May First Light Newsletter1 message

May, 2014 Issue 119

www.AlachuaAstronomyClub.org

Member astrophoto of the month

(Click to enlarge)

Occultation of Beta Cap (Oct 12, 2013)

Visitors to International Observe the Moon whostayed past 9:00 experienced a seldom seenevent by the public - the occultation of amoderately bright star (Beta Capricorni) by thelunar dark limb! Beta Cap is left center in theimage. Moments after the image was taken,Beta Cap slipped behind the moon's dark limb,

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which glows dimly.

http://www.astroadventures.net/cohen/pic_moon.html

The Hottest Planet in the SolarSystem

Space Place article by Dr. Ethan Siegel

When you think about the four rocky planets in our Solar System -Mercury, Venus, Earth and Mars - you probably think about them in thatexact order: sorted by their distance from the Sun. It wouldn't surpriseyou all that much to learn that the surface of Mercury reaches daytimetemperatures of up to 800 °F (430 °C), while the surface of Mars nevergets hotter than 70 °F (20 °C) during summer at the equator. On both ofthese worlds, however, temperatures plummet rapidly during the night;Mercury reaches lows of -280 °F (-173 °C) while Mars, despite having aday comparable to Earth's in length, will have a summer's night at theequator freeze to temperatures of -100 °F (-73 °C).

Those temperature extremes from day-to-night don't happen so severelyhere on Earth, thanks to our atmosphere that's some 140 times thickerthan that of Mars. Our average surface temperature is 57 °F (14 °C), andday-to-night temperature swings are only tens of degrees. But if ourworld were completely airless, like Mercury, we'd have day-to-nighttemperature swings that were hundreds of degrees. Additionally, ouraverage surface temperature would be significantly colder, at around 0 °F(-18 °C), as our atmosphere functions like a blanket: trapping a portion ofthe heat radiated by our planet and making the entire atmosphere moreuniform in temperature.

But it's the second planet from the Sun -- Venus -- that puts the rest ofthe rocky planets' atmospheres to shame. With an atmosphere 93 timesas thick as Earth's, made up almost entirely of carbon dioxide, Venus isthe ultimate planetary greenhouse, letting sunlight in but hanging ontothat heat with incredible effectiveness. Despite being nearly twice as faraway from the Sun as Mercury, and hence only receiving 29% thesunlight-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 circumnavigatethe 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 longin the pre-dawn skies, as it waxes towards its full phase, moving awayfrom the Earth and towards the opposite side of the Sun, which it willfinally slip behind in November. A little atmospheric greenhouse effectseems 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 placesin the Solar System at NASA’s Space Place: http://spaceplace.nasa.gov/planet-weather.

SchoolsMike Toomey

I

Outreach & Star PartiesIvo Rabell

Millhopper BranchLibrary - Fun Fridays

The Millhopper BranchLibrary will be conductingFun Fridays throughoutthe summer. On Friday,

June 13, the AAC will be providingsafe solar viewing or an indoorprogram if weather does not allowfor that activity. The program willrun from 2 to 3 p.m. If you wouldlike to participate with show-and-tellor provide solar viewing, pleaseregister online. If you do not have asafe solar telescope, you can borrowthe AAC's Coronado Personal SolarTelescope (PST). Please advise theschool or outreach coordinator ofyour interest in borrowing the PST.

Mike Toomey

A thank you card fromHidden Oak Elementary School:

"Amazing! The evening was a HUGE success- thanksto you!! We're so grateful for all the time, patience,equipment, and enthusiasm you shared with Hidden

Oaks families. If you're up to it, we'd love to puton this event in the future.

Blessing to you all!"

Thursday night's May8th WilliamsElementary schooloutreach was asuccess.

Chuck Broward, Howard Cohen,Lisa Eager, Pat McSween andmyself entertained around 35enthusiastic students, parentsand teachers.

The school changed Science Dayto another date and forgot tomention it. Instead of having over200 students, parents andteachers we ended up with theMagnet Academy for GiftedStudents. Kids and parents wereso enthusiastic that we ended upstaying until around 9:30 p.m.

It is always a pleasure when youmeet smart enthusiastic and wellbehaved 4th and 5th graders. Itwas a pleasure. With kids likethese, America still has a brightfuture in the sciences. I haveattached some pictures that I willpost on AAC's Facebook page.Chuck also took some pictureswhich are posted on AAC'swebpage and AAC's PhotoGallery.

A young star gazer looks through an AACmember's telescope at the WilliamsElementary School outreach.

Cheers,Ivo Rabell

Upcoming Events

Alachua Astronomy Club PublicMeetingTuesday, June 10, 2014 7-9 p.m.Florida Museum of NaturalHistory, University of Florida,Cultural Plaza3215 Hull RoadGainesville, FL 32611-2710

Star Party @ Newberry Star ParkSaturday, June 28, 20148:30 p.m.-11:55 p.m.24880 NW 16th AvenueNewberry, FL 32660

For full details of events, pleasevisit our website's eventscalendar.

Kanapaha Moonlight WalkTim Malles

New Member of the MonthLaura Wright-First Light Newsletter

Clouded out, but notdown and out, the AACshowed up to make thebest of it for our annualpublic outreach at theKanapaha Moonlight

Walk.

Thank you volunteers!

Chuck and Judy BrowardHoward and MarionCohenLisa EagarJoe and Gay Haldeman

The Alachua AstronomyClub would like to thankAlexandrea Matthews forthe excellent job editingthe First LightNewsletter. We wish her a

wonderful summer.

My name is Laura Wright, I live inThe Villages, Florida and work at theCollege of Central Florida in Ocala asCoordinator, Special Events for theVisual and Performing ArtsDepartment.

Tim and Joanne MallesAlexandrea MathewsClint and Paula McClainPat McSweenJames QuinlanIvo RabellFrances SeilerTerry Smiljanich

Around 500 visitors wanderedthrough our star party gardenduring the 4 hour event and weretreated to a display of themember's telescopes, apresentation by Howard Cohen,Ivo's meteorite and the McLain'sgreen laser bliss lights.

Thank you Howard, Marion, Ivo,Clint and Paula for providing theseexcellent presentations andentertainments for our guests andsaving the show again on a cloudynight.

The clouds prevented us fromshowing the real moon and stars,so we created our own! Visitorsenjoyed many beautiful images ofthe moon within Howard's bigscreen presentation and they coulddance with the stars within theMcLain's projection of a bigglobular star cluster.

Thank you greeters Frances,Alexandrea and Lisa for puttingsuch friendly and welcoming faceson our club and Ivo for helping to

Cat's Eye Nebula

Source: Hubblesite.org

I have been a member of the AAC forat least a year and have an interest,if not a technical knowledge, ofastronomy.

Horsehead NebulaSource: Hubblesite.org

The AAC First Light Newsletter isone of the first contacts ourmembers and many times the publichas with our group. For that reasonit is important to report past andpresent events and continue a lively,interesting discussion aboutastronomy in its articles and photos.

Cosmic Jet from a Black HoleSource: Hubblesite.org

stage everything. It turned out tobe a very relaxed, social andenjoyable evening for everyone.Cheers to all the optimisticmembers who showed up, set upequipment, braved the mosquitosand put smiling faces on ourguests.

Thank you and all the best!

Laura Wright

Hydra: Constellation 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, measuringover 1,300 square degrees and over 100 degrees in length. Hydra doesnot contain any bright stars. The brightest star is Alphard at visualmagnitude 1.99. It is a K-type giant (orange, 4,100K), so it has evolvedoff the main sequence (used up the hydrogen in its core) even though it isonly about 420 million years old. It has a mass about three times that ofthe Sun, but its diameter is about 50 times that of the Sun. The secondbrightest 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 millionyears 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 tothese stars are about 180 and 130 light-years, respectively. There are 16stars with a total of 20 known exoplanets in Hydra.

The image below, produced using Sky Safari Pro for the Macintosh, showsthe sky looking South at 10:00 Daylight Saving Time on June 1. Click onthe 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: FirstLight@alachuaastronomyclub.org

Alachua Astronomy Club, Inc.P.O. Box 141591Gainesville, FL 32614-1591

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