Lockwood
Custom Optics at the
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It is always a great day when we crest the hill on a normally sun-baked two-lane highway in northwest Oklahoma and the observing field for the Okie-Tex Star Party comes into view. This means that we have arrived, and more importantly, that John Pratte (of JPAstrocraft.com) has not gotten annoyed enough with me to kick me out of the van after we have driven for a day and a half to get to the place. This year, we arrived in the early afternoon of Saturday and found the observing field quite full - this was a good sign, but we had to look around a bit to find enough space to set up. However, as is becoming tradition, we first stopped off in quiet and sunny Boise City, Oklahoma, and pulled into the gas station to fill up the tank and order a Subway salad.  You see, this is cattle country, and we won't see many vegetables until we leave. I'm not a vegetarian and I never will be, but I do love my veggies, and the diet at the star party is somewhat beef-centric, shall we say. So, Saturday lunch is sort of our farewell to veggies (at least for 6 days or so) meal. (This is becoming a running joke with the amazing star party staff, so I hope they get a good laugh here.) During our meal I noticed Howie Glatter and his wife Poksun pulling up in their RV/van, so we said our hellos and soon were on our way the final ~35 miles to the star party site. As usual, we brought John's 32" f/3.6, which he built, and for which I made the optics. In other years we have brought additional instruments, but this year we didn't have to cram another instrument into the van. I am blessed with really good spatial reasoning skills (meaning I'm good at putting stuff into available space), so it is my job to figure out how to pack, pile, and jam all of the weirdly shaped stuff that astronomers travel with into the transport vehicle, which is John's full-size Ford van. This is what I normally end up doing when I arrive at John's house, early on Friday morning, eager to get down the road. When we arrive at the star party, it's time to find all of my stuff, quickly drag it into the bunkhouse, and then we find a spot on the field.... if we can. Okie-Tex has really grown! We found space and set up in an area similar to the one from last year, but this year Joe and his 32" did not make the trip because he was busy. So, the task of operating one of the largest telescopes on the field and entertaining people as they walked by (if we were awake!) fell to us. Our site was in the east field, one row north of the south edge of the field. This means a bit of a walk to get to the enclosed facilities, dining tent, bunkhouse, or other buildings, but we got a lower southern horizon, which we took advantage of on at least one night later in the week. We settled into the star party rhythm. Below John Pratte lounges in his reclining chair (vital equipment for a star party if you ask me), and he is also pictured with the 32" f/3.6 telescope that he built. A true Okie-Tex afficionado, he's wearing the t-shirt from the 2011 Okie-Tex.   Saturday night was clear and cool which is typical Okie-Tex weather. I stayed up until about 2am viewing the typical Okie-Tex objects under good skies, but poor seeing. We started working on an observing list that was put together by my friend Bob. Speaking of Bob, he (right) and our friend Mike (left) are pictured below.   Damn cell phones.As some of you might notice, things have changed a little bit at Okie-Tex. Cell phone coverage has improved, and what used to be a nearly cell-signal-free zone has now degenerated into a covered area. This is convenient, but slightly sad if you're like me and don't really like to always have a phone in your pocket. (My phone still, blissfully, does not work there, so I stick to email for communication.) Okie-Tex used to be a nice bubble of isolation from people who wanted to call you and text you, or, more importantly, it kept annoying people from annoying you while being annoying on their phone in the middle of the night. However, this is no longer the case. Oh well, at least it's still dark, though it is definitely a bit noisier, and it was a rather annoying election year so political conversations were occasionally heard spilling out across the dry field. In the photo at right, I am getting ready for our first night of observing, all 6' 2" of me dwarfed by John's beautiful 32" telescope that we would use to collect some memorable photons and views over the next six nights. No, that's not a cellular antenna sticking out of the secondary mirror cage at the top of the telescope - it's the plastic handle that you manipulate to work the filter slide, which makes using filters roughly twenty times faster and more convenient than the old fashioned way of screwing filters into eyepieces while trying not to drop them in the dirt. It was a warm evening, and t-shirts were the norm as darkness fell. This would not last, however. I believe partly cloudy skies, wind, and rather poor seeing hastened my departure to the bunkhouse, but that's OK, it is always good to start slow at a long event. As is normal for the first night, I got tired and headed for bed. Sunday dawned much cooler after the passage of a front, which caused the wind. I took advantage of the cool, sunny morning to go for a run into Kenton and beyond and back. Then I worked on my talk as the sun warmed the high plains and canyons around Okie-Tex. Sunday night ended up being very cold, around freezing. After being used to summer weather, combined with lower activity levels during observing, this is a bit of a shock, and it was time for the heavy parka to keep warm. I managed to stay out until about 1am when I crawled into bed under some warm blankets. My friends Bob and Mike were around, but due to the cold and an early morning departure, they turned in early as well. The temperature change between Saturday and Sunday was fairly significant, and that brings up another important point - your optics perform best when they are as close to air temperature as possible. This is not easy to achieve with larger mirrors, so John and I have been experimenting with different fan-aided cooling arrangements for years. Coincidentally, this was also part of the subject of the talk that I would give on Wednesday.  Above is an image of the interior of the 32" mirror box, with three fan systems visible in one photo. First, at top left and right, under the front baffle and reflected in the primary mirror, are fans that blow down and toward the center of the mirror from the corners of the mirror box. These help mix the air in front of the primary mirror. There are four of these total, one in each corner. By blowing on the mirror from four angles, the air streams combine to produce turbulence, which is good for faster cooling. They also cool the mirror fairly evenly because they are spread around the mirror. Next, above the mirror we have five fans set up to exhaust upward, thereby removing the warm air that can collect under the top of the mirror box when the telescope is not pointed high in the sky. These also aid in drawing more fresh air into the mirror box so that other fans can mix it up. Finally, out of focus in the bottom-center of the image above is a fan that is suspended about eight inches above the surface of the primary mirror using wire which also conducts the electricity that runs it. The wire is aligned with the spider vanes. The fan blows directly at and on the center of the mirror, and this air stream hits the mirror and spreads out nicely. This produces a nice diverging breeze of air that helps remove the warm air that likes to cling to the front of the mirror.  Above is a better view of the center fan, mounted on a hinge so that that it can be swung out of the way for collimation with a laser. The fan is not removed for transport. The mirror's center spot is visible out of focus at lower left. Together these fan systems helped cool the 2.1"-thick 32" mirror quite nicely, and I think it performed a little better than other years thanks to the four extra corner fans and the exhaust fans in the top of the mirror box. We observed at over 600x on at least one night, and at a fast-cooling site this this I couldn't complain. The fans certainly sounded impressive, eleven fans total singing in the cooling evening air as the Milky Way blazed overhead. Sounded like progress to me! On Monday night it was not as cold, and we had good transparency. We set out to work on an observing list that John made up. Unfotunately that list got lost later on after it blew away in the wind (another normal feature at Okie-Tex), and I don't have a record of what we looked at.  Above is an image of the northern sky showing a meteor, a plane, and red and green bands of skyglow, which was quite plentiful during this week. A tiny amount of light pollution is reflected on the northern horizon, and the source is an unidentified town in Colorado.  Of course not much outdoes the stunning splendor that is the southern Milky Way. John Pratte tends his instrument, bathed in red light below the horizon. Many planes take a route that has them passing low along the southern horizon, right through photos such as this. What an inconsiderate air travel system! Antares is seen within the glow of nebulae low and to the right, just above the long streak from a cruising airplane. Dark nebulae show plentifully in this beautiful region of sky. The five exhaust fans can be seen on the top of the mirror box of the 32" scope.  I always enjoy the rising winter Milky Way, and the above shot is of the northeastern sky in the early to mid-evening at Okie-Tex as the winter constellations start to tempt observers. M31 is obvious at the top, and the double cluster just above center. For me, though, I am not tempted by the winter constellations so much because I am an annual attendee of the Winter Star Party in the Florida Keys, where we can observe Orion in February in a civilized manner - eleven degrees higher in the sky, and in t-shirts and sometimes shorts! For me that break during the winter is absolutely necessary to shop morale! All star parties offer different things, so it's good to travel around and find the ones that you like. For me it's Okie-Tex for prodigious amounts of observing time (because it's usually clear) and great people, and WSP helps me get through the winter without losing my mind (because it's usually warm). Of course WSP also has great people, too. Tuesday night brought an amazing dinner, and then it brought a revelation. First, the dinner......   Above left we see some of the organizers staying busy organizing, delegating, and supervising from their shady vantage point by the bunkhouse before dinner. In contrast, above right we see Poksun, Howie Glatter's wife, slaving away over a hot wok cooking up a delicious dinner of Korean food. Howie makes the best laser collimators available, in my opinion, see his site here.  Above we see the delicious beef that she cooked, spicy bean paste, and lettuce to wrap it in. It was a filling and very memorable dinner with may great characters at the table, whom I have a agreed not to identify or show in photos. What happens at dinner stays at dinner. Soon night came. As we observed, enjoying a nice warm Okie-Tex breeze, a group of people arrived with a mysterious case. The case contained a third generation image intensifier eyepiece. By removing the filter slide and running the SIPS inward eight turns, we were able to get the eyepiece to come to focus in the 32" f/3.6 scopes. While we lost optimal coma correction, we gained so much more. We used the 32" scope to view M16, the Veil, M51, NGC 281, and more. In all cases the intensifier brought out details and made each object look like something we had never seen. The pillars of creation in M16 were almost three-dimensional and quite obvious, the Veil showed things and bits that we had never noticed, and other objects were greatly enhanced. It was very impressive, and I will be experimenting with one of these more in the future. We visited with some other friends, and then closed down when clouds started to come in later on in the evening.  Above Howie Glatter (left) and Charlie Warren (right), the editor and publisher of Amateur Astronomy Magazine, talk as they wait for darkness to fall. This year Charlie was there to cover the event, and was doing imaging. Charlie's article about Okie-Tex is in the Winter 2017 issue, which is just coming out as I write this. On Wednesday afternoon I gave two talks, the first about mirror cells and mounting optics (see my article on the subject here), and the second about thermal issues in telescopes and the effects on structures and optics. The latter topic will be the subject of an article in the near future, or when I finally get time to write it. They were both well received, and I am happy to report that no one threw anything at me at any time during either talk, and I was able to keep most of the audience awake - now that's a success at a star party where observing fatigue sets in before it is half over! Wednesday night was when we started "rapid-fire observing" of globulars, nebulas, planetaries using the Pocket Sky Atlas. At this point the really, really, really serious observers have stopped reading and dismissed me as a sad excuse for an observer, but I don't like looking for faint, boring stuff, I like objects that show detail. We really had fun using this compact, inexpensive chart that contains many deep sky highlights. By rapid fire, I mean we enjoyed the view but then we moved on to something else fairly quickly. There were few people walking around asking to see something through the large telescope, so we worked through northern Scorpius and part of Sagittarius before going up to Aquila due to clouds coming in from the south. In that region it was good to observe quickly anyway, because every minute brought many of the objects closer to invisibility behind the trees and rocks on top of the ridge to the west of the camp. We viewed M51, then went over to the Milky Way, checking out M107, M9, M10, M12, NGC 6357, 6309, 6369, 6445, and M20. We did not find NGC 6526 or 6559, but observed NGC 6629, 6537, 6567, M16, 6751, 6891, and 6886. NGC 6905 was an excellent planetary with some detail at ~400x. Finally we viewed M27 as clouds arrived. Using John's filter slide, we concluded that the UHC filter is our favorite under dark Okie-Tex skies. The OIII has more attenuation, so it is better under skies with more light pollution where its narrower bandpass is more advantageous. I worked on relearning a few faint constellations that I forget, and turned in around 1:30am and caught up on sleep.  The Thursday night door prize drawing/giveaway *always* runs long at Okie-Tex. As we waited for our name to be called, we watched the International Space Station (ISS) pass high overhead during the drawing. High clouds had been significant during the day and evening, but they dissipated as night fell. The giveaway concluded and we walked away cold and empty handed as it got dark, but ready to take advantage of the clearing sky. On the next orbit the ISS passed through our sky again, but further east and much lower, and I managed to capture an exposure of it arcing over John's 32" telescope, as seen in the image above, just before we started in with our observing. On this night we did some very efficient observing in the southern and southeastern sky. The sky was clearer than the night before, so we repeated a few objects. The wind gusted to 20 mph occasionally and we just waited for the gusts to subside. The telescope does not budge in this type of wind, but it does shake the view a bit. Virtually all observing was done with a 13mm Ethos in the Starlight SIPS giving ~260x. Again, some purists might be horrified at our haste, but we really had fun seeing many objects in a reasonable period of time. This is fun for us, and keeps us moving around more, thus we are wider awake. Entertaining the public with views of objects through large telescopes is fun in its own way, but it is also nice on some nights to not have to wait around for ten people to view an object before moving on to the next target. Objects observed included IC 4776, unexciting nebulas NGC 6589 and 6595, planetaries NGC 6644 and 6629, globulars NGC 6638, 6642, 6726-7, and NGC6723, NGC 6629 (nebula), M55, NGC 6907, M75, M72, M73, Barnard's Galaxy - NGC 6822, the Little Gem planetary NGC 6818, diffuse globular Palomar 11, planetaries NGC 6790 and 6751, M11, M26, and M14 in Ophiuchus before it set. We went back to the Milky Way region to revisit some favorites - M20, M21, M25, M23, M16, and M17 as usual. Next we headed the telescope east as Capricornus was up high and clear. NGC 7009, the Saturn Nebula, showed glow and extensions with the UHC filter, and the central star was visible when seeing and wind settled down. We also enjoyed M30, the Helix Nebula (NGC 7293), galaxy NGC 7184, and the beautiful globular M2 up in Aquarius. It's always fun to look at bright objects in a giant telescope. Looking a the chart, I noticed a constellation that I hadn't observed much - so we continued south into Grus because we could! It was at its highest point, so I directed the telescope to an object that I noticed on the chart. This was IC 5148, (nicknamed the "Spare-Tyre Nebula" according to Wikipedia, which I only just now looked up as I write this), just below the top-most star in Grus, and I was curious. We directed the scope to it just to see what we could see. I was surprised to find a nice ghostly planetary that had arcs of diffuse nebulosity on both sides, and thus appeared as a broken ring, making for a very nice surprise and a nice object at our southern limit of observing! I called about five people observing around us over to enjoy the view. At -39º 23' declination, we all had to bend over to look in the eyepiece of the 32" f/3.6 telescope at this surprising object. As it turned out, this was one of the most memorable objects (to me) that we viewed during Okie-Tex 2016. Next we moved on to galaxies - NGC 7314 and 7507 in Piscis Austrinus, NGC 7377, 7723, 7727, 7606, 7721, and 7556. There were many faint galaxies in the areas of these objects. We moved the scope up to M33, and enjoyed views of many H2 regions in the 13mm Ethos. After this came NGC 672 and IC 1727, a nice pair of one brighter and one much fainter galaxy close together. Nearby NGC 784 was grouped with a couple of other galaxies in a line. M74 did not show a lot of detail, and NGC 660 was observed. This brought our number of objects for the evening to about 50. I think this ended our night, and concluded our observing at the event. Having had our fill and a good time, we had to get to bed at a reasonable hour so we could get up and start our trip home on Friday. As usual, the wind in Kansas was strong and was blowing the van around despite John's best steering, and we were pulled over by a very friendly Kansas state trooper who wanted to make sure we were not drowsy or drunk. No, we were just astronomers in a van being tossed around by a Kansas gale. We spent the night in the middle of Missouri. We were back at John's by mid-day on Saturday. I wish you clear, dark skies, calm winds, cooled optics, big telescopes with good optics, and good friends to share all of that with. And some good Korean food! See you at Okie-Tex 2017! -Mike Lockwood, Lockwood Custom Optics |