It’ll be up for 9 hours and 53 minutes, setting at 5:53. The Moon, 1 day before first quarter, will set at 12:24 tomorrow morning.
The crescent Moon is in the southwestern sky. It is revealing a group of lunar seas, dark gray areas that portrays an upside down rabbit. From the top down are the seas Serenity as his body, the sea of Tranquility as his head. His two ears are different sizes, the larger is the Sea of Fertility, and the smaller ear is the Sea of Nectar. All of these seas seem to be connected. The unconnected sea is the Sea of Crises, a pretty good symbol for our times, but unconnected to our upside down rabbit. One word about the Latin names for these. The Latin name for a sea is Mare, spelled like the female horse but pronounced Mar-ē. The plural is Maria, spelled like the lady’s name but pronounced with the accent on the first syllable.
At 5:11 am EDT (10:11 UT) Venus and Mars will appear at their closest to each other at 5.4° or about 11 Moon diameters. From then on, Venus will back away. That is the Sun will overtake Venus faster than it will Mars. They will eventually pass each other on October 5, 2017.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
An animation showing how the rabbit in the Moon as might be seen tonight February 2, 2017, demonstrating my complete lack of artistic talent. Created from a Moon image from Stellarium, Overlay from Libreoffice Draw, and animated GIF from GIMP.
Search [rabbit in moon] in Google images for more artistic examples.
02/01/2017 – Ephemeris – February’s first look at the planets
Ephemeris for Wednesday, February 1st. The Sun will rise at 8:00. It’ll be up for 9 hours and 50 minutes, setting at 5:51. The Moon, 2 days before first quarter, will set at 11:15 this evening.
Let’s check out the bright planets for this week. Saturn can be glimpsed this morning in the southeast at 7 a.m. It will rise tomorrow at 5 a.m. in the east-southeast. Jupiter can be seen in the south-southwest this morning above the star Spica in Virgo. Jupiter will rise tonight at 11:43 p.m. Venus and Mars are in the evening sky. At 7 p.m. these planets will be seen in the southwestern sky. Venus is unmistakable as the brilliant evening star, Mars will be above and left of it and much dimmer, the Moon higher still and in line. Mars will set at 10:14. Venus itself will set at 9:52 p.m. Venus exhibits a dazzling fat crescent in small telescopes now, but a month from now as it gets closer to Earth the thinning crescent will be big enough to be seen in binoculars.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Note: If you are looking for the February Preview post check out yesterday’s post.
Addendum
Jupiter in the south above the star Spica with Saturn the southeast at 7 a.m. this morning, February 2, 2017. Created using Stellarium.
Jupiter as it might appear in telescopes this morning at 7 a.m. February 1, 2017. Created using Cartes du Ciel (Sky Charts).
Saturn and Titan as they might appear in telescopes this morning at 7 a.m. February 1, 2017. Created using Cartes du Ciel (Sky Charts).
Venus, Mars and the Moon in the evening twilight of about an hour after sunset, 7 p.m. February 1, 2017. Click on the image to enlarge. Created using Stellarium.
Venus as it might appear in a telescope tonight February 1, 2017. I processed the image to overexpose it as it would appear in a telescope. Created using Stellarium.
What the Moon might look like in binoculars tonight at 7 p.m. February 1, 2017. Created using Stellarium.
Planets and Moon at sunset and sunrise of a single night starting with sunset on the right on February 1, 2017. The night ends on the left with sunrise on February 2. Click on image to enlarge. Created using my LookingUp program.
Bob Moler's Ephemeris Blog 