Image Credit: Jim Pollock

Transcription

1 Image Credit: Jim Pollock Longmont Astronomical Society Newsletter April 2017

2 Bio Dr. Hendrix has 20 years of experience in planetary science research. As a graduate student and post-doctoral research at LASP/Univ. Colorado, Hendrix gained valuable experience in UV spectroscopy and instrumentation and began a career of investigating solar system surfaces (largely airless bodies) in the UV. After LASP, she spent 12 years at JPL, progressing from a science planner on Cassini to Deputy Project Scientist, before moving to PSI in She is a coinvestigator on the Cassini UVIS instrument and a Participating Scientist on the LRO LAMP instrument. She has participated in numerous mission studies, including the Europa Orbiter of the Jupiter Joint Science Definition Team ( ) (serving as its Deputy Study Scientist) and the Jovian System Orbiter Science Definition Team (2007). She has led programs and published results in the JSDAP, PG&G, OPR, LASER and CDAP programs, among others. Besides research, she enjoys teaching and sharing her love of planetary science with students and the public. She lives in Boulder, CO. Location: The meeting will be at the IHOP Restaurant, 2040 Ken Pratt Boulevard, Longmont. Please join us for coffee, dinner, or just desert around 6 pm; the general meeting and presentation will begin at 7 pm Page 1 Copyright April, All rights reserved. Longmont Astronomical Society.

3 Upcoming Events April 3 rd 8:00 9:00 pm Lyons Elementary School, 4 th Grade Astronomy night LAS Meeting April 20 th 7:00 pm Cassini End of Mission by Dr. Amanda Hendrix. April Celestial Highlights Moon First quarter: Apr 3 rd 12:41 pm Full moon: Apr 10 th 12:09 am Third quarter: Apr 18 th 3:58 am New moon: Apr 26 th 6:17 am Mercury Mercury is difficult to see low in the western sky after sunset. It disappears into bright twilight around the 8 th. Venus Venus is visible low in the east morning sky in constellation Pisces. Early in the month it is magnitude -4.1 in brightness and quite large at 59 arc sec across. Early in the month is a great time to view it through a scope as it will appear as a very thin waning crescent. It decreases in size to 33 arc sec and increases in brightness to magnitude -4.5 by months end. Mars Mars is visible in the evening sky in constellation Aries. It moves into constellation Taurus on April 12 th. It decreases in brightness from +1.5 to +1.4 and its apparent size decreases from 4.2 to 3.9 arc sec this month. Jupiter Jupiter will be at opposition on April 7. It rises about sunset in constellation Virgo. It is magnitude -2.5 in brightness and its disk is 44 arc sec across this month. GRS mid transit times this month based on GRS longitude of 266 See Date Time Altitude Date Time Altitude Apr 1 1:58 am 45 Apr 16 3:28 am 30 Apr 2 9:49 pm 24 Apr 16 11:19pm 44 Apr 4 3:36 am 36 Apr 19 12:57pm 45 Apr 4 11:27pm 39 Apr 21 10:26pm 41 Apr 5 5:13 am 20 Apr 22 11:28pm 39 Apr 6 1:05 am 46 Apr 24 12:04 am 46 Apr 9 2:43 am 40 Apr 24 7:56 pm 22 Apr 10 10:34pm 35 Apr 26 1:42 am 39 Apr 11 4:21 am 25 Apr 26 9:34 pm 38 Apr 12 12:12 am 45 Apr 27 3:20 am 23 Apr 14 1:50 am 43 Apr 28 11:12pm 47 Apr 14 9:41 pm 31 May 1 12:50 am 42 Apr 16 3:28 am 30 May 1 8:41 pm 34 Copyright April, All rights reserved. Longmont Astronomical Society. Page 2

4 Saturn Saturn is visible low in southeastern morning sky in constellation Sagittarius. It is magnitude 0.4 in brightness and disk is 17 arc sec in apparent size. Uranus Uranus is not visible this month. Neptune Neptune is visible in the morning sky in constellation Aquarius. It is magnitude 8 and 2.2 arc sec across. Comets Comet C/2017 E4 (Lovejoy) was discovered in early March by Terry Lovejoy. It is expected to brighten to about magnitude 6.5 this month and so should be visible in binoculars. Look for it in the east-northeast around 5 am. It is currently magnitude 7.1 and predicted to brighten to 6.5 about mid-month. Coma is predicted to be 2.5 arc min across. Comet currently has a 1 long ion tail. Page 3 Copyright April, All rights reserved. Longmont Astronomical Society.

5 Comet 41P (Tuttle-Giacobini-Kresak) is now magnitude 6.5 and predicted to brighten to magnitude 5.5 this week when it gets within 0.1 AU distance from earth. Image credit: Paul Robinson Copyright April, All rights reserved. Longmont Astronomical Society. Page 4

6 Comet C/2015 ER61 (PANSTARRS) is now in the constellation Capricornus. It is magnitude 8.6 in brightness and the coma is 4.1 arc min in size. It is expected to brighten to magnitude 8.2 by the end of this month. Comet C/2015 V2 (Johnson) is slowly moving through constellation Hercules this month. It is now magnitude 9.2 and its coma is 3.1 arc min in size. It is expected to brighten to magnitude 8.1 with a 4.3 arc min coma by month end. Page 5 Copyright April, All rights reserved. Longmont Astronomical Society.

7 Overhead Sky at 9 pm April 15 Created with SkyTools3 Copyright April, All rights reserved. Longmont Astronomical Society. Page 6

8 The constellation Leo is now center stage after darkness begins. The bright stars in the backwards question mark of Leo s head and triangle shaped tail are easily recognized. Just below 3 rd magnitude star Chort are the Leo Trio M65, M66, and NGC 3628 captured by Jim Pollock and shown on this month s cover. Also within its boundaries are M95, M96, and M105. After adjusting brightness in the image above these galaxies maybe spotted. Image credit Vern Raben. Page 7 Copyright April, All rights reserved. Longmont Astronomical Society.

9 LAS Meeting Thursday, March 16, 2017 Vern opened the meeting and announced agenda for the evening. Club officers present were introduced: Vern Raben president, Gary Garzone vice president, Mike Fellows treasurer, Brian Kimball board member, Tally O Donnel board member and Chris Fauble board member. New members Joan Burkpile, Daryl Hedges, and Mike Wyn were present and welcomed to LAS. Also in attendence were Bob Spohn who was founder of LAS and 1st year member Bob Nobel. Presentation The Beevo Dome by Stephen Garretson. Stephen retired from being school princial after 20 years in that capapcity; prior to that he was counseler for youth agency and criminal justice system. It is called the Beevo Dome because his daughter called him Beevo when she was quite young and its been a family nickname for him ever since. Rationale for building the dome Stephen has always facisnated by astronomy and after he retired he wanted to learn more about it. As a professional educator he realized that an educator must first be good learner. He postulated that if he built a dome he would use the scope he had purchased. And if he used his scope he would learn more about astronomy. How did he think he had the skills to pull this off? He had built stuff around the house such as a bench, garden shed, fence gate, some canopies, ramp in back yard, kitchen cabiniets, and put in a sky light. Since these came out more or less great he felt had the necessary skills. Fortunately in the City of Louisville if you are building something less than 120 square feet and not over 18 feet high you don t need a building permit (most other cities have similar regulations). Construction Stephen likes to use off the shelf materials. He prefers to save money for scope and accessories not for fancy materials. Construction started with a 12 inch diameter pier for the telescope. He included 3 gang electical box and flex cables. The flex cables used to route electrical power and usb cables to the telescope. He bought a 3/8 inch aluminum plate for the scope base. Placing the 4 all thread bolts to connect ot the plate and getting it oriented northward while pouring the concrete was one of the hardest parts to do. Next he put in floor joists. For the walls he used cedar pickets and cut off the tops. He alternated old ones and newer ones for interesting pattern. Subfloor was built of 12' #2 pine from Home Depot. It needed many of coats of Copyright April, All rights reserved. Longmont Astronomical Society. Page 8

10 urethane but worked great. Corrugated, galvanized sheeting for roof. This was the building that the dome is going to sit on. He wanted the dome to be inexpensive, light, and fairly strong. Stephen had met Bucky Fuller about 20 years ago and so knew about geodesic domes. Drilling free hand into round tube is rediculous. To install it he started from bottom and work up to overlap seams. To attach the FRP triangular piece he used self drilling hex head with gusset on the outside and pop rivet with aluminum flashing on back on the inside of the triangle section. It is funky looking on inside but works great. The dome was painted sky blue to not be obnoxious to his neighbors. He bought a 8 dome track kit from local Exploradome dealer, Craig Betzini. The shutter rides on oversized door slides. He bought some linear actuators and plans on using rechargeable batteries to power them. He bought a kids play geodesic dome. To form a slot for the shutter he used conduit and squished ends. The gusset around the dome slot is galvanized is galvanized lawn edging -- stuff is amazingly strong and easy to work with. For the triangular sections for the dome he considered several materials. He did not want to use fiberglass as its toxic to work with and plywood is very heavy. He settled on FRP wall board. FRP wallbaord is a PVC material 4 x8 in size and incredibly strong and flexible. It can be sanded and painted easily. It is used in car washes and commercial kitchens. He would tape kraft paper over a section to form a pattern and then cut the FRP. The small warm room is heated by a 4x4x4 radiant heater. It is very comfortable with the door closed and is a great place to work. He was concerned about heat build up inside the dome so he put in some double screen on north side of the building (cool area). He added a solar powered fan. Dome doesn't get above 80-85F at 4 o'clock in summertime. Business Meeting Mike Fellows gave the finance report. Biggest expense last month was $ for club liability insurance. The total paid membership is now 68. We will pick up a few more during the year. Next big expense is Astonomical League dues. LAS Page 9 Copyright April, All rights reserved. Longmont Astronomical Society.

11 bought 500 eye shades for the eclipse. We'll figure out how to distribute later this summer. There is another going through central US on Aug 12, 2045 for those still around. August 21st solar eclipse by Vern Raben The last two total solar eclipse in the continental US was on March At that time Vern was in the army and based at Ft. Brag, NC. He got orders for Vietnam and returned to Colorado. The eclipse was the next day. Damn missed that one! Only needed to spend another couple days in Ft. Brag. The next total solar eclipse was Feb 26, Vern showed animation from NASA Goddard which shows path of the eclipse and the umbra shapes taking into account elevation differences on earth and the silouette of mountains on moon. He did get to see this one; remarkable that he could get there that time of year. After this August, the next one is on April 8, 2024 about 7 years ago. It goes though Texas, Missouri, and Ohio. Note that the shape of the umbra is not oval; occasionally flat on top and other sides. This effects the duration at a particular location. Copyright April, All rights reserved. Longmont Astronomical Society. Page 10

12 For us the eclipse will begin at 10:26:54 MDT (first contact). The diamond ring marks the beginning of totality (11:48:57 MDT). Lots of cheering happens! Totality ends at 11:51:27 MDT with another diamond ring. (More cheering!) The partial eclipse ends at 1:16:27 pm Page 11 If you have not signed up to view the eclipse Vern encourages you to do so. Just send him an and how many folks are in your party. Copyright April, All rights reserved. Longmont Astronomical Society.