Snake River Skies The Newsletter of the Magic Valley Astronomical Society July 2014 Membership Meeting Message from the President – Robert Mayer Astronomy Day Saturday July 12th 2014 7:00pm at the Herrett Center for Arts & Science College of Southern Idaho Public Star Party follows the Annual Picnic at Centennial Obs. Club Officers: Colleagues, Robert Mayer, President If there was any doubt, summer is now upon us. July figures to be a busy month. The main th [email protected] event is the annual MVAS barbecue on July 12 at 7 p.m. As has been done in past years, 208-312-1203 members are asked to bring a side dish or dessert. MVAS will provide the meat and soft drinks. Jim Hoggatt, Vice President A couple of star parties are also in the works. July 26th will be our annual Pomerelle Star [email protected] Party, with daytime events including water bottle rockets and solar viewing, and nighttime 208-420-7690 viewing on the top. Help is also encouraged, but it will be just as helpful to let your friends and neighbors know to enhance our publicity efforts. Gary Leavitt, Secretary [email protected] In May, we had a positive experience over at the Hagerman Fossil Beds National Monument. 208-731-7476 Leaders there have asked that we come one more time this year. A handful has already volunteered to go over on July 19th, but we can always use more help. Jim Tubbs, Treasurer / ALCOR [email protected] Clear Views, 208-404-2999 Rob Mayer David Olsen, Newsletter Editor [email protected] Rick Widmer, Webmaster [email protected] Magic Valley Astronomical Society is a member of the Astronomical League In this Issue President’s Message / Board Members Contact Page 1 Table of Contents / July Overview Page 2 Calendar Page 3 Planisphere Page 4 Idaho Skies Page 5 - 6 Solar System Page 7 Comets and Meteors for May Page 8 - 12 Deep Sky Page 13 Club Announcements Page 14 Looking Through the Eyepiece / Trivia Page 15 - 16 NASA Space Place Page 17 Observatories / Planetarium Schedules Page 18 - 19 About the Magic Valley Astronomical Society Page 20 July Overview ● The length of the day shortens by 46 minutes this month ● Earthshine on the moon is visible in the evening on the 1st and again in the morning starting on the 22nd 7/1 Mercury is stationary. 7/2 Venus is 4 degrees north of the first-magnitude star Aldebaran (Alpha Tauri) 7/4 The Earth is at aphelion (152,093,481 kilometers or 94,506,462 miles from the Sun); Pluto (magnitude +14.1, apparent size 0.1") is at opposition; the Lunar X, also known as the Werner or Purbach Cross, an X-shaped illumination effect involving various rims and ridges between the craters La Caille, Blanchinus, and Purbach, is predicted to occur at 22:13 7/6 Mercury is at its greatest heliocentric latitude south today; Mars is 0.2 degree south of the Moon, with an occultation occurring in the northern half of South America, the west coast of Central America, and the Hawaiian Islands; asteroid 4 Vesta is 0.2 degree south of asteroid 1 Ceres. 7/8 Saturn is 0.4 degree north of the Moon. 7/12 Mercury is at greatest western elongation (21 degrees); Mars is 1.4 degrees north of the first-magnitude star Spica (Alpha Virginis). 7/15 Mercury is 3 degrees south of the bright open cluster M35 in Gemini; Neptune is 5 degrees south of the Moon. 7/18 Uranus is 1.4 degrees south of the Moon. 7/20 Venus is 1.5 degrees south of M35; the Curtiss Cross, an X-shaped illumination effect located between the craters Parry and Gambart, is predicted to occur. Apollo 11 Lunar Module “Eagle” lands on the Moon 45-years ago. 7/21 Saturn is stationary. Apollo 11 Astronauts Neil A. Armstrong and Buzz Aldrin become the first humans to step foot on our celestial neighbor, the Moon. 7/22 Uranus is stationary; the Moon is 1.8 degrees north of the first-magnitude star Aldebaran (Alpha Tauri). 7/24 Venus is 4 degrees north of the Moon. Jupiter is in conjunction with the Sun. 7/25 Mercury is at the ascending node today; Mercury is 5 degrees north of the Moon. 7/29 Mercury is at perihelion today. Friedrich Bessel was born this month. The first photograph of a star, namely Vega, was taken on July 17, 1850. The first photograph of a total solar eclipse was taken on July 28, 1851. Brightness, apparent size, illumination, distance from the Earth in astronomical units, and location data for the planets and Pluto on July 1st: Mercury (+2.5 magnitude, 10.5", 11% illuminated, 0.64 a.u., Gemini), Venus (-3.9 magnitude, 12.0", 85% illuminated, 1.39 a.u., Taurus), Mars (0.0 magnitude, 9.5", 88% illuminated, 0.99 a.u., Virgo), Jupiter (-1.8 magnitude, 31.7", 100% illuminated, 6.22 a.u., Gemini), Saturn (+0.4 magnitude, 17.9", 100% illuminated, 9.26 a.u., Libra), Uranus (+5.8 magnitude, 3.5", 100% illuminated, 19.87 a.u. on July 16, Pisces), Neptune (+7.8 magnitude, 2.3", 100% illuminated, 29.23 a.u. on July 16, Aquarius), and Pluto (+14.0 magnitude, 0.1", 100% illuminated, 31.69 a.u. on July 16, Sagittarius). Calendar July 2014 Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 Independence Day First Quarter Moon 51% Visible 6 7 8 9 10 11 12 General Membership Mtg at 19:00 Herrett Center Kinney Ct. Picnic Social Yum! Full Moon On Saturday 100% Visible 13 14 15 16 17 18 19 Moon is at Last Quarter Perigee Moon On Saturday 20 21 22 23 24 25 26 New Moon 1% Visible On Saturday 27 28 29 30 31 Moon is at Apogee Snake River Skies is the Newsletter of the Magic Valley Astronomical Society and is published electronically once a month Snake River Skies is copyrighted, except where noted and credit is via permission of the respective author. Snake River Skies © 2014 by David Olsen for the Magic Valley Astronomical Society, All Rights Reserved. Images used in this newsletter, unless otherwise noted, are in the public domain and are courtesy of NASA, Wikimedia, or from MVAS File Photos. Planisphere Be Safe – Get Out There – Explore Your Universe! Solar System at a Glance Mercury is at its greatest heliocentric latitude south on July 6th. It reaches greatest western elongation on July 12th. On July 15th, Mercury passes three degrees south of the bright open cluster M35 in Gemini. The speediest planet is at the ascending node on July 25th. It reaches perihelion on the 29th. By month’s end, Mercury shrinks to an angular diameter of 5.3 arc seconds but increases in illumination from 11 to 92% and brightens from magnitude +2.5 to magnitude -1.4. Venus increases in illuminated extent from 85 to 92%, while its angular size decreases from 12.0 to 10.8 arc seconds. Its brightness drops slightly to magnitude -3.8, the dimmest the planet will be for 2014. Mercury and Venus are separated by less than seven degrees from July 12th to July 20th. An appulse takes place on July 16th, when Mercury lies just over six degrees to the east of Venus. Venus lies 1.5 degrees south of M35 on July 20th. Mars fades from magnitude 0.0 to +0.4 and shrinks to 7.9 arc seconds in apparent size, as it heads eastward through Virgo this month. It reaches eastern quadrature on July 19th. As a result, the planet displays a somewhat gibbous phase during July. Jupiter disappears into the glare of the Sun early this month. It reaches conjunction with the Sun on July 24th. Saturn rings span 40 arc seconds and are inclined by this year’s minimum angle of 21 degrees. The disk of the planet subtends 18 arc seconds at the equator. Saturn is stationary in right ascension on July 21st and afterwords resumes direct or eastward motion. Saturn’s odd satellite Iapetus lies to the west of the planet and shines at tenth magnitude early this month. Uranus can be found about two degrees south of the fourth-magnitude star Epsilon Piscium. The seventh planet is stationary on July 22nd. It then begins to retrograde, moving westward with respect to the fixed stars, a change in apparent motion that results from the faster-moving Earth overtaking Uranus. Pluto reaches opposition on July 4th. The dwarf planet lies within 30 arc minutes of the fifth-magnitude star 29 Sagittarii this month Asteroid Asteroids 1 Ceres (magnitude +8.4) and 4 Vesta (magnitude +7.1) are on a southeastward course through north-central Virgo this month. They are separated by only 19 arc minutes on the evening of July 1st. By July 4th, the gap between the two "minor planets" decreases to only ten arc minutes. Comets Comet C/2012 K1 (PanSTARRS) will be lost in evening twilight. The comet may reach seventh magnitude, as it heads southwestward through northwestern Leo in the vicinity of the fourth-magnitude star Mu Leonis and the third-magnitude star Epsilon Leonis. Meteors Moonlight will not interfere with the July 29th peak of this year’s Southern Delta Aquarid meteor shower. The other minor meteor showers with southern radiants occurring this month are the Alpha Capricornids, the Piscis Austrinids, and the Northern Delta Aquarids. Idaho Skies July 2014 / Vol. 8 No. 7 Idaho Skies is a column for beginning amateur astronomers and those interested in astronomy.