09/22/2017 – Ephemeris – September star party at Sleeping Bear Dunes National Lakeshore tomorrow night

September 22, 2017 1 comment

Ephemeris for Friday, September 22nd. The Sun will rise at 7:29. It’ll be up for 12 hours and 9 minutes, setting at 7:39. The Moon, 2 days past new, will set at 9:14 this evening.

Autumn starts at 4:02 this afternoon.

The first star party of autumn will be held at the Sleeping Bear Dunes National Lakeshore tomorrow evening starting at 9 p.m. at the Dune Climb if it’s clear. It will be hosted by the Park Rangers and the Grand Traverse Astronomical Society. The society invites all to come, especially those with telescopes willing to share the wonders of the Milky Way, which will span the skies from horizon to horizon, and the planet Saturn. The park has one of the darkest skies in the Lower Peninsula, and the Milky Way is especially impressive in late summer and early autumn.

Please call 231-326-4700, ext. 5005 if in doubt about weather conditions. A decision will be made by 2 hours before the event.

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

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09/21/2017 – Ephemeris – Summer ends and autumn begins tomottow

September 21, 2017 1 comment

Ephemeris for Thursday, September 21st. The Sun will rise at 7:28. It’ll be up for 12 hours and 12 minutes, setting at 7:41. The Moon, 1 day past new, will set at 8:45 this evening.

Enjoy the last full day of summer. Summer will last until 4:02 p.m. (20:02 UTC) tomorrow when the center of the Sun will cross the celestial equator, an imaginary line above the Earth’s equator, heading southward. At that instant autumn will begin. Shortly the Sun will be up less than half the day. The day and the point in the sky that the Sun crosses is called the autumnal equinox. The word equinox means equal night, implying that day and light are of equal length. Geometrically that’s true, but the Earth’s atmosphere and the definition of sunrise and sunset, prolong daylight by a few minutes. The amount of heat we are getting and will get from the Sun cannot sustain our current temperatures, and it will get a lot colder before it gets warmer again.

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

Addendum

Autumnal equinox from space

Image from the Earth Polychromatic Imaging Camera (EPIC) on NOAA’s DSCOVR satellite in halo orbit around the Earth-Sun L-1 point 1 million miles sunward from the Earth last autumnal equinox (2016) at about the same time the autumnal equinox will occur this year.

Sunrise on the autumnal equinox

That is not a pumpkin on the head of the motorcyclist. That’s the Sun rising as I’m traveling east on South Airport Road south of Traverse City Mi. on the autumnal equinox. This is the east-west section of the road. The Sun is rising over the hills some 6 miles to the east. Credit: Bob Moler.

09/20/2017 – Ephemeris – Looking for the bright planets

September 20, 2017 Leave a comment

Ephemeris for Wednesday, September 20th. The Sun will rise at 7:27. It’ll be up for 12 hours and 15 minutes, setting at 7:43. The Moon is new today, and won’t be visible.

Let’s take our weekly look at the bright planets. Jupiter is really low in the west-southwest after sunset setting in twilight at 8:47 p.m. Saturn can be seen low in the southwest tonight. The reddish star Antares is below and right of Saturn before it sets at 10:18 p.m. Saturn’s rings are spectacular in telescopes. With the demise of the Cassini spacecraft orbiting Saturn for the last 13 years, there is no telescope closer to Saturn than yours. The planet will set at 11:35 p.m. In the morning sky, brilliant Venus will rise at 5:03 a.m. in the east-northeast. The first magnitude star Regulus in Leo the lion will be to the upper right of it. Dim Mars will rise in the east-northeast at 5:50 a.m. followed by the brighter Mercury which will rise at 6:12 a.m.

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

Addendum

Setting Jupiter

The setting Jupiter and Saturn at 8:15 p.m., September 20, 2017. Created using Stellarium. Click on the image to enlarge.

Saturn in the evening

Saturn and constellations in dark skies at 9 p.m. September 20, 2017. Created using Stellarium. Click on the image to enlarge.

Saturn and moons

Saturn and its brightest moons overnight September 20/21, 2017. Created using Cartes du Ciel (Sky Charts).

Morning planets close up

Morning planets close up at 6:30 a.m. September 21, 2017. Created using Stellarium.

Planets and the Moon on a single night

Planets at sunset and sunrise of a single night starting with sunset on the right on September 20, 2017. The night ends on the left with sunrise on the 21st. Click on the image to enlarge. Created using my LookingUp program.

09/19/2017 – Ephemeris – The Great Rift

September 19, 2017 1 comment

Ephemeris for Tuesday, September 19th. The Sun will rise at 7:26. It’ll be up for 12 hours and 18 minutes, setting at 7:45. The Moon, 1 day before new, will rise at 7:43 tomorrow morning.

High overhead the Milky Way is seen passing through the Summer Triangle of three bright stars. Here we find the Milky Way split into two sections. The split starts in the constellation of Cygnus the Swan or Northern Cross very high in the east. The western part of the Milky Way ends southwest of the Aquila the eagle. This dark dividing feature is called the Great Rift. Despite the lack of stars seen there, it doesn’t mean that there are fewer stars there than in the brighter patches of the Milky Way. The rift is a great dark cloud that obscures the light of the stars behind it. Sometimes binoculars can be used to find the edges of the clouds of the rift, as stars numbers drop off suddenly. This is especially easy to spot in Aquila the eagle.

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

Addendum

The Great Rift in the Milky Way. Created using Stellarium.

The Great Rift in the Milky Way. Created using Stellarium.

09/18/2017 – Ephemeris – The constellation of the shield

September 18, 2017 1 comment

Ephemeris for Monday, September 18th. The Sun will rise at 7:25. It’ll be up for 12 hours and 21 minutes, setting at 7:46. The Moon, 2 days before new, will rise at 6:35 tomorrow morning.

In the evening sky, in the south after it gets dark can be seen part of the Milky Way. There is actually a constellation here located between Sagittarius the archer, which really looks like a teapot, below and Aquila the eagle above. It’s Scutum the shield of John Sobieski the Polish king who stopped the advance of the Turks at Kalenberg in 1683. Scutum is the only official constellation I know of which is related to a real person. The Polish half of me is very proud. However the stars here are so dim and embedded in the glow of the Milky Way as to be nearly impossible to discern. Scutum lies in one of the richest portions of the Milky Way, wonderful to scan with binoculars and telescopes for star clusters and nebulae or clouds of dust and gas.

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

Addendum

Scutum Finder Chart

Scutum Finder Chart animation. For 9 p.m. September 18, 2017. Created using Stellarium and GIMP.  Click on image to enlarge.

DSOs in Scutum

Deep sky objects in Scutum and surrounding area. September 2017. Created using Stellarium.  Click on image to enlarge.

09/15/2017 – Ephemeris – Two local astronomy events tomorrow

September 15, 2017 1 comment

Ephemeris for Friday, September 15th. The Sun will rise at 7:21. It’ll be up for 12 hours and 30 minutes, setting at 7:52. The Moon, 2 days past last quarter, will rise at 3:10 tomorrow morning.

There are two local astronomical events tomorrow. Tomorrow the Leland Heritage Celebration will take place from 10 a.m. to 4 p.m. at Fish Town in Leland. The Grand Traverse Astronomical Society will be there to show the Sun through member’s telescopes and give out NASA items for the kids. We’ll exhibit pictures gained from last month’s total solar eclipse. Then starting at 9 p.m. the crew will be at Northwestern Michigan College’s Rogers Observatory for a star party, viewing Saturn and the wonders of the Milky Way including star clusters and nebulae of clouds of gas and dust that mark locations of either the birth or death of stars. Rain will affect the Leland event. The observatory is located on Birmley Road.

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

Addendum

GTAS telescopes at Leland Heritage Celebration in 2011.

GTAS telescopes at Leland Heritage Celebration in 2011.

09/14/2017 – Ephemeris – Cassini will go out in a blaze of glory tomorrow morning

September 14, 2017 2 comments

Ephemeris for Thursday, September 14th. The Sun will rise at 7:20. It’ll be up for 12 hours and 33 minutes, setting at 7:54. The Moon, 1 day past last quarter, will rise at 2:05 tomorrow morning.

Just about 24 hours from now the Cassini spacecraft will end its 20 year mission to Saturn and its 13 years of orbiting the planet. Monday, 4 days ago, it passed the great moon Titan for the last time, giving it one last gravitational boost into a suicidal plunge into Saturn’s atmosphere. At 7:55 tomorrow morning EDT (11:55 UTC), Cassini is expected to lose its stabilization in the thin upper atmosphere or Saturn and lose its connection with the Earth. It is expected to burn up, traveling at 70,000 miles an hour to become a part of the planet it investigated for 13 years. Instead of recording data for transmission to Earth later, it will be taking real-time atmospheric sampling, transmitting immediately up to the very end.

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

Addendum

Cassini in the gap

An artist’s visualization of Cassini slipping between the rings and the atmosphere of Saturn. Credit NASA/JPL.

Here’s a link to yesterday’s news conference at JPL on the end of the Cassini Mission:  https://youtu.be/gs-dscW95PE.

Link to Emily Lakdawalla’s Planetary Society post on the final days of Cassini including NASA TV coverage:  http://www.planetary.org/blogs/emily-lakdawalla/2017/0911-cassini-eom-timeline.html.