May First Light Newsletter 1 message

May, 2014 Issue 119

www.AlachuaAstronomyClub.org North Central Florida's Amateur Astronomy Club

Member astrophoto of the month Serving Alachua County since 1987

Member Member Astronomical League NASA Night Sky Network

(Click to enlarge)

Occultation of Beta Cap (Oct 12, 2013)

Visitors to International Observe the who Find us on Facebook! stayed past 9:00 experienced a seldom seen event by the public - the of a moderately bright (Beta Capricorni) by the lunar dark limb! Beta Cap is left center in the image. Moments after the image was taken, Beta Cap slipped behind the moon's dark limb, which glows dimly. http://www.astroadventures. net/cohen/pic_moon.html

The Hottest in the Solar System

Space Place article by Dr. Ethan Siegel

When you think about the four rocky in our Solar System - Mercury, Venus, Earth and Mars - you probably think about them in that exact order: sorted by their distance from the . It wouldn't surprise you all that much to learn that the surface of Mercury reaches daytime temperatures of up to 800 °F (430 °C), while the surface of Mars never gets hotter than 70 °F (20 °C) during summer at the equator. On both of these worlds, however, temperatures plummet rapidly during the night; Mercury reaches lows of -280 °F (-173 °C) while Mars, despite having a day comparable to Earth's in length, will have a summer's night at the equator freeze to temperatures of -100 °F (-73 °C). Those temperature extremes from day-to-night don't happen so severely here on Earth, thanks to our atmosphere that's some 140 times thicker than that of Mars. Our average surface temperature is 57 °F (14 °C), and day-to-night temperature swings are only tens of degrees. But if our world were completely airless, like Mercury, we'd have day-to-night temperature swings that were hundreds of degrees. Additionally, our average surface temperature would be significantly colder, at around 0 °F (-18 °C), as our atmosphere functions like a blanket: trapping a portion of the heat radiated by our planet and making the entire atmosphere more uniform in temperature. But it's the second planet from the Sun -- Venus -- that puts the rest of the rocky planets' atmospheres to shame. With an atmosphere 93 times as thick as Earth's, made up almost entirely of carbon dioxide, Venus is the ultimate planetary greenhouse, letting sunlight in but hanging onto that heat with incredible effectiveness. Despite being nearly twice as far away from the Sun as Mercury, and hence only receiving 29% the sunlight-per-unit-area, the surface of Venus is a toasty 864 °F (462 °C), with no difference between day-and-night temperatures! Even though Venus takes hundreds of Earth days to rotate, its winds circumnavigate the entire planet every four days (with speeds of 220 mph / 360 kph), making day-and-night temperature differences irrelevant. Catch the hottest planet in our Solar System all spring-and-summer long in the pre-dawn skies, as it waxes towards its full phase, moving away from the Earth and towards the opposite side of the Sun, which it will finally slip behind in November. A little atmospheric greenhouse effect seems to be exactly what we need here on Earth, but as much as Venus? No thanks!

Image credit: NASA's Pioneer Venus Orbiter image of Venus's upper- atmosphere clouds as seen in the ultraviolet, 1979.

Check out these “10 Need-to-Know Things About Venus”: http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus.

Kids can learn more about the crazy weather on Venus and other places in the Solar System at NASA’s Space Place: http://spaceplace.nasa.gov/ planet-weather.

Schools Outreach & Star Parties Mike Toomey Ivo Rabell

Millhopper Branch Thursday night's May Library - Fun Fridays 8th Williams Elementary school The Millhopper Branch outreach was a Library will be conducting success. Fun Fridays throughout the summer. On Friday, Chuck Broward, Howard Cohen, June 13, the AAC will be providing Lisa Eager, Pat McSween and safe solar viewing or an indoor myself entertained around 35 program if weather does not allow enthusiastic students, parents for that activity. The program will and teachers. run from 2 to 3 p.m. If you would like to participate with show-and-tell The school changed Science Day or provide solar viewing, please to another date and forgot to register online. If you do not have a mention it. Instead of having over safe solar telescope, you can borrow 200 students, parents and the AAC's Coronado Personal Solar teachers we ended up with the Telescope (PST). Please advise the Magnet Academy for Gifted school or outreach coordinator of Students. Kids and parents were your interest in borrowing the PST. so enthusiastic that we ended up staying until around 9:30 p.m. Mike Toomey It is always a pleasure when you A thank you card from meet smart enthusiastic and well Hidden Oak Elementary School: behaved 4th and 5th graders. It

"Amazing! The evening was a HUGE success- thanks was a pleasure. With kids like to you!! We're so grateful for all the time, patience, these, America still has a bright equipment, and enthusiasm you shared with Hidden future in the sciences. I have Oaks families. If you're up to it, we'd love to put I attached some pictures that I will on this event in the future. Blessing to you all!" post on AAC's Facebook page. Chuck also took some pictures which are posted on AAC's webpage and AAC's Photo Gallery. Cheers, Ivo Rabell

Upcoming Events

Alachua Astronomy Club Public Meeting Tuesday, June 10, 2014 7-9 p.m. Florida Museum of Natural History, University of Florida, Cultural Plaza 3215 Hull Road Gainesville, FL 32611-2710

Star Party @ Newberry Star Park Saturday, June 28, 2014 8:30 p.m.-11:55 p.m. 24880 NW 16th Avenue A young star gazer looks through an AAC Newberry, FL 32660 member's telescope at the Williams Elementary School outreach. For full details of events, please visit our website's events calendar.

Kanapaha Moonlight Walk New Member of the Month Tim Malles Laura Wright-First Light Newsletter

Clouded out, but not The Alachua Astronomy down and out, the AAC Club would like to thank showed up to make the Alexandrea Matthews for best of it for our annual the excellent job editing public outreach at the the First Light Kanapaha Moonlight Newsletter. We wish her a Walk. wonderful summer.

Thank you volunteers! My name is Laura Wright, I live in The Villages, Florida and work at the Chuck and Judy Broward College of Central Florida in Ocala as Howard and Marion Coordinator, Special Events for the Cohen Visual and Performing Arts Lisa Eagar Department. Joe and Gay Haldeman Tim and Joanne Malles Alexandrea Mathews Clint and Paula McClain Pat McSween James Quinlan Ivo Rabell Frances Seiler Terry Smiljanich Cat's Eye Nebula Around 500 visitors wandered through our star party garden Source: Hubblesite.org during the 4 hour event and were treated to a display of the I have been a member of the AAC for member's telescopes, a at least a and have an interest, presentation by Howard Cohen, if not a technical knowledge, of Ivo's meteorite and the McLain's astronomy. green laser bliss lights.

Horsehead Nebula Thank you Howard, Marion, Ivo, Source: Hubblesite.org Clint and Paula for providing these excellent presentations and The AAC First Light Newsletter is entertainments for our guests and one of the first contacts our saving the show again on a cloudy members and many times the public night. has with our group. For that reason it is important to report past and present events and continue a lively, The clouds prevented us from interesting discussion about showing the real moon and , astronomy in its articles and photos. so we created our own! Visitors enjoyed many beautiful images of the moon within Howard's big screen presentation and they could dance with the stars within the McLain's projection of a big globular .

Thank you greeters Frances, Alexandrea and Lisa for putting Cosmic Jet from a Black Hole such friendly and welcoming faces Source: Hubblesite.org on our club and Ivo for helping to stage everything. It turned out to be a very relaxed, social and Thank you and all the best! enjoyable evening for everyone. Cheers to all the optimistic Laura Wright members who showed up, set up equipment, braved the mosquitos and put smiling faces on our guests.

Hydra: for May

by Larry Lebofsky and Don McCarthy (University of Arizona)

From the NIRCam Education & Outreach Newsletter May/June, 2014. Used with permission.

Hydra (The Serpent) is the largest constellation in the sky, measuring over 1,300 square degrees and over 100 degrees in length. Hydra does not contain any bright stars. The brightest star is Alphard at visual magnitude 1.99. It is a K-type giant (orange, 4,100K), so it has evolved off the (used up the hydrogen in its core) even though it is only about 420 million old. It has a mass about three times that of the Sun, but its diameter is about 50 times that of the Sun. The second brightest star in Hydra is Gamma Hydrae. It is a G-type giant (yellow, 5,100K), so has evolved off the main sequence and is about 370 million years old. It has also has a mass of about 3 times that of the Sun but is “only” 13 times the diameter of the Sun. The distances from Earth to these stars are about 180 and 130 light-years, respectively. There are 16 stars with a total of 20 known in Hydra.

The image below, produced using Sky Safari Pro for the Macintosh, shows the sky looking South at 10:00 Daylight Saving Time on June 1. Click on the image to enlarge and print it.

Hydra is highlighted in dark gray (looking Southwest, June 1 at 10pm EDT) (click image to enlarge)

Copyright © 2014 Alachua Astronomy Club, Inc. All rights reserved.

Contact email: [email protected] Alachua Astronomy Club, Inc. P.O. Box 141591 Gainesville, FL 32614-1591

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