Sunday, November 29, 2015

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"!

Friday, November 27, 2015

Thanksgiving, Ketelsen Style!

Whenever two or more Ketelsens get together, you can bet there is food involved! Especially at holiday time family gatherings revolve around meals. While we normally avoid the travel madness in November and December, we found ourselves at "Ketelsen East" at Thanksgiving, so naturally found ourselves travelling across the state to far western Illinois to Morrison, this year's central location where sister Linda hosted the family in their church. It was a great venue - lots of room for kids to run around, a huge kitchen to spread out for preparation, and a projection system and an array of couches for kids videos afterwards (Smurfs, anyone?). Even the adults enjoyed it, or else used the couches for snoozing...

Arriving at noon, food preparation was already in high gear! My minor contribution was chocolate cheesecake - I know, sort of anti-traditional Thanksgiving fare, but folks seem to enjoy it, and as long as I can make it for an event where there aren't leftovers (so I can't eat the whole thing!), it is easy to do. Shown at left is the cheesecake portrait...  Linda's oldest daughter Marsha now supervises a local bakery and after I asked her about pumpernickel rye, she makes sure I now have a good supply, last summer making me some pumpernickel brat buns, and for this occasion - dinner rolls!  Fantastic!

Taking a risk and entering the "work zone" in the kitchen, Linda's husband Lauren and son Mitchell were at work slicing the meat.  Lauren has been a butcher or worked in the meat industry for as long as I've known him and great to have his expertise at our gatherings (every family should be so lucky!). Anyway, here Lauren was at work slicing turkey and Mitchell working on a ham. Rumor has it that Lauren wanted to be sure there was dark meat for those who wanted it (myself included) and added ham to the menu to distract so there would be enough to go around! His plan worked perfectly - even as I went back for seconds, there was still dark meat available!

Star of the show was baby Natalie, daughter of nephew Jeff and his wife Sandy, first documented here last June when we first met her. She was enjoying a pre-feast snack of various cereals. While she was pretty indifferent to me and the camera (unlike her dad and aunts who were always mugging for my camera as kids), her eyes are locked on her Granddad Rich who was right behind me coaxing smiles out of her.

Finally it was mealtime and the camera was put away after a couple documenting shots. As you can see at right, it was quite the buffet for the 24 of us. Everyone added a dish or two so besides the turkey and ham there were the other standards dressing, yams, mashed potatoes, veggie casseroles (broccoli and green bean), corn of course, cranberries, and an assortment of veggies - you get the idea... It was a pretty impressive spread - we did our parent's memory proud with the feast! My mom was the best cook ever and you could tell she taught my sisters well!

After seconds, and thirds for some, the meal wound down.  I was embarrassed to follow the age-old prescribed standards of the family - the men wandered off to watch football, or in this case, the Smurf Movie with the kids, while the women folk retired to the kitchen to clean up, do dishes and divvy up the leftovers. I only felt a little guilty, though... Even before the movie ended, the party started to dissolve as some had to leave. I quickly organized a portrait of (my sister) Kathy and Rich with Jeff and Sandy and granddaughters Claire and Natalie, shown at left. I should have taken more photos earlier, but guess I got lazy... The only other great niece I got a photo of was of Mya shown at right, who hasn't appeared solo here in a while, though she appeared here with her uncle Dean just a year ago!

It was a great time - thanks to Linda for doing the heavy lifting! I makes me miss my family for those long months we spend without them so far away...

Wednesday, November 25, 2015

The Winter Wonderland Fades...

That first heavy snowfall of the season here in Illinois has passed. It was exceedingly beautiful, the trees covered in snow for a couple days, but with warmer temps, it has all but disappeared. Thanksgiving Day is expected to bring an inch of rain, so will be transformed to a muddier mess than it is now!

But it was spectacular! After the snow the skies cleared and the contrast between the snow and blue skies was breathtaking. Visiting our niece Kathy who is living at "Ketelsen East", it was almost enough to make us volunteer to take her beagle Jethro on his walks just to step outside! Cold temperatures kept the snow hanging off the branches and eaves of the roof for a couple days, and a walk down to the Fox River was just striking!

I didn't see a lot of the normal deer tracks this trip, mostly our own as we took Jethro on his obligatory loop to check out the smells as he did his doody duty. Beagles are supposed to have about the best olfactory senses, and I can believe it after watching him sniff out every gap in the snow for the stories it told. But the only wildlife tracks I saw were the bird tracks at left, and the usual rabbit tracks. It hadn't been cold long enough to get any ice on the Fox - just the barest hint of some forming at the bank - at right is the start of an ice cover, but I can't tell if it is forming from the edge, or if some of the crystals were drifting downstream and accumulating at shoreline.

On one of the snow banks, I was trying to catch the sun glinting off the individual snowflake crystals. I know a little bit about exposing for snow - you are supposed to overexpose a little or your snow will look dull. Watching the histogram on the camera, I make sure not to saturate (overexpose) it though. Normally you get something like the left exposure, lots of brilliant white, with the glints sort of lost in all the white. However, if you raise the black point of the image so that all ranges from black to white are stretched out (effectively an "auto-contrast), you get the image at right. It is the same exposure, just treated slightly differently. Now the subtle shadows, the "darkest" part of the frame are now represented as black. An interesting representation of the brilliant snow, but showing much more detail, even though the snow isn't really as dirty as shown here!

The last time we were here the first week of August, they were just starting work on a new water tower up the road about a half mile. I didn't have a clue how far they would get in nearly 4 months, but it looks like it is nearly finished! There really isn't a place to pull off and examine the site closely, but it looks as though the pieces are formed elsewhere and welded in place. It is neat seeing the center jib crane and safety rail near the top where the team is working. There was quite the spaghetti strings of welding lines reaching up the south side, and since they are working at the very top, I could see the glint of the welder only at a great distance. It is looking like they will be finishing the exterior in a couple days, but it is cool to see with the welding seams unpainted and realize how it has gone together.

The weather has gone from clear to overcast a dozen times it seems the last few days, but generally we've been having a little warmer weather. Though gone today, the last few days we've had some nice icicles form off our porch. Now that I see the image at left, it would have been nice to see a closer view of the right icicles - it seems as if they are starting to show internal structure or refraction from the distant trees. But they're all gone today. Yesterday we had some clear afternoon weather and had an "Arizona-worthy" sunset, shown here at right. It would have been nice to go do a little more astronomy, or at least constellation-gazing, but has been rough with the full moon. The rest of the week sounds cloudy/rainy, so will have to concentrate on friends, family and a holiday stuffing! Have a great Thanksgiving wherever you are!

Saturday, November 21, 2015

Blizzard Conditions!

I usually introduce our travel posts with photos from the plane trip. Well, we didn't have a window seat this time, so shot this from the aisle seat over Melinda and the fellow hoggin' the view. It was an uneventful trip to the Midwest, here showing the gentle-looking clouds below illuminated by the last rays of light before sunset. But we'd been warned what to expect - snow! All the national weather forecasts had predicted a narrow band of heavy snow grazing Chicago, our flying destination. Still we were expecting 4-8 inches of snow, hopefully arriving after we safely got home!

It seemed to work out perfectly - temps were mid-30s, and the ground was still dark-colored as we landed. Making our way to baggage claim, we called our niece Kathy who was on our way to pick us up. By the time we got out bags and made our way to the street, she appeared out of the darkness to rescue us! But the respite didn't wait long - shortly after we headed west, the drizzle turned to snow and with traffic slowdowns, it shortly seemed to be a full-fledged blizzard. By the time we rescued our car at friend Caroline's house it already had 3+ inches of snow on it! We took them out for Pizza at one of our local favorites and were home by 9pm. At right is "Ketelsen East" by late-night ambient light and a blanket of newly-fallen snow. While it should have been dark, with the snow reflecting streetlights into the sky, there was an ethereal light that imaged well in the 6 second exposure...

After the chores of Sherpa-ing the bags, I grabbed camera for a couple more photos. Though with it still coming down hard and wet, I didn't spend much time on it. But I did capture a few stereo pairs, of which one is shown here. Grab your red/blue glasses to enjoy the depth of the image pair combined here for an anaglyph view. With the high-contrast of black and snow there is a bit of ghosting, but still looks nice...

I left the camera unpacked to dry off overnight, but looked for shots this morning. The snow was starting up again, and the first view I had was out the bathroom window. At left is an "HDR" image looking out at snow-covered branches. The High-Dynamic Range technique combines 3 images of different exposures to recreate details from dim and brightly lit parts of the view. As a result, you can still read the clock and see the bright exterior details too. This still-life has appeared here before - with a more verdant exterior from a couple summers ago! A walk around the house revealed a few shots - our neighbor's house looks chilly across our adjoining yards!

And finally, the bushes that define the edge of our parking area are weighted down with the wet, overnight snow at left. If we get nice conditions for snowflakes, I've got the macro lens at the ready to try to capture them, which I've never done before. I'm thinking this morning it was just a little too warm - an attempt to image on tree bark (full camera resolution displayed) produced some crystal structure at right, but nothing close to entire snowflake crystal. I'll keep trying, though - wish me luck!

Saturday, November 14, 2015

"Bad Dog" Sunset

It was such a lovely afternoon yesterday, and with Melinda feeling a little better every day since she is skipping the chemo this month, we battled rush-hour traffic for an evening drive! I had seen on some planetarium software that the post-sunset skinny crescent moon would be low in the southwest somewhere near the silhouette of Kitt Peak, so we headed east towards one of our favorite outlooks, "Bad Dog" (in actuality, Babad Do'ag - the native name of the mountain range north of town, "Frog Mountain"). Similar to "A" Mountain, it is paved to a nice parking lot a few hundred feet above the local elevation, though instead of overlooking the downtown Tucson skyline, you have a panorama view of the entire Tucson valley from the south to the west.

Traffic was bad enough that we missed the sunset, though we watched the last golden rays disappear on the peaks and witnessed the Belt of Venus rising as we sped down Tanque Verde. Missing the sunset was ok, almost expected, and we arrived pretty far into twilight. The views are such that almost anything you take pictures with comes out great, so had brought a number of lenses from the TEC 140 to the kit lenses for the camera. Since the former was longer to set up, I did it first and captured Kitt Peak against the twilight. First thing I noticed was that the seeing was quite poor. Granted we were looking through 60 miles of atmosphere, the stiff surface breezes were doing a number on the image sharpness.

Undeterred, I went on - setting up another scope, the smaller Meade 80mm, which at F/6 has less than half the focal length of the TEC scope, and corresponding wider field. And to make things more interesting, I shot some images with a vertical format, shifting between them to make a panorama. Shown at left, this is the result of cropping somewhat from the panorama made from 7 individual frames. Of course, I could have shot it with a single 180mm lens or so, but I like having the higher resolution the longer focal length provides, though the blog limit of 1600 pixels puts a crimp on displaying the full resolution images. Granted, with the poor seeing, a single exposure with shorter lens wouldn't have been a bad idea... More on that below...

Next up, since the TEC was still set up but the lighting behind Kitt Peak was dimming, I took a series of shots of the "Tucson skyline", such as it is. This is built up from 3 exposures of 4 seconds duration each and shows the University of Arizona area, from the Arizona Stadium at left to Aloft Hotel at right a half mile to the north. From Babad Do'ag, it just happens to lie on the same path as Tucson's downtown area, then up beyond that you can see housings up what I suspect is the Star Pass area up west into the Tucson Mountains. There were some lights on in the stadium for preparations for a game today, and also there was an NCAA Soccer match on the field to the south, thus all the lights. There also appear to be other lighting centers on campus, and I'm thinking it might have been a pep rally for today's football game.

Finally, as it got a little darker, the crescent moon sank low enough to get it into a picture with a normal camera lens. So here I can make the comparison between a single wide shot or panorama from several shots. At left is a single shot with my kit lens for the Canon XSi, set to 60mm focal length. At right is a 4-frame panorama with the same lens set to 70mm, and combined with Photoshop. Unfortunately, with the blog's 1600 pixel-wide limit, you can't really tell the difference between them, so these likely look pretty identical. Certainly with the original files, the panorama was 8500 pixels wide and the single shot only 4500, so the panorama should be sharper, all things being equal!

Even when you go to the full-camera-resolution, the difference is hard to see, but perhaps detectable. At left is the cropped image at Kitt Peak both from the panorama and single shot with no subsequent processing. Since the panorama was taken at a little longer focal length on the zoom (70mm vs 60mm), the image looks larger. Also, the single exposure was a 4 second exposure at F/5.6, while the panorama was taken for 10 seconds at F/7.1, pretty much equivalent. Looking at the 4-meter and 90" telescope profiles on the right side of Kitt Peak (the flat-topped mountain), I think the longer focal length helps pull out a little more resolution. If more exposures at longer focal length were taken I think the difference would be more visible...

We didn't wait for moon set - it would have been against a black horizon anyway, so packed up and headed home, stopping at Pinnacle Peak for a steak dinner on the way. A fun evening and a chance to get out of the house!

Sunday, November 8, 2015

Solar Filter Workshop

The advantages of an astronomy club are many - of course there are the social aspects of spending time with people who share your interests and passions. But occasionally there are more utilitarian roles when volunteers with experience step up and show others techniques or how to do things. A case in point is yesterday's solar filter workshop. Former TAAA (Tucson Amateur Astronomy Association) president Bob Gilroy, assisted by Dennis, ran a half-day workshop on making solar filters for your telescope (22 attendees!). Now there are many types and kinds of telescopes, but Bob sticks to a standard design that can be adapted from a big Dobsonian to a pair of binoculars. Indeed, all kinds were produced yesterday! And fortunately, with group buying power, total workshop expense was only $12, a small percentage of what a commercial filter would cost.

So starting at the ungodly hour of 8am (on a Saturday!), we gathered at the USGS building on campus. Bob explained in general terms what the design was and how to implement it. He had emailed us the set of instructions earlier. Most had printed them out - unfortunately, I hadn't thought that far ahead, but his description made sense and I was able to wing it as I watched others.

Folks jumped right in with rulers, straight edges and sharp implements (razor blades and compasses!). In general terms, you measure the circumference of your telescope and cut a foam-core board long enough to wrap it. Crease one side with a ruler edge to dimple it so it can be bent around the telescope. Then cut a pair of pieces to sandwich the Mylar filter material between them, all attached with good-ole Elmer's or wood glue. Before handing out the fragile and expensive filter material, Bob inspected our handiwork. Rough edges could damage the filter with time, and gaps in construction where sunlight could leak in were not allowed.

The morning flew by. While supplies were furnished, folks were asked to bring in tools and supplies as well to minimize wait times. I had a ruler and glue which got passed around, and I made numerous use of neighbor's straight edge, tape and sandpaper. While the workshop was scheduled for 4 hours, I think only one fellow finished in that time. Bob had the additional foresight that since the filter is pretty fragile, we would also make a storage box for it, so that added to the time. By that time, though, we were old hands at foam board construction, and with the straight edges, boxes were easy! Still, time flew by, and I finally finished about 1pm.

Of course, the final test is to examine the sun through your completed filter. We needed to bring in our scopes to get the most perfect fit, though I didn't have a mount for it. At left, Dennis inspects the filter than Alan at right had made for his binoculars (a non-standard design). At right, my modest efforts are documented. I chose to made a visual filter for the TEC 140, so the filter has a clear aperture of 140mm. I also chose the "Baader" solar filter material. While there was also a "Seymour" filter material that gave a very pleasing yellowish disk of the sun, the Baader film gave a slightly brighter image, and since I do a lot of sunset images, I figured more light with the sun so low would be very useful.

So I waited until I got home to try out my handiwork on the scope. Good thing that I didn't wait too long - when I went to open my box, I found that the glue had leaked enough that it was glued shut! Fortunately, with only a little foam core damage on the box, I was able to extract the filter and try the fit and performance on the TEC 140. It fit perfectly and the brightness was great as well. At right is a 2000th second exposure of the sun after setting up. North is up in this image - a few small sunspot groups can be seen, as well as limb-darkening (edge is slightly darker) from looking through more of the Sun's atmosphere at its edge. For a non-tracked image, resolution and sharpness is great. And even though I would have preferred a more yellowish cast, I can always add that in Photoshop if I need to!

Anyway, it was a great morning, many thanks to Bob and Dennis.  It was fun to spend time with members and get to know them a little better.  Seems like back in "olden" days, we had a lot more social activities both under dark skies and also at meetings and other activities which seem lacking today.  But it was nice to get a "twofer" with both the social activity and get something to show for it!