Newsletter of the Desert Foothills Astronomy Club
Issue #49: October 18th, 2010

About Quid Novi

Past Issues

DFAC Events

Next Meeting

Last Meeting

State of DFAC

Quote of the Month

Space Debris

Contact the Editor: Dan Heim, phone: 623.465.7307 or email:

DFAC Events for 2010:
Date   Time   Event   Location
Jan 14   6-8 pm   Astronomy Night   YMCA at 34250 N. 60th Street (just south of the Carefree HWY)
6-8 pm (setup 5:30-6:00 pm)
Jan 20   6:30-8:30 pm   DFAC Lecture Meeting #4
Speaker: Dan Heim
Topic: The Physics of Weightlessness
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
Feb 17   6:30-8:30 pm   DFAC Lecture Meeting #5
Members' Night
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
Mar 17   6:30-8:30 pm   DFAC Lecture Meeting #6
Speaker: Scott Schoneman
Topic: New Launch Systems at Orbital Sciences Corporation
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
Mar 20   6:00 pm-???   Members-only Astronomy Night   Heimhenge in New River
Apr 21   6:30-8:30 pm   DFAC Lecture Meeting #7
Speaker: Rick Tejera
Topic: How to Use a Star Atlas - Finding Your Way Around the Night Sky
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
May 25   6:30-8:30 pm   Annual Business Meeting   North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
Jun 19   5:00-9:00 pm   June Summer Social at Heimhenge, featuring Asteroids Snooker, snacks and drinks provided by your hosts Dan & Sandi.   THIS EVENT HAS BEEN CANCELLED.
Jul 17   Noon-?   July Summer Social at the Walker Ranch, with a double-feature (The Thing, original and remake) on his BIG screen home theater, food and drinks provided by your hosts Ron and Julie. Please RSVP by July 5th.   Walker Ranch in Cave Creek
Aug 21   5:00-9:00 pm   August Summer Social at the Renn Estate, with a patio BBQ, food and drinks provided by your hosts Jim and Jean. Please RSVP by Sunday, August 15th.   Renn Estate in Anthem
Sep 15   6:30-8:30 pm   DFAC Lecture Meeting #1
Speaker: Dan Heim
Topic: Light Pollution Update
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
Oct 13   6:30-8:30 pm   DFAC Lecture Meeting #2
Speaker: Br. Guy Consolmagno, S.J.
Topic: Are Asteroids Fluffy?
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086
NOTE: This meeting is the 2nd Wednesday of the month to accommodate our speaker.
Nov 17   6:30-8:30 pm   DFAC Lecture Meeting #3
Speaker: Roger Serrato
Topic: Astronomy 101 (+ How to Buy Your 1st Telescope)
  North Valley Regional Library, 40410 North Gavilan Peak Parkway, Anthem, AZ 85086

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Next Meeting: Wednesday, November 17th, 2010
DFAC Treasurer Roger Serrato will present his annual "Astronomy 101" lecture, covering the basics of stargazing, as well as scope, eyepiece, and filter selection. This is a popular meeting each November, and specifically scheduled to be of use to people who are thinking about getting that special someone (including themselves) a scope as a holiday gift. We always publicize this meeting heavily, and in the past have drawn many curious astronomy wannabees, a few of whom have since become DFAC members.

Doors will open at 6 pm. Hope to see you all there!

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Last Meeting: Wednesday, October 13th, 2010
Br. Guy Consolmagno S.J. of the Vatican Observatory presented "Are Asteroids Fluffy?" He believes there a strong evidence that many asteroids are not the stereotypical solid blocks of iron-nickel or rock as often pictured (as well as imaged). Rather, they could be loose agglomerations of boulders and gravel, held together by mutual gravitational attraction. Depending on total mass and rotation speed, such structures would indeed be stable. With too rapid rotation, centrifugal force would rip them apart.

We opened the doors a little earlier in expectation of a larger-than-average audience. When the first club members arrived, the good Brother was already there, having enjoyed smooth traffic on his drive up from Tucson. He's either checking his notes or his email here, as he waits patiently for the meeting to begin.

Members arrived early, as advised, to claim good seats. There was plenty of time for discussion before the meeting.

We had several special guests, two from TAAA down in Tucson (left) and two from PAS (right), the club Dan Heim was a member of before starting DFAC. Dan is, in fact, working with Terri Finch to arrange a joint observing session at Heimhenge. More on that later.

By the time Dan convened the meeting (a little past 6:30 pm), we had 26 people in the room. It was a good turnout. We had enough chairs for 40, but that would have felt crowded. We did learn that the Fire Marshall had specified a "maximum occupancy" limit of 52 for the Library classrooms. That's a good thing to know.

VP Jim Renn, who arranged and scheduled Br. Guy, did the honor of introducing him. His list of honors, affiliations, and publications was impressive. In fact, he was President of the IAU during the Pluto controversy and reclassification.

Br. Guy's presentation had the intriguing title "Are Asteroids Fluffy?" Jim turned the lectern over to Br. Guy at around 7 pm.

Br. Guy began his presentation with a brief history of the Vatican Observatory, explaining the cooperation between "religion" and "science" that has been part of the Church's legacy. From there, he recounted how his earlier work led him to "fluffy asteroids." Some of the first research he did involved measuring the density and porosity of a wide variety of meteor types. This required development of a novel method for measuring their volume, since the traditional "water displacement" method would contaminate the samples. Two solutions emerged, one of which involved using pressure differences in a pair of interconnected chambers filled with inert helium, and the other using displacement of tiny polystyrene spheres instead of water. The former method provides information about the porosity of the sample, since the helium gets into microscopic cracks and pores. Surprisingly, in what looks and feels like solid rock, you find an amazing amount of "empty space." Actual samples ranged from 10% to 50%, and Br. Guy believes some asteroids might run as high as 70-80%. And these are the "fluffy" asteroids in his theory, consisting more of empty space than anything.

The meeting ended early enough for some Q&A, and Br. Guy fielded about a dozen questions before we called it a night. He did have a long drive back to Tucson, so we adjourned the meeting just past 8 pm. We thank the good Brother for an excellent presentation, and wish him well with his ongoing research. And thanks also to VP Jim Renn for handling all the details.

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State of DFAC: By Dan Heim, President
Item 1. After consultation with our Treasurer, Roger Serrato, we've decided we need to set a more firm deadline for renewal. Henceforth it will be May 31st, as our League dues come due in June. We'll still welcome you with open arms if you renew late, but you might miss an issue or two of The Reflector. We have also simplified our record keeping by changing our membership application to specify full dues by May 31st (doing away with the pro-rated system). Since people are welcome to attend even as non-members, it really makes no difference to our treasury. However, when May 31 rolls around, dues are due, and all regular participants will be encouraged to remit. You'll see these changes reflected on our Join DFAC page.

I have to report that we got "burned" this season, assuming members would renew, paying their Astronomical League dues (so they will continue getting The Reflector), and only finding out too late that they are apparently "lost in space," to employ an apt metaphor. We're almost halfway through this season, so at this point all we can do is bite the bullet and move on. We've got a couple new potential members in the wings, and we are nurturing their interest in DFAC. Hopefully we can make something up here.

Item 2. DFAC member Ron Walker wants to start a new regular ("about once a month" in his words) club activity involving a "double feature" in his massive home theater. This last Saturday about 6 of us were there to see the BluRay versions of "Avatar" and "Journey to the Edge of the Universe" (by National Geographic). If you haven't yet experienced Ron's home theater, you really should check this out. Next month's will feature Stanley Kubrick's classic 2001: A Space Odyssey and the sequel by Peter Hyams 2010: The Year We Make Contact. Both movies are based on books by Arthur C. Clarke.

Here's how it works ... Ron & Julie choose the date (usually 1 pm on a Saturday) that works best for them. After all, it's their food & drink, their electricity (What is the total wattage of that home theater Ron?), and most of all their gracious hospitality. Ron emails me the date and time, and I send it out to all DFAC members for response. If you can make it, cool. RSVP to Ron (his email link will be included) and we'll see you there. Their popcorn is at least as good as AMC.

Item 3. We have an opportunity to do a "field trip" in southeastern Utah with Wild River Expeditions. If you were at the September meeting, you heard the sales pitch I presented. If you missed it, and might be interested, you can download the file WRE.pps on our Downloads page. It's a self-playing PowerPoint slide show, so you don't need to have PowerPoint to view it. It's fairly self-explanatory, even without my narration. Bottom line is we'll have a professional archeologist and geologist onboard to educate us on those topics, and I will fill the roll of astronomer for education at night. I'm hoping by then to have replaced my trusty 10x80 binocs with a pair of these babies: Carpooling for the 7-hour drive to Bluff, Utah would be required. Dates are yet to be determined, but would be one of those listed in the slide show. I'll be pitching this to the other astronomy clubs as well. If you are interested, let me know and I'll add you to my list. If we can round up the requisite 10-20 people we'll have all systems go. You know how to reach me. It might be possible to jump in late, but the sooner you let me know, the more likely this will happen. I already have 2 interested just from DFAC.

Item 4. Time for another "members only" observing session here at Heimhenge. I propose Saturday, November 13. There will be a 1st Quarter Moon, plus many other good targets. Sunset @ 5:15 pm, so arrival and setup starts at 5 pm. I will also be inviting PAS to join us, so there will likely be many scopes deployed. Plenty of parking and restrooms, but nothing else provided except clear skies. I still get SQM readings over 20 here at Heimhenge, and can clearly see the Milky Way. Not a bad place for observing. Please RSVP to me at:

Item 5. Bad news ... due to increased responsibilities at work, VP Jim Renn will not be continuing at that position next year. He'll still be a member, but time constraints dictate his decision. So we'll be looking for some member to step up and run for this VP position, to be voted on at our May Business Meeting. Here's the job description from our Constitution:

ARTICLE 2: Officers and Duties

b. Vice President: The Vice President shall assist the President in the performance of all duties, and assume responsibility for those duties should the President be unable to do so. The Vice President will maintain and a list of potential speakers for our Lecture Series, contact and schedule those speakers, and coordinate stipends as needed with the Treasurer.

If you think you can fill this position, please let me know. A few things to be aware of ... first, we maintain a "speaker contact list" with both phone numbers and emails for some 24 potential speakers to make the job of scheduling easier (not that you can't add to the list, which grows yearly). Second, as #1 for the President, your attendance at meetings is crucial. Should the President, for whatever reason, be unable to preside, you will need to be there. And third, should you become our new VP, you'll get an unlimited supply of these cool DFAC business cards:

I count on our membership to help make DFAC work. I appreciate the support of those who do, and encourage those who haven't to consider it. Bottom line is, none of the Officer positions really dominate your schedule, and you have considerable flexibility in choosing how to make it work. So please consider it, and I appreciate your thinking about it.

Thanks for reading Quid Novi. If you have feedback, you know where to reach me. Until next we meet, clear skies!

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Quote of the Month:
[Ed: This quote seemed especially appropriate after Br. Guy's presentation. At the start of his talk, he quoted from the evocative Psalm 19 "The heavens declare the glory of God."]

“The world is my country, and science is my religion.”

Christiaan Huygens, 17th century Dutch astronomer

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Space Debris: A very nicely done moonrise video
Many of you know how digital still images can be "stitched" into an animation using image processing software. In fact, there are several such videos in the Astrophotos gallery on our website. One of the nice things about participating in the AZ-Observing forum is that amateur astronomers from all over the state often contribute their photo/video work. The video linked below was done by Jon Christensen using his DSLR with a 300 mm lens and doubler. Looks like about one frame/second. Because his tripod was shaking every time he pushed the shutter button, the Moon image jumped around from frame to frame, and so each frame had to be manually re-centered to restore smooth motion. Jon says next time he'll use his computer to trigger the camera, which is easily done with modern DSLRs. See his video on YouTube at:

To join the AZ-Observing forum, simply go to and sign up. It's easy and free.

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