Have you ever wondered what it’s like to visit one of the big research observatories, like Keck, Gemini, or the European Southern Observatory? What’s it like to use gear that powerful? What’s the facility like? What precautions do you need to take when observing at such a high altitude?
We record Astronomy Cast as a live Google+ Hangout on Air every Monday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.
The mighty Arecibo Radio Observatory is one of the most powerful radio telescopes ever built – it’s certainly the larger single aperture radio telescope on Earth, nestled into a natural sinkhole in Puerto Rico. We’re celebrating the 50th anniversary of the construction of the observatory with a special episode of Astronomy Cast.
Millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture. Credit: ESO
A small, isolated dark nebula known as a Bok globule was described as “a drop of ink on the luminous sky” by its discoverer, astronomer Edward Emerson Barnard. Through a small telescope, the object seen here, Barnard 86, does appear as though someone may have dropped a blob of dark ink on the telescope lens. Or perhaps it appears as a spot where there are no stars, or a window into a patch of distant, clearer sky. However, this object is actually in the foreground of the star field — a cold, dark, dense cloud made up of small dust grains that block starlight and make the region appear opaque. It is thought to have formed from the remnants of a molecular cloud that collapsed to form the nearby star cluster NGC 6520, seen just to the left of Barnard 86 in this image.
Some say Barnard 86 looks like a gecko … can you see the resemblance?
This image was taken with the Wide Field Imager on the MPG/ESO 2.2-meter telescope at ESO’s La Silla Observatory in Chile. This cosmic pair is set against millions of glowing stars from the brightest part of the Milky Way — a region so dense with stars that barely any dark sky is seen across the picture.
It is located in the constellation of Sagittarius in one of the richest star fields in the whole sky, the Large Sagittarius Star Cloud. The huge number of stars that light up this region dramatically emphasize the blackness of dark clouds like Barnard 86.
A beautiful planetary nebula, Sh2-174. Credit: T.A. Rector (University of Alaska Anchorage) and H. Schweiker (WIYN and NOAO/AURA/NSF)
We space-nerds like to express our amorous feelings, just like the rest of the population (although admittedly some of need more help/prodding in this area than others). And so just in time for Valentine’s Day comes this new image of a planetary nebula, which looks like a rose — or even a tulip – to share with your very spacey valentine.
The name of this planetary nebula, however, is not so romantic: Sh2-174. We need some suggestions for a better name!
And the way this object was created is not so romantic, either, as planetary nebulae come about in violent events. Sh2-174 was created when a low-mass star blew off its outer layers at the end of its life. The core of the star remains and is called a white dwarf. Usually the white dwarf can be found very near the center of the planetary nebula. But in the case of Sh2-174 it is off to the right. (It is the very blue star near the center of the blue gas). This asymmetry is due to the planetary nebula’s interaction with the interstellar medium that surrounds it.
This image was obtained with the wide-field view of the National Optical Astronomy Observatory (NOAO) Mosaic 1 camera on the Mayall 4-meter telescope at Kitt Peak National Observatory. Travis Rector from the University of Alaska Anchorage made the observations for this image, taken through four different filters which are assigned colors that approximate what the human eye can see: B (blue), I (orange), Hydrogen-alpha (red) and Oxygen [OIII] (blue) filters. In this image, North is up, East is to the left.
The Siding Springs Observatory after bush fires rage. Photo by NSW Rural Fire Service.
The Siding Springs Observatory complex has suffered damage from wild fires burning across New South Wales, Australia. An initial assessment, according to the Australian National University, indicates that while no telescopes appear to have received major damage, five buildings have been severely affected or damaged, including the Lodge used to accommodate visiting researchers and a number of cottages and sheds. Additionally, it appears the Visitor Center has been severely damaged.
Apparently, firefighters from the New South Wales Rural Fire Service worked through the night to save the telescopes. “This is a large and dangerous bush fire,” the RFS said. Crews were battling difficult conditions, with temperatures in the area above 40 degrees Celsius (104 Fahrenheit) and hot north-westerly gusts of about 60 kilometers per hour, according to news reports.
Bush fires destroyed the Lodge where visiting astronomers stayed while working at the Siding Springs Observatory. Photo via the New South Wales Rural Fire Service.
The observatory is located in the Warrumbungle National Park to the West of Coonabarabran, about 500 kilometres (310 miles) north-west of Sydney. Siding Spring is the largest optical observatory in Australia and a major infrared observatory that is home to 10 operating telescopes run by international researchers.
All observatory staff were evacuated before the fire and were safe, according to astronomer Robert McNaught, who posted an update on a comet and asteroids researchers user group site. Unfortunately, several homes in the area were destroyed.
Ten years ago this week the Mt. Stromlo Observatory in Australia was almost completely destroyed by bush fires.
Anglo-Australian Observatory, Siding Springs, with the approaching fires. Via Amanda Bauer.
Temperatures inside some of the telescopes were dangerously high, according to remote readings, and some damage may have occurred to the delicate instruments. Until the staff can return to the complex and check on the telescopes, the extent of the damage won’t be known.
“I fear a lot of damage has been done though, even if not the wholesale destruction we faced in 2003 at MSO,” said astronomer Brian Schmidt, who heads the SkyMapper telescope at the site, via Twitter. “Tomorrow will tell, and then will come the long, slow process of recovery.”
This timelapse is different than most because it allows you to see the actions of the South African Large Telescope (SALT) from a unique point of view: the camera is mounted on the mirror structure, but also visible is the awesome field of view. Dr. Bruno Letarte compiled this video from 3 consecutive nights observing in July 2012 showing SALT in action. He also provides a tour of the inside of the telescope as well.
Additionally, Letarte provides detailed info of what is being observed, what scientist or team is doing the observing, and additional details of what is actually happening. If you want a more traditional timelapse of the night sky, see below for Letarte’s Volume I of this pair of videos. It shows a stunningly beautiful look at the southern sky, and points out several of the constellations and other objects that are visible. Continue reading “Timelapse From Inside a Telescope”
Last week, a report issued by the National Science Foundation’s Division of Astronomical Sciences suggested de-funding several ground-based observatories along with other money-saving strategies to help offset budget shortfalls in US astronomy which have been projected to be as much as 50%. The report recommended the closure of iconic facilities such as the Very Long Baseline Array (VLBA) and the Green Bank Radio Telescope, as well as shutting down four different telescopes at the Kitt Peak Observatory by 2017.
Universe Today talked with the Director of the National Optical Astronomy Observatory (NOAO), Dr. David Silva for his reactions to the report.
Universe Today: What is your initial reaction to the STP portfolio review:
David Silva: “It’s disappointing, but not completely unexpected. I think the biggest challenge for the overall US community is they’re going to lose access to a lot of world-class, cutting-edge facilities. This is roughly somewhere between eight hundred to a thousand nights of open access time which is going to be defunded over the next three years or so. That’s a huge culture change for US astronomy.
UT: Do you see this affecting the researchers at smaller facilities and universities the most?
Silva: Definitely. Clearly, the situation is now that if you’re at an institution that has its own facility, everything should be OK. But if you’re at an institution that does not have access to its own facility, you’re in a bad situation. So that naturally segregates the bigger universities versus the smaller universities.
I should say there is a caveat, in that we are in an era now in professional astronomy where surveys are now becoming a much stronger component of what we do. Surveys are the big wide-field surveys both from space and from the ground which are producing massive datasets that are open to everyone. So, what’s really happening is this culture change from people having to compete for one or two nights a year on a telescope to potentially working on the big datasets. So, how that transition occurs remains to be seen. But the loss of all these open access nights will definitely be a shock to the system.
UT: Do you see the new report as being overly pessimistic or do you think it’s spot on of what’s actually going to be taking place in astronomy next few years, such as in one scenario which described that only 50% of projected funding will be available?
Silva: I have no opinion on that. That was a boundary condition that the report used, and if I could predict that I would be in a different industry!
UT: Do you see any potential silver lining here, that this kind of tight funding could streamline things, or could help in the “persistent mismatch between the production rate of Ph.D.s and the number of tenure-track faculty or long-term astronomy positions” that the report talked about?
Silva: No. I think the higher-level issue is that astronomy in the last 20 years has been a field where the number of people who are professional astronomers has grown in this country because of a fortuitous funding cycle from all three of the major funding agents, NASA, NSF and the Department of Energy. But we are now in a downward cycle in funding for astronomy at the federal level and there is going to be a squeeze now. I think that one of the choices we’re going face as there is this squeeze and people begin to leave the field, how do we make sure that the those who are still in the field — especially our younger colleagues – that they are given the mentoring and nurturing and support they need to have vital careers.
But there’s a growing mismatch between the numbers of people who want funding and the funding that is available, there’s no two ways about it.
UT: Any final thoughts or things that you think are people I’m important for people to know about?
Silva: One of the opportunities that it creates on Kitt Peak is the ability to continue to move forward on our BigBOSS collaboration, which is a proposal to put a 5,000 target, multi-object spectrograph on the 4-meter Mayall telescope at Kitt Peak National Observatory, which allows you to do a large dark energy characterization experiment. The instrument is also exceptionally powerful for doing a variety of other investigations like galactic archaeology to map out kinematics in the galaxy, the chemical composition and the motions of galaxies and stars, and other very large data projects like that.
This report was actually quite supportive of that project moving forward. So even though reports recommend the NSF divest funding in the Mayall Telescope as an open-access telescope, it suggests there are ways forward to convert it from an open access platform to a survey facility. And that’s, I think, a silver lining in this. It doesn’t solve that cultural issue, but it was does mean we can continue to do high impact science with that instrument.
But I do see this as a big cultural change. A key question perhaps is, does the US have strong national observatory or not? And this report is leaning in the direction of not.
Inspired by SETI Chief, Jill Tarter’s 2009 TED ‘Prize Wish’ to “Empower Earthlings everywhere to become active participants in the ultimate search for cosmic company” the Energetic Ray Global Observatory or ERGO is an exciting new to project that aims to enlist students around the world to turn our whole planet into one massive cosmic-ray telescope to detect the energetic charged particles that arrive at Earth from space. Find out how it works and how your school can get involved Continue reading “ERGO – Students Sign up to Build the World’s Largest Telescope!”
The side of the SOFIA aircraft shows it's joint roots, a collaboration between NASA and German Scientists. Credit: Nick Howes
[/caption]
One of the most remarkable observatories in the world does its work not on a mountaintop, not in space, but 45,000 feet high on a Boeing 747. Nick Howes took a look around this unique airliner as it made its first landing in Europe.
SOFIA (Stratospheric Observatory for Infrared Astronomy) came from an idea first mooted in the mid-1980s. Imagine, said scientists, using a Boeing 747 to carry a large telescope into the stratosphere where absorption of infrared light by atmospheric water molecules is dramatically reduced, even in comparison with the highest ground-based observatories. By 1996 that idea had taken a step closer to reality when the SOFIA project was formally agreed between NASA (who fund 80 percent of the cost of the 330 million dollar mission, an amount comparable to a single modest space mission) and the German Aerospace Centre (DLR, who fund the other 20 percent). Research and development began in earnest using a highly modified Boeing 747SP named the ‘Clipper Lindburgh’ after the famous American pilot, and where the ‘SP’ stands for ‘Special Performance’.
Maiden test flights were flown in 2007, with SOFIA operating out of NASA’s Dryden Flight Research Center at Edwards Airforce Base in the Rogers Dry Lake in California – a nice, dry location that helps with the instrumentation and aircraft operationally.
This scale model shows the telescope position and how the aircraft design works around it. Credit: Nick Howes.
As the plane paid a visit to the European Space Agency’s astronaut training centre in Cologne, Germany, I was given a rare opportunity to look around this magnificent aircraft as part of a European Space ‘Tweetup’ (a Twitter meeting). What was immediately noticeable was the plane’s shorter length to the ones you usually fly on, which enables the aircraft to stay in the air for longer, a crucial aspect for its most important passenger, the 2.7-metre SOFIA telescope. Its Hubble Space Telescope-sized primary mirror is aluminium coated and bounces light to a 0.4-metre secondary, all in an open cage framework that literally pokes out of the side of the aircraft.
As we have seen, the rationale for placing a multi-tonne telescope on an aircraft is that by doing so it is possible to escape most of the absorption effects of our atmosphere. Observations in infrared are largely impossible for ground-based instruments at or near sea-level and only partially possibly even on high mountaintops. Water vapour in our troposphere (the lower layer of the atmosphere) absorbs so much of the infrared light that traditionally the only way to beat this was to send up a spacecraft. SOFIA can fill a niche by doing nearly the same job but at far less risk and with a far longer life-span. The aircraft has sophisticated infrared monitoring cameras to check its own output,and water vapour monitoring to measure what little absorption is occurring.
The Sofia Telescope resides behind the multi tonne frame and control mechanism. Credit: Nick Howes.
The 2.7-metre mirror (although actually only 2.5-metres is really used in practice,) uses a glass ceramic composite that is highly thermally tolerant, which is vital given the harsh conditions that the aircraft puts the isolated telescope through. If one imagines the difficulty amateur astronomers have some nights with telescope stability in blustery conditions, spare a thought for SOFIA, whose huge f/19.9 Cassegrain reflecting telescope has to deal with an open door to the
800 kilometres per hour (500 miles per hour) winds .Nominally some operations will occur at 39,000 feet (approximately 11,880 metres) rather than the possible ceiling of 45,000 feet (13,700 metres), because while the higher altitude provides slightly better conditions in terms of lack of absorption (still above 99 percent of the water vapour that causes most of the problems), the extra fuel needed means that observation times are reduced significantly, making the 39,000
feet altitude operationally better in some instances to collect more data. The aircraft uses a cleverly designed air intake system to funnel and channel the airflow and turbulence away from the open telescope window, and speaking to the pilots and scientists, they all agreed that there was no effect caused by any output from the aircraft engines as well.
Staying cool
The cameras and electronics on all infrared observatories have to be maintained at very low temperatures to avoid thermal noise from them spilling into the image, but SOFIA has an ace up its sleeve. Unlike a space mission (with the exception of the servicing missions to the Hubble Space Telescope that each cost $1.5 billion including the price of launching a space shuttle), SOFIA has the advantage of being able to replace or repair instruments or replenish its coolant, allowing an estimated life-span of at least 20 years, far longer than any space-based infrared mission that runs out of coolant after a few years.
Meanwhile the telescope and its cradle are a feat of engineering. The telescope is pretty much fixed in azimuth, with only a three-degree play to compensate for the aircraft, but it doesn’t need to move in that direction as the aircraft, piloted by some of NASA’s finest, performs that duty for it. It can work between a 20–60 degree altitude range during science operations. It’s all been engineered to tolerances that make the jaw drop. The bearing sphere, for example, is polished to an accuracy of less than ten microns, and the laser gyros provide angular increments of 0.0008 arcseconds. Isolated from the main aircraft by a series of pressurised rubber bumpers, which are altitude compensated, the telescope is almost completely free from the main bulk of the 747, which houses the computers and racks that not only operate the telescope but provide the base station for any observational scientists flying with the plane.
PI in the Sky
The science principle investigators get to sit in relative comfort close to the telescope. Credit: Nick Howes.
The Principle Investigator station is located around the mid-point of the aircraft, several metres from the telescope but enclosed within the plane (exposed to the air at 45,000 feet, the crew and scientists would otherwise be instantly killed). Here, for ten or more hours at a time, scientists can gather data once the door opens and the telescope is pointing at the target of choice, with the pilots following a precise flight path to maintain both the instrument pointing accuracy and also to best avoid the possibility of turbulence. Whilst ground-based telescopes can respond quickly to events such as a new supernova, SOFIA is more regimented in its science operations and, with proposal cycles over six months to a year, one has to plan quite accurately how best to observe an object.
Forecasting the future
Science operations started in 2010 with FORCAST (Faint Object Infrared Camera for Sofia Telescope) and continued into 2011 with the GREAT (German Receiver for Astronomy at Teraherz Frequencies) instrument. FORCAST is a mid/far infrared instrument working with two cameras between at five and forty microns (in tandem they can work between 10–25 microns) with a 3.2 arcminute field-of-view. It saw first light on Jupiter and the galaxy Messier 82, but will be working on imaging the galactic centre, star formation in spiral and active galaxies and also looking at molecular clouds, one of its primary science goals enabling scientists to accurately determine dust temperatures and more detail on the morphology of star forming regions down to less than three-arcsecond resolution (depending on the wavelength the instrument works at). Alongside this, FORCAST is also able to perform grism (i.e. a grating prism) spectroscopy, to get more detailed information on the composition of objects under view. There is no adaptive optics system, but it doesn’t need one for the types of operations it’s doing.
FORCAST and GREAT are just two of the ‘basic’ science operation instruments, which also include Echelle spectrographs, far infrared spectrometers and high resolution wideband cameras, but already the science team are working on new instruments for the next phase of operations. Instrumentation switch over, whilst complex, is relatively quick (comparable to the time it takes to switch instruments on larger ground observatories), and can be achieved in readiness for observations, which the plane aims to do up to 160 times per year. And whilst there were no firm plans to build a sister ship for SOFIA, there have been discussions among scientists to put a larger telescope on an Airbus A380.
A model of the telescope shows its unique control and movement mechanism as well as the optical tube assembly. Credit: Nick Howes.
Sky Outreach
With a planned science ambassador programme involving teachers flying on the aircraft to do research, SOFIA’s public profile is going to grow. The science output and possibilities from instruments that are constantly evolving, serviceable and improvable every time it lands is immeasurable in comparison to space missions. Journalists had only recently been afforded the opportunity to visit this remarkable aircraft, and it was a privilege and honour to be one of the first people to see it up close. To that end I wish to thank ESA and NASA for the invitation and chance to see something so unique.
Cracks in the secondary mirror on the Blanco telescope in Chile after an accident on February 20, 2012. Credit: Cerro Tololo Inter-American Observatory
[/caption]
An accident at the Blanco 4m telescope at Chile’s Cerro Tololo Inter-American Observatory has severely damaged a secondary mirror. The telescope is currently shut down for installation of the highly anticipated Dark Energy Survey Camera, and on February 20, 2012, the telescope’s f/8 secondary mirror was dropped during testing, resulting in fractures in the glass in the center of the mirror. Officials at the telescope said they are analyzing the extent of the damage to the mirror, and whether it extends beyond the visible cracks on the surface. They are also reviewing how the accident might affect the installation of the “DECam.”
Two staff members were injured during the incident, but are expected to fully recover. According to a post on the CTIO website, the f/8 had been removed for the installation of the DECam, and the f/8 was on the dome floor to test the focus mechanism. “The mirror and its back end assembly were being transferred to a handling cart to enable the tests. Unfortunately, the mirror was improperly installed on the cart and when the mirror was being rotated on the cart, the entire cart/mirror assembly toppled over injuring two of our technical staff,” said the report.
The mirror itself impacted the dome floor, causing the fractures, pictured above.
At this time, officials say it is not clear if the mirror is repairable or not and are reviewing what needs to be done to stabilize the cracks in the mirror. The accident is being investigated and initially, officials said they didn’t expect the incident delay the installation and commissioning of Dark Energy Camera as the f/8 is not required for the installation or operation of the Dark Energy Camera system. However, a later update said the DECam installation schedule was being modified to allow for the absence of the f/8 mirror.
The Dark Energy Camera will map 300 million galaxies with an extremely red sensitive 500 Megapixel camera, with a 1 meter diameter, 2.2 degree field of view prime focus corrector, and a data acquisition system fast enough to take images in 17 seconds.
The CTIO website said they would be providing future updates on the status of the mirror and the DECam installation.
