Category: Astronomy

Exploring the cosmos

Discovery of the Most Distant Galaxy in the Cosmic Dawn

W. M. Keck Observatory press release…

A team of astronomers has used the Subaru Telescope and the W. M. Keck Observatory to discover the most distant galaxy yet, at 12.91 billion light-years from the Earth. This new galaxy, dubbed SXDF-NB1006-2, is slightly farther away than the previous record holder, galaxy GN-108036, which was found last year.

To identify SXDF-NB1006-2, the team used the Subaru Telescope to observe a total of 37 hours in seven nights in two wide fields of the sky. The team, led by Takatoshi Shibuya (The Graduate University for Advanced Studies, Japan), Dr. Nobunari Kashikawa (National Astronomical Observatory of Japan), Dr. Kazuaki Ota (Kyoto University), and Dr. Masanori Iye (National Astronomical Observatory of Japan), carefully processed the images they had obtained. Shibuya measured the color of 58,733 objects in the images and identified four galaxy candidates at a redshift of 7.3, which translates into about 12.9 billion light-years. A careful investigation of the brightness variation of the objects allowed the team to narrow down the number of candidates to two.

SXDF-NB1006-2Color composite image of the Subaru XMM-Newton Deep Survey Field of galaxy SXDF-NB1006-2, credit NAOJ

Finally, the team needed to make spectroscopic observations to confirm the nature of these candidates. They observed the two galaxy candidates with two spectrographs, the Faint Object Camera and Spectrograph (FOCAS) on the Subaru Telescope and the Deep Imaging Multi-Object Spectrograph (DEIMOS) on the Keck II Telescope, and identified one candidate for which a characteristic emission line of distant galaxies could be detected. The results are slated to be published in the June 20, 2012, edition of Astrophysical Journal.

In addition to locating the galaxy, the team’s research verified that the proportion of neutral hydrogen gas in the 750-million-year-old early Universe was higher than it is today. These findings help to decipher the early Universe during the “cosmic dawn,” when the light of ancient celestial objects and structures first appeared. They concluded that about 80 percent of the hydrogen gas in the ancient Universe, 12.91 billion years ago at a redshift of 7.2, was neutral.

Continue reading “Discovery of the Most Distant Galaxy in the Cosmic Dawn”

Summer Solstice

Summer solstice occurs today at 13:09HST. Today the Sun will occupy the most northerly position in the sky of the year. The term solstice comes from the latin terms Sol (the Sun) and sistere (to stand still). On this day the Sun seems to stand still as it stops moving northwards each day and begins move to the south. This is the first day of summer as marked by many cultures in the northern hemisphere.

2012 Solstices and Equinoxes
  UT HST
Perihelion Jan 5 03:59UT Jan 4 17:59HST
Spring Equinox Mar 20 05:14UT Mar 19 19:14HST
Summer Solstice Jun 20 23:09UT Jun 20 13:09HST
Apehelion Jul 4 23:59UT Jul 4 13:59HST
Fall Equinox Sep 22 14:49UT Sep 22 04:49HST
Winter Solstice Dec 21 11:12UT Dec 21 01:12HST
 
Source: USNO Data Services Website and the NASA Sky Calendar

 

Venus and the Hyades

As Venus approaches maximum elongation it will pass through the Hyades star cluster. Because Venus reaches it maximum western excursion on July 1st the planet will sweep out an arc that runs just inside the V-shape of the cluster. Thus the planet will remain within the main body of the cluster for the next 20 days.

Today the planet is only 26′ from εTau at one corner of the V-shaped cluster. On July 8th the planet will pass about 1° from Aldebaran as it exits the cluster at the other corner of the V.

Postcard from the Universe – Galactic Center

The last time out I fitted a camera ball mount to the counterweight shaft of the Losmandy mount. This allowed me to shoot an additional camera at the same time, along with the camera attached to the telescope. The second camera can be aimed at a different target completely. With a relatively wide angle lens, tracking errors become insignificant.

With the center of the Milky Way high overhead it made an obvious first target to test this wide-field setup. The results are quite nice, a series of one minute exposures reveal the star clouds in fine detail. The camera for this run was the Canon 60D, as the 20Da was shooting the Lagoon at the time. I need to swap places and try the shot again with the 20Da to see what the Hα sensitivity reveals, capturing more of the nebulae that is mingled with the stars.

The lens was an older Nikon 50mm f/1.8 stopped down to f/2.8, nice round star images right into the corners of the frame. Yes, a Nikon lens mounted to a Canon camera, you can do that. A very nice lens, I will be using it again for this work.

Galactic Center
The galactic center region on the Sagittarius-Scorpius border

The Moon, Venus and Jupiter

A nice trio will grace the dawn tomorrow, the morning of June 17th. Three bright objects will be visible just before sunrise. A brilliant Venus will be 14° above the horizon at sunrise. Above Venus will be a very thin crescent Moon, only 4% illuminated, will be 4° above Venus. About 8° above Venus will be Jupiter, shining brightly at -2.0 magnitude. Thus Jupiter will be the first to rise, at 04:02HST. Sunrise will occur about 05:43, leaving plenty of time to enjoy this bright conjunction.

Employment Opportunity at Keck – Machinist

W. M. Keck Observatory position announcement…

Senior Machinist-Infrastructure Technician

The W.M. Keck Observatory operates two of the world’s largest and most scientifically productive optical/infrared telescopes located on the summit of Mauna Kea on the Big Island of Hawaii. A highly capable and motivated staff operates, maintains and develops the complex telescope systems and infrastructure on the summit. We seek a Senior Machinist-Infrastructure Technician to join this high-caliber team.

This position is responsible for conventional and CNC machining of mechanical parts; interpreting complex mechanical fabrication drawings; and performing mechanical fabrication, assembly, adjustment and troubleshooting of precision mechanisms. In addition, this position will participate in maintenance of the summit infrastructure, including repairs of mechanical systems and preventative maintenance.

Minimum requirements are: Knowledge of materials, their properties, and suitability in different mechanical applications; five years of experience in an industrial environment with proven capability for installation, maintenance, and troubleshooting of mechanical systems; and eight years of experience as an industrial machinist building high precision parts.

Commitment to WMKO’s core values, working well with others, and the ability to handle multiple tasks and priorities within a fast paced environment are all essential. Additional information about WMKO and this position may be found on our website at www.keckobservatory.org/about/employment

This position requires you to submit your resume on-line at: http://keckobservatory.iapplicants.com/ViewJob-319065.html with your cover letter that states why you are uniquely qualified for the position.

EEO Employer

Postcard from the Universe – Lagoon

Another product of this last new Moon star party at the MKVIS. An easy target, suited to checking the performance of the new setup. As usual, click on the image to view the larger size…

The Lagoon
The Lagoon Nebula, NGC6523, in Sagittarius, 11 x 8min exposures, Canon 20Da and AT6RC

Venus Appears in the Dawn

This week Venus will appear in the dawn sky. Today the planet will be over 10° from the Sun at dawn. This will increase over a degree each day as Venus climbs higher into the dawn sky. Maximum elongation will occur on August 14th.

A few nice conjunctions will occur with both Jupiter and the Moon over the coming weeks. Stay tuned to Darker View for postings that will keep you up to date.

Transit Webcast Comments

Almost a week later and the comments keep coming in… E-mails to the observatory, comments on my blog, people are still pulling me aside to offer their comments in person. It is somewhat overwhelming. Did we really manage to do this?

Transit Webcast
The transit webcast station while on-the-air, photo courtesy Mark Senft

I spent 6 and change hours with you guys and I really appreciated your dedication to keeping everything up and running for us all around the world. HATS OFF YOU YOU ALL! – Kyle

We are in currently rainy Western Australia, and your webcast was the only way that we got to see the transit at all. My kids’ primary school all tuned into you at some point during the day. 🙂 – Carina

I have been reading the comments as they come in. It is truly gratifying that we managed to share this unique event with so many people.

You made my wife’s day! She was stuck at work & had you and the Keck team in the background for the entire transit! She is eternally grateful! Mahalo nui loa! – Joel

I watched your webcast of the transit from start to finish (with a few breaks here and there). What a great job you guys did! Fascinating, funny and I learned a lot in the process. Thank you for your efforts, and I too look forward to other webcasts from Keck. – Carol

I do not expect we will be doing this again right away. It takes the right sort of event. The one previous webcast was during the close approach of the asteroid 2005 YU55 in November of 2011. That time we webcast from the remote operations room in Waimea. It was also a good success, with great cooperation from the astronomers doing the observation. Need to take advantage of the best opportunities.

Thank you all for your hard work and dedication. I signed on t minus 10 min and stayed until you guys went off the air. I enjoyed myself the entire time. I know for a fact that a lot of people learned tons during this broadcast. My wish, hope and dream is that you continue to do events like this. You all gave it such a warm (beep) behind the scenes feel that made us all feel “part of the science.” The picture in picture was awesome and the graphics support mid-show was much appreciated. I can’t wait until next time! – Eric

We supported an average of between 5k and 6k viewers at any given time, with a total of over 100,000 live views. This viewer count may have badly underestimated the actual number of viewers, often the feed was being shown to large crowds at other public venues. Andrea Ghez mentioned that they were showing our feed at the UCLA event, the feed was on at at least two schools, and our own crowded Hualalai auditorium at Keck Headquarters in Waimea. I keep learning of other crowds the feed was shown to…

“Our observatory in Sonoma County was clouded out much of the day so we had your feed up for our 300+ visitors to supplement live viewing between the clouds. After sunset I went home to watch the rest of the transit on UStream and read the firehose of comments. It was a giant star party! Thanks for all the effort. Best outreach ever!” – Cecelia

A great experience shared with so many people across the globe. Thanks to everyone who made the Transit of Venus such a great day… Our Keck crew and the viewers who were there with us.