10/27/2010 — November Skies
by Dick Cookman
Highlights: Comet Journal, Martian Landers, Meteor Showers, Planet Plotting, November Moon
Focus Constellations: Ursa Major, Draco, Ursa Minor, Cepheus, Cygnus, Pegasus, Andromeda, Perseus, Cassiopeia
Comet 103P/Hartley 2 (2010) was observed at 5th magnitude southwest of Capella in Auriga when closest to Earth on October 20th. After passing Earth, the comet's flat tail was oriented edge-on to Earth and appeared as a thin line visible only in large binoculars or telescopes. The flat side of the tail will reappear in mid-November after the comet passes through perihelion on Oct. 28th and drops below the orbital plane of the Earth. The comet's coma is large and diffuse and is spread out over a wide area making it hard to see against the background glow of the sky. At the beginning of October its apparent size was as large as the full moon and grew to 1° diameter by the 13th.
The comet appears to exit southern Gemini on Nov. 3rd and move into Canis Minor. It will continue southwestward through Monoceras from the 8th through the 21st then enter Puppis at the end of the month.
According to NASA the comet may generate a meteor shower: "On Oct 16th, a pair of NASA all-sky cameras caught an unusual fireball streaking across the night sky over Alabama and Georgia. It was bright, slow, and--here’s what made it unusual--strangely similar to a fireball that passed over eastern Canada less than five hours earlier. The Canadian fireball was recorded by another set of all-sky cameras operated by the University of Western Ontario (UWO). Because the fireballs were recorded by multiple cameras, it was possible to triangulate their positions and backtrack their orbits before they hit Earth." This led to a remarkable conclusion:
“The orbits of the two fireballs were very similar,” Cooke says. “It’s as if they came from a common parent.”
There’s a candidate only 11 million miles away. Small but active Comet Hartley 2 is making one of the closest approaches to Earth of any comet in centuries. It turns out that the orbits of the two fireballs were not only similar to one another, but also roughly similar to the orbit of the comet. Moreover, meteoroids from Comet Hartley would be expected to hit Earth’s atmosphere at a relatively slow speed--just like the two fireballs did.
After altering course on Sept. 16th (Sol 2363) to observe a pitted, rust-coated 0.5 meter diameter rock dubbed “Oileán Ruaidh” after an island off the coast of Ireland, Opportunity examined the rock with its microscopic imager and alpha particle X-ray spectrometer and determined that the nickel-iron composition confirmed that it was an iron meteorite.
On Sol 2374 (Sept. 28, 2010), Opportunity resumed the trek to Endeavour Crater. Since the solar panels are now producing better than 600 watt-hours of electricity per sol the rover achieved excellent progress in its trek. By Sol 2395 (Oct. 19, 2010) it was 829.56 meters closer to the crater and has traveled a total of 24,192.63 meters (24.19 kilometers, or 15.03 miles) since landing on Mars in January, 2004.
The problems encountered in May with the Miniature Thermal Emission Spectrometer (Mini-TES) instrument continue. The spectrometer is still under investigation and the Mini-TES elevation mirror which has had accumulated dust on its surface since last year continues to be opened to the environment at regular intervals in order to accomplish a wind-induced cleaning event.
Spirit has not been heard from for 7 months and is still silent. Improving solar insolation levels may allow the rover batteries to recharge thus increasing the likelihood of hearing from Spirit in the future.
The Southern Taurid and Northern Taurid meteor showers peak on the 5th and 12th respectively. Both typically produce about 5 meteors per hour in dark skies and are favored by the almost new and waxing crescent Moon. They are comprised of debris derived from previous passages of Comet 2P/Enke which circuited through perihelion on the other side of the Sun in August of 2010.
In 2010, the Leonids on the 17th must contend with a bright waxing gibbous Moon in nearby Pisces which will overwhelm all but the brightest meteors. The best viewing will be after the Moon sets about 5AM.
The Leonid shower averages about 20 meteors per hour. It produced numerous meteor storms following the 1998 passage of its parent, Comet 55P/Tempel-Tuttle, including a meteor storm of over 100 per hour in 2002. The Leonids produced the famous meteor storm of Nov. 13, 1833 which inspired Joseph Henry Waggoner to commission a drawing by Karl Jauslin. Seventh Day Adventists made printings from a wood block engraving based on the drawing.
"During the 4 hours preceding dawn, skies were lit up by meteors. Reactions varied from hysterics of the superstitious claiming Judgment Day was at hand, to just plain excitement by scientists, who estimated that 1000 meteors a minute emanated from the constellation Leo. Newspapers reveal widespread awareness of the spectacle, those not awakened by cries of excited neighbors were awakened by the glow cast in dark bedrooms by the fireballs."
The Alpha Monocerotids are a minor shower on the 21st which will be lost in the glare of the Full Moon in Aries until the Moon sets before dawn. Hourly rates have varied from 3 to 400+, the latter figure obtained by observers in Europe in 1995. A similar outburst occurred when F. T. Bradley of Crozet, Virginia first named the shower in 1925 and again in India in 1935. In 1985 observers in California saw 36 meteors during a 16 minute interval. The orbit of Comet van Gent-Peltier-Daimaca (1944 I) comes closest to matching that of the meteor debris stream.
The brightest evening planets are Mercury and Jupiter. Uranus in Pisces and Neptune in Capricornus are much dimmer. The former is slightly east of Jupiter in Pisces and the latter is on the western side of the border between Aquarius and Capricornus. Jupiter is high and bright in the southern and southwestern sky in the evening. Although not as bright as it was at opposition in September it is better positioned for evening viewing by those who are early to bed, early to rise. The evening apparition provides a splendid opportunity for viewing the changing positions of its 4 Galilean Moons through the month with a small telescope.
Mercury appears deep in the western twilight with a much dimmer Mars on the 20th and then rises higher each night as it approaches maximum eastern elongation from the Sun on Dec. 1st. Mars falls deeper into twilight after the 20th and is lost for the rest of the year as it approaches conjunction with the Sun in February.
Venus and Saturn are morning planets. Venus passed inferior conjunction on Oct. 30th and will get even brighter during November. It starts the month as a bright crescent and will present its maximum illuminated area early in December. Saturn in Virgo rises at 5:30 AM EDT on the 1st and before 3AM EST on the 30th. The rings are now tilted more than at any other time in the last 2 years and present a spectacular telescopic view in November.
|Sun||Libra, Scorpius, Ophiuchus||-26.8|| |
|Mercury||Libra, Scorpius, Ophiuchus, Sagittarius||-0.7 to -0.4 to -0.5||Mars, 1.7°N, 11AM EST, 11/20|
|Venus||Virgo||-4.3 to -4.9|| |
|Mars||Scorpius/Ophiuchus||+1.4 to +1.3||Mercury, 1.7°S, 11AM EST, 11/20|
|Jupiter||Aquarius||-2.8 to -2.6|| |
November's Full Moon occurs at 12:27 EST on the 21st. When the Harvest Moon occurs in October, the Full Moon of November is called the "Hunter's Moon." It is also known as the "Frosty" Moon and colonial Americans called it the "Beaver" Moon.
The Celts referred to it as the "Dark Moon" and the Chinese are more upbeat because they call it the "White Moon." Medieval English knew it as the "Snow Moon." To the Anishnaabe (Chippewa and Ojibwe) of northern Michigan it is "Gashkadino-giizis(oog)" (Freezing Moon).
This lunation (11/6 to 12/5) is 1087 of Brown's series which started in 1923. It is 29.49 days long. Perigee on the 3rd occurs when the Moon is at a distance of 226,298 mi. from Earth, a distance equal to 57.10 earth radii. Perigee is repeated on the 30th when the distance is 229,553 mi. (57.92 earth radii). At apogee on the 15th the Moon is 251,426 Mi. (63.44 Earth Radii) from Earth.
|Planet||Constellation||Magnitude||Moon Passage||Moon Phase/Age|
|Sun||Libra||-26.8||12:52AM EDT, 11/6 ||New ~ 0 days|
|Mercury||Libra||-0.5||1.8°SSW, 10PM EST, 11/7||Waxing Crescent ~ 1.88 days|
|Venus||Virgo||-4.4||1.1°W, 3 EDT, 11/5 ||Waning Crescent ~ 28.51 days|
|Mars||Scorpius||+1.4||1.6°S, 5PM EST, 11/7 ||Waxing Crescent ~ 1.67 days|
|Jupiter||Aquarius||-2.7||7.0°N, 11AM EST, 11/16 ||Waxing Gibbous ~ 10.42 days|
|Saturn||Virgo||+0.9||8.0°S, 2AM EDT, 11/4 ||Waning Crescent ~ 27.47 days|
|Uranus||Pisces||+5.7||6.0°N, 5PM EST, 11/16 ||Waxing Gibbous ~ 10.67 days|
|Neptune||Capricornus||+7.9||5.0°N, 1AM EST, 11/14 ||Waxing Gibbous ~ 8.00 days |