Monday, October 27, 2014

Partial Solar Eclipse

Last Thursday we witnessed a partial solar eclipse of the Sun- and for some reason this particular eclipse did not grab the attention of the media the way that the past few have.  It seemed that there were far more stories in the popular media for the lunar eclipse a couple weeks ago than for this event, despite the lunar eclipse happening in the middle of the night and the solar eclipse happening in mid-afternoon.  I was up at the Mount Lemmon SkyCenter with my colleagues (we streamed the eclipse live) and took the opportunity to take some images of the eclipse of my own.

I was using my Stellarvue 90mm triplet refractor with a Lunt Solar Systems Herschel Prism and my Canon T2i.  All the images were taken at 1/4000 of a second, ISO 100 and were shot in raw format.  I was shooting at a very high shutter speed in order to try and minimize the effects of atmospheric turbulence in my images.  I later used photoshop to increase the exposure value and stretch the contrast of the images.  Overall, the seeing conditions ranged from good to spectacular during the first part of the eclipse, but as mid-eclipse approached the conditions deteriorated slightly.  Below are a few of the best images that I captured, and as always, click to enlarge.

Start of Eclipse

Sharpest of my images, quite happy with this one!

Near greatest eclipse

A nice view after maximum eclipse, atmosphere not as stable

EDIT: The large sunspot region on the face of the Sun during the eclipse, Active Region 12192, has produced (as of yesterday) 9 X-class flares and is obviously quite large.  "How large" you are wondering?...well the blog of the SDO mission has published an interesting post comparing AR 12192 to previous spots.  If you look at the graph they provide you will see that this is the largest spot region (by area) in the past two solar cycles!  They report that it is the 33rd largest on record, and within the top .01% of all spots.  Pretty impressive stuff!

We were rather lucky to have this spot during the eclipse, and even luckier that it was in the Sun's southern hemisphere and not eclipsed by the moon, making for some pretty pictures.  Looking forward to the August 2017 Total Eclipse!

Sunday, October 12, 2014

Visiting Griffith Observatory

Perched high above Hollywood, California is another landmark of American astronomy- Griffith Observatory.  While Mount Wilson has a unique place in the history of astronomical discovery, Griffith is best known for its significant outreach program.  It is an iconic structure, visible from 360 degrees below, and is recognizable even to those not (yet) interested in astronomy and space sciences. From Rebel Without a Cause to The Terminator and the Transformers, the building has captured the imagination of many since its completion in 1935.

I was visiting the observatory with my colleague Adam to tour the facilities and to meet with Griffith staff to discuss best practices and ways that we could be mutually supportive of each other.  We were treated to a comprehensive tour of the facilities and also took in a planetarium show in the Samuel Oschin theater, Centered in the Universe, which was without a doubt the best planetarium theater show either Adam or I had ever seen.

As mentioned, the observatory was completed in 1935 as the result of the vision of Griffith J. Griffith who had visited Mount Wilson and observed through the largest telescope in the word at the time, the 60-inch reflector.  He was so moved by the experience that following consultation with Mount Wilson founder George Ellery Hale, he established a fund with the goal of providing all of mankind the opportunity for inspiration that he had experienced at Mount Wilson. Unfortunately, Griffith passed away in 1919 and his dream was not realized until after his death.

Griffith Observatory
The observatory was opened with the same telescope still in use today, the 12-inch Zeiss Refractor.  This telescope is a work of optical and mechanical art and is housed in the east dome (at left in the above image) of the observatory.  I have provided a few images of this telescope below, on its original mounting.  Riding atop the 12-inch is a 9-inch refractor and Celestron 9.25-inch Schmidt Cassegrain.

In the west dome of the observatory (at left) is a Coelostat; a telescope dedicated to observing the Sun.  Coelostat is from the Latin and means "Sky Stopper."   Below, you can see Griffith's Coelostat which consists of three 13-inch mirror flats.  These are actually the 'second' mirrors in the optical path, as there is a larger flat out of view in the image which is pointed at the Sun and reflecting the image to the three flats.  Each of these three mirrors directs an image of the Sun to a different display inside the observatory exhibit hall: A white light image, a hydrogen alpha image, and a solar spectrum.  The other two images below are of the shaft of light being focused down through the dome floor to another flat and into the hydrogen alpha telescope assembly.

Finally, a fun image from inside the exhibit hall where there is a large Tesla Coil.  This is among the most popular exhibits at Griffith and certainly is unique.  Our host fired up the coil and I managed to take a picture of it in action.  At left  is an image of the whole exhibit, as well as a full resolution crop of the electrical current below.

After a week in LA, it is good to be home!

Thursday, October 9, 2014

A visit to Mount Wilson Observatory

100-inch Hooker Telescope
I am in Los Angeles this week visiting my sister and her family and also doing a bit of business related to my day job as Director the Mount Lemmon SkyCenter.  My colleague Adam and I are visiting some of our partners in astronomical outreach on the west coast, and yesterday we visited Mount Wilson Observatory where we received an informative and inspiring tour from one of their senior docents and 60-inch telescope operator Nik Arkimovich.  Walking around the site with Nik for 2.5 hours discussing the history, politics and economy of the early 1900's provided wonderful context for considering the astronomical facilities that were erected, as well as the groundbreaking discoveries that were made at Mount Wilson.

As an amateur astronomer the visit was as impressive as a visit to any significant landmark or museum of American history.  Progressing through the afternoon was akin to progressing through a history of American Astronomy.  We walked in the footsteps of Mount Wilson Observatory founder George Ellery Hale, as well as visionaries such as Edwin Hubble, Harlow Shapley, Fritz Zwicky, and some physics genius named Albert Einstein.  Much of the site remains as it was during the early to mid 1900's when some of the most significant discoveries in astronomy were made at the the observatory.  While improvements have been made related to safety, access and technological advances, the original Snow solar telescope, the 60 and 150 foot solar towers, the 60-inch and the 100-inch Hooker telescope as well as the large trees throughout the observatory grounds bear witness to the people and ideas that have walked the paths over the past century.  Briefly, these are some of the highlights of our visit to Mount Wilson:

150 and 60 foot Solar Towers
Snow telescope enclosure
Shortly after beginning our tour, the 60 and 150 foot solar towers (image at right) came into view.  These telescopes were actually the second and third solar telescopes on site, with the first being the famous Snow telescope.  Mount Wilson's founder, George Ellery Hale, installed the Snow solar telescope in 1904 following its relocation from Yerkes Observatory in Wisconsin.  It is the oldest telescope at Mount Wilson and it's optical path is actually horizontal (parallel to) and just above ground.  At left is an image of the Snow telescope enclosure running along the ground, with the 60 foot solar tower in the background.  The design of the Snow proved to be rather poor as the image of the Sun was dramatically impacted by thermal currents swirling all along the optical path.  We were told that Hale quickly surmised that a vertical optical path would be better and the story is that he climbed various trees on site with a telescope to evaluate the localized seeing conditions.  By 1908, Hale had arranged for construction of the 60 foot solar tower and it was using this instrument that he soon identified magnetic fields in sunspots, and thus for the first time proved that magnetic fields existed outside of Earth!  Given his success and the utility of the solar tower design Hale then constructed a 150 foot solar tower in 1912, and began a daily recording of sunspots and study of their position, polarity, and strength that continues today.  You can see the most recent daily sunspot drawing from Mount Wilson by visiting this webpage.  Below is an image of the 150 foot Solar Towers.

150 foot Solar Tower
As we progressed further into the observatory grounds we were soon within the dome for the 60-inch telescope.  The 60 inch telescope was built by Hale in 1908 and funded primarily by the Carnegie Institution.  The mirror blank itself had been cast in 1894 in France and was acquired by Hale as a gift from his father.  While currently used exclusively for public outreach, this telescope was utilized for many of the pioneering studies in spectroscopy that led to the stellar spectral classification system.  Impressively, this was the largest telescope in the world until 1917 when the 100-inch Hooker telescope was finished.  Below are two images of the telescope in its dome.

Immediately below the 60-inch observatory floor are a darkroom and the original lockers that were provided for observers.  These two pictures of the lockers are worth enlarging in order to read the names...

Next up was a quick pass by the CHARA array of Georgia State University that sits atop the observatory grounds.  At right is one of the six enclosures that make up the Center for High Angular Resolution Astronomy array at Mount Wilson.  Together, these 6 one-meter "telescopes are dispersed over the mountain to provide a two-dimensional layout that provides the resolving capability (but not the light collecting ability!) of a single telescope a fifth of a mile in diameter. Light from the individual telescopes is conveyed through vacuum tubes to a central Beam Synthesis Facility in which the six beams are combined together. When the paths of the individual beams are matched to an accuracy of less than one micron, after the light traverses distances of hundreds of meters, the Array then acts like a single coherent telescope for the purposes of achieving exceptionally high angular resolution." (Quoted from this source).  Among the many notable achievements of this array was the first direct image of an interacting binary star (Beta Lyrae).

100-inch Hooker
Hooker Dome
Continuing on we approached the building and dome housing the 100-inch Hooker Telescope (at left).  The Hooker telescope was completed in 1917 and served as the largest telescope in the world until 1948 when the 200-inch telescope was installed at Palomar Mountain to the south.  The telescope is beautiful to behold and along with the furnishings and the building itself hearken back to to a time of seminal discoveries in astronomy.  In 1919, representing the first ever use of an interferometer in astronomy, an optical interferometer was used on this telescope to measure the sizes of distant stars.  Most famously, on the night of October 5-6, 1923 (almost exactly 91 years ago!) Edwin Hubble imaged a Cepheid variable star in the great Andromeda Galaxy and for the first time proved with certainty that the Andromeda 'nebula' was outside of our own galaxy and in fact a galaxy completely separate from our own.  This discovery was a key part of Hubble's pioneering work on the expansion of the Universe and the establishment of a cosmic distance scale.

Below are two images of the original, and still functional control panel for the telescope.  At left you can see the two periscope like devices that using a series of prisms allowed the observer to see the distant setting circles mounted on the telescope to note it's position.  At right you can see a close up of the brass control buttons for the telescope

If you have read this far and are interested in seeing more pictures (such as of the backside of the 100-inch mirror, or the mounting and gear system of the 60-inch) email me!  For the rest of you, I did make a one-minute video of the 100-inch Hooker telescope as I stood on the rotating platform (at the base of the dome) above the observatory floor.  Click on the settings icon (looks like a gear) to set it to HD and watch it full screen:

Again, a big thank you to Mount Wilson for hosting us, and especially to Nik for taking the time to show us around.

Wednesday, October 8, 2014

Lunar Eclipse in LA

I am in Los Angeles visiting my sister and her family in advance of some meetings related to work over the next three days (I hope to post some photos from today's meeting later...).  Very early this morning there was a total lunar eclipse, which is the type of event that even the drastic light pollution of Los Angeles can not diminish.  After spending yesterday at the beach, I was too tired to watch the whole eclipse, but I did manage to pull myself out of bed at about 2:50 AM to watch the moon slip towards totality at 3:25 AM PDT.  I was joined by my insomniac sister, who despite having instructed me not to wake her to watch the eclipse is rumored to have enjoyed it.  Below are two images I took with my Canon T2i and my 70-200mm f/4 lens during the eclipse.  Somehow in all my fiddling I did not extend the zoom all the way, so the images are taken at 180mm.

First, approaching totality at 3:19 AM (1019 UT), 1/2 second at ISO 400.  Note the blue dot to the left of the moon...and be sure to enlarge the image to see the blue dot.

Second, at 3:35 AM (1035 UT) about 10 minutes into totality.  1/3 second also at ISO 400...again, note that blue dot about a half-degree left of the moon...Anatomical jokes aside, that little blue dot is Uranus!  Make sure to enlarge to full size to see it.

And just in case you are having a hard time, here it is labelled!