02/15/2019 – Ephemeris – Venus will pass Saturn Monday morning

February 15, 2019 Leave a comment

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

Venus-Saturn Conjunction

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.

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02/14/2019 – Ephemeris – How about a heart shaped nebula for Valentine’s Day

February 14, 2019 Leave a comment

Ephemeris for St Valentine’s Day, Thursday, February 14th. Today the Sun will be up for 10 hours and 24 minutes, setting at 6:09, and it will rise tomorrow at 7:43. The Moon, 2 days past first quarter, will set at 4:18 tomorrow morning.

Nebulae, or clouds of gas and dust, sometimes have shapes when seen in telescopes that remind us of familiar objects, like the Horsehead nebula, the North American Nebula, the Saturn Nebula and so on. So on Valentine’s day I’ll direct you to nebula IC 1805, the Heart Nebula. In the center of the nebula is a nest of stars, many of which are massive with strong stellar winds that blew out the original birth cloud which collided into other clouds of gas to shape it into a rough heart from our vantage point. The color for Valentine’s day is red. Red is the nebula’s true color, it’s the primary color the element hydrogen gives off when excited. In this case excited by those hot young stars in its center.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Heart Nebula

IC 1805 (Heart Nebula) Credit: s58y [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)%5D, via Wikimedia Commons

Categories: Nebula Tags:

02/13/2019 – Ephemeris – Let’s look at the bright planets for this week

February 13, 2019 Leave a comment

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

Evening planets

Mars and the Moon tonight at 8 p.m. February 13, 2019. Click on the image to enlarge. Created using Stellarium.

Mars and Uranus

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.

Moon and Aldebaran

The Moon and Aldebaran at 8 p.m. February 13, 2019. Created using Stellarium.

Morning Planets

The morning planets at 6:30 a.m. February 14, 2019. Saturn is joining Venus and Jupiter. Created using Stellarium.

Telescopic Planets

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 on a single night

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

February 12, 2019 Leave a comment

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

First closeup of Ultima Thule

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.

Crescent Ultima Thule

The crescent of Ultima Thule, looking back after closest approach. Credit NASA/JHUAPL/SwRI.

Possible side view of Ultima Thule

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

February 11, 2019 Comments off

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

Gemini with Castor and Pollux. Created with Stellarium.

Castor star system

The Castor star system exploded in this JPL/NASA infographic.

02/08/2019 – Ephemeris – Sirius has a companion

February 8, 2019 Comments off

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

Orion’s Belt points to Sirius. Created using Stellarium.

Sirius' path

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

Sirius A and B (near the diffraction spike to the lower left), A Hubble Space Telescope photograph. Credit NASA, ESA.

Categories: Ephemeris Program, stars Tags: , ,

02/07/2019 – Ephemeris – Siriusly, folks.

February 7, 2019 Comments off

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

Orion’s Belt points to Sirius. Created using Stellarium.