04/08/2014 – Ephemeris – Mars is at opposition today!
Ephemeris for Tuesday, April 8th. The sun will rise at 7:10. It’ll be up for 13 hours and 7 minutes, setting at 8:18. The Moon, 1 day past first quarter, will set at 4:10 tomorrow morning.
Mars is at opposition from the Sun today. That doesn’t mean that Mars and the Sun are opposed to each other. Well, I guess they are, sort of. It really means that the Sun and Mars are opposite one another in the sky with Mars rising at sunset, staying up all night and setting at sunrise. That puts the earth smack dab between the Sun and Mars. For most planets this is the time of closest approach. Mars, however, has a markedly elliptical orbit, and in its orbit, it is moving closer to the sun, so it will actually come a bit closer to the Earth this go around on April 14th, next Monday when it will be 372,000 miles closer. That’s not much out of 57 million miles. Still Mars is a tiny planet in telescopes.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars’ closest approaches with the earth 2003 to 2018. Created with my LookingUp program.
Mars through a telescope tonight (April 8, 2014). Apparent diameter 15.1″. Created using Stellarium.
Mars at its closest approach in 50,000 or so years on August 27, 2003. Apparent diameter 25.1″. Created using Stellarium.
Apparent diameters are in seconds or arc. One second of arc is 1/3600th of a degree. or about 1/1800th of the width of the Moon or Sun.
04/07/2014 – Ephemeris – Why does the Moon have all those craters?
Ephemeris for Monday, April 7th. The sun will rise at 7:12. It’ll be up for 13 hours and 4 minutes, setting at 8:17. The Moon, at first quarter today, will set at 3:37 tomorrow morning.
Today the Moon is at first quarter. That moment in time actually occurred a couple of hours ago, so by tonight the Moon’s terminator, the sunrise line on the Moon will be slightly bowed to be a slight gibbous phase. With binoculars or small telescope it’s a fine time to spot craters and mountains near that terminator where the shadows are longest. On the Earth mountains are thrown up by the collision of tectonic plates or volcanoes. There are no tectonic plates as such on the Moon. Mountains that we recognize are the walls of the seas, which are really vast craters caused for the most part by collisions with small asteroids. The reason the Earth doesn’t carry those scars is that the Earth erodes and recycles its surface.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon tonight (10 p.m. April 7, 2014). Created using Virtual Moon Atlas.
Tax Day Eclipse – April 15, 2014
From the April 2014 Stellar Sentinel, the newsletter of the Grand Traverse Astronomical Society
If you stay up April 14th or get up early on April 15th to watch the total lunar eclipse that morning, make sure your taxes are done, because you might not be good for much of anything during the day on the 15th.
That being said, let’s take a look at the what and where of the eclipse. Lunar eclipses only occur at full moon. The Sun, Earth and Moon have to line up so the the Earth casts its shadow on the Moon. This occurs in about one in six full moons. Below is the Moon and the earth’s shadow at the March full moon.
On March 16, 2014 the full Moon missed the Earth’s shadow, so no eclipse was seen. Created using Cartes duCiel.
In the illustration above the “bulls-eye” is the Earth’s shadow as it would appear at the Moon’s distance. The outer gray circle represents the Earth’s penumbra, where the sun’s light is increasingly blocked by the earth. The umbra (in red for emailed PDF versions of this newsletter) is the Earth’s inner shadow where no direct sunlight enters. When the Moon enters the umbra the partial phase of the eclipse begins. When the Moon is entirely within the umbra the Moon will be totally eclipsed. The Moon back on March 16th missed the earth’s shadow by passing several degrees south of it. When the moon is in the umbra it is still dimly lit indirectly to some degree by the combined rays of the sun that are refracted through Earth’s from all the accumulated sunrises and sunsets occurring around the Earth at that time. Back in 1967 the robotic lunar soft lander Surveyor 3 was able to take some images of the earth during a lunar eclipse. For Surveyor this was a solar eclipse and illustrated the light being refracted around the earth.
Solar eclipse by the Earth as viewed by Surveyor 3, April 24, 1967. Credit: NASA
The current Chinese Chang’e 3, should it survive one more lunar night, has a chance to take a better quality photograph of the eclipsed Sun this April 15th if its camera can tilt far up enough.
The light that illuminates the Moon in the Earth’s umbra is generally red in color, though the edge of the umbra generally has a gray cast to it. The light level is so low in the umbra, that, to the naked eye, it appears that the Moon is indeed being eaten by something invisible as the ingress partial phase progresses. About three quarters the way in the color of the umbra can be perceived even to the naked eye.
There are exceptions. Two notable lunar eclipse of this person’s memory occurred in 1982. On July 6, 1982 the early morning eclipse when the Moon passed centrally through the umbra the Moon was unevenly lit. The top or northern half was much darker than the southern half. In late March and early April that year the El Chichón volcano erupted in southern Mexico sending 20 million metric tons of ash high into the stratosphere. Apparently it masked the light from the northern hemisphere making it into the earth’s shadow. That year’s December 30th lunar eclipse was exceptionally dark. In fact during totality one had to hunt to find the Moon at all with the naked eye.
The events of the April 15th eclipse
The Moon travels through the Earth’s shadow from right to left. What are seen are points of contact with the shadow and mid-eclipse. From Five Millennium Canon of Lunar Eclipses (Espenak & Meeus) NASA.
Contact times are labeled P1, U1, U2, U3, U4, and P4. P2 and P3 are omitted because they are synonymous with U2 and U3 respectively:
P1 – 12:53:37 a.m. Enter the penumbra (unseen). By about 1:30 the duskiness on the left edge of the Moon will start to be pronounced.
U1 – 1:58:19 a.m. Enter the umbra (partial eclipse begins).
U2 – 3:06:47 a.m. Totality begins.
Mid eclipse 3:49:40 a.m.
U3 – 4:24:35 a.m. Totality ends, egress partial phase begins.
U4 – 5:33:04 a.m. Partial phase ends. The Moon’s upper right edge should appear dusky for the next half hour or so.
P4 – 6:37:37 a.m. Penumbral phase ends (unseen).
Note: The duskiness of the penumbral phase of the eclipse can be enhanced by viewing through sunglasses.
Weather permitting there will be two Grand Traverse Astronomical Society venues to view this eclipse. The first will be the NMC Rogers Observatory. The second will be at the Sleeping Bear Dunes National Lakeshore in the Dune Climb parking lot on M109. Both start at 1:30 a.m. if it’s clear.
Note: All times are Eastern Daylight Time. For locations other than Northwestern Lower Michigan, check with your local astronomy club. However this is a perfect event to be viewed from one’s back yard. No optical aid is required.
Correction: The U2 timing was incorrectly stated in the original post.
04/04/2014 – Ephemeris – Follow the Moon this weekend
Note: Sorry for the late post.
Ephemeris for Friday, April 4th. The sun will rise at 7:17. It’ll be up for 12 hours and 55 minutes, setting at 8:13. The Moon, 3 days before first quarter, will set at 1:32 tomorrow morning.
During this weekend the Moon will be slowly crossing the evening sky, approaching the planet Jupiter. Pay attention if you can to each night’s position and how its phase changes. It is moving farther from the sun in the sky, so we see it more and more illuminated by the sun. Sunday night it will draw even with Jupiter, with the planet some 10 moon widths north or above the Moon. It doesn’t seem at first thought that the Moon rotates, since we see the same face from the Earth all the time,. But the Moon does rotate, once a month. If it didn’t rotate we’d see all of it from our changing view of it over the month. The part of the Moon we can’t see from Earth is not the dark side, it is the far side which is fully illuminated at our new moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Motion and phase of the Moon for April 4, 5, and 6 2014. Created using Cartes duCiel (SkyCharts).
Click on image to enlarge. Yes, the moon is really that small.
04/03/2014 – Ephemeris – Astronomy events in the Grand Traverse Region
Ephemeris for Thursday, April 3rd. The sun will rise at 7:19. It’ll be up for 12 hours and 52 minutes, setting at 8:12. The Moon, half way from new to first quarter, will set at 12:39 tomorrow morning.
This evening the Grand Traverse Astronomical Society or GTAS will be at the Boardman River Nature Center for “A Night at the Nature Center”. This is a closed event sponsored by the Grand Traverse Conservation District, but it reminds me that the society hosts these types of events for schools, scouts and other youth groups along with other non-profit organizations. We’re now lining up some summer reading clubs at at least two area libraries. In the daytime we have that one great star the sun. At night we have the rest of them including the Moon and planets. If its cloudy we have hands on activities. Contact the society at info@gtastro.org for more information. The GTAS may also pop up at a summer festival near you.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A partial solar eclipse projected for all to see. Credit: Eileen Carlisle
The start of a Star Party at Sleeping Bear Dunes National Lakeshore. Credit: Eileen Carlisle
Looking at the Transit of Venus through a solar telescope. Credit: Eileen Carlisle.
04/02/2014 – Ephemeris – When it’s Wednesday it’s Planet Time!
Ephemeris for Wednesday, April 2nd. The sun will rise at 7:21. It’ll be up for 12 hours and 49 minutes, setting at 8:11. The Moon, 3 days past new, will set at 11:41 this evening.
Wednesday is Bright Planets Day here on Ephemeris. Jupiter will be in the south-southwestern sky as darkness falls tonight. It’s cruising against the stars of Gemini now, and moving slowly eastward after spending a couple of months backtracking to the west. It will set at 3:31 a.m. in the west-northwest. Reddish Mars is in Virgo now above and a bit left of the bright star Spica in the late evening, which it now outshines. Mars will rise at 8:39 p.m. It will pass due south at 2:18 a.m. It’s 58.6 million miles away now. Mars is 6 days from opposition and 12 days from closest approach this go round. Saturn will rise at 11:23 p.m. in the east-southeast and pass due south at 4:20 a.m.. It’s seen against the stars of Libra the scales this year. Venus will rise at 5:37 tomorrow morning and be seen in the southeast.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter, the Moon and the winter constellations at 10 p.m. on April 2, 2014. Created using Stellarium.
The Moon through a small telescope at 10 p.m. on April 2, 2014. Created using Stellarium.
Jupiter and moons through a small telescope at 10 p.m. on April 2, 2014. Created using Stellarium.
Mars rising at 10 p.m. on April 2, 2014. Created using Stellarium.
Mars through a telescope at 11 p.m. on April 2, 2014. Created using Stellarium.
Mars and Saturn with some spring and summer constellations at 6 a.m. on April 3, 2014. Created using Stellarium.
Mars through a telescope at 6 a.m. on April 3, 2014. Created using Stellarium.
In the morning Mars currently turns a more interesting face to us than in the evening. The big dark area on the lower left of Mars is Syrtis Major, which translates to the “Great Swamp”. I prefer the Latin. It is the most recognizable dark features on the planet. Where it appears on the face of Mars depends on the optical arrangement and eyepiece placement in your telescope.
Saturn through a telescope at 6 a.m. on April 3, 2014. Created using Stellarium.
Venus in twilight at 6:30 a.m. on April 3, 2014. Created using Stellarium.
Venus through a telescope at 6:30 a.m. on April 3, 2014. Created using Stellarium.
04/01/2014 – Ephemeris – Viewing Zodiacal Light
Ephemeris for April Fools Day, Tuesday, April 1st. The sun will rise at 7:23. It’ll be up for 12 hours and 46 minutes, setting at 8:09. The Moon, 2 days past new, will set at 10:37 this evening.
There is a faint glow visible to the careful observer at twilight’s end at 9:51 p.m. This glow is in the west. It’s Zodiacal Light, the reflected glow from countless bits of cometary dust in the plane of the solar system. You’ll need to go to a spot with no towns or cities immediately to the west of you. The glow will appear as a thin pyramidal glow tilted to the left. It’s tough to find the first time, but once seen you’ll easily find it again. A recent study of the glow confirms the source of it. While bright comets are fairly rare, small comets are very plentiful, including plenty that graze the sun and evaporate liberating their dust into interplanetary space. After tomorrow night the Moon will interfere for two weeks.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
I could never photograph Zodiacal Light when I wanted to. However I did catch it inadvertently.
Zodiacal Light and Comet Hale-Bopp April 1997. My image.
Zodiacal Light and Comet Hale-Bopp April 1997. Enhanced contrast.
03/31/2014 – Ephemeris – Previewing April skies
Ephemeris for Monday, March 31st. The sun will rise at 7:25. It’ll be up for 12 hours and 43 minutes, setting at 8:08. The moon, 1 day past new, will set at 9:30 this evening.
The 4th month of the year begins tomorrow. Daylight hours in the Interlochen/Traverse City area and will increase from 12 hours and 46 minutes tomorrow to 14 hours 11 minutes on April 30th. The altitude, or angle, of the sun above the southern horizon at local noon will be 50 degrees tomorrow and will ascend to 60 degrees on April 30th. The altitude of the sun in the Straits area will be a degree lower. The actual time of local apparent noon this month for the Interlochen/Traverse City area, when the sun passes due south, will be about 1:43 p.m. The big event for this month will be a total lunar eclipse visible from our area in the wee hours of the morning on April 15th. It’s the first or two lunar eclipses visible from here this year. The other is in October.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Star Chart for mid-month for April 2014 at 10 p.m. Credit: Bob Moler.
Add a half hour to every week before the 15th and subtract and hour for every week after the 15th.
For a list of constellation names to go with the abbreviations click here.
03/28/2014 – Ephemeris – Mars approaches
Ephemeris for Friday, March 28th. The sun will rise at 7:30. It’ll be up for 12 hours and 34 minutes, setting at 8:04. The moon, 2 days before new, will rise at 6:40 tomorrow morning.
The planet Mars is making its every 26 month on average close approach to the Earth. Mars will reach opposition from the sun on April 8th, rising at sunset and setting at sunrise. Due to Mars’ strongly elliptical orbit, it will actually be closest to us 6 days later on April 14th. That distance will be about 57.4 million miles, nearly twice that if its closest distance of 34.6 million miles it came back in 2003. But take heart, the opposition distances are closing. On July 31, 2018 it will again be below 36 million miles away. Even at its closest, Mars is a tiny object for the telescope. It’s half the size of the Earth and at its closest will appear less that half the size that Jupiter appears to us.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Mars’ closest approaches with the earth 2003 to 2018. Created with my LookingUp program.
03/27/2014 – Ephemeris – Hydra and the Great Underwater Panther
Ephemeris for Thursday, March 27th. The sun will rise at 7:32. It’ll be up for 12 hours and 31 minutes, setting at 8:03. The moon, 3 days before new, will rise at 6:06 tomorrow morning.
Today I will take a fresh, for me at least look at the constellation of Hydra the water snake of Greek origin and the Great Underwater Panther of our local Anishinabek people. Between the bright star Regulus in Leo the lion and Procyon in Canis Minor, Orion’s small hunting dog is a drooping group of 6 stars that makes up the head of Hydra. The rest of his stars trail snakily to the southeastern horizon at 10 p.m. He won’t be fully risen until 1 a.m. In the mythology of the Anishinabek people The head of Hydra is the head of the Great Underwater Panther, his back and tail run to Regulus and the front of Leo. In the spring of thinning ice when someone broke through it was credited to this panther, who pulled the person underwater.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Anishinabek people contain the Ojibwe or Chippewa, Ottawa or Odawa, and Algonquin peoples. The Chippewa and Ottawa are indigenous to much of northern Michigan.
Alternately showing Leo and Hydra of our “Western” constellations and the Anishinabek constellation of the Great Underwater Panther. Created using Stellarium. The constellation drawing of the panther is mine after Michael Wassegijig Price.
The constellation Great Underwater Panther screen shot taken from the YouTube video “Stellar Connections: Explorations in Cultural Astronomy – Pt. 2” by Michael Wassegijig Price.
Below is the video source for the above image.
Here is a link to the video.
