Archive for month: May, 2015

Focus Constellations: Draco, Cepheus, Cassiopeia, Perseus, Camelopardalis, Auriga, Taurus, Gemini, Canis Minor, Cancer, Leo, Lynx, Coma Berenices, Bootes, Ursa Major, Ursa Minor

Comet Journal

Comets 88P/Howell (2015) and C/2014 Q2 (Lovejoy) are still at 8th magnitude and are dimming. Both are on their outward journeys after passing perihelion with the Sun in April and January respectively.

Comet Lovejoy is currently high above the Sun between Cepheus and Camelopardalis on its 5000+ year return to the Oort Belt in an orbit almost perpendicular to that of Earth. It will pass the North Star in late May.

Comet Howell is a short period comet that currently has a period of 5.5 years. This is its 8th return since 1955 and its period has been shorter each time due to the gravitational influence of Jupiter as it passes the giant planet with each revolution. Comet Howell moves from Aquarius to Pisces in May in an orbit which almost parallels that of Earth. It is now very close to the orbit of Mars.

C/2014 Q1 (PanSTARRS) will make a foray into northern hemisphere skies in May where it will remain in June and most of July. It will follow a steeply tilted parabolic orbit through Pisces and into Aries in May. It is currently very dim at 13th magnitude. It will brighten and may be visible to naked eyes in early July when it may reach 3rd or 4th magnitude while it is closest to the Sun near perihelion.

Mars Landers

Opportunity is in the west rim region of Endeavour Crater at Marathon Valley where satellite imaging revealed an abundance of clay minerals which may retain complex organic molecules possibly indicative of ancient Martian life. The Flash files system which was reformatted on Sol 3964 (March 19, 2015), has been functioning well except for amnesia events starting on the evening of Sol 3969 (March 24, 2015). The amnesia event was benign and did not impact rover operations nor result in any loss of science data. The rover circuited around a crater called “The Spirit of St. Louis” and approached a light-toned rock outcrop on Sol 3970 (March 25, 2015). An in-situ (contact) examination of the rock outcrop with a Microscopic Imager (MI) mosaic was followed by the placement of the Alpha Particle X-ray Spectrometer (APXS) for a multi-hour integration. During further examination of other rock outcrops in the valley more amnesia events occurred on the evenings Sols 3979 and 3980 (April 3 and April 5, 2015) and Sols 3987 and 3988 (April 12 and April 13, 2015). All were benign with no loss of science data. On Sol 3993 (April 18, 2015), further MI mosaics were collected followed by another APXS placement, but during the preparation for the afternoon UHF relay pass the rover experienced a reset, stopping all sequences. The cause of the reset is unknown and still under investigation. Further, an amnesia event occurred later that night during the wakeup to start Deep Sleep. Opportunity was restored to master sequence control on Sol 3996 (April 21, 2015).

The rover has now traversed 26.25 miles (42.24 kilometers) over the Martian surface. Solar energy in the last month has averaged about 600 watt hours per day.

Following completion of the 6 month examination of Pahrump Hills, Curiosity continued its ascent of Mt. Sharp, the layered mountain in the center of Gale Crater, and found “Garden City”, a rock outcrop shot through with two-tone (dark & light) mineral veins emplaced after the lake bed sediments were lithified into rock. The the 1 to 1.5 inch wide veins are more resistant to erosion than the surrounding rock so they project upward from the outcrop about 2 to 3 inches like a line of ice cream sandwiches on their sides.

Samples from older rocks drilled earlier at Pahrump Hills include clay rich minerals at “Confidence Hills” which were probably formed in a wet environment with moderate temperatures and pH levels, jarosite (calcium & sulfur) at “Mojave” formed in acidic, oxidizing conditions, and quartz (silicon & oxygen) and cristobalite (silicon, oxygen, and water) at “Telegraph Peak”, minerals which, on Earth, can be associated with crystallization from hydrothermal fluids moving upward from deep sources. The above order of drilled samples range from oldest to youngest and probably represents the sequence of environmental change in Martian geologic history.

Meteor Showers

The Eta Aquarid Meteor Shower peaks on the night of the 6th and morning of the 7th. The meteors result from a river of dust and debris left in the wake of previous passages of Comet 1P/Halley, the comet which Edmund Halley predicted to return in 75 years based on equations developed by his friend Isaac Newton. May all you readers have the opportunity to see its return in 2061 and congratulations to those who viewed it during its last visit in 1986. Before that it was in the sky in 1911 when Mark Twain died, 75 years after its visit when he was born. Guy Ottewell in his 2015 Astronomy Calendar notes that the orbit of the comet also crosses the October part of our orbit and debris in that area creates a sister meteor shower to the Eta Aquarids which appears to emanate from the constellation Orion. Both showers are highly variable ranging from 10 meteors per hour to as many as 140 per hour. This year the timing of the Eta Aquarid Shower coincides with the waning Gibbous Moon which presents major viewing difficulties due to its location below eastern Ophiuchus in the southern sky when Eta Aquarius rises before 3AM.

Milky Way Galaxy

In May, the evening sky presents a unique view of the Milky Way within which we reside. We are near one of the great spiral arms within the 100,000 light year diameter disk, about 30,000 light years from the center. The disk of the galaxy can be viewed along the horizon because the horizon is parallel to the plane of our spiral galaxy at this time of year. It is at the horizon in all directions at 35°N latitude. At 45°N, the center of the Milky Way is at the horizon in the southeastern sky and follows the horizon through the northern sky and into the western sky. The Milky Way Galaxy is below the horizon in the south and southwest.

Planet Plotting

Evening planets in May include Mercury, Venus, Mars, and Jupiter.

Mercury (-0.4 to +3.0) presents its best apparition of 2015 when it is at maximum eastern elongation on the 5th and is long gone from the evening sky when it reaches inferior conjunction on the 30th.

Venus (-4.2 to -4.4) dominates the early evening sky in Taurus and Gemini in May. On the 29th it will be within 5° of first magnitude Pollux (+1.2), providing a nice comparison of relative brightness of the two. Venus is moving closer to Earth as each revolves around the Sun and will catch up in mid-August when it reaches inferior conjunction with the Sun.

Mars (+1.4) is on the other side of the Sun in Taurus and is lost in its glare. It is right next to the 15 hour old waxing crescent Moon on the 18th. It will move into the evening sky in June.

Jupiter (-2.1 to -1.9) rises in Cancer before noon. It dominates southern and southwestern early evening skies before setting in the west after midnight. It is slightly dimmer than when it was at opposition in February but still presents an impressive image in the sky. On the 24th, the waxing crescent Moon appears almost 5.0° from Jupiter before they set.

Saturn in Scorpius, Uranus (5.9) in Pisces, and Neptune (7.9) in Aquarius are morning planets. Saturn rises in the early evening and reaches opposition on the 22nd when it is at peak visibility and at its brightest (0.0) for 2015. It outshines Antares (1.0), the nearby red supergiant by a factor of 2.5X. Antares is 600 times bigger than the Sun but a 600 light year distance reduces the brightness of Antares by almost 4 billion times.

The rings of Saturn are tilted rather steeply away from us in May revealing a wide open view of their expanse. Best viewing is near midnight when the planet is highest in the southern sky.

Planet……Constellation……Magnitude……Planet Passages

Sun……..Pisces, Taurus………-26.8……………New Moon, ………………………………………………………5/18, 12:13AM EDT Mercury..Taurus, Gemini..-0.4 to +3.0…Max. Eastern
……………………………………………………………..Elongation, ……………………………………………………….5/7, 1AM EDT
……………………………………………………….Inferior Conjunction ………………………………………………………..5/30, 1PM EDT
Venus…..Taurus, Gemini………-4.2 to -4.4
Mars…….Taurus……………….+1.4
Jupiter…..Cancer………………-2.1 to -1.9
Saturn…..Scorpius…………….+0.1………….Opposition, 5/22,
…………………………………………………………………..10PM EDT
Uranus….Pisces………………..+5.9
Neptune…Aquarius…………..+7.9

May Moon

Lunation 1142 started with the New Moon of April at 2:57PM EDT on the 18th. It will end 29.39 days later with the New Moon of May at 12:13AM EDT on the 18th.

The Full Moon of May in Virgo is at 11:42PM EDT on the 3rd. It is the “Planting Moon.” Colonial Americans called it the “Milk Moon”, Celts called it the “Bright Moon”, and Medieval English referred to it as the “Hare Moon.” Chinese call it the “Dragon Moon” and Anishnaabe (Odawa and Ojibwe) of the northern Great Lakes call it “Zaagibagaa-giiziz” (Budding Moon).

Apogee distance (maximum distance) is 251,186 miles (63.38 Earth radii) from Earth on the 26th at 6:12AM EDT. The Moon is nearest (perigee) in its orbit (227,437 miles or 57.39 Earth radii) on May 14th at 8:18PM EDT.

Planet..Constellation…….Magnitude……..Moon Passage
……………………………………………………Moon Phase/Age

Sun………Pisces……….-26.8…………12:13AM EDT, 5/18 ……………………………………………………..New ~ 0 days Mercury..Taurus……….+3.0………6.0°S, 3AM EDT, 5/19 …………………………………………Waxing Crescent ~ 1.12 days Venus…..Gemini……….-4.3………8.0°S, 3PM EDT, 5/21 …………………………………………Waxing Crescent ~ 3.62 days
Mars…….Taurus………..+1.4……4.7°SSE, 3PM EDT, 5/18 ………………………………………….Waxing Crescent ~ 0.62 days Jupiter….Cancer………..-2.0……….5.0°S, 3AM EDT, 5/24 ………………………………………….Waxing Crescent ~ 4.12 days Saturn….Scorpius………+0.1……….2.0°N, Noon EDT, 5/5 ………………………………………….Waning Gibbous ~ 16.88 days Uranus….Pisces…………+5.9………0.2°S, 8AM EDT, 5/15 ………………………………………….Waning Crescent ~ 26.71 days Neptune..Aquarius……..+7.9……..3.0°N, 5PM EDT, 5/12 ………………………………………….Waning Crescent ~ 24.09 days