2012 October

AEA Astronomy Club Newsletter                      October  2012

Contents
AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 5
Astronomy News p. 8
General Calendar p. 10
    Colloquia, lectures, mtgs. p. 10
    Observing p. 11
Useful Links p. 12
About the Club p. 12

Club News & Calendar.

Calendar

Club Meeting Schedule:

18-Oct-12	High/Wide Dynamic Range CMOS Imagers	Blake Jacquot (and Hung Ngo)	Aerospace	A1/1029A/B
15-Nov-12	Upper Atmospheric Disturbances Using RAIDS and Ground-Based Measurements	Rebecca Bishop & Andrew Christensen	Aerospace	A1/1029A/B
19-Dec-12	Beyond Next Generation Access To Space	Scott Martinelli and Jay Penn	Aerospace	A1/1029A/B

AEA Astronomy Club meetings are on 3^rd Thursdays at 11:45am.  For 2012, April-May we meet in A1/1026; June-July & Oct.-Dec. in A1/1029A/B; Aug. in A1/2143 and Sept. in A3/1607A/B.

News:  

16-Inch Truss Dobs Assembly & First Light

Wed. Sept. 12 Jason Fields, a friend & I met in D8 to assemble the new 16-inch Truss Dobsonian (see photos).  After about an hour and a half, without much trouble, we had it assembled and collimated w. the eyepiece laser collimator.  First light came 2 nights later in the parking lot of D8 (photo). 

Here is my [Jason Fields’] report from Saturday night [Sept. 15, 2012]. Feel free to abridge for the newsletter. [I chose not to, to show what a REAL observing report can look like]

9/15/12 Mt Pinos	end of astronomical twilight	midnight
temp [deg F]	59	47
RH [%]	36	27
seeing diam [arcsec]	1.1	0.8
seeing (1-10)	5	4
transparency (1-10)	7	5
zenith limiting [mag]	6.2	5.9
zenith sky bg [mag/arcsec**2]	19.9	19.4

As you can see in the table, it was a rather subpar night. In my experience a dark mountaintop site should expect a sky brightness below 21 mag/arcsec**2 and a zenith limiting mag of 7 or fainter. For reference, the sky brightness with a full moon is close to 18 mag/arcsec**2. Even though the Orion Nebula would be up within an hour, due to clearly deteriorating sky conditions I packed up around 1 am. Neither the zodiacal glow nor Gegenschein were ever apparent and even the Milky Way was difficult to see much north of Cepheus. Throughout the night the seeing was poor but highly confined: small blur circles with rapid variation in starlight intensity and color.  The transparency was also quite low and worsened as the night progressed. It was obvious at sunset that there was a lot of dust and smoke in the air from various fires and the Santa Ana winds; by midnight, the sky transparency noticeably decreased after sunset: by midnight there was clearly an additional magnitude loss on both Polaris and Vega (both at a zenith angle of about 60 by then). On a good night, a high-altitude site would have an extinction coefficient of say 0.17 - 0.20 and it was more like 0.70 - 0.80.

All this to say that testing the telescope was challenging.

Collimation was challenging, in great part due to the poor seeing, evidenced quite clearly in both in-focus, slightly out-of-focus, and grossly out-of-focus star testing, each focus position telling me something about the collimation of the telescope, the stability of the atmosphere, thermal currents within the telescope (an impressive sight if you've never looked for it), etc.

There is some flex in the spider vanes and in the secondary mirror holder which makes precise collimation of the secondary more time-consuming than I expected. Getting used to the primary mirror cell collimation screws (white thumbscrews) and collimation lock screws (black thumbscrews) took a bit of time as well. It is not difficult to find oneself putting strain on the back of the primary mirror if one is not careful. Based on star testing, there is some evident primary mirror sag and as well as some flex in the truss supports (the secondary cage droops) when looking at low elevation angles.

Meade 16" f/4.5 1829 mm fl	magnification	actual FOV (calculated)	apparent FOV
26 mm Meade QX	70	1.00	70
16 mm TeleVue Nagler	114	0.72	83
7 mm TeleVue Nagler	261	0.31	83

There is some coma when looking near the edge of field with the supplied 26-mm eyepiece. It is not yet clear to me if this is due to the primary mirror or the eyepiece as I did not use the drift method to measure the actual FOVs -- it was my sense that the FOV with the 26 mm was more like 1.1 or 1.2 degrees as, for instance, the double cluster easily fits in the FOV. The focus appeared very flat across the entire FOV through my 16 mm Nagler. Due to the poor seeing, the view through the 7 mm was troubled by star twinkling. Focus remained soft throughout the night due to both atmospheric seeing and lack of precise collimation.

Stray light: even at a dark site, the background sky brightness from most of the overhead sky is contributing to the background observed in the eyepiece. I experimented a little bit with a large black cloth but results were inconclusive other than a slightly darker background in the eyepiece. I think the easiest baffle would either be a mask at the top of the rocker box and/or a shroud for the open truss.

On to the fun stuff: here is a partial list of objects observed.

object	type	notes
M26	open cluster	very rich starfield
M11	open cluster	"
M20 Trifid	nebula	very faint color; expected more vivid color; star colors were quite evident though!
M8 Lagoon	nebula	very bright but pale; one knot of obvious pink
M24 starcloud	open cluster	numerous star colors; very nice!
Veil Nebula	supernova remnant	both halves very easy; light puple color; knots and strands very obvious
M57	planetary nebula	Ring Nebula; very bright with little color; obvious structure and wisps on long axis; central star mag=14.8 seen
M27	planetary nebula	Dumbbell Nebula; very bright, pink and purple; many faint stars across disk; central star mag=13.5 seen easily
M71	globular cluster	unconcentrated; nice star colors
M10	globular cluster	well resolved
M12	globular cluster	bright center
M5	globular cluster	very nice
M13	globular cluster	bright; nice star colors
6207	galaxy	easy with apparent structure and obvious dust lane; mag=12
IC 4617	galaxy	very difficult; mag=14.6; 1.2"x0.4" 550 M ly
891	galaxy	nice edge-on galaxy; fainter than expected
M31	galaxy	Andromeda Galaxy; two dust lanes very obvious; some HII and globulars observed
M32 & 110	galaxy	Andromeda satellite galaxies; easy, apparent structure
M33	galaxy	Triangulum Galaxy; rather faint; vague teal color; some HII and globulars observed
Double Cluster	open cluster	framed very nicely in 26 mm eyepiece
M45	open cluster	Pleiades; obvious blue reflection nebula
Jupiter	planet	too bright! need a neutral density and/or color filter; cloud bands evident despite poor seeing

Final thoughts:

The telescope should not be assembled or disassembled without a second person to assist. With a capable assistant who knows the telescope, one can set up and be observing in minutes. Meade has done a very fine job with both the balance and the smoothness of motion: moving the telescope while looking through the eyepiece is very pleasant, even when tracking an object at high power. The is extremely minimal telescope jitter or rebound when one stops moving the telescope.

The results of my optical testing were incomplete / inconclusive due to the poor viewing conditions; I still have some questions about the primary mirror figure. I suggest that a highly educational club activity would be to test the primary mirror (Foucault knife edge test, Ronchi test, etc).

Cheers,

[Following are in answer to M. Clayson’s question as to how he estimated/measured all those metrics]

Briefly, the weather data was obtained online from several sites nearby (temp, RH, and dewpoint) and site RH was determined from the dewpoint of those sites, altitude corrected. A rule of thumb is 3 deg F / 1,000' of elevation change in humid air and as much as 5 deg F / 1,000' in extremely dry air. On Saturday, based on weather data from multiple directions and elevations, the slope was 4.7 deg F / 1,000' -- very dry air indeed. I used to carry a small, old analog temp, RH, pressure gauge and if I start "seriously" observing again, I may return to that practice.

Seeing diameter was determined by looking at quite a few closely spaced double stars of known separation. Near midnight, I was able to split several 0.9" doubles and one 0.8" double near zenith (each star of which was twinkling rapidly but in place) but nothing at 0.7" or below.

Seeing (1-10) and transparency (1-10) are subjective and based on nearly three decades of observing experience. Likewise, I estimated the (naked eye) limiting zenith magnitude and the apparent brightnesses of Polaris and Vega around midnight as they had become noticeably fainter than normal, noted their approximate zenith angle (Z = ~60 degrees), determined the airmass (X = sec Z = 2), and from that came up with an approximate extinction coefficient k from m = m0 + kX.

In three decades of observing, I've experienced only two nights where the seeing and transparency both rated a 10. On those nights with my 10", blue color in the arms and yellow cores were clearly apparent in hundreds of galaxies, the colors of hundreds of blue reflection nebula and pink emission nebula were apparent in our Milky Way as well as several galaxies in the local group (M31, M33, ...), Saturn was razor sharp and steady at 650x, the zodiacal light and Gegenschein were as obvious as the Milky Way all night long, etc. For faint, extended sources like galaxies, the seeing can be as low as 5 as long as the transparency is 8 or better; conversely, for closely separated double stars, planetary observing, etc, the seeing is paramount and the transparency can be as bad as a 2. In fact, nights with high, thin altostratus clouds, which usually belie a very stable atmosphere, can be spectacular nights for visually observing doubles and planets but are of course terrible nights for photometry and for visually observing faint, extended sources. So, I find it important to gauge both the seeing and transparency as they both affect what kind of observing can be done.

As far as mirror testing, it is inexpensive and not too difficult to assemble various test setups; again, it might be useful and instructive for the club to do this.

Not listed in my observations from Saturday night were probably a dozen other Messier objects, probably a dozen Cr (Collinder) open clusters, a few Barnard dust clouds in Sagittarius and Ophiuchus, a few more globular clusters, and numerous galaxies mostly in Pegasus.

Jason

Mallincam Extreme Video Camera First Light

Friday Sept. 21 I was on the road to Las Vegas when the Shuttle was flying over L.A.  That evening I set up the LX-200 & videocamera for a 1-hour presentation to about 15 young Boy Scouts & their leaders at my brother’s request.  I'd arranged for someone to also bring a large-screen TV, table & generator (amazingly quiet & long cord) for it, and we set up in a parking lot.  

Shortly before the boys arrived at 8pm, and after making all the connections, doing the LX-200 alignment & commanding to go to the moon, I was pleasantly amazed to see a huge, sharp (after focusing) image of about one-eighth of the moon filling the large screen monitor (& a small preview window on my laptop).  See attached photo.  It was like looking out of the window of an orbiting spacecraft as I slewed w. the directional buttons on the LX-200 controller.  

The boys were amazingly well-behaved (according to their leaders, and I agree) -- clearly impressed w. the moon image upon arrival, asking astronomical questions but also about the equipment cost, etc.  I first oriented them in the sky using the laser pointer (Polaris & diurnal motions, constellations & bright stars, ecliptic & Milky Way, etc.).   Then I took them on a GoTo tour (the LX-200 was hitting objects spot on in the FOV), showing examples (Messier & NGC) of open & globular clusters, nebula, & galaxy (no visible planets), and explaining the astronomy merit badge requirements (I’m a certified counselor).  I need to learn to finesse the gain/exposure on the DSO's, as there was difficulty getting sharp images w. them -- possibly also an artifact of the monitor (I understand CRT monitors are better), as well as the thin cirrus and heat turbulence?  And I thought I'd captured a screen shot, but think I forgot a menu item or 2.  But all within an hour, w/out long lines at an eyepiece.  

Looking forward to a great large-screen show of the sun w. the H-alpha scope at the AEA October Festival.

Green Flash!

After a lifetime of failed attempts, Mark Clayson finally saw the green flash Sat. Sept. 29 from Crystal Cove Beach in Newport Beach.  Unfortunately, no photo for proof, but my sister & brother-in-law visiting from Cody, Wyoming, can vouch as they also saw it.

Astronomy Video(s) & Picture(s) of the Month

(from Astronomy Picture of the Day, APOD: http://apod.nasa.gov/apod/archivepix.html)
Video(s)

Aurora and Fireball Over Norway
Image Credit & Copyright: Ole C. Salomonsen (Arctic Light Photo)

Explanation: What's happening behind that mountain? A convergence of variable sky spectacles. One night in mid-September near Tromsø, Norway, high red aurora could be seen shimmering through lower green aurora in a way that created a striking and somewhat unusual violet glow. Suddenly, though, the sky flashed with the brightest fireball the astrophotographer had ever seen, as a small pebble from outer space violently crashed into the Earth's atmosphere. The glow illuminated the distant mountain peak known as Otertinden of the Lyngen Alps. The bright meteor, which coincidently disappeared behind the same mountain, was also reflected in the foreground Signalelva River. Although you might consider yourself lucky to see either an aurora or a bright meteor, pictures of them together have been recorded several times previously.

A Space Shuttle Over Los Angeles
Image Credit & Copyright: Stephen Confer

Explanation: It's not every day that a space shuttle lands at LAX. Although this was a first for the major Los Angeles airport hub, it was a last for the space shuttle Endeavour, as it completed its tour of California skies and landed, albeit atop a 747, for the last time. During its last flight the iconic shuttle and its chase planes were photographed near several of California's own icons including the Golden Gate Bridge in San Francisco, the Hollywood Sign, and the skyline of Los Angeles. Previously, in May, the space shuttle Enterprise was captured passing behind several of New York City's icons on its way to the Intrepid Sea, Air, & Space Museum. Pictured above, the piggybacking shuttle was snapped on approach last week to LAX as it crossed above and beyond a major Los Angeles street. Now retired, the space shuttles are all museum pieces, with the above shuttle scheduled to be towed along the streets of LA to the California Science Center.

An Ancient Stream Bank on Mars
Image Credit: NASA, JPL-Caltech, MSSS

Explanation: Fresh evidence of an ancient stream has been found on Mars. The robotic rover Curiosity has run across unusual surface features that carry a strong resemblance to stream banks on Earth. Visible in the above image, for example, is a small overhanging rock ledge that was quite possibly created by water erosion beneath. The texture of the ledge appears to be a sedimentary conglomerate, the dried remains of many smaller rocks stuck together. Beneath the ledge are numerous small pebbles, possibly made smooth by tumbling in and around the once-flowing stream. Pebbles in the streambed likely fell there as the bank eroded. Circled at the upper right is a larger rock possibly also made smooth by stream erosion. Curiosity has now discovered several indications of dried streambeds on Mars on its way to its present location where it will be exploring the unusual conjunction of three different types of landscape.

Astronomy News:

NASA's Chandra shows Milky Way is surrounded by halo of hot gas

Published: Monday, September 24, 2012 - 14:33 in Astronomy & Space

NASA/CXC/M.Weiss; NASA/CXC/Ohio State/A.Gupta et al.

Astronomers have used NASA's Chandra X-ray Observatory to find evidence our Milky Way Galaxy is embedded in an enormous halo of hot gas that extends for hundreds of thousands of light years. The estimated mass of the halo is comparable to the mass of all the stars in the galaxy. If the size and mass of this gas halo is confirmed, it also could be an explanation for what is known as the "missing baryon" problem for the galaxy.
Baryons are particles, such as protons and neutrons, that make up more than 99.9 percent of the mass of atoms found in the cosmos. Measurements of extremely distant gas halos and galaxies indicate the baryonic matter present when the universe was only a few billion years old represented about one-sixth the mass and density of the existing unobservable, or dark, matter. In the current epoch, about 10 billion years later, a census of the baryons present in stars and gas in our galaxy and nearby galaxies shows at least half the baryons are unaccounted for.

In a recent study, a team of five astronomers used data from Chandra, the European Space Agency's XMM-Newton space observatory and Japan's Suzaku satellite to set limits on the temperature, extent and mass of the hot gas halo. Chandra observed eight bright X-ray sources located far beyond the galaxy at distances of hundreds of millions of light-years. The data revealed X-rays from these distant sources are absorbed selectively by oxygen ions in the vicinity of the galaxy. The scientists determined the temperature of the absorbing halo is between 1 million and 2.5 million kelvins, or a few hundred times hotter than the surface of the sun.

Other studies have shown that the Milky Way and other galaxies are embedded in warm gas with temperatures between 100,000 and 1 million kelvins. Studies have indicated the presence of a hotter gas with a temperature greater than 1 million kelvins. This new research provides evidence the hot gas halo enveloping the Milky Way is much more massive than the warm gas halo.

"We know the gas is around the galaxy, and we know how hot it is," said Anjali Gupta, lead author of The Astrophysical Journal paper describing the research. "The big question is, how large is the halo, and how massive is it?"

To begin to answer this question, the authors supplemented Chandra data on the amount of absorption produced by the oxygen ions with XMM-Newton and Suzaku data on the X-rays emitted by the gas halo. They concluded that the mass of the gas is equivalent to the mass in more than 10 billion suns, perhaps as large as 60 billion suns.

"Our work shows that, for reasonable values of parameters and with reasonable assumptions, the Chandra observations imply a huge reservoir of hot gas around the Milky Way," said co-author Smita Mathur of Ohio State University in Columbus. "It may extend for a few hundred thousand light-years around the Milky Way or it may extend farther into the surrounding local group of galaxies. Either way, its mass appears to be very large."
The estimated mass depends on factors such as the amount of oxygen relative to hydrogen, which is the dominant element in the gas. Nevertheless, the estimation represents an important step in solving the case of the missing baryons, a mystery that has puzzled astronomers for more than a decade.

Although there are uncertainties, the work by Gupta and colleagues provides the best evidence yet that the galaxy's missing baryons have been hiding in a halo of million-kelvin gas that envelopes the galaxy. The estimated density of this halo is so low that similar halos around other galaxies would have escaped detection.
The paper describing these results was published in the Sept. 1 issue of The Astrophysical Journal. Other co-authors were Yair Krongold of Universidad Nacional Autonoma de Mexico in Mexico City; Fabrizio Nicastro of Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.; and Massimiliano Galeazzi of University of Miami in Coral Gables, Fla.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge.

For Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

General Calendar:

Colloquia, Lectures, Seminars, Meetings, Open Houses & Tours:

Colloquia:  Carnegie (Tues. 4pm), UCLA, Caltech (Wed. 4pm), IPAC (Wed. 12:15pm) & other Pasadena (daily 12-4pm):  http://obs.carnegiescience.edu/seminars/ 

Carnegie astronomy lectures – only 4 per year in the Spring www.obs.carnegiescience.edu.    Visit www.huntington.org for directions.  For more information about the Carnegie Observatories or this lecture series, please contact Reed Haynie.

5 Oct

SBAS Monthly General Meeting at El Camino College planetarium. 7:30 PM Topic: “Looking for Life on Mars and Other Places” Speaker: Dr. Max Coleman, JPL/CalTech:.  http://www.sbastro.net/.

Oct. 11 & 12 The von Kármán Lecture Series: 2012

Herschel Opens Up the Cool Universe

The Herschel Space Observatory, launched on May 14, 2009, is designed to carry out astronomical observations at wavelengths from ~1mm to 100 microns. This region of the spectrum, between radio waves and heat radiation, is a unique probe of the “cool” universe, that is, of objects at temperatures between a few degrees and 100 degrees above absolute zero. This includes material out of which new stars are forming in locations ranging from distant galaxies to nearby cold clouds of gas. To carry out these observations, Herschel has the largest precision telescope launched for astronomy, and three very sensitive instruments. Among many projects, Herschel has followed the “water trail” – observing this molecule in a wide range of sources ranging from giant molecular clouds to protoplanetary disks around young stars to comets in the solar system. This talk will present some of the highlights of Herschel observations and describe how they are changing our picture of how new stars and planets form.

Speaker:

Dr. Paul Goldsmith

Locations:	Thursday, Oct 11, 2012, 7pm The von Kármán Auditorium at JPL 4800 Oak Grove Drive Pasadena, CA › Directions Friday, Oct 12, 2012, 7pm The Vosloh Forum at Pasadena City College 1570 East Colorado Blvd. Pasadena, CA › Directions
Webcast:	We offer two options to view the live streaming of our webcast on Thursday: › 1) Ustream with real-time web chat to take public questions. › 2) Flash Player with open captioning If you don't have Flash Player, you can download for free here.

18-Oct-12

High/Wide Dynamic Range CMOS Imagers

Blake Jacquot (and Hung Ngo)

Aerospace

A1/1029A/B

22 Oct

LAAS LAAS General Meeting.

Griffith Observatory Event Horizon Theater 8:00 PM to 10:00 PM

Observing:

The following data are from the 2012 Observer’s Handbook, and Sky & Telescope’s 2012 Skygazer’s Almanac & monthly Sky at a Glance.

A weekly 5 minute video about what’s up in the night sky:  www.skyandtelescope.com/skyweek.

Sun, Moon & Planets for October:

Moon: Oct 8 last quarter, Oct 15 new, Oct 22 1^st quarter, Oct 29 full                                 

Planets:  Mercury and Mars are visible just after sunset. Jupiter rises 10pm the first of the month, 8pm the last of the month. Venus is visible in the pre-dawn sky.  Saturn is hidden by the sun.

Other Events:

5 Oct. Jupiter 0.9 deg N. of moon

6 Oct

SBAS Star Party (weather permitting): RPV at Ridgecrest Middle School 28915 North Bay Rd.

8-9 October Draconid Meteor Shower

Expect a peak rate of 10 yellow meteors per hour under clear, moonless conditions. These are fairly

slow meteors, coming in at 12.5 miles per second. They radiate from the head of the constellation

Draco. This shower was once known as the Giacobinids.

13-27 Oct Zodiacal Light visible before morning twilight.

13 Oct	LAAS Dark Sky Night : Lockwood Valley (Steve Kufeld Astronomical Site; LAAS members and their guests only)
13 Oct	SBAS out-of-town observing – contact Greg Benecke http://www.sbastro.net/.

17, 18 Oct – Mercury 1.3 deg S. of moon, Mars 2 deg S. of moon

20 Oct

Public  Star Party: Griffith Observatory Grounds 2-10pm

20-22 October Orionids Meteor Shower

This shower produces a peak rate of 20 yellow and green meteors per hour, which are fast moving

at 41.6 miles per second and are known to produce fireballs. They radiate from a point in the sky

not far from Orion’s red giant star Betelgeuse.  Best pre-dawn.

26 Oct Mercury  at greatest eastern elongation – 24 deg from the sun (in the evening)

Internet Links:

Link(s) of the Month

A weekly 5 minute video about what’s up in the night sky:  www.skyandtelescope.com/skyweek.

General

e! Science News Astronomy & Space

NASA Gallery

Astronomical Society of the Pacific (educational, amateur & professional)

Amateur Online Tools, Journals, Vendors, Societies, Databases

The Astronomy White Pages (U.S. & International Amateur Clubs & Societies)

American Astronomical Society (professional)

More...

Regional (esp. Southern California)

Western Amateur Astronomers (consortium of various regional societies)

Mt. Wilson Institute (www.mtwilson.edu/), including status for visits & roads

Los Angeles Astronomical Society (LAAS)

South Bay Astronomical Society (SBAS)

Orange County Astronomers

The Local Group Astronomy Club (Santa Clarita)

Ventura County Astronomical Society

About the Club

Club Websites:  Internal (Aerospace): https://aeropedia.aero.org/aeropedia/index.php/Astronomy_Club  It is updated to reflect this newsletter, in addition to a listing of past club mtg. presentations, astronomy news, photos & events from prior newsletters, club equipment, membership & constitution.  We have linked some presentation materials from past mtgs.  Our club newsletters are also being posted to an external blog, “An Astronomical View” http://astronomicalview.blogspot.com/. 

 
Membership.  For information, current dues & application, contact Jim Johansen, or see the club website where a form is also available.  Benefits will include use of club telescope(s) & library/software, discounts on Sky & Telescope magazine and Observer’s Handbook, field trips, great programs, having a say in club activities, acquisitions & elections, etc.
Committee Suggestions & Volunteers.  Feel free to contact:  Paul Rousseau, Program Committee Chairman (& club VP), TBD, Activities Committee Chairman (& club Secretary), or Jim Johansen, Resource Committee Chairman (over equipment & library, and club Treasurer).

Mark Clayson,
AEA Astronomy Club President