A Telescope's Second Life!

It is said that a home-built telescope is never finished. Likely true as a commercial version upon which thousands have been spent are likely never to be touched by their owners outside a dusting of the mirror or lens. But one built with your own hands in your workshop are easily tweaked or modified to meet one's changing needs. Case in point has been my 11.25" scope built late in the last century... On the long drive back from the Riverside Telescope Makers Conference a couple decades ago, my mind full of new ideas, I was thinking of a "fast" telescope system (needing only short exposures). Besides a short focal length, it would feature a built-in guide scope that would minimize deflection between the scopes that would lead to trailed images. The result is shown at left, set-up at a Kitt Peak Star-B-Que in 2010, likely the last time it was used in that form. Check the link for commentary on the star party and a nice collection of images taken that night. For a home-built, it worked pretty well - the guide scope actually focused through the main scope to the silver focuser, where manual or autoguiding could take place. Off-axis stars were easily found by adjusting the small 5.5" guide mirror's collimation. My favorite from that evening is shown at right - 17 minutes on a supernova remnant called the Veil Nebula - an outstanding result from a short set of exposures.

While the scope was a little unwieldy with the weight and mass distribution of the guider telescope, the focal length was perfect (about a meter), and the speed, about F/3.5 allowed exposures of only a few minutes. What spelled its doom as far as being my "go-to" scope was getting the Hyperstar attachment for the C-14 scope. With the larger 14" aperture and faster-still (F/1.9!) optics, it had a wider sharp field of view with nearly equivalent exposures less than a minute! Also, if you wanted to switch to visual observing, slip out the Hyerstar, put in the secondary and you had a C14 with its excellent optics. But I missed my lil' home-built! We had spent a lot of hours together in figuring the mirror (twice, to get the curve just right!) and building the thing. And we had won prizes together - both a Merit Award when it appeared at RTMC. and again a few years later when we saw all 110 Messier Objects on a single night at the All-Arizona Messier Marathon, when for a week or two in the Spring, you have the chance to track down all of Charles Messier's little fuzzies he cataloged as he hunted comets in the 18th century. Plus, the longer focal length allows a little larger scale of celestial objects.  So I was thinking of resurrecting the scope...

In reality, telescopes are simple devices. The tube of the scope rigidly mounts the optics and focuser, along with any other ancillary optics and accessories. The glass is fragile, and the mechanics of a focuser are beyond most, otherwise there is little complicated in one. Shown at left is how the scope has been in stasis since that Star-B-Que 5 years ago. At right is a view down the working end, and you can see how I made a simple spider to hold the secondary mount, and you might see how the guide scope at left is focused through the main scope to the silver focuser at right - handily next to the camera mounted on the main scope.   Besides removing the guide scope to make it lighter, the only changes I had in mind was a new set of commercial rings from Telescope Support Systems, a small garage shop run by some friends in Michigan, and a focuser to replace the plastic-and-PVC version I'd started with so long ago. I decided on a sturdy 2" focuser from Antares for $180 - seemingly a good step up.


After removing the primary mirror and cell, I reached up the tube and removed the nearly 20 bolts with which I had attached the guide scope to the main tube. The guide scope then came off without any issues. The new tube rings went on perfectly! They had wanted my tube dimensions to a couple thousandths of an inch, and I had 3 ways to measure and report it to the company for accurate machining, and it shows in the product. The two saddle plates I got do double duty - one side attaches to the mount, the other holds the new, much smaller guide scope that I use now for accurate tracking. The new installed rings are shown installed at left, the new focuser still in plastic on the right. After some careful measurements and layout, I drilled 4 new holes for the focuser and attached that too, so literally, in a couple hours of work, the scope was reconfigured and brought back to life. It is now much lighter and easier to manage by myself, and occupies a seat of honor in the van with its own special seatbelt made of a couple clamps and 2" webbing from REI! You might have spotted its initial use here in Tucson at friend Dick's house when he held a little star party early in the month. I mounted it on an alt-az mount designed and built for my TEC 140, but worked fine for some wide-field views through the 11".


I was able to get out for a couple partial
nights to a friend's house near Benson. Not perfectly black skies, but plenty good enough for some trial runs. Shown at left it is mounted on the AP1200 mount. When I acquired the mount a couple years ago, I got a stumpy pier for use with Newtonian scopes, but never used it till now. But the combo seemed to work well, though I've got to crawl on the ground to use the Polaris scope to align the mount to the Earth's rotation axis. And once done, I forgot to lock some of the adjustable bolts the first night out allowing some trailing... The entire huge guide scope I took off has been replaced by the little white scope between the tube rings at left and a digital autoguider camera. You no longer need anything close to the focal length of the main scope (the old standard 20 years ago) these days... Because of the mentioned trailing issues due to some loose bolts, the images aren't too impressive, but I was able to collect 7 frames of 3 minutes each on NGC 891 shown at right. Blobby stars, but shows some promise. Still getting some weird diffraction patterns around brighter stars - saw that also on the earliest images from Dick's house.  I originally blamed it on the coma corrector extending into the beam, but I'm thinking there may be a turned down edge too...

The next time I was out to Benson and Pat's (the night of the Trident Missile launch on 7 November), I made sure to tighten all the bolts, and also made a mask slightly smaller than the mirror to block unwanted diffraction. This time the seeing was poor, but was still reasonably dark. At left is shown a fisheye picture (8mm lens for 90 seconds) showing our sky with Roger Ceragioli's newish 11" refractor and my 11" Newt working side-by-side as the Winter Milky Way started rising. Finally, just as we packed it in, I took a few frames of the Pleiades rising in the east, of which only 2 frames were suitable for stacking. So this is 4 minutes total exposure, with some cropping. Stars are excellent, as are the diffraction patterns. The Pleiades sits in the middle of a dust cloud, which is illuminated by some of the stars here. Note on the right side, about an inch from the edge when looking at the full-size image, there is a little edge-on galaxy halfway from bottom to top. I'm looking for the name of that guy and will report it here if I find out. Anyway, I'm thinking the scope is showing promise again as I get back into some dark sky imaging. Stay tuned!

It has a name!  The lil' galaxy near the Pleiades was tough for me to track down, but thanks to professional astronomer Brian Skiff of Lowell Observatory, who did all the heavy lifting in IDing it, it has a name.  It is UGC 2838, nearly 350 million light years distant (!).  The Uppsala General Catalogue is a catalog of all galaxies brighter than magnitude 14.5 north of the Celestial Equator, using the first generation of the Palomar Sky Survey as its source material.  The image at right shows a little closer view with the galaxy indicated - again, only 4 minutes of total exposure, so you shouldn't expect much!  In some of the writings about it, its brightness is quoted as nearly 18th magnitude, but in others it is listed at about 15th magnitude - still faint by visual standards, but obviously easy to catch photographically with the 11"!

Star Party!

When talking to "normal people", ie, NOT astronomy nuts, you often get a strange look when talking about "star parties". Most are taken aback, not knowing what you mean. A few think of the idols of the screen as "stars", but that is certainly not what we mean. Generally, a Star Party consists of folks with telescopes or other optical gear (binoculars work too, or even naked eyes!) set up at a location to observe, generally willing to share equipment with others for viewing the sky.

Our friend Dick had put out a call about midweek last week pointing out that good weather was forecast and he had a number of newly acquired scopes to try out. Dick is an optical designer by trade as well as a bit of a connoisseur , purchasing (normally) used equipment, trying them for days or weeks, then selling them back on the market for the same or bargain prices. His specialty is refractive optics - those that use lenses to focus the light for the eyepiece to magnify before going into the eye. Since there isn't really any such thing as a perfect refractive optic (they all have at least miniscule flaws), he ferrets out the details of why a particular design can work well, or more typically, is mediocre or of poor quality.

I've been working on refurbishing a telescope (more on that in a subsequent post), and was about to the point where I wanted to take it to a dark site, but Melinda was up for some social activity, so we attended. My 11.25" Newtonian scope uses a concave mirror to focus light off a smaller secondary mirror to the eyepiece. On this night, it was handy to use the alt-az mount I made for my TEC 140, so pointing was done by shoving it away or towards you, and up or down to find various objects. A couple views of the scope on the mount are shown here.

I had some work to do on it - a final
collimation (alignment) of the optics on a star, after doing a preliminary version with a laser beforehand. With the 17mm eyepiece I used, we got nearly 60X, which was just about perfect for manually moving around the sky with such a largish instrument. Thinking ahead to a blog post, I thought I'd try a selfie with a big, bright object like the Pleiades that was low in the east. Setting up the tripod and camera, I used a delay, ratcheted down flash, and a long exposure (30 seconds) to catch the scene with myself and star cluster. It only took 3 attempts to get the "perfect" image shown at left.

Dick held little interest in reflective optics - not sure he even looked thru my scope, but he had just gotten one of his "babies" back from factory repair. His Meade LS8 is advertised as the perfect scope for newbies as it uses GPS technology and a built-in camera to find its way around the sky and give the user a sky show with no knowledge of where anything is located. After obtaining it used, it never worked satisfactorily, and it spent 4 months getting "fixed". At right, Dick looks at an object that it found. The happy ending is that after failing to find its way around the sky initially, after turning it off and back on, it worked!

The star party was rather under-attended, but the 4 astro-nerds had fun, and we took occasional breaks to go into the house and mingle with the Significant Others. We all got a good look at a couple of 4" diameter F/8 refractors of high quality, and with Dick's tutelage, looked for the indicators that pointed out the flaws in one of them. Thanks to Dick and the other attendees to make it a memorable evening - always fun to be under a clear sky with friends, even with some light pollution!


We didn't stay late - Melinda tires easily and I was anxious to put my camera in place of the eyepiece to take a couple images. But I'd forgotten a key camera adaptor piece, so had to wait till we got home. Set up in the front yard, with the non-tracking mount, the only object I could shoot with more than a few seconds of exposure was the North Star - Polaris, shown here at left in a 30 second exposure. There is a weird artifact in the diffraction pattern on the bright star - I suspect that it is because it is in a tube that is a little small (12" diameter) for the size mirror (11.25"). In addition, I think the coma corrector, which fixes the aberration in fast reflectors, sticks into the beam slightly, so that is the likely cause. But for 30 seconds, in town, most stars are pretty tiny, so I'm pleased. If you click the image for the full-size view, you will see there is even a little trailing in 30 seconds so close to the pole star. Just for fun, I decided to move the scope about 5 degrees south to NGC 188, a star cluster very close to Polaris. Shown at left, note that the same 30 second exposure shows a huge amount of trailing!

The key is to use the tracking mount (that takes a lot more to set up) which allows exposures of unlimited length from a dark sky - sometime soon, I hope!

Seeing the Unseen!

I was up on Kitt Peak last evening, helping out with their beginning astro-photography class. It was a very nice group - one fellow who lives 25 miles from our house in St Charles, IL, a couple from Florida and even a couple from Tucson! All were fans of astronomy and getting into trying to image the sky. My little presentation was about some of the time lapse that I do. Of course, you can click on the "time-lapse" keyword on the right side of the page, or go to this link, which does the same thing!   My motivation for most of my time lapses is sort of seeing the unseen by demonstrating the motion of the sky or objects, instead of static images.

Last night, the second night of the workshop, we got them going exposing on they sky with their own equipment on tracking platforms or piggyback on the TEC 140 piggyback on the 16" scope at the Roll Off Roof. As first time astro-photographers, we ran into the usual issues - not having adaptors for all cameras, or not having the intervalometers or cable releases to take long exposures, but we got past them mostly. Most were truly enthused about their first images, and all seemed inspired to push forward into this new aspect of their hobby.

While we were away for dinner, I had set up my tripod-mounted XSi with a 300mm lens shooting at the VLBA telescope about a mile down the road near the picnic area. The 80 foot dish is part of a 10-telescope array scattered around the hemisphere. I was hoping to demonstrate how time-lapse techniques show things you had no idea were going on. Take an image of the dish and yea, looks interesting, but take a second and third and you realize that it is changing its pointing between EVERY frame taken at 30 second intervals! Of course, I knew nothing of the observing program - the telescope is run remotely from the VLA headquarters near Socorro, NM. I do know that IR and radio wavelength observations used to take data by offsetting off the object to measure the background signal. This is what appears to be happening here. You can see offsets both N-S and E-W in the time-lapse.

Anyway, I took the VLBA sequence and also one of the sun setting in a clear gap in the west, to demonstrate how easy it is to use Microsoft's Moviemaker program to make the time-lapse. But the constant motion of the radio telescope was more interesting in my book. However, the sunset was interesting too in that it set directly behind the Pinicate Mountains, visible as the more distant peaks here. They have been featured many times on the blog as we drive past them on the way to Puerto Penasco on the Sea of Cortez. At left is a pre-sunset image of where the sun eventually set. The flat-topped mountains are the Mesquite range, nearly due west of Kitt Peak. The more distant mountains are the volcanic Pinacates, just over 100 miles distant. At right is the same horizon with the sun entering the image...

Finally, here is the time-lapse I constructed during the workshop, here with an intro shot and uploaded to Youtube. The radio telescope is a flurry of activity, moving between nearly every frame taken at 30 second intervals.  Go to full screen and HD if you have a high speed internet connection!




We fought a few thin clouds through the evening, but fun was had by all as they say, and hopefully we all learned a few things.

Latest From The Edge Of The Solar System!

I just saw the most incredible image yet from the New Horizon spacecraft, just sent from Pluto and I had to share it with someone!  Shown at left is the image, with NASA's caption reading:

Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 3,500 meters high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights over a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 18,000 kilometers to Pluto; the scene is 1,250 kilometers wide.

NASA / JHUAPL / SwRI

 

While taken mid-July, over 2 months ago, data from the close encounter is continuing to trickle down, and will continue to do so for something like a year! The gift that keeps on giving... Since this blog is limited to images only 1600 pixels wide, the original image is much larger. I won't try to add my own interpretations, nor give the details of how it was taken - I leave that to the experts - in particular, Emily Lakdawalla's excellent blog, where I first saw the original image.  She has an excellent summary describing what we are seeing and how it was taken. Be sure to read it and visit ALL the links she has on her post. Incredible stuff!

Phoenix??? Yes, Phoenix!

We like to kid that the only reason we have to go to Phoenix is to get through it to more interesting places beyond - mostly the Grand Canyon or California... But this is not strictly true - a few times a year, like yesterday, we go up to the great metropolis to the north to attend the Saguaro Astronomy Club (SAC). I've developed quite a number of friendships among their membership over the years, have spoken to their club on several occasions, and they even made me an honorary member, ostensibly for restarting and running the Grand Canyon Star Party for a generation. Overall, they are a friendly outspoken group of quite avid amateur astronomers, and their meetings are always fun to attend. So even though Melinda was 26 hours past getting her latest chemo treatment, and I had a long day of meetings and work, 5pm found us hitting the road for points north.

The 2 hour trip door to door at Grand Canyon University is pretty boring unless you enjoy expanses of flat desert (even less exciting than expanses of cornfields in the Midwest!). The monotony is interrupted by passing between Picacho and Newman Peaks (left-to-right) about a third of the way there, and continues past occasional cotton fields, pecan groves (thanks to prodigious irrigation pumping), and small desert communities. About 70 minutes after the picture at left (including a 10 minute bathroom break along the way), we descend a hill into the urban jungle with a view of Camelback Mountain at right(because of its resemblance to a reclining camel). We got to enjoy a pretty sunset over the downtown skyline, but no place to pull over for a picture.

Right on schedule at 7:15 we walked into the meeting room to surprise our friends there. Melinda was just about tackled by our friend Jennifer who repeated her hug so I could get the picture at left. I can personally attest she gives great hugs! After greeting and pestering a few of our buddies, the meeting got underway - the topic this time was a "Member's Night", where 9 members gave short presentations about items of interest or projects they are working on. These are great opportunities to see what a club's members are doing and how serious they are in their pursuits. The show tonight was uniformly very good and interesting. One of the first was from Steve Dodder, shown at right, who had replaced the heavy base of a club telescope with one that only weighed half as much -assuring it would get used more often. Steve stepped up a decade or more ago and runs the North Rim version of the Grand Canyon Star Party, so it was good to see him, though he didn't bring his better half, Rosie to the meeting...

Another great talk was by SAC president Michael Poppre. He's developed a friendship with Lowell Observatory mechanical engineer Ralph Nye. While Ralph's work has lately been wrapping up the refurbishment of the 24" Clark refractor at Lowell Observatory, Michael talked about a similar task - resurrecting a John Brashear 9" F/9 astrograph that he had found abandoned at the Observatory in his spare time over a 4.5 year period. The telescope (along with a 6" astrograph and 4" guide scope), is again used for imaging by Ralph using sheet film. Supposedly the walls of his wife's restaurant "Crickets" in Montezuma's Well is lined with images from the "new" century-old telescope.

Another thing I like about the SAC meetings is that there is a break early in the meeting for some socializing, refreshments, as well as a small swap meet in the rear of the room. I wasn't too interested in much (after a stern look from Melinda), but ended up with an adaptor, and a t-shirt for a $5 donation. There were a pair of 20X100 binoculars that were tempting for only $175, but with my very own even larger antique pair, I couldn't justify the deal. At right Paul Lind tries them out while the inset shows the details. If any of you are interested, I can get you in touch with the owner...

Speaking of Paul Lind (trying out the binoculars above), I loved his t-shirt, so include it here. Along with the "ascent of man", the last view shows the modern man using a telescope... I love it!

Saving one of the best talks for last, former SAC president Tom Polakis talked about some of his recent projects, which included some sunsets over Lake Michigan on a recent trip to the Upper Peninsula of Michigan, his home state. While those were spectacular enough, he worked through some atmospheric models that output the shape of the sun, given its altitude. At right the chart at the right edge shows the sun's actual position relative to the horizon shown in blue, and the atmosphere's effect on both the refracted position and flattened shape. With the sun appearing to sit on the horizon, the actual position of the sun is completely below the horizon as shown. The scale of both axes is in arc-minutes, with the sun being about 30 arc-minutes (a half degree) in diameter. He also had some great images of Venus as it moved through inferior conjunction recently, about 8 degrees from the sun. These Venus crescents were imaged by combining thousands of images to get the best results. Many of his planetary images are quite breathtaking and can be seen posted on his Pbase site, along with his many other adventures. He closed out his talk with some telescopic images of the International Space Station passing overhead - quite spectacular and again, can be found on his Pbase site.

The meeting ended promptly at 10pm (where it was still in excess of 100F outside!) and most of the members went off to a nearby restaurant to continue the socializing. While only a few miles away, it was in the wrong direction for us, and we headed back to Tucson, getting home right at midnight. A tiring drive, but a lot of fun - we'll certainly be doing it again when our schedules allow!

While Cooling My Heels...

In the last post, I told the story of chasing down the (Dwarf) Planet Pluto from the back yard last weekend with the C14. Pluto wasn't in a great position for observing till a little later in the evening, so was looking for other projects to come to mind. Well, Saturn was sitting right there on the meridian staring down at me, so decided to do something with that. While playing peek-a-boo with clouds, the temps stayed warm, and the air muggy and I never got very good shots of Saturn itself, but with a few second exposure, the moons of Saturn were easily recorded. I ended up taking a series of exposures every 30 minutes for just over 3 hours starting at 8:20 (12 July, 0320 UT). I took a series of 2.5 second exposures, then for grins took some 15 second exposures as well. Turns out I used all of them, stacking them together for a single image for each of the 6 time stamps. Unfortunately, one of my 30m samples was completely clouded out...

Once all the images were taken, I wasn't sure what to do with them... Since Saturn is nearing the Milky way, immediately obvious was a number of stars as well as the planet and moons. I tried aligning on a star, but unfortunately, picked the moon I think is Iapetus, and got a weird stacked image. At left is shown a proper stack referenced to an actual star. Saturn is, of course, the way-overexposed oval in the center. While it is obvious that the planets move slowly across the sky, I was surprised to see how much Saturn and moons moved during the 3 hour observation period! Each of the moons appear as a series of points as their motion carries them along relative to the stars...

Again, how to display them and show the dynamics of the system... After finding the gif software for the last Pluto post (a free download called PhotoScape), that seemed to be a natural. I first made a sequence as above, aligning all the frames on the star at the lower edge below Titan. I decided to use the images at full camera resolution, just showing the inner 6 moons. This first gif is shown at left.

After showing it to a couple friends for feedback, one suggested centering on Saturn, since that is what the moons were circling. He thought the motion of planet and moons relative to the stars was a distraction. So I worked on that tonight. Unfortunately, most stacking routines won't automatically register on an extended object like an overexposed image of Saturn, and I wasn't smart enough to do it manually. Fortunately Nebulosity has an automatic non-stellar alignment, and it worked ok, but not great. It is shown at right with a little jerkiness, with a couple labeled frames included for identification... I liked the effect, but would like some better images, perhaps on a future cooler night.

Anyway, another fun project - am already looking forward to next June during an opposition night when the coverage could be at least doubled or more.

Happy Aphelion Day!

So did you notice that it was a little cool yesterday, perhaps compared to last January? Well, of course, those of us in the northern hemisphere would of course say no, it was colder last Winter. But yesterday the Earth passed aphelion - the point in its orbit farthest from the sun. I noted last January that we were passing the near point, perihelion at that time. The elliptical nature of the Earth's orbit is a little over 3%, but is not responsible for the seasons. It happens to be warmer near aphelion for us because in the northern hemisphere, the sun is shining more directly down on us and for longer days. It happens to be cooler when we're closer to the sun in Winter because of the shallower angle of sunlight and shorter days - again, in the northern hemisphere. The image above was taken of the sun this afternoon, and shows part of the disk at full camera resolution through the TEC 140 telescope.  North is approximately up, and shows active region (AR) 2381 that is transiting the Sun's disk now.

Since I used the same camera and telescope combination last January, we can compare the apparent change of the Sun's diameter. I've never seen this demonstrated, though I did it for the Moon last year. In that case, the difference in the moon's size between apogee and perigee is 14%, so is much more dramatic. In the case of the Earth's orbit around the Sun, 3.4% is much less dramatic, but easily visible here at left. By chance there happened to be active regions at the same solar longitude when both images were taken - AR 2381 in the top image taken today, and AR 2253 on the bottom image from 3 January. An alternative display is shown at right, where both were aligned in Photoshop with an opacity of 50% so both images can be compared, around their edges anyway...

I was actually a day late in my aphelion imaging session, though yesterday was a much cloudier day without much chance to image and the difference of a day doesn't amount to much, distance wise... Rounded off to the nearest 1000 miles in the left image, they reflect both the aphelion/perihelion distances and the distance when the images were taken...

Even though the change in apparent solar diameter is small, it was neat to see the difference. While the Moon's change in apparent size might be detected by eye over the course of a couple weeks, you have to go search for the Sun's change - not a readily observed difference!

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!

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!