March '16 ARGOS Run

Regular readers know that I love recording things in the sky. While the Large Binocular Telescope (LBT) and the ARGOS system are not a natural phenomenon, since I worked on the fabrication of the mirrors of the huge telescope, I feel a natural bond to it atop Mount Graham. I've posted about it many times before - most recently in October, I was in position at a new observing spot about 20 miles south, but a stubborn cloud cap remaining from a clearing storm prevented their opening while I waited below. However, that post resulted in my finally putting together a nice time-lapse nearly 2 years earlier from November '13. A more general post describing the instrument and the other telescopes atop Graham is from that earlier date. This time (a couple weeks ago on 12 March) the weather was great, though a little chilly with a bone-chilling breeze. I was set up about a mile south of a small development, and about 16 miles south of the brilliant lights of Fort Grant, a State Prison, visible at the left side of the above image. From 20 miles, the laser was barely visible to the naked eye, but with binoculars could be spotted nearly to Polaris about 30 degrees high! In this image, I'm lit up by a several-day-old moon in the west, that was to set about 11pm.

Once the scope and telephoto lens was set up, you realize how difficult it is to align and focus in pitch black conditions! I ended up focusing on the rising stars of the Big Dipper's handle, but alignment on the LBT (before the laser started up) was tough requiring many short exposures as trial. It would have been much easier to get there an hour or so earlier, but time seems a rarity lately!

Finally success, as shown at left is the view of Graham with LBT and ARGOS with the 70-200 zoom set to 70mm. You can spot some of the local lights and how much the lights of the prison illuminate the southern flanks of Graham. At right in this wide image is Heliograph Peak, and while it looks to be the tallest peak, because of perspective (it is a little closer to my position) it isn't... At right is a shot of the mountaintop through the TEC 140 with its nearly 1,000mm of focal length, and the scopes atop the peak labeled. You can even spot the illumination from Fort Grant on the side of the LBT enclosure! Amazing what a minute will show in the exposure, since the laser was barely imagined to the naked eye.

All was going swimmingly - I ended up shooting over 2 hours of images with the TEC 140, potentially for a time-lapse (see below!). But when I took a first-look at the images later, I found a surprise! Shown at left is an image taken less than an hour into my shooting. While LBT had moved on to its second object of the night, there appeared to be a second "laser" appearing to emanate from the Sub-Millimeter radio telescope. But there were 2 clues about it's real source. First, clicking to load the full-size image, you can see wiggles in it as the source was affected by atmospheric disturbances, like the distant stars themselves... Also the telephoto caught part of the trail as it was disappearing behind the mountain. It was likely a distant sun-illuminated satellite disappearing over the horizon... Unfortunately, using Heavens-Above, I couldn't locate any possible candidates...


And yes, I did put together the time-lapse sequence, after editing the 140 images taken that evening with the TEC 140, and uploaded it to Youtube for your convenience! Note that the change in lighting over the time-lapse is due to the moon setting towards the end.




In conversations with the LBT director, he ended up using the shot of mine of the satellite disappearing over Graham in the LBT blog, which also includes highlights of the ARGOS run. Evidently ARGOS, which projects laser spots 10km up for partial correction of atmospheric turbulence, improved the seeing over a moderate field of view to .2 arcseconds. See the blog entry for more info.



Addendum: When I published this post late last night, I totally spaced that I got more shots of this run from a different perspective a few days later! Joe Bergeron, visiting from out of town, and I went up to San Pedro Vista on the Mount Lemmon Highway and spent an hour or so shooting towards Graham. Four days later and the moon was a lot brighter, and we were over twice as far away as above at nearly 50 miles. As a result, it was sort of murky and bright, but managed a few frames. Three images were stacked together to make the image at left. You can see a moderately bright star, heavily reddened by the the low elevation rising past the telescope and ARGOS laser. There is also enough ambient light that you can see snow on some of the higher slopes of Graham.

Another thing I've found in the last 24 hours is that when you play the above time-lapse, one of the clips it will auto-play is one made by the ARGOS team from adjacent to the LBT! It is a spectacular clip, showing what is possible with the short exposures and wide angle lens as a result of being 40 yards away, as opposed to shooting from 20+ miles with a meter-long focal length! Impressive stuff - copied here for your convenience - enjoy!

Evolution of the LBT

I've been looking at so many images of the Large Binocular Telescope (LBT) the last few weeks that I'm going cross-eyed! You all likely know by now that I had a hand in polishing both of the 8.4 meter mirrors (about 28 feet across each!) for the scope, and that was back a decade ago. Once both mirrors were installed in the telescope, I sort of lost track of it, but looking at those images now on my rare visits, the telescope never looks the same two consecutive trips! On a huge project like this, evolution past the basic telescope structure takes time, so even now, new instruments are coming on line and making new discoveries. Just last week, the Steward Observatory director notified us of an early use of the LBT imaging interferometer to image volcanos on Jupiter's moon Io. Be sure to visit the page, and scroll to the bottom where there is a movie clip showing Io being eclipsed by another moon Europa!

So let's look at some of the major changes in LBT over the years... From my first trip there in April, 2007, the basic telescope was complete.  The only instrument commissioned at the time were the prime focus cameras. Each of the big mirrors had it's own camera - the right mirror (called the SX side) had a blue-optimized camera, the left mirror (DX) had a red-optimized, both co-aligned precisely to the same field. Compared to recent images, the scope looks like a basic framework, which is pretty true...

On my next trip there a year later, May of 2008, it looked pretty much the same, but some major changes can be pointed out. Shown at labeled at right, perhaps the most obvious is a large tank between the elevation bearings.  The explanation is simpler than you can imagine - liquid is used, pumped between several storage tanks around the structure to balance the telescope as instruments and observing configurations are changed.  Of course, antifreeze is required as temperatures much below freezing is frequent.  More importantly, in preparation for new instrumentation, a Gregorian secondary mirror has been installed atop the SX telescope, and a tertiary mirror is also mounted now, where just the mounting jigs were in place a year before.  The LBT is designed for many instruments to be mounted simultaneously and the light can be brought to each in a few minutes with these auxiliary optics.  More on that in a paragraph or two.

Shown here at left is a close-up of the Gregorian secondary (taken in May, 2008).  When inserted into the telescope beam, it re-directs the light down to instruments either below the primary mirror, of via the tertiary to instruments located between the two primaries.  In this shot, the mirror wasn't in the beam, but nearly the entire primary mirror can be seen reflected in it.

Many modern telescopes use a convex secondary mirror, but LBT uses a concave for a couple reasons - one, it is easier to test a concave mirror, and in this optical configuration, it clears the prime focus camera, as shown at right.  If a convex mirror were used, it would interfere with the camera mounted closer to the primary mirror.  There is a clip at the end of this post that will show the change between camera and Gregorian secondary - it is really cool!

Also from May, 2008 is this shot in twilight of the space between the two mirrors from the "rear" of the telescope. Looking out the open enclosure, the "peak" of Mount Graham can be seen. At left is the "SX" mirror, the "DX" mirror at very far right. The thing to note is that the big mounting rings and the walkway between them is... empty!

Now check out the same space on our visit last month, April, 2015 at right. It is now packed with different instruments - I think the main one in center is the imaging interferometer, referenced in the link in the first paragraph above. PEPSI is an echelle spectrograph at lower left, LINC-NIRVANA at right, and LUCIFER (now LUCI) is mounted somewhere in there too...

A wider shot (also last month) at left shows how the light is fed to the various instruments. Though not in the beam here, the tertiary mirror is shown at left, and that feeds the light to the desired instrument (mounted in the ring flanges) when in place, and rotated to the proper alignment. This particular night, the observers were using the MODS spectrograph located below the primary, so the light went through the hole in the big mirror. The huge spectrograph is permanently mounted below the primary cell, shown at the bottom of the SX mirror at right. Since I've mentioned the ARGOS lasers in previous posts, I'm also pointing out some of the ARGOS optical system in the image at upper left. ARGOS uses 18 watt (!) lasers to project spots about 10km up in the atmosphere to partially correct turbulence that would blur the image.

The wide variety of instruments available and the ease of switching between them allows for most efficient use of telescope time should observing conditions change.

Finally, my favorite time-lapse clips are collected here in one sequence. Labels introduce each one, and should be self-explanatory. Full screen and HD should be used if you have the bandwidth. Any questions should be asked in the comments...




I think after recent posts I'm about LBT'ed out! Until my next trip up there, anyway!

A New View of LBT!

It is never my intention to go a month between blog posts - it just seems to work out to that lately - I have no excuse! Case in point is this post about the Large Binocular Telescope (LBT) - the photos were taken nearly 2 months ago! I was initially looking for permission from their director to ok the release of the images, but after so long, I guess I'll be looking for forgiveness rather than permission if they complain!


I feel sort of possessive of the LBT telescope as I supervised the polishing operations on the primary mirrors. Entering "LBT" in the upper left search window will return a number of posts, including some on the ARGOS instrument - my current favorite. ARGOS, of course, stands for "Advanced Rayleigh guided Ground layer adaptive Optics System" - an instrument mounted on the telescope that uses lasers to focus 10km above the telescope, those artificial "stars" are used to analyse and correct the atmospheric turbulence along the path. It really is exciting stuff, as it can improve seeing over a relatively large (up to 4 arc-minutes) field by a factor of 2 or 3.  While a factor of 2 or 3 doesn't sound that groundbreaking, note that the INTENSITY or brightness of a focused star goes up a factor of 4 or 9, by improving the sharpness that factor of 2 or 3.  Improving your star detection ability by a factor of up to 9 really is a big deal! This post really isn't about the instrument, merely observations of the lasers involved. For more information of the system and results, even from this run, go to the Max Planck Institute site - the sponsor of the instrument.

There was an ARGOS run in early March. With fresh snow on the mountain, I didn't even consider an observing site on Mount Graham, instead, went to the town of Safford, some parts of town enjoying a direct view of the telescope. I had obtained telephone permission to observe from the Discovery Park campus, but their view was a bit too obscured, so moved about a mile eastward for the good view shown above right at about sunset. You can see in the photo if you go west or north, the rise to the right of LBT starts blocking it. From my vantage point, LBT was 12 miles away - the closest I've been for an ARGOS run! The image at left shows my setup - from 2 sturdy tripods I was running a 500mm lens on the Canon 6D (full 35mm format) for a wide angle shot of the telescope, and the TEC140 (1,000mm with Canon XSi APS format) for the narrow field-of-view.

Looking very carefully at the above image, the laser projecting upwards from near the peak of Mount Graham can barely be seen. It was much more obvious through the optical aid of the telescopes and telephotos! At left is the view through the 500mm. Coupled with the larger format of the 6D, it gives a very nice wide field of view.

Through the TEC140, as with the photo at the top of the post, lots of details can be seen, including antennae in the sunset shot above! I took a series of photos with both setups, typically 30 second exposures under the nearly full moon was sufficient to get a good histogram. In the wide shot above, a wisp of clouds can be seen hugging the mountain. There was a layer of smoke that I suspect was from a controlled burn from the Tucson water treatment plant. The "Sweetwater Wetlands" had a burn of vegetation to control mosquitos, and can be seen as an enhancement in the laser scatter just over the telescope in some of the shots.

I chose to use only the narrow field in making the time-lapse of the evening, since the details were so stunning. In addition, I was able to start taking images before the dome opened, another advantage of knowing the phone number of the telescope operator and getting briefed on the observer's plans. So shown here are about 270 frames taken over a 3 hour period covering the dome opening, setup and following the first object of the evening. While it looks like the telescope is tracking across the sky much more slowly than the stars in the field, realize we are looking just over the horizon with a considerable focal length while the telescope is looking much higher in the sky.




Note that at no time was the green beam of the ARGOS laser visible to the naked eye. Even in my decent pair of 9X63 binoculars was it barely seen. Of course, as seen above, it photographs well! Finally as I was driving home with the telescope on its second object, I could barely detect a "green star" from inside the enclosure directly by eye, but that was all that was visible in my nearly 4 hours there! I've heard rumors that locals are upset at the lasers, but as you need optical aid to detect them, it hardly seems obtrusive! At the same time, with the gains in observing efficiency they are seeing it is proving its worth.

Before leaving, I took a few frames of the Discovery Park campus a mile to the west from my location. It is a cool place with interesting displays of both historical interest from the region, and the ground-breaking science going on at LBT and the optics from the Mirror Lab, including a cool 20" Tinsley telescope in the dome. Shown here is a 2-frame mosaic illuminated by ambient moonlight, and some security lights on the grounds that give it a nice glow...

Death Ray? No, Artificial Stars!

We had a great speaker at our Tucson Amateur Astronomy Association (TAAA) meeting last Friday on the adaptive optics system of the Large Binocular Telescope. Guido Brusa filled us in on the technical details and results using the flexible, actuated 80cm diameter secondary mirror to allow resolution measured in the tens of milli-arcseconds. He mentioned in passing that the ARGOS artificial star system was being tested currently on the telescope, and sure enough, on Wednesday came the announcement on the LBT blog of the successful test.

ARGOS stands for the Advanced Rayleigh guided Ground layer adaptive Optics System.  It is a method of correcting the distortions caused by turbulence in the atmosphere.  If the star images can be made smaller by using these methods, you make them much brighter, allowing to see much fainter as well as finer structure in the image.  A good introduction to this system is given on the ARGOS page of the Max Planck Institute.

After seeing the above announcement on the LBT blog, I was wondering if the projected beams might be visible from the Tucson area, so last night Melinda and I went up to Mount Lemmon to San Pedro Vista where the LBT can be spotted at a distance just over 40 miles away.  Sure enough, though not visible to the naked eye, in binoculars the beam could be seen against the sky! Over the course of 2 hours it varied in visibility, sometimes only barely visible in binoculars, but could be easily revealed in a few second exposure. Shown here is a 2 minute exposure with the 70-200 lens set to 70mm later in the evening.  This approximates the view of the beam in binocs, and shows the bright Jupiter breaking the horizon just left of the LBT.  From this vantage point LBT appears between the faint skyglow from the town of Safford, and a significant glow from Ft Grant, a prison and former army outpost just south of the Pinaleño Mountains.  At right is a single 2 minute exposure with the lens set to 200mm.  What looks like a single laser beam is, in fact, a set of 6 aligned beams from a Nd:YAG laser (neodymium-doped yttrium aluminum garnet) of 14-18 watts each...

While the blustery wind was evident on our drive up the mountain, the little saddle we were in was dead calm, though the wind was howling up in the treetops - weird!  I wanted to set up a small telescope too, trying to catch more details of the telescope/laser.  I have a small 80mm F/6 Meade APO refractor that works well for applications like this, so set it up on a substantial tripod.  Another single 2 minute exposure is shown at left, along with the headlights of a car coming down the switchbacks of the one-lane dirt road on the last section of the Observatory road.  Note the wiggles in the star trails due to turbulence at the low elevation, or the breeze wiggling the telescope - again, don't forget the LBT is over 40 miles away!  In an attempt to reduce the speckles of this exposure, I tried stacking 3 exposures to smooth the electronic noise from the ISO 1600 used.  At right is this exposure, but note that with the telescope tracking the sky, the laser moved between exposures!  I was using in-camera noise reduction, so for every 2 minute exposure, it took a 2 minute dark, so in those 2 minutes it wasn't exposing, the laser moved to a slightly new position.

Unfortunately, after Friday night, ARGOS won't be on the telescope again until next Spring...  I may need to make a trip to get another view of the Observatory from a closer vantage point tomorrow night!

A New View!

Long time readers know I'm justifiably proud of some of the Mirror Lab accomplishments, including the twin mirrors of the Large Binocular Telescope, each 8.4 meters (about 27.5 feet) in diameter. In particular, I've been on a quest of sorts of imaging the telescope while it does interesting things. It seems to have culminated last Spring when I caught the ARGOS laser propagating into the sky from a distance of 12 miles. From the town of Safford, through a small telescope, I almost had a front-row view of the instrument, visible at left, which is used to project a constellation of artificial stars in the field of view of the telescope to partially correct atmospheric turbulence. Several hundred similar frames were combined to make a short video seen here.


Well, without permission from the powers that be to get any closer (made more difficult by the recent severe fire this last spring that approached within 50 meters!), my most recent query was - from how far away can you see it?! From a post a few years back, I knew that LBT was line-of-sight from Kitt Peak National Observatory, very close to 120 miles away! The image at left is from that post and demonstrates that if you can see KPNO from LBT (flat-topped mountain in center), you can see LBT from KPNO!




So last night after work (working evenings this week at the Mirror Lab), I found my way driving westward - this after confirming with the LBT telescope operator that indeed ARGOS was operating properly. Being that it was dark-of-the-moon, I parked on the last pullout before turning towards the Observatory so that my lights would have no effect on operations there. It was an interesting night - totally clear, but obviously above an inversion layer. I watched the thermometer climb as the van ascended. It was 60F at the base of the mountain, 70F on top! The wind seemed a little blustery, alternately blowing out of the south or the north - weird! But fortunately, I was very comfortable in shorts and a long-sleeved t-shirt.

I had several optics to try - the first was easiest to set up - the 500mm F/4 "big bertha" telephoto. I had it up, pointed and focused on the lights of Tucson in a few minutes. It took me a couple shots to find where the LBT would appear - I'd never seen it from Kitt Peak, as it is quite small. But I knew it would be left of the red-lit radio transmission towers atop Mount Lemmon, so used that as my guide. About my 3rd shot - there it was! The green laser standing out from the occasional star and headlight visible on the Mount Lemmon Highway. At left is shown a 6-frame panorama of part of Tucson. with the green spot of the 18 watt ARGOS laser visible. At right is a single frame at a little larger scale better showing the laser beam.


I then broke out the big gun - the TEC 140 - a 5.5" diameter telescope with 1,000mm of focal length. Again, because of the large magnification, it took a couple practice frames to get it pointed properly. Note that at NO TIME was the ARGOS laser visible to the naked eye or even visible in the camera viewfinder. It was only the power of a 20 to 30 second exposure that revealed it was there. I had started an exposure sequence for a possible time-lapse, and interestingly, the inversion layer is visible just under LBT. In a couple minutes of exposure, it slowly dropped and became a little brighter in the less-affected air. Also visible in the exposure is the south slope of the mountain, brightly illuminated by the lights from Ft Grant prison at its base.


Most of my outings, I usually finish with a practice shot or mini-project that can be completed while putting away gear. This night, approaching 1:30 in the morning, I mounted the 16mm fisheye on the Canon 6D and took a couple frames of the sky from Andromeda to the rising Winter Milky Way. What is most interesting, besides the reddish airglow that looks like clouds to the west (right), is the oval glow just below center. This is called the Gegenshein, or counter-glow - a spot defined by being opposite to the sun in the sky. An optical effect allows sunlight to reflect from meteoritic dust back to us. This may be my best photo of it, and from only 2 stacked exposures shown here. Each of the 2 exposures were 2.5 minutes with the fisheye working at F/4.

Always great fun to be under a clear dark sky, and while chasing an ARGOS viewing might be only an excuse, it doesn't take much to get me out looking up!

A Scouting Adventure!

One of the engineers at work, and fellow photographic adventurer Steve West is fond of telling me that "Luck rewards the well-prepared".  I guess that is true as experience goes a long way towards a successful conclusion.  This last weekend, the Large Binocular Telescope (LBT) had another ARGOS run, which uses a laser to help correct the atmospheric distortion of the telescope image.  I had some fortune in imaging the laser beams from a distance the last observing run in November, and wanted to improve on it.  I consulted with another staff photographer and the implication was that we weren't welcome at the Observatory this run, so decided to check out Heliograph Peak (HP) - shown at left here when I last visited the LBT last October.  If we had a good view of HP from LBT, conversely there should be a good view of LBT from there!  Time for a scouting reconnaissance run...


Fortunately the 2 day run fell on a weekend, but clouds early on Saturday delayed my plans - we decided to take in a movie instead of the road trip, even though it cleared late...  Oh well, that left Sunday.  Even though thick clouds were moving in, I decided to hit the road to scout out the situation.  Actually, there had been some homework to do first.  I checked with the Forest Service about access to Heliograph Peak earlier in the week.  No permits were needed, but unfortunately, there was a locked gate where the access road met the main road - motorized access for the antennas and fire lookout only.  I also wanted to run a couple cameras and a small telescope from a single tripod to save weight, so tried and found that one of my adaptors would hold both the little Meade 80mm APO plus hold the 70-200 zoom with my wife's camera.  The setup is shown at right.  So I figured the tripod, pair of cameras and optics would be packable.  Good to go!

It is a good 3 hour drive to get to the top of Mount Graham.  While it had been weeks since we last had rain, I was a little surprised to see snow on the upper elevations of the mountain, given the warm temperatures we've had lately.  I got to the locked gate about 45 minutes before sunset, loaded the lil' scope and zoom in a backpack with a water bottle and snacks, made a sling from some webbing for the tripod and had 2 cameras in a lightweight case.  Hitting the trail, I was immediately hit with the quadruple whammy - first, I'm not in that great of shape, second, the hike started at over 9,000 foot elevation and the mile-long hike included over 600 feet of elevation gain, third, the hike was over mud and slushy ice and snow, and fourth, I was humping about 30 pounds of gear.  Let me tell you - that hour-long hike to cover that mile was the closest thing to real work I've done in recent years!  My heart rate climbed faster than the elevation, and even stopping frequently, like every 40 yards, it was hard to get the heart rate to drop or catch my breath. 

By the time I got to the switchback that provided the view I was after, I was soaked in sweat and just about exhausted.  And it was so dark that there was barely enough light to use live-view for focusing the 2 cameras - but it has potential to be a great vantage point!  The view to the left is the wide-field view with the zoom set to 200mm.  Besides the Large Binocular Telescope, the Sub-Millimeter Telescope (radio telescope), and the Vatican Advanced Technology Telescope are labeled.  While it looks pretty light yet, it is a 16 second exposure!  At left is the view with the 80mm F/6 (480mm equivalent).  I'm thinking if it was possible to drive to the site, it is just about perfect as there are very few places where there are good vantage points of the Observatory on the Mountain because of the forestation.  For about the first time since leaving the main road, there was also good cell reception, so was able to check in with Melinda, and also with fellow photographer Ray who was shooting the ARGOS from San Pedro Vista on Mount Lemmon.

I had planned to stay a while in case it cleared, and while there were some stars visible, there seemed to be some low clouds hanging over the Mountain.  But I had also started shivering, and knew I needed to get back down, as the temperature was dropping below freezing and my sweaty clothes weren't helping me much.  I repacked and headed down by flashlight - fortunately going down was much easier, though the mud and slush was starting to freeze.  There were a couple slippery spots, but was mostly good going.  Reaching one of the western switchbacks, I got a text from Ray, who had heard from LBT that they were going to shoot the laser shortly.  By then it had nearly totally cleared (of course, since I was headed down), but my decision was made and it had been a good choice.  Rounding a corner to head towards the NW towards the LBT, bam - there was the ARGOS beam!  While from my previous observations from tens of miles away the beam was at best barely visible, from here at only 4 miles distant there was no mistaking this beacon.  I stopped, too tired to even set up the tripod, but mounted the fisheye lens (the only lens I had packed besides the zoom and little scope), leaned it on a rock and exposed for 30 seconds.  It looked very much like the picture - the brightened areas are evidently where there were a thin layer of clouds to better scatter the light.

Even stopping to take a few exposures, the hike down was faster than the trip up.  I waited to get back to the van to munch on my snack and ran the heater on the drive down.  It was an uneventful trip back to Tucson, arriving about 12:30.  But even with the death march, it had been a good evening, and I learned a lot about the area.  I need to see how many hoops I need to jump through to get access past the gate next time!

More on LBT...

Image by Ken Spencer

It seems as if I'm stuck in a time warp - it has been a week already since we did the trip to Mount Graham and LBT, and yet, there doesn't seem enough hours in the day to post about it. I also had taken so many images (many for time-lapse sets and stereo-pairs) that it takes time to go through and do something with them.

Image by Stan Honda

So I'm going to start tonight's program with a couple images that are not my own! I know, I shouldn't do it, but since our little band of travelers were a tight-knit group, it's ok this time. Particularly filling in the coverage gaps that I didn't get! At left is a nice view of the LBT telescope enclosure taken from near the Vatican Advanced Technology Telescope. Ken took this shot - he is a former photographer from Newsday and runs a great blog - you should go visit! Anyway, it is an interesting structure. The opening (which is closed here) is facing away, and the doors you see here open to promote exchange of air in the dome while observing. The big tubes also help exhaust warm air from the big machinery room where compressors, air conditioners and other heat sources are located.

The image at right was a group shot of our intrepid band of astro-nerds at LBT that night!  Of course, that is the Large Binocular Telescope in back of us - two,  count 'em, two mirrors of 8.4 meters (about 28 feet) diameter working together for some instruments, separately for some.  That is Anne and Kevin at left, the observers for the night.  Then there is Mike and Ken from our group.  Elliot is an LBT engineer who was taking care of our needs, then Stan Honda and myself.  Stan is also a pro photographer, and infamous in our little group for getting an Astronomy Picture of the Day about 5 weeks earlier for his image of the solar eclipse from northern Norway!

Our tour started with the highlight - the telescope itself! I've been working around big scopes at Kitt Peak and big optics at the Mirror Lab most of my working life, but just being next to this gargantuan is breathtaking! And I can lay claim to polishing the pair of mirrors! At left is one of the primary mirrors, the SX or left hand one as viewed from the rear of the scope. You will note that the structure is huge, but they've never engineered a proper mirror cover, so it stays exposed to the telescope enclosure, but always point the telescope to the horizon before opening the shutter to make sure snow, ice, dead birds or whatever else doesn't fall onto the mirror.  While it looks a little dusty, they actually cleaned it a week or two before.  You might notice a swirl pattern in the surface - they use a CO2 cleaning system, much like a carbon dioxide fire extinguisher.  When horizon-pointing, the snow particles stick to the dust, and when it sublimates to a gas, lifts the dust off the mirror.  From the swirl pattern, it looks like the mechanical action of the spray did more to clean off the dust. Elliot informed us that much of it may be sticky pollen that is tough to clean off easily. This mirror is scheduled to be coated this summer shutdown, so will be good as new in a few months. At right is a view of the Gregorian secondary mirror which redirects the light to a focus through the hole in the primary to the instrument located below. In the reflection part of the primary mirror and support structure can be seen. The observers were doing spectroscopy with MODS, the Multi-Object Double Spectrograph. The spectrograph, big as a small house, splits the light into a spectrum allowing the astronomers to measure motions of many star-formation areas at once.

 

 

With such a huge structure, it is difficult to get oriented, let alone get it all in a single shot without the distortion of a fisheye. Here at left is a 6-frame mosaic of the telescope in an attempt to take it all in without distorting it too much. The primary and secondary in the SX system is seen. The large cylinder at upper left is the prime focus blue camera, swung out of the beam, as is the tertiary mirror at lower left. You can see the large ports near the center of the mirror where other large instruments are permanently located. The flat tertiary mirror swings into the beam and rotates to feed the instrument of choice. Way over on the far side of the enclosure, the secondary for the DX telescope can be seen. The DX MODS instrument isn't quite commissioned, so the observers were using just the SX side shown here.
The array of instruments is dizzying! Besides the MODS and prime focus cameras, there is PEPSI - the Potsdam Echelle Polarimetric and Spectroscopic Instrument, LUCIFER - the LBT near-infrared spectroscopic Utility with Camera and Integral Field unit for Extragalactic Research, and NIRVANA - the Near-IR/Visible Adaptive iNterferometer for Astronomy.  Astronomers love their acronyms! Starting this week, ARGOS will be in action again - I've posted about it before - ARGOS is the Advanced Rayleigh guided Ground layer adaptive Optics System.  It remains to be seen if I'll have time to track down images of it this run.

The tour ended with the inner workings of the building, including the "bogies". Turns out that this is one of the problem issues of the Observatory. The entire building rotates on a single circular rail on these 4 bogies. The weight is high enough on these 20 wheels that small shards of metal are occasionally peeled off the rail. Talking to one of the mechanical engineers at work who designed much of the telescope and building, he recalls the weight is 50 tons per wheel, so something over 1000 tons of weight supporting the precision motion of the structure... He was also telling me stories of replacing bearings in the drive that failed because of under lubrication. Always something interesting going on in big science!

They opened the telescope right at sunset, when Stan took our group shot above. One of my plans was to borrow Ken's new Canon 6D camera to take some time-lapse images. When I last did it in 2008 with my Canon 20D, I had to use 6 minute exposures in the dark enclosure with ISO 1600 and an F/3.5 lens. Such a long exposure necessitated using in-camera darks to reduce the hot pixels, doubling the exposure again - only 5 frames per hour! With Ken's new camera with its larger, full 35mm format, I used an F/2.8 lens and ISO 6400 for only 60 second exposures, no noise reduction required! The difference was night and day - likely the subject of a subsequent post. At left is one of these 1 minute exposures. The red lights at lower left is Mike or Stan at their camera taking exposures. Thru the open door at left center, the peak of Mount Graham can be spotted and to the left of that door, the crescent moon was casting shadows of the enclosure on the far wall. There were a few thin clouds in the sky, but spectroscopy isn't much affected by them. After my hour or so of 1 minute exposures, before packing up, I took an image or two out the dome enclosure. Shown at right, the lights of Safford, Thatcher and Pima can be seen. Off in the distant left, the bright spot is likely Fort Thomas, the more distant glow over distant mountains is likely Pinetop-Lakeside/Show Low, reflecting off the clouds from over 100 miles away. The North Star, Polaris is the brightish star at upper left center, and the constellation Corona Borealis is in the clear spot at upper right. Also spotted is a greenish layer of airglow low in the sky...

Being a one-time telescope operator myself, it was fun to spend some time with Geno, who was just starting his week-long shift at the scope. Turns out in a former life we worked together - he worked at WYKO here in Tucson and measured some samples for me. Anyway, the work as a telescope operator has certainly changed in 35 years, though technology has too. He demonstrated how he optimized the mirror figure in real time using a star and Schack/Hartman sensor to fine-tune the mirror supports. In a couple minutes the image improved from about 2 arcseconds to sub-arcsecond. At his fingertips he had everything from weather satellite images, all-sky cameras, and readouts from all around the building. They were all needed as he was responsible for the safety and well-being of the telescope. Unfortunately, when I took his photo (an HDR where several exposures are blended), for some reason I had turned off the autofocus and they were out of focus... Oh well, I like it well enough to include.

Well, I've more to show you, but will have to wait for another time...  Stay tuned!

More ARGOS!

Well, I took my own advice from our last post.  Last night was the last night of the first engineering run of ARGOS, the Advanced Rayleigh guided Ground layer adaptive Optics System. It will allow making artificial guide stars to partially correct atmospheric turbulence.  Since it won't be in use again until next Spring, Melinda and I took off for the Willcox area - where the observatory is readily visible and closer than the view we got from Mount Lemmon Wednesday...

But also more visible, the moon had grown 2
days brighter and partially affected the visibility.  While we were about half the distance (about 20 miles due south) to the Large Binocular Telescope, the brighter sky partially hid the beam, though I was convinced that I could barely see it naked eye.  It was, of course, evident in binoculars from the fallow field where we set up...  These wide-field images, while apparently illuminated as bright as day in the long exposures, approximates the view of the laser - I could follow it in binoculars nearly up to Polaris as shown here.  The bright sodium lights at left is the prison Fort Grant, a mere 6 miles (and a mile below) the Observatory.  The picture at right shows the 2 lenses I had set up - a 70-200 zoom at left shooting 60 second exposures, and the William Optics 11cm APO refractor at right taking 2 minute exposures.  Clicking on either will load the full-size images and the laser will be visible...  Both of these pictures were taken with the Canon 10-22 zoom, the one at left near 20mm, the one at right near 10mm...

Both setups took nice images of the
mountaintop.  The wider 200mm showed a wider field of the mountaintop and caught several cars going up and down the mountain, though not in this particular frame at left.  It is a 60 second exposure at F/3.5, and shows the LBT structure and the twin beam, one for each of the primary mirrors of LBT.  The shot at left is from the 11cm F/7, so 770mm of effective focal length and is a 2 minute exposure.  It shows not only the LBT structure and laser scattering from the interior of the building, but to the left of it is the moon reflecting off the dome of the Vatican Advanced Technology Telescope (VATT), a 1.8 meter (72") telescope also built at the Mirror Lab.  Dimly visible between them (if you look at the full image) is the Sub-Millimeter radio Telescope (SMT).  Each beam actually consists of 3 beams that map out  the turbulence over a wider field of view, but they can't be resolved from 20 miles.  For more close-up pics, info and links, visit the LBT news blog.

It is fun seeing the developments in this product of the Mirror Lab and the first two 8.4 meter mirrors that I had a hand in polishing.  It would be great being on site during the next round of testing - will have to ask some favors and see if I can be up there next Spring!

Road Trip!

I've got some friends visiting from back east - both professional photographers and amateur astronomers, so I scheduled a road trip to some astronomical sites! What better location than the Mecca of astronomy in Arizona but the Large Binocular Telescope (LBT) atop Mount Graham! It is an engineering marvel and should be the top of anyone's list to visit, were it not for an arduous 3 to 4 hour trip with ending with 29 miles of rather harsh mountain roads...

But the adventurers that we are, we set out yesterday morning, heading east on Interstate 10. Believe it or not, about the best view-from-a-distance is from Willcox, nearly 30 miles away! The shot at left is with the 300mm lens, and shows the towering box-like structure of the LBT enclosure, and the bright spot to its left is the sun reflecting off the Vatican Advanced Technology Telescope.

After a bite of lunch and caching away some snack supplies for later, we continued another 25 miles and turned north towards Safford.  We approached town early enough that I decided we had time to drop in and visit Paul and Jackie at the Discovery Park Campus of Eastern Arizona College - a great little local science center. They had helped us a lot with our Russian visitors a few years back, and for these newcomers, it was a great short visit. One of the highlights for us science-types was the "camera Obscura", which is a large lens system, projecting a distant view on a projection screen. Shown here at right is our group shot under the inverted image of Mount Graham, which we were about to go visit.

The trip up the mountain was interesting if not challenging, but we made it in fine shape, arriving close to 5pm. We found an engineer waiting to give us a guided tour, and what a tour it was! We went nearly everywhere, and he was very patient in trying to answer our barrage of questions and letting the 4 of us photographers take gigabytes of images! Eventually, as sunset approached, we ended up on the telescope floor as they opened the dome for the evening. At left is shown a 3-frame mosaic with fisheye lens to fit everything in!

We had an amazing evening - we got to go pretty much wherever we wanted to go to image. I'm keeping this post short because we've got more adventures today. But I'll close with an image taken from the LBT "patio" with a great southern and western view. Shown at right is a wide-angle shot to the west showing Orion, Winter Milky Way and Moon and Venus setting with part of the LBT structure to the right. The two yellow glows are the light domes of Tucson (to left) and Phoenix at right.  Yes, there were some high thin clouds, but it didn't seem to bother the astronomers much (they were taking spectra of star-formation areas in galaxies), and the clouds make our exposures more interesting as well.

Much more coming up, and I suspect today's adventure will generate more posts.  Stay tuned!