The Newsletter of the Astronomical Society of Greenbelt
My medical issues have mostly been resolved. I was able to return to work on the day after New Year’s Day, although it hasn’t always been easy. I have found, temporarily, that I am more sensitive to cold than I was before, so it may be some time before I can come back out to Northway at night.
“Fireworks of Star Formation Light Up a Galaxy”-courtesy of Great Images In NASA
Elected officers for 2012-2013
martylou AT gmail.com
stvns.jacht AT yahoo.com
Cleton.Henry AT gmail.com
wb3enm AT amsat.org
Astronomical Events Around Greenbelt in Feb. 2013
Star party @ Northway Field @ 6:30
Owens Science Center: Public Planetarium show
Star party @ Northway Field @ 6:30
Sidewalk astronomy @ Roosevelt Center @ 7
General meeting @ the Owens @ 7:30
For other astronomical events in the DC area, see: Astronomy in DC
Star Party & Business Meeting Reports
Jan. 5: Star Party (redacted from Doug’s report): The [observatory] door was difficult to unlock. I took a battery that I had just charged and put it in the gang of 3. The one I replaced it with went on the lights, and it didn't work. Kevin and I spent some time trying to start the generator. We got it started once, but then killed it and it wouldn't start again. We also turned the dome with the slit motor plugged in, and the strain on the pulley stretched it.
The City has mowed right around the Observatory. It looks great. And the mulch pile is back to the side of our access road. If they would just replace the missing chain-holder and the chain, we would again have a secure facility.
[Also, Doug pointed out that the observatory needs some maintenance & repairs. While your editor can’t go out & help, due to doctor’s orders about how much he can carry, please consider helping Doug.]
Jan. 7: Officers’ meeting: Doug reported that the generator had been a problem, & Martha offered to bring hers. Also, Doug noted, the dome needs to be painted. Sue will send out membership dues notices with new calendars. Martha will contact the Night Sky Network with regards to outreach activities.
Jan. 19: Star Party (Doug’s report): It was pretty good. Kevin Balch brought his refractor. Martha came and left early. [S]he must've caught your shoulder pain. Skies were pristine although windy, and Jupiter showed all its' bands. The moon was half, and when I first saw it, there was an orange glow over the evenly spaced hills just north of Herschel. We had lots of appreciative visitors, including some very large folks who got up and down the ladder. At least one philosopher who had some interesting comments, and will be contacting us. I already got 1 email from the crowd. Cleton helped with crowd control. As always, I involved some of them in the closedown procedures, hoping to get them interested in helping. We closed about 9:30, and Kevin stayed on.
Jan. 31: (General meeting): Martha opened the meeting. We still need people who can come & speak at the feb & March meetings.
Our speaker was Dr. Keith Strong, a scientist at Goddard. His topic: What Has Happened to the Solar Cycle?
The Sun seen in in X-rays (showing the corona) is highly variable over the 11 year cycle, but the Sun mostly emits visible light, & it’s pretty constant there on a rough scale-there’s about 0.1% variation. Other stars, like Cepheids, are much more variable, as they expand & contract. The Sun’s variation is due to changes in its magnetic landscape.
Dr. Strong then briefly described the anatomy of the Sun, with the core-where fusion happens, the radiative zone, where γ rays bounce around off of the tightly packed atoms of that solar layer. The rays can take thousands or millions of years to get to the convective zone, which is not as dense as the layers below it, & its atoms rises to release heat at the surface (the photosphere), cool off, & sink back down again.
Shear between the radiative layer & the convective layer creates a current, which, of course,creates a magnetic field. There’s also a shear in latitude. These fields store up energy, which is released in creation of sunspots & prominences. Spots are dark because they inhibit convection, but they’re still 80% as bright as the sun! Do faculæ-the bright “anti-sunspots”-drive coronal loops or other way around?
The sunspot cycle isn’t perfect-amplitude changes, frequency changes. The Sun’s magnetic field flips on every 22 years, twice the length of the sunspot cycle, as trailing sunspots of each hemisphere, which have the opposite polarity of that magnetic pole, interact & cancel out the field generated by the poles. Other stars have similar periods.
Do polar fields drive cycle? Do sunspots moving from eq to poles drive cycle? Helioseismic examination of different flows-strange lumpy bumpy flows & cycles in the convective layer, which have only become visible to us since the Space Age, are introducing the possibility of new cycles. Unfortunately, in spite of these new discoveries, nothing explains Maunder min, & we are lousy at predicting solar cycles.
Right now, the Southern cycle of magnetic activity has slowed. What’s stopping the N/S interaction & the feeble activity on the photosphere?
Dr. Strong demonstrated resonant oscillation, & hypothesized that we could be be seeing one of many res.
oscillators in action, with the sunspot cycle just being the one that we know best.
An Invitation to the Theater
[From Anna Socrates], a board member of Alight Dance Theater: [...] I would like to invite the
members of the Astronomical Society of Greenbelt to Alight Dance Theater's Sneak Peek Season Preview at the Greenbelt Arts Center. One of the new works that will be shown is Alight's work-in-progress, "Stargazing," which is about the wonder in the night sky and in our own backyard. We would love to
have members of the Astronomical Society come and give us input and ideas as the piece is growing and evolving. There will also be an educational component to the work since Angella Foster is working with a NASA Goddard astronomer to develop a school educational program.
The details about the performances are below:
Friday, February 1 and Saturday, February 2, 8 p.m.
"Sneak Peek" Season Preview & Dance Party
Greenbelt Arts Center 123 Centerway Greenbelt, MD
Tickets are $14-$17 and include hors d'oeuvres by Jeremy Ehrenreich & a complimentary signature cocktail. Plus, you can bid on silent auction items, including the work of local artists, and try out your own moves at our post-show dance party with DJ. For tickets, visit www.greenbeltartscenter.org
Special Report from the NASA Inaugural Star Party
by Elizabeth Suckow
Star party went excellently. [NASA Deputy Associate Administrator for Public Outreach] Alan Ladwig's rough guess at attendance is 350-400 people, based on # of planetarium tickets sold and giveaway bags distributed. 17 local amateur astronomers participated, including myself. As far as I could tell, all the local astronomy clubs were represented (with the possible exception of the NCA). There were enough breaks in the crowd, though, that even the astronauts got some 'scope time, including one astronaut who met her family there and was able to be "Mom showing child the wonders of the sky" instead of "astronaut X of NASA" for a bit.
I had a chance to talk to a number of people, but all the locals were from northern VA. So, I wasn't able to drum up much interest for ASG. Did point several people in the direction of NOVAC, hopefully a few new amateurs had their fires kindled. One woman I talked to said her seven-year-old had just decided to become an astronomer when she grew up. I gave her a few suggestions for starting out, such as mounted binocs and the various star party opportunities, as well as a warning about department store 'scopes, so she doesn't wind up with a telescope gathering dust.
“N81 in the SMC”-courtesy of Great Images In NASA