Archive
02/21/2019 – Ephemeris – Greenspire School’s STEM Night is tonight
Ephemeris for Thursday, February 21st. Today the Sun will be up for 10 hours and 45 minutes, setting at 6:19, and it will rise tomorrow at 7:32. The Moon, 2 days past full, will rise at 9:05 this evening.
Tonight the Greenspire School is sponsoring its annual STEM Night from 6 to 8 p.m. at the school on Red Drive at the Grand Traverse Commons. Red Drive is a block west of Silver Drive that connects to Silver Lake Road at Franke Road. STEM is an acronym for Science, Technology, Engineering and Math. The Grand Traverse Astronomical Society will be there for the sixth year with Gary Carlisle finding out what comets are made of by helping the kids create dry ice comets. We’ll have other exhibits too, and telescope kits to raffle off. Other exhibitors have hands on activities in science, technology, engineering and mathematics for the whole family. There’s also cookies and hot chocolate.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Grand Traverse Astronomical Society members at STEM Night. Credit: Eileen Carlisle.
02/20/2019 – Ephemeris – Theoretical all 5 bright planets are now visible
Ephemeris for Wednesday, February 20th. Today the Sun will be up for 10 hours and 42 minutes, setting at 6:18, and it will rise tomorrow at 7:34. The Moon, 1 day past full, will rise at 7:47 this evening.
Let’s look at the planets for this week. We have two evening planets visible now. Tiny and elusive Mercury should be visible low in the west for about a half hour after 7 p.m. It should be visible for a little over a week. Binoculars are a big help in spotting it. Mars will be in the southwestern sky this evening and will set at 11:46 p.m. In the morning sky we have Jupiter which will rise tomorrow at 3:32 a.m. It is second to Venus in brightness. Saturn will be next to rise at 5:22 a.m. It is just to the right of Venus which will rise at 5:29 a.m. tomorrow. In small telescopes Saturn will show its rings and Venus will show a small slightly gibbous moon shape which will shrink and grow more full over the next months
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars, Mercury and bright stars in twilight at 7 p.m. February 20, 2019. Created using Stellarium.
Morning planets and the Moon at 6:30 a.m. February 21, 2019. Click on the image to enlarge. created using Stellarium.
The waning gibbous Moon as it should appear tomorrow morning with binoculars. Created using Stellarium.
Jupiter, Saturn and Venus with the same magnification at 6:30 a.m. tomorrow morning February 21, 2019. See the table of Jupiter moon events tomorrow morning. Created using Cartes du Ciel (Sky Charts).
| Satellite | Event | Date | UT | EST | Notes |
| Ganymede | Occultation start | 21 Feb 2019 | 07:05:00 AM | 2:05 a.m. | Not visible from Michigan |
| Europa | Shadow start | 21 Feb 2019 | 08:36:00 AM | 3:36 a.m. | |
| Ganymede | Occultation end | 21 Feb 2019 | 09:15:00 AM | 4:15 a.m. | |
| Europa | Transit start | 21 Feb 2019 | 10:57:00 AM | 5:57 a.m. | |
| Europa | Shadow end | 21 Feb 2019 | 10:58:00 AM | 5:58 a.m. | |
| Io | Eclipse start | 21 Feb 2019 | 11:49:00 AM | 6:49 a.m. | |
| Europa | Transit end | 21 Feb 2019 | 01:21:00 PM | 8:27 a.m. | Not visible from Michigan |
Jupiter satellite events are from https://www.projectpluto.com/jevent.htm
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 20, 2019. The night ends on the left with sunrise on the 21st. Click on the image to enlarge. Created using my LookingUp program.
02/19/2019 – Ephemeris – The Moon ain’t just super near the horizon
Ephemeris for Tuesday, February 19th. Today the Sun will be up for 10 hours and 39 minutes, setting at 6:16, and it will rise tomorrow at 7:35. The Moon, at full today, will rise at 6:28 this evening.
Tonight we will have a super full Moon. It will be the closest full moon of the year, not that you could really tell. The full moon, or waning moon looks large near the horizon when it’s rising. The same is true of waxing moons setting. The same is true of sunrises and sunsets. However if you look closely at the rising or setting Moon or Sun right at the horizon you will notice that it appears a bit squashed. This is due to atmospheric refraction or bending of the light which makes the them appear higher in the sky than they actually are. It is most pronounced near the horizon. In fact by the time the Sun appears to touch the horizon, it is already completely below the horizon, and would appear be if we didn’t have an atmosphere.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon just after moonrise 1 day past full. The Moon appears squashed vertically by about 10% compared to circumscribed circle. Credit Eileen Carlisle.
How the atmosphere bends the light of the Sun or Moon rising or setting to appear higher than it actually is. Credit Francisco Javier Blanco González, 2017
02/18/2019 – Ephemeris – Super Moon, super math
Ephemeris for President’s Day, Monday, February 18th. Today the Sun will be up for 10 hours and 36 minutes, setting at 6:15, and it will rise tomorrow at 7:37. The Moon, 1 day before full, will set at 7:52 tomorrow morning.
Ready for some math this morning? This will be easy, because you will only have to think about it. Let’s say the Earth’s radius is 4,000 miles. That is pretty close to its actual value. OK, it is 3961 miles (6,378 km) at the equator. The Earth is nearly spherical. At 4 this morning the Moon passed perigee, its closest point to the Earth, making tomorrow’s full moon a super-moon. Let’s say it will be at today’s distance of 221,600 miles (356,800 km). That’s center to center. At moon rise or moon set the Moon is near that center to center distance, but if it moves overhead it’s 4,000 miles closer because we are on the Earth facing the Moon. Even though the Moon looks smaller than when it appears on the horizon. It’s an optical illusion that the Moon appears larger when it is rising. Super moon or not.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
This illustrates the difference in the Moon’s distance at rising (or setting) versus when it is overhead. BTW today’s perigee puts the Moon at only 56 Earth radii from the Earth. The illustration is mine.
02/15/2019 – Ephemeris – Venus will pass Saturn Monday morning
Ephemeris for Friday, February 15th. Today the Sun will be up for 10 hours and 27 minutes, setting at 6:11, and it will rise tomorrow at 7:41. The Moon, 3 days past first quarter, will set at 5:21 tomorrow morning.
The planets Venus and Saturn cross paths in conjunction next Monday morning at about 9 a.m. This weekend you can watch them inch closer and closer together before sunrise. Venus is a whole lot brighter than Saturn and will be seen to move above Saturn Monday morning. As I noted on the Jupiter-Venus conjunction three and a half weeks ago, these two planets are nowhere close to each other. Venus will be 92.9 million miles (149.6 million km) away, about as far as the Sun. Saturn will be a bit over 1 billion miles (1.612 billion km) away, making Saturn almost 11 times farther away as Venus. The only effect this conjunction will have on me is that it will be a cool sight to see those two planets together in the sky.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Daily animation of the morning planets featuring the Venus-Saturn conjunction at 6:30 a.m. on February 16th through 19th 2019. Click on the image to enlarge. Created using Stellarium and GIMP.
02/13/2019 – Ephemeris – Let’s look at the bright planets for this week
Ephemeris for Wednesday, February 13th. Today the Sun will be up for 10 hours and 21 minutes, setting at 6:08, and it will rise tomorrow at 7:44. The Moon, 1 day past first quarter, will set at 3:10 tomorrow morning.
Let’s look at the planets for this week. Our only evening planet visible now is Mars. It will be in the southwestern sky this evening and will set at 11:48 p.m. Mercury should become visible next week. In the morning sky we have Jupiter which will rise tomorrow at 3:55 a.m. It is second to Venus in brightness, and now is west of Venus. In small telescopes up to four of Jupiter’s moons are visible. Venus, which is about to pass Saturn next Monday morning, will rise at 5:24 a.m. tomorrow. In small telescopes it is a smalls slightly gibbous moon shape. Its phase will now grow more toward full as its size shrinks as it moves around and behind the Sun. Saturn will rise at 5:47 a.m. tomorrow in the east-southeast.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars and the Moon tonight at 8 p.m. February 13, 2019. Click on the image to enlarge. Created using Stellarium.
Mars and Uranus as it would be seen in binoculars or small telescope at 8 p.m. February 13, 2018. The planets will be about a degree apart (2 Moon widths). Created using Stellarium.
The Moon and Aldebaran at 8 p.m. February 13, 2019. Created using Stellarium.
The morning planets at 6:30 a.m. February 14, 2019. Saturn is joining Venus and Jupiter. Created using Stellarium.
Venus, Jupiter and Saturn with the same magnification at 6:30 a.m. tomorrow morning February 14, 2019. The moon Io is behind the planet at that time. Created using Cartes du Ciel (Sky Charts).
Planets and the Moon at sunset and sunrise of a single night starting with sunset on the right on February 13, 2019. The night ends on the left with sunrise on the 14th. Click on the image to enlarge. Created using my LookingUp program.
02/12/2018 – Ephemeris – Ultima Thule is not what it first seemed
Ephemeris for Tuesday, February 12th. Today the Sun will be up for 10 hours and 18 minutes, setting at 6:06, and it will rise tomorrow at 7:46. The Moon, at first quarter today, will set at 2:03 tomorrow morning.
This is just nuts. When the New Horizons spacecraft got around behind the body nicknamed Ultima Thule New Years Day and took a crescent view of it, they got a much thinner crescent than they thought. Instead of two round balls in contact, that they saw on approach they saw two very flattened lumps. From the approach side the body looked like a small ball sitting on a larger one. It turns out that the two components of Ultima Thule, named Ultima for the part with the greater diameter and Thule the smaller actually have the same mass. The spin axis runs right through the narrow neck that connects them. That’s their center of mass, or center of gravity. It’s sending planetary scientists back to the blackboard.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Ultima Thule on approach combining low resolution color image with the high-resolution monochromatic image shows the body in almost true color. Credit NASA/JHUAPL/SwRI.
The crescent of Ultima Thule, looking back after closest approach. Credit NASA/JHUAPL/SwRI.
Side view of Ultima Thule: Top as it was from the approach images. Bottoms as it actually appears to be. The blue dash lines the limits of what the flattening could be. Credit NASA/JHUAPL/SwRI.
02/11/2019 – Ephemeris – The stars Castor and Pollux
Ephemeris for Monday, February 11th. Today the Sun will be up for 10 hours and 16 minutes, setting at 6:05, and it will rise tomorrow at 7:47. The Moon, 1 day before first quarter, will set at 12:57 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, 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.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Gemini with Castor and Pollux. Created with Stellarium.
The Castor star system exploded in this JPL/NASA infographic.
02/08/2019 – Ephemeris – Sirius has a companion
Ephemeris for Friday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:01, and it will rise tomorrow at 7:52. The Moon, half way from new to first quarter, will set at 9:48 this evening.
Sirius is the brightest night-time star and is located in the south-southeast at 9 p.m. below and a bit left of Orion the Hunter. We’ve visited Sirius yesterday. But there is another star in the Sirius system that is practically invisible due to Sirius’ dazzling glare. Its name is 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 against the more distant stars. Sirius and the Pup have 50 year orbits of each other. The Pup was first seen in 1862. The Pup was the first of a new class of stars to be discovered, white dwarfs. The Pup is a dying star with the mass of the Sun, collapsed down to the size of the Earth.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion’s Belt points to Sirius. Created using Stellarium.
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.
02/07/2019 – Ephemeris – Siriusly, folks.
Ephemeris for Friday, February 8th. Today the Sun will be up for 10 hours and 7 minutes, setting at 6:01, and it will rise tomorrow at 7:52. The Moon, half way from new to first quarter, will set at 9:48 this evening.
At 9 in the evening the great constellation of Orion the hunter can be seen in the south. Its large rectangle of bright stars is now upright, while in the center is a row of three stars, his belt. These stars tilt downward to the left to a very bright star merrily twinkling in the south-southeast. This star is called Sirius, also known as the Dog Star because it’s in the heart of Orion’s larger hunting dog, Canis Major. It is an arc light white star as seen in binoculars or telescope. It’s a neighboring star, just twice the distance of the closest star to the sun at 8.6 light years. It’s name, Sirius, has nothing to do with a dog, but is from the Greek meaning scorching for its brightness or sparkling, due to its intense twinkling.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orion’s Belt points to Sirius. Created using Stellarium.
