StarWatch: Moravian College Astronomy

StarWatch for the greater Lehigh Valley

APRIL 2015

APRIL STAR MAP | MOON PHASE CALENDAR | STARWATCH INDEX | NIGHT SKY NOTEBOOK

Print Large Sky Charts For 10 p.m. EDT: NORTH | EAST | SOUTH | WEST | ZENITH

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972 APRIL 5, 2015: First Light for Kono: One of the big misconceptions in astronomy involves the individual who invented the telescope. It wasn’t Galileo, but most likely a Dutch-German optician by the name of Hans Lippershey (1570-1619). The year was 1608. As a master lens grinder, making glasses, the pun goes that Lippershey really made a spectacle of himself. Galileo was not even first to point a telescope towards the heavens, but he was the first to publish his findings in a book called Sidereus Nuncius (Starry Messenger) in 1610. The type of telescopes Lippershey and Galileo built were refractors, and optically they were horrible for many reasons, but primarily because their lenses acted like prisms, bending but also dispersing the light passing through them, causing objects to be saturated in false colors. The refractor has undergone a revolution in the past 400 years, with modern computers designing optical systems utilizing exotic types of glass that eliminate the problem of color (chromatic aberration), and virtually all other types of optical defects. Because there are no obstructions in the light path, like in a reflecting telescope which uses mirrors instead of lenses to gather light, the physics of image formation is optimized, allowing refractors to produce jaw-dropping starscapes. In lens diameters between two and eight inches, an apochromatic (color free) refractor reigns supreme. I bought a newly designed apochromat this past December, picked it up in early February, and then it got cold, snowed, got even colder, snowed some more, got unbelievably frigid, and snowed heaps. The telescope was set up in my study for nearly two months, but it finally got its first workout last week when the weather cooperated for just a few hours. In astronomy, looking through a telescope for the initial time is called “first light.” I’m naming my scope Kono, after Grace Park who plays Officer Kono Kalakua in TV’s Hawaii Five-0. You might imagine that first light was spectacularly sweet.

973 APRIL 12, 2015: Lyrids: Start of the Meteor Season: Mid-April marks the beginning of the meteor season with the Lyrid shower providing the first major activity in nearly 3-1/2 months of meteor idleness. During the winter months and early spring, the Earth simply does not intersect with any large amounts of organized cometary debris. Comet Thatcher, an interloper that requires 415 years to travel around the sun, is responsible for the Lyrid display which can be dated back to about 600 BCE. It is the dust from a comet’s tail coming close to our planet which triggers an increase in the rate of shooting star activity, as well as the radiant, the undisputed indicator that these meteor events are related to each other. The larger silicate particles released by the nucleus in the comet’s outgassing processes generally follow the comet’s orbit. These particles are moving parallel to each other. When they enter the Earth’s atmosphere, they appear to diverge, similarly to a long stretch of roadway which appears to diverge from a vanishing point far off into the distance. In astronomy this is called the radiant. Lyrids emerge from a location that can be traced back to a part of the summer sky in the constellation of the Lyra the Harp, just to the right (south) of the brilliant, blue-white star Vega. Vega is almost mid-sky in the ENE by 1 a.m. on the morning of the 22nd when the Lyrid meteors are predicted to be most active. Do not expect the sky to be ablaze with shooting stars, although outbursts sometimes occur. Rates are normally about 10 events per hour from a rural locale. The optimal time for viewing Lyrid activity should be after midnight. Vega will be that really bright star in the east. Face eastward inside the cozy comfort of a sleeping bag with a soft pillow under your head and gaze straight up. Lyrids will seem to trace back to Vega. Just don’t let the stillness and serenity of the morning sky and the fragrance of the pungent spring air put you to sleep. Good observing!

974 APRIL 19, 2015: Five Planets and a Moon: The week of April 19 presents an ideal opportunity to view all five “naked eye” planets and the moon, if you are willing to find yourself a good western horizon and are able to stay up until midnight. The week commences on April 19 with a razor thin crescent moon to the left of the planet Mars, 30 minutes after sundown and very low in the west. Binoculars will be needed to spot the moon initially, and an unobscured western horizon is a must. The moon will be only three degrees to the left of Mars and six degrees from Mercury (right and below). By Tuesday, April 21, the 14 percent lit moon stands seven degrees to the left of Venus, making for an impressive twilight view and high enough in the west so that buildings and trees should not pose a problem. Mercury continues to climb rapidly into the western sky so that by Tuesday and Wednesday, April 21-22 the Messenger God is only about one degree distant from Mars. This is also not an easy observation. Again, a very good western horizon will be needed, as well as binoculars to spot Mercury, 30 minutes after sundown. As it gets darker, Mars should appear to Mercury’s right if your local horizon is low enough. Mercury continues to gain altitude though the first week in May and is visible for several more weeks, but it also becomes significantly fainter, while Mars is lost in the twilight glare of the encroaching sun. Saturday and Sunday, April 25 and 26, a fat waxing crescent, then first quarter moon stands nine and seven degrees respectively from Jupiter, high in the south after sundown. You can easily catch the pair prior to midnight before trees and buildings begin to interfere. By midnight anytime during the week, the ringed world of Saturn is gaining altitude in the southeastern part of the sky. This is not a very star friendly region of the heavens, so if what you are observing is bright and in the SE, it will be Saturn. The luminous moon rendezvous with Saturn by May 5.

975 APRIL 26, 2015: Boots on Mars: Boots on the moon occurred with Neil Armstrong’s first historic steps onto its surface on July 20, 1969, but since those glory days of the late 60’s and early 70’s, little has been done by NASA to encourage further human exploration of the solar system. Three wars at a trillion dollars plus hasn’t helped US efforts to afford such “extravagance.” The Chinese will probably put boots on the moon next, but now some private foundations are seriously competing to go to Mars well ahead of NASA’s planned first human flyby of the Red Planet in 2033 and its first landing in 2039. Mars Inspiration, the brainchild of Dennis Tito, an investment banker with solid scientific credentials, is currently funding and formulating plans to send a male and a female astronaut on a 589-day Martian flyby mission which would first use a gravity assist from Venus to slingshot the spacecraft towards Mars and bring it to within 60 miles of its surface before returning home. Launch is scheduled for 2021. A reentry vehicle, along with a tubular-shaped pod, would serve as the astronauts’ personal and storage areas during the mission. The crew would have about 600 cubic feet of living space, with no spacesuits and no airlock to exit the craft. Perhaps even wilder is a Dutch initiative named Mars One which plans to send a crew of four astronauts to the Red Planet about once every two years to establish a permanent Martian base. The Living Unit is envisioned to be a lander that would utilize an inflatable section for the habitat and an airlock to access the surface. It would be fully functional by arrival time. Mars One is to be paid for by selling subscriptions to view the crews while on the planet. Boots on Mars for them is 2028, pushed back from 2023 because of funding issues. Oh, I failed to mention one critical fact about Mars One. The astronauts would become the first true residents of another world because there are no return provisions. “Wanna go for a ride?”