Wallpaper Wednesday

30 11 2011
MSL Launches to the Red Planet

MSL Launches to the Red Planet. Image credit: NASA/Darrell L. McCall

Today’s choice of wallpaper will come as no surprise to anyone (except perhaps my colleagues at the university, who don’t seem to care how I spent my Thanksgiving). I love this photo for its symmetry—the United Launch Alliance Atlas V rocket with the Mars Science Laboratory hovers above the launch pad, perfectly aligned with the towers of its lightning protection.

You can download the full size of this photo by clicking on the image above. It is also available in 1600×1200, 1024×768, and 800×600 formats in the NASA Image of the Day Gallery (currently image 4, but the gallery changes by the day, so you might have to click through a few photos to find it).





#MSL #NASATweetup

14 11 2011
Topographic Map of Gale Crater

Topographic Map of Gale Crater, with MSL landing site indicated by circle

I’m starting to ramp up for the NASA Tweetup next week. My initial burst of excitement about the Tweetup drowned in the subsequent flood of information related to the event—transportation and lodging options, meals before, during and after the Tweetup and launch, T-shirt designs (multiple), pin and patch designs, press releases, social media introductions, etc. Add to that the details of arranging travel to Florida, finding a housesitter, working through some personal stuff (see a couple posts back), planning ahead so I wouldn’t be swamped at work when I returned from the trip, and all I really wanted to do was take a nice, long nap, not to wake up before the New Year.

But that stage is over. My partner, who isn’t part of the official tweetup, landed her Rocket Launch Transportation Ticket (excuse me, RLTT) today, and that was the last stressful detail I needed to work out between now and our departure. We have a sixteen hour drive from home to Florida, so we’ll be entertaining ourselves with choice passages from the Mars Science Laboratory Launch Press Kit. Also, we’ll be playing Slug Bug.

In the meantime, I’ve been studying topographic maps of Mars. Curiosity, the Mars Science Laboratory rover, is projected to land near the edge of Elysium Planitia in the Aeolis quadrangle.

Aeolis Map

Map of Aeolis Quadrangle

If the name of the quadrangle sounds familiar, that’s because the Spirit rover landed there in 2004. However, Spirit explored Gusev Crater (at the right in the above image), while Curiosity is bound for Gale Crater (at the left). Spirit’s mission centered mostly around the search for water activity on Mars. Although Curiosity will also be seeking water, the mission as a whole is broader then previous ones, in that the rover will be seeking water as evidence of past or present habitable environments on the planet. It’s not seeking signs of life, per se, but rather trying to determine if and when conditions in Gale Crater might have been capable of supporting life. The presence of water would be a particularly strong piece of evidence, but it would be even better if it coincided with a possible energy source or other chemical ingredients considered necessary for the creation/sustenance of life.

Daybreak at Gale Crater

Daybreak at Gale Crater (computer simulation)

As the #MSL #NASATweetup draws nearer, I’ll be posting more information about Curiosity’s mission. I’ll do my best to post regular updates, if not about MSL itself, then about the wicked fun we’re bound to have during our trip. Oh, and “Lunch with an Astronaut” on Thanksgiving Day. You can bet I’ll be telling you all about that.





NASA Tweetup

12 10 2011

Those of you who are sitting in my kitchen with me already know this, because I’ve been bouncing off the walls for the past two hours. Those of you who are fortunate to be at some distance from me, well, let me tell you about my Thanksgiving plans. I am one of the lucky 150 people chosen to attend the NASA Tweetup for the Mars Science Laboratory Mars Curiosity rover launch. And here I was feeling excited about the fact that I was going to be able to visit a new observatory during a conference trip next week. THAT IS NOTHING compared to getting to go to Kennedy Space Center to see the launch. NOTHING.

I’ll still let you know how the observatory visit goes next week, though.





Wallpaper Wednesday

5 10 2011
Asymmetric Ashes

Asymmetric Ashes. Image courtesy: ESO

Today’s wallpaper shows an artist’s depiction of what the early stages of a Type Ia supernova might look like.  The image of the “exploding” star shows at its edges the asymmetrical shape of the resultant blast cloud. Using data gathered while making spectro-polarimetry observations with ESO’s Very Large Telescope and the McDonald Observatory’s Otto Struve Telescope, astronomers have concluded that the varied composition of a white dwarf star would lead to an unevenly-shaped debris cloud, rather than a perfect blast sphere, during the supernova event.





Wallpaper Wednesday

28 09 2011
Knockin Radio Telescope

Knockin Radio Telescope, MERLIN/VLBI

Today’s wallpaper features the Knockin Radio Telescope, the Shropshire terminus of the MERLIN/VLBI (Multi-Element Radio Linked InterferometerNetwork/Very Long Baseline Interferometer). Click on the image to reach the download page (iPhone, Blackberry and Full-screen versions available).





Mount Wilson II

25 09 2011
Mount Wilson Observatory

Mount Wilson Observatory

And speaking of Mount Wilson Observatory, it was featured in a souvenir postcard booklet I picked up in the same antique shop in which I found my Jules Vernes classic comic. Founded in 1904 by George Ellery Hale, the observatory now consists of multiple instruments, both historic (Hale’s 60-inch Telescope, for instance) and “cutting edge” (the Berkeley Interferometer and Georgia State University’s CHARA Array). The observatory is located ideally for tourism: 30 miles from Los Angeles, on the summit of Mount Wilson above Pasadena in the San Gabriel Mountains, just an hour drive from the city. Today, the observatory’s public program is focused on a guided tour that includes a visit to the observing floor of the Hooker 100-inch Telescope.

100-inch Telescope

100-inch Telescope, Mount Wilson Observatory

There is also a museum and a cafe on site so you can make a leisurely day of your visit. If you are feeling a need to spend a lot of money, you can organize a group of your friends (up to 25) and spend a night observing with the 60-inch telescope. As of 2011, the fee was $900 for a half-night of viewing, but you should check the fee schedule for the current rates (also, check out the glossy brochure).

The postcard booklet demonstrates the longevity of the tourist industry on the mountain. At the time of the booklet’s publication, the observatory was reached via the Mount Wilson Toll Road (now a hiking trail). While fully one-half of the descriptive text in the booklet described the wonders of the observatory, Mt. Wilson Hotel (first built 1904, no longer extant) was clearly the planned money-maker in this organization. Road tolls, meals and accommodation went to support the Mt. Wilson Toll Road Company—later the Mt. Wilson Hotel Company. Unfortunately, according to Marv Collins’ article at OldRadio.com, neither the toll road nor the resort were good financial investments, eventually going belly up despite public interest in the observatory.

Mount Wilson and Observatory Tourist Description

Mount Wilson and Observatory Tourist Description

As far as visual astronomy is concerned, it seems to me that the hotel and the observatory must have been at odds from the very beginning of their relationship. The first attraction listed for the resort? “Sixty towns illuminated by their own lights at night, a wonderful sight that will live forever in your memory.” Did the astronomers working at the observatory sense they were witnessing what would eventually become the almost global problem of light pollution? Or were they just happy to be able to buy a good meal for Sunday dinner at the hotel?

View of Pasadena

View of Pasadena and Los Angeles from Mt. Wilson





Harvard College Observatory

28 08 2011

Harvard University

One of the most interesting birthday presents I received this year was a booklet published in 1932 called A Brief Account of the Harvard Observatory. Before I even read the first full page of the book, I found myself on a chase through archives, intent on drawing out a more feminist history on its author, a research assistant named Jenka Mohr. Mohr was a frequent collaborator with and the principal assistant to the director of the observatory, Howard Shapley.[1] Biographical details for Mohr are hard to find, but while she worked at Harvard, she gave lectures on topics such as Beyond the Milky Way and The Magellanic Clouds: Our Neighboring Galaxies. She published at least one article as first author and a few as second and third author.[2] She served as the editor to the THE TELESCOPE—An Illustrated Magazine of Astronomy, published bi-monthly by the Bond Astronomical Club at the Harvard Observatory.[3] She also played the violin well enough to entertain her colleagues.[4] Mohr’s tenure at Harvard slightly postdates the era of the Harvard Computers (see George Johnson’s book, Miss Leavitt’s Stars: The Untold Story of the Woman Who Discovered How to Measure the Universe), but her workload seems to compare well with some of the assignments given to that cohort of women. For example, in addition to her more science-based duties at the observatory, she was charged with quite a bit of bibliographic work by the senior astronomers.[4]

Frontispiece, A Brief Account of the Harvard Observatory

There’s a longer story in Jenka Mohr’s career, I’m sure, and perhaps one day I’ll detail it on this website. In the meantime, you might notice the second distraction on the title page of the booklet, reproduced above. How often do you see a telescope poking upward through a second-story window? According to Mohr, this image depicted the 12″ “polar equatorial” telescope, installed in the observatory c. 1907. The telescope, with its axis parallel to that of Earth, is fixed in position on the south side of the observatory. The observer, sitting comfortably inside the building, looks through the eyepiece in the direction of the South Pole. The images of the stars are brought into the field of vision not by moving the telescope, but by moving a 12″ mirror installed in the instrument after the dismantlement of a horizontal photometer.[5]

The American Astronomer

"A New Polar Equatorial," from The American Astronomer, Vol. 1, No. 3, June 15,1907, p. 11

The entire southern sky could be viewed from a comfortable chair inside the observatory. According to both Bailey and Mohr, the telescope was used primarily for the observation of variable stars.

That’s the cover page of the book. Imagine what I will have to write about the history of the Harvard College Observatory if I ever make it beyond the opening pages.

###

 [1] See “Interview with Leo Goldberg by Owen Gingerich in Gingerich’s Office, Harvard University, August 9, 1983.” [http://www.aip.org/history/ohilist/28196_1.html] Goldberg is somewhat dismissive of her skills (calling her Shapley’s “Girl Friday,” for instance), but Mohr’s publications suggest that she knew what she was doing when working as an astronomer. In 1938, she served on the committee on nebulae and star clusters at the annual meeting of the International Astronomical Union in Stockholm, Sweden.

[2] Jenka Mohr and Harlow Shapley, “A comparison of the magnitude sequences in the two magellanic clouds,” Annals of the Astronomical Observatory of Harvard College, Vol. 105, No. 11, Cambridge, Mass. : The Observatory, 1937, p. 237-240; Harlow Shapley and Jenka Mohr, “Summary of a Variable Star Survey in an External Galaxy“, Proceedings of the National Academy of Sciences of the United States of America, Vol. 19, No. 12 (Dec. 15, 1933), pp. 995-996; Harlow Shapley, Virginia McKibben and Jenka Mohr, “Galactic and Extragalactic Studies, VII. Magnitudes of Forty Cepheids in the Large Magellanic Cloud,” Proceedings of the National Academy of Sciences of the United States of America, Vol. 26, No. 5 (May 15, 1940), pp. 326-332.

[3] See Star Fields, the Newsletter of the Amateur Telescope Makers of Boston Including the Bond Astronomical Club, Vol. 2, No. 2, Feb. 2001, p. 3.

[4] Jenka Mohr, Bibliographies of Edward Charles Pickering, 1846-1919 and Solon Irving Bailey, 1854-1931 Wash. D.C.: National Academy of Sciences, 1932; Annie Jump Cannon and Jenka Mohr, Biographical Memoir of Solon Irving Bailey, 1854-1931, Washington: National Academy of Sciences, 1932.

[5] Solon I. Bailey, The History and Work of Harvard Observatory, 1839 to 1927, New York: McGraw-Hill, 1931, p. 45.





Spitzer Telescope

25 08 2011
"Awash in Green and Red"

"Awash in Green and Red," constellation Perseus. Image credit: NASA/JPL-Caltech/2MASS/B. Whitney (SSI/University of Wisconsin)

Happy Birthday to the Spitzer Telescope!





Dawn

15 08 2011
Close-up View of 'Snowman' Craters, Vesta.

Close-up View of 'Snowman' Craters, Vesta. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Although the mission website is written in the future tense, NASA’s spacecraft Dawn is operating in the present tense. As of August 11, Dawn has been actively studying the asteroid Vesta in an attempt to clarify the creative processes of our early solar system. As the photo above shows, Vesta is a dry asteroid with a basaltic surface formed approximately 4.5 billion years ago. The surface has remained mostly intact ever since (that is, there is not sign of later extrusions of lava from the interior of the asteroid), although it does seem to be significantly cratered in certain sectors. In surveying the asteroid and comparing the results to other objects with origins in the early solar system, NASA hopes to determine the “evolutionary path” objects have followed during their (very long) lives.

Using three different instruments, (a visible Framing Camera, a Visible and Infrared Mapping Spectrometer, and a Gamma Ray and Neutron Spectrometer), Dawn is attempting to capture data that will reveal both the external and the internal characteristics of Vesta. The framing camera is providing images of object in the visible range of the spectrum. The Visible and Infrared Mapping Spectrometer is taking measurements for comparison with laboratory samples to determine Vesta’s mineral composition. The Gamma Ray and Neutron Spectrometer is measuring the energy from gamma rays and neutrons emitted by or bounced off the asteroid. With these measurements, the research team will be able to determine the elemental composition of the asteroid as deep as three feet below the surface.

After Dawn finishes it survey of Vesta, it will move on to study of the dwarf planet Ceres. Ceres is quite different from Vesta—it has a “primitive surface” containing water-bearing minerals and appears to be similar to several of the icy moons of the outer planets of the solar system. It’s possible it may have a weak atmosphere. We’ll know soon (relatively speaking). Dawn is scheduled to depart Vesta in July 2012 and arrive at Ceres in February 2015. Once the Ceres survey is completed, NASA should be able to make an informed comparison of the paths different objects followed during the early years of our solar system.

Dawn baseline interplanetary trajectory for primary mission. Dashed lines represent orbits of Mars, Vesta, and Ceres. Image courtesy of NASA

Dawn baseline interplanetary trajectory for primary mission. Dashed lines represent orbits of Mars, Vesta, and Ceres. Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

 





First Light

3 08 2011

When the world’s greatest telescopes opened their eyes.








Observatories and Instruments