Archive
08/12/2013 – Ephemeris – The perseid meteors are not done yet
Ephemeris for Monday, August 12th. The sun rises at 6:41. It’ll be up for 14 hours and 10 minutes, setting at 8:52. The moon, 2 days before first quarter, will set at 11:26 this evening.
The Perseid meteor shower is still active. Their peak will be this afternoon. So starting at moon set at 11:26 or so it will be dark enough to see them. Meteor showers are caused when the earth crosses the path of a periodic comet and runs into the debris liberated by the comet’s past visits near the sun. Comet Swift-Tuttle is the comet responsible for the Perseids. It has an orbit of the sun of 130 years. Every time the comet comes close to the sun, it liberates a cloud of small gravel that’s too massive to be swept into the comet’s tail, however it is affected by the pressure of sunlight. These make the prediction of the time of the meteor shower interesting, or that a particular cloud may miss the earth this time to hit it some other passage.
Addendum
My best Perseid photo. From the 70’s.
08/09/2013 – Ephemeris – A weekend full of local astronomical events
Ephemeris for Friday, August 9th. The sun rises at 6:38. It’ll be up for 14 hours and 18 minutes, setting at 8:56. The moon, 3 days past new, will set at 9:55 this evening.
This weekend is packed with events by the Grand Traverse Astronomical Society starting tonight with Friday Night Live on Front Street in Traverse City. We’ll start by looking at the sun if it’s clear, and at Saturn as night falls. Tomorrow night its a Star Party and meteor watch at Thoreson Farm at Sleeping Bear Dunes National Lakeshore see the map at http://www.gtastro.org for location. Sunday night it’s Meteors and S’mores at Leelanau State Park. The Perseid meteor shower will reach its peak between 2 and 4 Monday afternoon, but we’re already seeing its meteors, which seem to come from the northeastern sky. The moon really won’t interfere until Monday night before midnight, so this is an excellent year for the Perseid meteor shower.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Friday Nite Live
Map to Thoreson Farm, northeast of Glen Arbor.
07/26/2013 – Ephemeris – South Delta Aquarid meteors at peak, but look for the Perseids
Ephemeris for Friday, July 26th. The sun rises at 6:22. It’ll be up for 14 hours and 51 minutes, setting at 9:14. The moon, 3 days before last quarter, will rise at 11:13 this evening.
We are now reaching the peak of the South Delta Aquarid meteor shower, which is hampered by the waning gibbous moon in the morning sky, where it’s visible. This is also the time to begin to look for the Perseid meteors that will reach peak next month on the morning of the 12th. The Perseids are an all night meteor shower because the radiant point, the point from which the meteors seem to come is far enough north so it never sets. The largest number of meteors appear when the radiant is highest in the sky, before dawn. However as soon as it gets dark the low position of the radiant in the northeast will result in fewer meteors but the streaks will be longer, as the meteoroids hit the atmosphere at a low angle.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
South Delta Aquarid meteor shower at peak and Persieds firing up at 1 a.m. July 27, 2013. PerR and DAqR are the radiants.
07/08/2012 – Ephemeris – How to find the Ring Nebula (M57)
Ephemeris for Monday, July 8th. Today the sun will be up for 15 hours and 22 minutes, setting at 9:28. The moon is new today, and won’t be visible. | Tomorrow the sun will rise at 6:06.
The constellation of Lyra is high in the east when it gets dark tonight. Its bright star Vega and the thin parallelogram of stars depict the harp it represents. Between the two stars at the bottom of the parallelogram opposite Vega hides a celestial wonder that can be seen in a small telescope, though the larger the telescope the better. It is the Ring Nebula, a smoke ring blown by a dying star. The telescope’s finder cannot show the ring. Center the finder between those two stars. The nebula will appear as a small dim gray spot in the telescope. Closer inspection may reveal that the center of the nebula is darker than the edges. It is about 2,300 light years away, but that’s a very approximate distance, which could be a thousand light years off.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The constellation Lyra with the location of the Ring Nebula shown. Created using Stellarium.
A closer look at the location of the Ring Nebula. Created using Stellarium.
05/14/2013 – Ephemeris – How to find two bright spring stars.
Ephemeris for Tuesday, May 14th. Today the sun will be up for 14 hours and 47 minutes, setting at 9:02. The moon, 4 days before first quarter, will set at 12:48 tomorrow morning. Tomorrow the sun will rise at 6:14.
The Big Dipper, now pretty much overhead points to several stars and constellations. It’s handle points to two bright stars. First we follow the arc of the handle to the bright orange star Arcturus, the 4th brightest night time star. The reason I say night time is that the sun is a star also but by definition is not out at night. The arc to Arcturus is a how to find Arcturus and a clue to its name. Arcturus, high in the east southeast, lies at the base point of the kite shaped constellation of Boötes the herdsman. From Arcturus, straighten out the arc to a spike and one soon arrives at Spica a blue-white star in Virgo the virgin, now low in the southeast. Saturn is to its left this year. Spica is also sometimes pronounced “Speeka”.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
My program that shows the arc to Arcturus and spike to Spica.
A more realistic view of the same part of the sky. Created using Stellarium.
05/08/2013 – Ephemeris – Where are the bright planets tonight?
Ephemeris for Wednesday, May 8th. The sun rises at 6:22. It’ll be up for 14 hours and 33 minutes, setting at 8:55. The moon, 1 day before new, will rise at 6:06 tomorrow morning.
It’s time to check out the bright planets for this week. Venus is starting to make an appearance in the western twilit sky after sunset, competing with the bright twilight glow. It will set in the west northwest at 9:48. Jupiter is located in the constellation of Taurus, above the V shape of stars, the face of the bull and is in the west during the evening. It will set at 11:28 p. m. In the west northwest. Jupiter is still high enough as it gets dark to get a very good view of its cloud bands and satellites. Saturn will be low in the east southeast when it gets dark in the evening. It’s located in eastern Virgo, but is moving back a bit toward the bright star Spica to its right. Saturn will move past due south at 12:58 a.m., and set at 6:14 a.m.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Venus, Jupiter and the fading stars of winter at 9:45 p.m. May 8, 2013. Created using Stellarium.
Saturn and the constellations of spring at 10:30 p.m. May 8, 2013. Created using Stellarium.
05/02/2013 – Ephemeris – The Eta Aquarid meteors will reach peak this weekend
Ephemeris for Thursday, May 2nd. The sun rises at 6:30. It’ll be up for 14 hours and 17 minutes, setting at 8:48. The moon, at last quarter today, will rise at 3:09 tomorrow morning.
Monday morning will see the expected peak of the Eta Aquarid meteor shower. The meteors will seem to come from the southeast. This shower has a very long peak and can be seen tomorrow morning. This shower’s claim to fame is that the meteoroids that produce this shower are bits shed by Halley’s Comet. The orbits of Halley’s comet and the earth nearly intersect at two points. The inbound Halley’s comet crosses the earth’s orbit where the earth is on October 20th., when we have the Orionid meteor shower. The comet’s orbit then passes between the orbits of Venus and Mercury then crosses the earth’s orbit again near where the earth is on May 6th. The shower has 12 year fluctuations of peak numbers, probably caused by Jupiter.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Eta Aquarid radiant
04/19/2013 – Ephemeris Plus* – Astronomy Day and the Lyrid meteor shower
Ephemeris Plus for Friday, April 19th. The sun rises at 6:51. It’ll be up for 13 hours and 41 minutes, setting at 8:32. The moon, 1 day past first quarter, will set at 3:51 tomorrow morning.
Tomorrow is Astronomy Day 2013. Astronomy Day is generally held on the Saturday closest to the first quarter moon in late April or early May. The Grand Traverse Astronomical Society will celebrate with a star party at Northwestern Michigan College. Tomorrow April 20th, from 9 p.m. to 11 p.m. There will also be activities inside the observatory, so clear or cloudy there will be something to see or do for all ages.
The Lyrid Meteor Shower will be active this weekend and reach a peak Monday morning. The meteors from this shower will seem to come from near the constellation of Lyra the harp, a northern summer constellation, with the bright star Vega with a small and narrow parallelogram of stars near it. We do have a moon problem this year, so it just might be caught by early risers in the next couple of mornings. It is not a super active shower, and has a peak rate of only 18 and hour when Vega is overhead, which it will be at 5 in the morning. With the experience of the bright meteor that broke windows in Russia, be comforted to know that meteor showers members are created with very small grains, not big boulders.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
*Ephemeris Plus contains more information in the post’s body that could not fit into the time constraints of the Ephemeris program.
Addendum
Lyrid meteor radiant. The bright star is Vega
04/18/2013 – Ephemeris – The moon at first quarter
Ephemeris for Thursday, April 18th. The sun rises at 6:52. It’ll be up for 13 hours and 38 minutes, setting at 8:31. The moon, at first quarter today, will set at 3:21 tomorrow morning.
Lets take a look at the moon tonight. It’ll be about 6 hours after first quarter and we’ll see features at the terminator, the sunrise line that cuts the moon in half. In small telescopes, at the north or top end of the moon, the wide flat crater Plato is just entering sunlight. Long shadows from its crater walls will retreat across its flat floor over the evening. If you look closely you’ll notice that the floor of Plato is slightly convex to conform with the curvature of the moon itself. Nearby is the straight gash in the Alps Mountains, called the Alpine Valley. Supposedly the crater Plato formed shortly after Mare Imbrium formed throwing up the Alps and the Apennine mountains to the south. The Straight wall, can be seen on the south end of the moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
First quarter moon April 18, 2013 Created using Virtual Moon Atlas
04/04/2013 – Ephemeris – Can you spot Zodiacal Light?
Ephemeris for Thursday, April 4th. The sun will rise at 7:17. It’ll be up for 12 hours and 56 minutes, setting at 8:14. The moon, 1 day past last quarter, will rise at 4:34 tomorrow morning.
After you try to spot Jupiter tonight, or hang around outside at the end of astronomical twilight, about 10 p.m. look to the west at Taurus the bull and Gemini. Then broaden your gaze. There will be a very faint triangular glow with broad base at the horizon leaning a bit to the left, with its apex near Jupiter and the V of the face of Taurus the bull and the bright star Aldebaran to the right of Orion. This glow is called Zodiacal Light, caused by the reflected sunlight off a cloud of dust located in the plane of the solar system. Most of the large bodies of the solar system orbit the sun in a single plane. The one exception to this are comets, which orbit at all angles to the sun. Zodiacal Light is best seen on spring evenings and autumn mornings.
Addendum
It seems the only good photographs of zodiacal light I get is when there’s a comet in that direction. It happened a year before with Comet Hyakutake. The images here were taken later in the month when the Hyades and the Pleiades were lower in the sky.
Zodiacal Light and Comet Hale-Bopp April 1997. My image.
Here’s a black and white image with enhanced contrast.
Zodiacal Light and Comet Hale-Bopp April 1997. Enhanced contrast.
