Wednesday, February 15, 2017

Lights in the Sky!

Always on the lookout for topics to blog, I watch certain websites, Heavens-Above among them. A few days ago I saw there was a good pass of the International Space Station (ISS) this evening, but promptly forgot about it! Thanks to the local weatherman at 5pm who mentioned it again, I was motivated to look it up again and set up a camera.

Now if you go to the website above, the first thing it wants to know is where you live - duh, it needs to know where you are located before it starts telling you where to look. Click the "change your location" button to tell it where you live, using the search box, or the google map to locate your city. The closer you can locate your observing location, the better! For some observations, like Iridium Flares, a mile or two off makes all the difference! Anyway, for tonight's ISS pass, I got the map at left. It is a map of the full sky with north at top and south at the bottom. You can see that Venus and Mars were bright in the west and Orion high in the southern sky. The path of ISS was to skim the three belt stars of Orion, and it ends before the bright star Sirius. What happens there? Well, since the ISS needs the sun to hit it to be visible, that is the sunset point - as the ISS continues to move eastwards, it moves into the earth's shadow!

I set up tripod and tracker so that the stars would look like points, working from the back yard. My sky glow from Midtown Tucson limits my exposures to 30 seconds or so before the orange glow from sodium lights starts to color the sky. For the exposure here, I used the Canon 6D and 85mm lens at F/3.5.  Seen is the streak of the moving ISS, just grazing under the 3 belt stars of Orion. Below the belt stars is the reddish glow of the Orion Nebula, and near the bottom are the 2 stars that make up the feet of Orion. I wasn't sure how long it would take to move through the field, so used 60 second on the intervalometer, planning to stop it when it blinked out to minimize skyglow.  This shot ended up being about 40 seconds, and I had to use Photoshop to neutralize and minimize the sky glow a little.

Surprisingly, the ISS didn't "blink out" once the sun net from its vantage. Just like it stays light right after sunset here on earth, the color of the ISS took on an orange-ish tint and faded out slowly - pretty cool!

Sunday, February 12, 2017

Saguaro Saturday!

My buddy Donna was down over the weekend. Since our Jeep outing last Fall, a group of fellow astronomy nuts has been debating where to go on a 4WD outing as the weather gets warmer, and someone suggested a petroglyph site in Saguaro National Park, western unit. It isn't a difficult drive even for a passenger vehicle, so Donna and I hit the road on a lovely Saturday yesterday to check it out. I haven't been there in a good 15 years, so reviewed the maps and hit the road for a couple-hour road trip.

The first stop was Gates Pass, where Speedway/Anklam Road crosses the Tucson Mountain Range. It is spectacularly scenic with groves of saguaro cacti, and as shown at left, the view opening up towards the west quite dramatically. The main photo was taken with a 16mm full-frame fisheye on the Canon 6D, so has a 180 degree diagonal field-of-view. To show some of the details at reasonable scale, the inset shows a blow-up of Kitt Peak National Observatory about 35 miles to the SW with a 500mm lens and blended with the magic of Photoshop...

The view towards the north is no less exciting, even in the dull light of midday - saguaros all the way up the slopes to the profile of the mountain ridge, though the fisheye lens doesn't show them much. It again takes the inset from the 500mm lens to bring out those details...

We drove down past the West Unit's visitor center and checked in (free, thanks to my Golden-Ager NPS pass). We continued north a bit on Sandario Road before hitting Golden Gate Road, a dirt road we followed for a couple miles to the Signal Hill picnic area. From there we could spot the petroglyph site about a 1km hike away, with the trail spiraling up the far north side. An image is shown at left, with a group atop the hill, behind a protective fence checking out petroglyphs. It didn't take us long to hike over a well-maintained trail - literally a freeway compared to some of the raw trails I've seen in the SW!

The petroglyphs were made by the Hohokam culture about 1,000 years ago and are quite striking. The main spiral is shown at left, with many others scattered about the stones of the hilltop. Besides the spirals and possible symbols for the sun and moon, you can also imagine figures of deer or sheep, scorpions and snakes. Niles Root has done some spectacular images and analysis, proving that the site was used as an astronomical calendar, finding dates of the summer solstice(first day of Summer) and vernal and autumnal equinoxes (start of Spring and Fall). His website with fascinating photos and descriptions is linked here.

A wider shot of the area showing a few more symbols is shown at left. The main spiral shown above is now near the left edge, with more visible at lower right. And at right is another large spiral on a nearly horizontal stone. Root's description didn't mention the symbols over here on the west side, so there are still mysteries about!

With all the examinations of the
petroglyphs, you forget you are still in Saguaro National Park, and the view towards the NE towards Mount Lemmon, shown at left shows the forest of Saguaros in the area. That is Mount Lemmon at far distance at center.

And because THIS IS MY BLOG, I've got lots of 3D photos too! So grab your red/blue glasses and follow along. Since I just showed the cactus forest at left, at right is an anaglyph (3D shot by adding another shot taken a couple feet away). Using the glasses, each of your eyes sees the appropriate frame and your brain reconstructs a stereo image.

And, of course, I've got 3Ds of the
petroglyphs too!  At left is a close-up of the main spiral at the site.  This was taken with a telephoto and is a "hyperstereo", taken with a baseline further apart than your normal eye separation.  Doing it this way emphasizes the stereo effect, amplifying the unevenness of the stone and spiral itself! 

At right is a wider field including some of the mountainous background too. and finally below, is the wide shot showing other petroglyphs...

We returned to Sandario Road, but rather than return the way we came, continued north and returned to Tucson on Picture Rocks Road  (so named because of the numerous petroglyphs), making a big loop for our Saturday adventure. 

Wednesday, February 8, 2017

Déjà vu All Over Again!

As my regular readers surmise, on travelling back and forth to "Ketelsen East" in Illinois, I enjoy looking out the window.  Looking at my fellow passengers, it seems I am nearly alone pressing nose to window watching the country pass by.  It seems most can't be bothered even having the shade open - how can you rather read a book than see the world zip by at 3/4 the speed of sound?!

I've also made comments that I suspect the pilots enter the destination or waypoints into the flight computer and it follows the same path. Every time. Not that I'm complaining, but it is fun to see the same landmarks swing by. This last flight I recognized a reservoir in NE Kansas, and my seatmate asked where I thought we were. I told him I thought we were near Topeka, and wouldn't you know the pilot came on and confirmed it 15 seconds later! He also said something about flying over El Paso, normally a ways out of our way. I got a little excited, but then I think he confused it with the normal Albuquerque waypoint! As shown here at left and at right, from Chicago O'Hare to Tucson, AZ, we ALWAYS pass just south of Albuquerque before turning south towards Tucson. That is it just east of the Sandia Mountains in the center of the left photo taken on 15 November. The most recent trip, on 31 January, you can see a little snow in the mountains. What is more interesting is that at the very top of the photo, you can see the snow-capped Rockies well up into Colorado!

The plane turns slightly more southwards and we pass down parallel to the Rio Grande River - yes, the very one that runs down and eventually becomes the border between Texas and the United States. About 6 minutes after making the turn, we always seem to pass over this remarkable mesa that I've yet to find on Google Maps, though I know pretty closely where it is located. The landform and subtle coloration is exquisite! And you can also see from the near-identical images that we are almost flying over the exact same spot! It is a big sky up there and I would think it would be tough to occupy the same spot without help!

A few minutes later and outside the right windows, we seem to always pass over the VLA - a huge radio telescope that uses 27 dishes, each about 82 feet diameter. As shown on the left photo, both these recent trips, we've passed over the very end dish of the east arm of the array. Each arm is 13 miles long - the best way to think of the radio telescope is as if the 82 foot dishes are tiny parts of a huge dish 25 miles across! The left photo was taken on the most recent return trip. The dishes are mounted near railroad tracks, so they can be moved to adjust the telescope's resolution and sensitivity, which happens on a regular basis. At right you can compare the center of the array 11 weeks apart. In the lower, more recent image, they are reconfiguring the array for the "D" close-pack configuration which has lower angular resolution, but the highest sensitivity.

Somewhere down in southwestern New Mexico, we adjust our course more to the west to pass over the big copper mine in Clifton/Morenci, and a few minutes later, Mount Graham and the Large Binocular Telescope(LBT). I always look for LBT as a waypoint, and also because we made the mirrors for it at the Mirror Lab where I work. Sitting atop the mountain very near the peak, it is easily visible. Once seen, the Sub-Millimeter Telescope is spotted adjacent to it, and the Vatican Advanced Technology Telescope is there too. You can also see here that in the 11 weeks between my return trips, Graham also picked up quite a snowpack, as seen at right.

From there we follow Interstate 10 into Tucson, usually circling over the north side of town before landing towards the southeast into the south-side airport.

Normally the photos I take include image pairs taken a few seconds apart for making 3D images, and there is no lack of them on these trips too. But I know that many of you don't have the glasses, so am slowing down my production of anaglyph images. I'm looking for an inexpensive source of them so I can offer them to you in exchange for a self-addressed-stamped envelope, but still looking for a suitably cheap source! In the meantime, open your window shades and enjoy the view out the plane!