Archive
10/26/2015 – Ephemeris – RIP Robert Farquhar interplanetary navigator extraordinaire
Ephemeris for Monday, October 26th. The Sun will rise at 8:12. It’ll be up for 10 hours and 28 minutes, setting at 6:40. The Moon, 1 day before full, will set at 8:10 tomorrow morning.
This morning Jupiter and Venus appear close together in the morning sky. They are said to be in conjunction. Also Venus is at its greatest separation from the Sun today. It will slowly begin to fall back toward the Sun. Last week Sunday Robert Farquhar died. He developed the technique of orbiting the L1 point between the Sun and the earth where the Earth nullifies the Sun’s gravity, so a spacecraft can stay there between the Earth and the Sun. He designed the trajectory for the ISEE-3 spacecraft that acted as an early warning for particles coming from the Sun. He also liberated it in 1982 and through a series of ingenious maneuvers worked it into a solar orbit that flew it through the tail of Comet Giacobini-Zinner.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
ISEE-3’s orbital path to the halo orbit at the Earth-Sun Lagrangian L1 point and out to cross the path of Comet Ziacobini-Zinner ahead of the fleet heading to Comet Halley. It was renamed ICE (International Comet Explorer). Credit: NASA/GSFC
Here’s a link to a page that recounts the quest to return the spacecraft to its L1 position by Farquhar and his band of “rouges” last year.
10/23/2015 – Ephemeris – Jupiter approaches Venus this weekend
Ephemeris for Friday, October 23rd. The Sun will rise at 8:08. It’ll be up for 10 hours and 36 minutes, setting at 6:45. The Moon, 3 days past first quarter, will set at 4:23 tomorrow morning.
Over the weekend the planets Venus and Jupiter will approach each other, until on Monday morning they will be a bit more than a degree apart, or twice the diameter of the Moon apart. Of course in reality Jupiter is far more distant than Venus. Jupiter is 563 million miles (906 million km) away, while Venus is only 63 million miles (101 million km) away, about a ninth of Jupiter’s distance. Also, on Monday Venus will be at its greatest western elongation from the Sun, that is its greatest angular separation from the Sun of 46 degrees. Venus, like Mercury, which went through its greatest western elongation last week have orbits of the Sun inside that of the Earth, so never stray far from it. Venus never rises or sets more than 3 hours from the Sun.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Jupiter passing Venus with Mars nearby in the east on the mornings of October 23, 24, 25, 26 and 27, 2015. Created using Stellarium and GIMP.
Check out my posts on the last two conjunctions of Jupiter and Venus in this series on August 18, 2014, and June 30, 2015. I discuss the possible connection to the Star of Bethlehem on my June 29th post.
10/22/2015 – Ephemeris – My favorite lunar feature
Ephemeris for Thursday, October 22nd. The Sun will rise at 8:07. It’ll be up for 10 hours and 39 minutes, setting at 6:46. The Moon, 2 days past first quarter, will set at 3:10 tomorrow morning.
The Moon tonight is revealing my favorite feature, Sinus Iridium or Bay of Rainbows. Unfortunately features on the Moon are not that colorful. The Bay of Rainbows is surrounded on three sides by a semicircular mountain range called the Jura Mountains which is actually a broken down crater wall. The Bay is a bay in Mare Imbrium, the Sea of Showers. It is the nomenclature of land forms on planets and moons that still have Latin names in astronomy. That and constellations. Of course the Bay of Rainbows and the Sea of Showers aren’t real bodies of water. These were the product of the imaginations of astronomers looking through their primitive telescopes, at a completely alien landscape.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Moon tonight with Sinus Iridium peeking out into the morning sunlight on the Moon, 9 p.m. October 2015. Created using Virtual Moon Atlas.
Sinus Iridium photographed by the Lunar Reconnaissance Orbiter as texture mapped on the globe of the Virtual Moon Atlas.
10/21/2015 – Ephemeris – The bright planets and an anniversary star party
Update 5:05 p.m.:
The star party at the Sleeping Bear Dunes has been canceled due to clouds.
Ephemeris for Wednesday, October 21st. The Sun will rise at 8:05. It’ll be up for 10 hours and 42 minutes, setting at 6:48. The Moon, 1 day past first quarter, will set at 2:00 tomorrow morning.
We’ve got a busy day. The planet Saturn will be low in the west-southwest after sunset and will set at 8:31 p.m. In the morning sky the brilliant planet Venus will rise at 4:05 and be quite high at this program’s air time. Jupiter will be just below and left of it. Mars will be below and left of Jupiter by a similar amount. Both rise within 20 minutes of Venus. Far below and left will be Mercury which will rise at 6:38. Tonight is the last star party of the year at the Sleeping Bear Dunes National Lakeshore. This is the lakeshore’s 45th anniversary. It will held starting at 8 p.m. at Pierce Stocking Drive Stop #3 the Dunes Overlook if it’s clear, Park at Picnic Mountain. The Moon will be the big attraction tonight. The Grand Traverse Astronomical Society has been holding star parties at the Sleeping Bear Dunes since the park’s 40th anniversary in 2010.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn and the Moon (at twice normal size) at 7:30 p.m. October 21, 2015. Created using Stellarium.
The telescopic Moon tonight, October 21, 2015, for the star party at Sleeping Bear Dunes. Created using Virtual Moon Atlas.
The morning planets at 7 a.m., October 22, 2015. Created using Stellarium.
This is a chart showing the sunrise and sunset skies for October 21, 2015 showing the location of the planets and the Moon at that time. The charts are rotated 90 degrees to more clearly show the traffic jam of the morning planets. Created using my LookingUp program. Click on the image to enlarge.
10/20/2015 – Ephemeris – Halley’s Comet returns… in bits and pieces
Ephemeris for Tuesday, October 20th. The Sun will rise at 8:04. It’ll be up for 10 hours and 45 minutes, setting at 6:50. The Moon, at first quarter today, will set at 12:53 tomorrow morning.
Halley’s Comet is back! Well sorta. In the form of the Orionid meteor shower. Bits of Halley’s Comet from previous passes by the Earth’s orbit make their twice yearly show in our skies as these bits collide with the Earth’s atmosphere. Halley’s orbit passes close to the earth’s orbit at points where the Earth is around May 6th and again near October 21st. Light dust get blown back into the tail of the comet. Heavier particles, still affected by the pressure of sunlight and the gravitational pull of the Sun and planets end up roughly following the comet’s orbit. Tonight night after the Moon sets should be the best time to see them. They will seem to come from a spot above Orion and below Gemini.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Orionid Radiant
We get two meteor showers from Halley’s Comet. The Orionids, when Halley is approaching the inner solar system, and the Eta Aquariids when it’s leaving. Credit my LookingUp program.
10/19/2015 – Ephemeris – Where did the Moon come from?
Ephemeris for Monday, October 19th. The Sun will rise at 8:03. It’ll be up for 10 hours and 48 minutes, setting at 6:51. The Moon, 1 day before first quarter, will set at 11:51 this evening.
Only two planets in the solar system have moons at least a quarter the size of the planet they orbit: The Earth and Pluto. The Moon is a bit more than a quarter the Earths diameter while Pluto’s moon Charon is half its size. Probably in the early days of the solar system, some four and a half billion years ago collisions were rather common. It is thought by many planetary scientists that a Mars sized protoplanet collided with the proto-earth with a glancing blow to rip off much of the Earth’s crust, thrust it into orbit where it coalesced into the Moon. It seems that Pluto’s Charon may have been formed much the same way. Some thing the varying axial tilts of the planets may have been caused the same way by smaller objects.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The hypothetical collision of a Mars sized body with the young Earth. Credit: Joe Tucciarone via NASA
Breaking News
Robert Farquhar the man behind the ISEE-3 spacecraft, the first to hang out at the Earth-Sun L1 point between the Earth and the Sun back in 1978 passed away yesterday. In 1982 he “stole” the spacecraft and through an amazing number of maneuvers using very little fuel managed to send it through the tail of Comet Gicobini-Zinner ahead of the fleet of spacecraft then aimed at Halley’s Comet. Last year when the then renamed spacecraft ICE approached the Earth, he hatched a plan to return the spacecraft to its L1 position. Unfortunately apparently there was not enough fuel pressure to complete the burns necessary for the task. I’ll have a program on Robert Farquhar next Monday.
10/16/2015 – Ephemeris – The topic this Saturday will be comets (Updated)
Ephemeris for Friday, October 16th. The Sun will rise at 7:59. It’ll be up for 10 hours and 57 minutes, setting at 6:56. The Moon, half way from new to first quarter, will set at 9:20 this evening.
Tomorrow I have a treat for youngsters of all ages. From 10 a.m. to noon ( Update: noon to 2 p.m.) I’ll be talking about and helping to make comets at the Betsie Valley District Library in Thompsonville. First we’ll explore comets as seen in our skies then travel along with the Rosetta space mission to get up close to Comet 67P/Churyumov–Gerasimenko to see what it’s made of and what happens when it comes close to the Sun. Then we’ll make our own comet nucleus using many of the ingredients that are found in actual comets, though we’ll leave out all the poisonous ones, and we’ll see if it survives this close to the Sun. If you want to help make a comet, bring your winter gloves. I do have extras, but yours will probably work better.
Times for astronomical events are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
10/15/2015 – Ephemeris – More planet and Moon action
Ephemeris for Thursday, October 15th. The Sun will rise at 7:57. It’ll be up for 11 hours and one minute, setting at 6:58. The Moon, 3 days past new, will set at 8:41 this evening.
Tonight the planet Saturn will be seen about 15 moon-diameters left of the thin crescent Moon. We are getting close to the end of Saturn’s evening visibility. It will be pretty much lost in the evening twilight by the end of the month. In the morning sky, Mercury will be at greatest elongation by tomorrow morning. It will be at an angle of only 18 degrees from the Sun, however that angle won’t diminish much over the next week, and Mercury will actually get a bit brighter because its phase becomes fuller. Remember it is illuminated by the sun and it is beginning to move around the back of the Sun. Both Mercury and Venus show phases in a telescope like the Moon as they move around the sun.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Animation rocking back and forth between 7:45 p.m. on October 15th and 16th (2015_. Created using Stellarium.
10/14/2015 – Ephemeris – The planet get together in the morning
Ephemeris for Wednesday, October 14th. The Sun will rise at 7:56. It’ll be up for 11 hours and 3 minutes, setting at 7:00. The Moon, 2 days past new, will set at 8:06 this evening.
Lets see what’s happening with the bright planets. Saturn is alone in the evening sky spotted by 8 p.m. low in the west-southwestern sky near the bright star Antares to its left. Antares has a reddish hue, while Saturn is brighter and yellowish. Both these colors are enhanced by being low to the horizon. Saturn will set at 8:56 p.m. The rest of the planets are in the morning sky and seeing more action. Brilliant Venus, the morning star, will rise at 4 a.m. a bit north of east. Below and left of Venus is bright Jupiter, though not as bright as Venus. Above it tomorrow is dim Mars. They will pass each other on Saturday. Jupiter will rise at 4:37 preceded by 7 minutes by Mars. Mercury is way below these, but brightening. It will rise at 6:20.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Saturn and Antares appear in west-southwestern twilight with the thin crescent Moon, shown twice its actual size to show up at all, at 7:45 p.m., October 14, 2015. Created using Stellarium.
The morning planets getting together at 7 a.m. Mercury will be falling back toward the Sun after tomorrow. Created using Stellarium.
Apparent sizes of the morning planets Venus, Mars and Jupiter as seen through a telescope. Created using Cartes du Ciel (Sky Charts).
This is a chart showing the sunrise and sunset skies for October 14, 2015 showing the location of the planets and the Moon at that time. Created using my LookingUp program. Click on the image to enlarge.
10/13/2015 – Ephemeris – Columbus was wrong!
Ephemeris for Tuesday, October 13th. The Sun will rise at 7:55. It’ll be up for 11 hours and 6 minutes, setting at 7:02. The Moon, 1 day past new, will set at 7:35 this evening.
Yesterday I recounted that Christopher Columbus was able to extort supplies from the native Jamaicans by using an eclipse table to predict a lunar eclipse. But let’s face it Columbus was lost. He wasn’t in India as he thought. He based his voyage on the erroneous belief that the Earth was less than 19,000 miles in circumference, when it’s actually 25,000 miles, which was the prevailing view of the day. That the Earth was round was known from the 3rd century BC, and measured quite accurately by Eratosthenes. Of course with the varieties of distance units of the day it was no wonder an error of that magnitude could be made. Of course did anyone think to remeasure the circumference of the Earth? Apparently not. Nowadays no scientist thinks of taking only one measurement. Columbus was lucky a continent was here, or no one would have heard from him again.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
A map of the western ocean (Atlantic Ocean) by Paolo dal Pozzo Toscanelli about 1474 which may have influenced Columbus. North America is superimposed at the proper longitudes. Credit: A literary and historical atlas of America, by Bartholomew, J. G. via Wikipedia. Click to enlarge.
Note that Cathay is China and Cippangu represents Japan. It was thought back then that the Eurasian continent spanned 180 degrees of longitude at the latitude of Spain, rather than 130 degrees it actually does Japan was thought to be bigger and farther off the Chinese coast. The phantom island of Antillia seems to date back to stories from Spain of the 8th century.
