NOW It's A Holiday!

Looking at the calendar, it is almost a week past Winter Solstice, long past the normal times I'd try the Kitt Peak solstice alignment.  The pull off along the Mount Lemmon Highway is normally the spot to be about 3 days before and 3 days after solstice for a good alignment, but it isn't an exact science.  Melinda and I were out of town on the normal dates, and to really make it seem like Christmas, I needed the tradition of chasing the alignment!  I also noticed something else to shoot for...  More on that later.

I helped the alignment a little by biasing my position along the pull off so that I was on the far southern edge of the spot along the busy highway.  The image at left shows the spot along a long bend to the left, paved pullout on the outside edge.  The image at right shows my setup this year - the TEC 140 (1,000 mm focal length), and a very sturdy home-built mount and tripod.  Of course, the smashed-in rear of my van is still there too, status still unknown... 

Even though I was pushing the limits of what I knew about the alignment, I was pretty confident I'd still catch it.  I got there in time to set up, let the telescope and optics cool down, and align the field to Kitt Peak National Observatory before the sun came into the field.  I was using a Thousand Oaks Type II photo filter which leaves the image too bright for visual use, but fine for photographic, especially near the horizon.

Finally the disk came into the field and I fine-tuned focus and exposure.  Sure enough, it is almost like I know what I'm doing as the Sun was just south enough to cover the extremes of the Observatory for just a couple seconds.  Taking a picture every 4 seconds, the one before and after the one shown I would call unacceptable...  There were even some nice sunspots showing a little activity!  With the XSi and TEC going on auto, I took a few hand-held shots with Melinda's T1i and a 300mm lens.  The unfiltered shot at right was a 2000th second exposure showing the 4-meter and peak of the mountain bifurcating the remaining disk of the sun.

It is always fun to tarry in putting gear away and looking to see what else can be seen in the twilight.  There are often some projection effects in the shadow of Kitt Peak, though the very clear sky minimized some of these effects, but still, the shadow of the 4-meter can be seen cast into the sky in the image at left.  At right, a transmitter array located atop  one of the peaks of the Tucson Mountains across the Tucson Valley is seen across a much nearer hilltop of the Catalina Mountains, where I was located.

While on the computer earlier in the day, looking up the sun's position to see if I could catch the alignment, I noticed that Venus, now up in the evening sky, was nearly at the same declination (north-south position) as the sun, so would also set behind Kitt Peak about an hour after sunset.  Actually, it was about a quarter of a degree north of the sun, so to help out the alignment again, I moved a couple hundred yards down the road to the "Thimble Peak Viewpoint" to bias my position a little.  Venus is now easily visible shortly after sunset, and re-setup my gear at the new position.  Sure enough, it moved almost into prime position, eventually setting behind the 4-meter telescope.  The left image shows a partially cropped view of Venus still above the observatory, the assemblage at right shows Venus at 10 second intervals setting behind the very peak of the mountain.  If Venus were more properly exposed, it would likely show more colors due to atmospheric dispersion.  Because it is so overexposed, the colors are re-blended into a mostly-white image.

Unfortunately, it was tough to balance exposure of the twilight-backlit observatory and brilliant Venus.  The planet remains very over-exposed, but needed a half-second exposure to catch the remains of twilight.  In addition, Venus, over 120 million miles away, subtends a very small disk.  It would be nice to try again when showing a skinny crescent.  So the opportunity for a "perfect" shot remains!

Just One More, And Then Another...

Tonight's title comes from a song.  Our movie buddy Larry makes a mix tape every holiday and we were lucky enough to get one last year. One country-tinged song, called "Just One More" by Tim O'Brien and Darrell Scott has the words: One more drink of wine/ And if you're still on my mind/ One drink, just one more, and then another". So it goes for my sunset sojourns - a week ago I said I was done with them for the season, but the more I thought of it, the more I wanted to go up again and chase the alignment further down the hill. Perhaps I should have done what the song suggests - stay home and drink, but after a two day trip to Mexico for Christmas, I again headed up the Mount Lemmon Highway in search of celestial alignments.



Using the Heavens-Above website to calculate the Sun's declination, it was obvious I would miss the alignment at my usual setup point (from my experience the week before), so it was time to bias my position to realign the sun and Observatory profile. TAAA member Jim O'Connor stayed on the turn, biased as far south as he could set up, and I went south a bit and up a hill a couple hundred yards to "Thimble Peak Vista". There, among the hordes of folks going down the road after playing in the snow atop the mountain, I set up the scope for imaging the sunset. Note from the left image that observing any further south isn't allowed as the side of the hill about 1km away would block the view... So this night was perhaps the REAL last chance for an alignment.


With the sun barely in the field of the telescope, I quickly checked focus and exposure, then started the sequence using an intervalometer, taking frames every 2 seconds. Once started, there was really nothing for me to do other than watch, so took a couple frames with Melinda's camera and 300mm lens (without filter) at left. I knew the sun would be overexposed, but wanted to catch the other mountains that aren't visible through the solar filter. This shot is F/10 and 1/2500 second. It turns out that the alignment was perfect! Shown at right is about the most-centered frame. All together, 142 frames were included in the sequence from start to finish, so I went through them all, cropped each down to the center 60% of the frame and fine-tuned levels slightly. No color or sharpening was done, otherwise straight shots through the Baader solar filter, TEC 140 scope and 1/80th second exposures at ISO 200.

Putting all the frames together, I made another GIF, but the artifacts similar to the last version bothered me, so I uploaded it to Youtube after making a clip in Moviemaker.  In this video I also added a couple frames where I ID the profile of the main scopes at Kitt Peak.  Here it is with 2 loops through the frames - full screen and HD if you can:



Unfortunately, while I had a perfect set of data, Jim O'Connor had some software issues and didn't catch an alignment on the usual curve.  Looking at some frames that his wife Susan took, I'm thinking they could have caught it there too.

And of course, in the theme of "Just one more, and then another", I decided that perfect wasn't good enough! I felt bad about chickening out about trying 1 frame/second for the intervalometer, so wanted to push that, and also wondered if I could catch one more alignment from the Thimble Peak Vista. The quick answers are yes and no.  Yes, if I didn't overload the camera by trying to write raw files, it seemed to write jpegs just fine at 1/second. But unfortunately, while the data streamed in quickly at 1/second for over 4 minutes, the alignment couldn't be seen a full week after Solstice. Examining the image at left, you can see the sun is north enough that it doesn't ever cover all the scopes at once, though it does over a period of several seconds. So in my book, the alignment season's limits are +/- 1 week. I'll likely write up a compendium of all this information for future alignment chasers - so look for that if you are interested...

Five Sunsets!

We've just passed the Winter Solstice, and for those that know me, it's the season for imaging the setting sun past the silhouette of Kitt Peak National Observatory. Like the ancients gathered around Stonehenge for celestial alignments, I've been drawn to this one for well over 20 years, first recording the sunset behind the Observatory in 1988! Those days was with my 12" Newtonian telescope and film (!) camera pointed out of my old van! It is much easier now with portable refractors and digital cameras. I can park and be set up in minutes these days. At left is a GIF file I put together on the "optimum" date of 17 December - click for a larger version. At right is shown my current setup - TEC 140 triplet apochromatic telescope and the venerable Canon XSi camera. Note the home-built solar filter that we made in the TAAA filter workshop about a month ago - it has gotten lots of use lately!

The GIF image at left is quite remarkable. While it shows a few circular artifacts that I didn't see in the original files, what is amazing are the layers in the atmosphere. Formed from air at different temperature profiles, you can see their effect on the image both at the suns edge, and also in the appearance and spacing of the two sunspots. It looks like watching an image at the bottom of a wavy pool!

Why the "Five Sunset" title? Well it hit me that I really didn't know how the image correlated to Kitt Peak very exactly. I knew if you were at "the spot" a few days before and after solstice, you could catch the alignment. I wanted to learn a little more about the situation. About the time I decided to do this, it was 10 days before solstice, so went up alternate days 5 times. It really was an amazing experience! Every sunset was different. Most were clear, one had some clouds during sunset, the last night it completely clouded up 30 minutes after sunset.

The end result is shown here at left.  I started on the 13th, when the sun was still moving southward more than a fifth of its diameter every 2 days. Of course, its southward motion slowed and stopped on solstice day on the 21st, taken just a few hours before the start of Winter. While the casual observer might think the sun wouldn't cover the observatory on most of those dates from this image, note the suns sweeping left-to-right motion for us here in the Northern Hemisphere. Because of the horizontal motion, I caught the full Observatory silhouette on 3 of the 5 evenings, all observations from the exact same spot. As you can see at right, after the first alignment happens about the 17th, the sun continues to move southward, appearing to lower from day to day as it sweeps past the Observatory. On solstice day, it BARELY covers the full silhouette - it helps to move northward as far as you can along the curve to help you catch more solar disk.

But the silhouette wasn't the only thing to see! Like I said above, every one was different - the first day it was very hazy - at least the inversion layer was above the observed level of Kitt Peak and it appeared very hazy. The result was that when the sun dropped below the observatory profile, the peaks projected their shadows into the hazy air, shown at left. Similarly, the next trip up on the 15th, I was shooting the disk (Meade 80mm F/6) as it dropped below the mountain and I caught a bit of blue/green flash between a crack in the mountain, and at the same time, caught more rays being cast upwards and outwards from the suns position, shown at right.



It often paid to not to hurry home. On the evenings when there were clouds, there were spectacular sunsets. At left is a nice example - a 3-frame panorama taken with a 300mm lens plus a 1.4X tele-converter. On another night, I had planned to pause at "Bad Dog" (actually Babad Do'ag) overlook near the lower slopes of the Catalinas to shoot Kitt Peak silhouetted not by the setting sun, but with late twilight glow with the city lights in the foreground. At right is a 5 frame panorama taken with the Meade 80mm F/6 (480mm focal length) and 10 second exposures. I love catching the contrast of the dark-sky observatory within view of the urban lights of Tucson. Besides the lights of Tucson's downtown skyline, the bright lights are from the UA football practice field, where the team was practicing for their upcoming bowl game.

I've got some more items of interest here, but will have to wait for a subsequent post.

Holiday Sunset Alignment!

It is that time of year again - if we are nearing the winter solstice and the holidays are upon us, it is time once again to travel up the Mount Lemmon Highway to once again document the sunset alignment against Kitt Peak National Observatory. I feel like an astronomer of old, looking for alignments to tell the turning of the seasons, and indeed this is true. From "my spot" (about milepost 8.7) along the Mt Lemmon Highway, the alignment is nearly perfect when the sun hits a declination of -23 degrees, 24 minutes which happens on the sunsets of the 18th and 24th this year. All of the telescope domes atop the mountain will fall within the observed disk of the sun.

This year we had 3 other TAAA members observing with us. Meeting at the base of the mountain at McDonalds at 3:30, it was a 30 minute drive up to the spot, providing plenty of time to set up equipment. This year, rather than take still images every few seconds and turn them into a movie like last year, we decided to use Melinda's T1i to take HD video - duh! It should look much nicer, and at 30 frames a second, with sound besides, it should be the ultimate reproduction of the sunset. Besides Melinda's Canon T1i, I also used the Celestron 5 I got from Elinor and David Levine - it provides the perfect image scale for the moon or sun to just fill the short axis of the APS-C sensor. I practiced using the video mode the night before on the moon, and freshly collimated on a star to provide the sharpest images.

While the alignment has been reduced to a science (no question anymore of a perfect alignment), the weather conditions were questionable even as we met at the base of the hill. High clouds were gathering and they looked even thicker towards the west, but we were all motivated to try, so off we went. After setup, focus and alignment, we got to gather, offer advice and guidance as "magic time" came. It appeared luck was with us as a clear strip appeared over the mountain, from our vantage point at least, 60 miles away. As the sun moved ever closer to the horizon, it finally came into the telescope's field of view and I pushed the "record" button. I was anxious as a cat near a rocking chair, but the image on the camera screen looked just about perfect. After the sun disappeared behind the 90" telescope, I removed the solar filter and recorded the sunset colors for a couple more minutes. In all, we got nearly 9 minutes of video, recorded at the medium-HD resolution. Still, it is about 1.4GB, so impossible to display on the blog at anything approaching full resolution - we'll have to see how we can display it publicly. Shown here are a few frames pulled from the video... It was fun gathering around and watching the replay. Playback at normal speed with the sound is quite fun, approaching the anticipation of even a total solar eclipse as it progresses!  {We have uploaded the video to YouTube.com.  If you click on this link "Mt. Lemmon/Kitt Peak Sunset" you will be able to watch it!  Remember, it is a huge file and if you have a slow internet connection it may take a very long time.}


But the fireworks were not quite over. Even well after the sun had gone down, the western sky was ablaze with color and shifting clouds. This was, without a doubt, the most amazing, dynamic sunset I've seen. Cloud patterns and colors shifted minute to minute and it seemed to go on for much longer than most colorful sunsets. Just amazing! And for dessert, we stopped on the trip down the hill at one of the overlooks showing the city lights, Kitt Peak far in the distance (the flat-topped mountain on the horizon). We continued on to a holiday party at my boss', but what we had just witnessed will stay with us for a long time!

An Alignment Scout Trip!

I'll bet you thought with the solstice sunset alignment with Kitt Peak 10 days ago that that stuff would be over for the season, but you would be wrong!  Again, based on my daily astronomical on-line reading, I "discovered" that in a week or so Mercury and Venus would have a lovely close conjunction in a week or so.  Knowing that Venus is in about the right spot to catch it behind Kitt Peak (again!) from the Mount Lemmon Highway, it was time to hit the road for another sunset!  Also, it is about the last field trip I'll be taking with the ole' Ford '88 van with the smashed-in rear end.  I take it and sign it over to the insurance company Wednesday...

Anyway, I made it out to "Bad Dog" over look (Babad Do'ag  for sticklers...) at about milepost 3 on the Mount Lemmon Highway just in time to catch the sunset.  Shown at left, it went down about 2 degrees south of where it needs to intersect the Observatory.  According to my calculations, for those who might want to observe the alignment of the sunset w/Kitt Peak at this lower location, rather than the one near MP9, Friday the 16th is the day to be at the "Bad Dog" overlook.  It moves much more every day than near start of Winter, so you only get the one chance on this side of solstice.

But I didn't come today for the sunset, only to get there before it got dark to get setup!  BTW, with snow atop Mount Lemmon, the highway was packed with cars heading down.  Luckily I had this lower overlook mostly to myself most of my 80 minutes there.  Venus popped out shortly after sunset, and about 10 minutes later, Mercury was spotted below the brighter planet.  Still a few degrees apart, by this next weekend they are less than a degree apart.  Waiting for it get dark enough to have it stand out from the sky and get a little lower with Tucson's city lights as well, it is shown at left.  That is Venus above and Mercury mostly below it and a little to the right.  I waited another 10 minutes to catch it just before Mercury set behind the Quinlan Mountains.  While the sky is darker, the rising Full Moon behind me helps light up the "A" of "A" Mountain, and in fact, the telescopes atop Kitt Peak have the pale illumination due to the moon.  In the next few days, Mercury will rise up nearly to the height of Venus and both will move to the right a couple degrees, so should be a pretty pair directly above the Observatory.  Perhaps I'll see you there!

I also had time to take a 5-frame mosaic of the pretty lights of Tucson with Kitt Peak in the background.  Down-sampled here to the 1600 pixel-wide maximum, you can't see a lot of the details of the original mosaic, but you can perhaps see why I do them to keep the details of the original files...  I also took a time-lapse of the twilight including the swiftly moving clouds...  Perhaps I'll be doing something with that soon.  I guess I'm just easily entertained!

Birthday Sunset Alignment!

After working some long hours, I've finally got a chance to post about my most excellent birthday on Sunday!  With the approaching Solstice and yet another Kitt Peak sunset alignment, I put out an e-mail alert to the Tucson Amateur Astronomy Association (TAAA) to see if there was interest.  Now the 16th is a little early for the alignment - normally we do it a couple days later, but since most work on weekdays, the trigger was pulled and we had about 8 people in 4 cars join us.  We had 5 virgins who had never seen it before, and I brought the big 20X120 binoculars with solar filters for a great view, while shooting video with Melinda's camera with an older Celestron 5" telescope. 

 

Sure enough, the sun moved over the silhouette of the National Observatory, a few clouds had little effect on the spectacular view...  But interestingly, the earlier date's view was readily apparent - the sun was just a bit further north than it usually is, so it covered all the scopes on the mountain for only a second or two, as opposed to the normal 5 or 6.  Note at left that the center of the sun is well above the mountain profile - compare it to the shot at right taken a couple years ago when the alignment was nearly perfect with lots of room on both ends of the mountain!

 

A few couldn't make it on Sunday, so another trip is planned for Monday, 24 December.  Yes, it is Christmas eve, but it seems to be becoming a Christmas tradition for a number of us.  I've heard rumors that there might be some weather coming in, but fingers crossed it will be a fun time of socializing and observing without staying up late!

 

Oh, and on my birthday Sunday, we were joined by our Phoenix buddies Bernie Sanden and Donna Tippens.  After the sunset we went out to a local steak place and had a great dinner.  All of our birthdays should be so much fun - thanks guys!

Solstice Sunset

Last night was the "sunset expedition" - the first time this season that the sun set behind Kitt Peak National Observatory (KPNO). After an announcement on the Tucson Amateur Astronomy Association's forum, there was a little interest in observing it, so the sunset hunt was on! In all we had 8 people and 7 scopes or lenses focused on the sunset.

We met at the McDonald's on Tanque Verde and Catalina Highway at 4pm. Melinda and I were the last to arrive with a few minutes to go, so made the drive up to just short of milepost 9 in short order with less than an hour to sunset. After indicating the spot to the group, we spread out and set up gear, some focusing and aligning on the sun, me - I did a quick focus on the sun then set up and aligned on the profile of KPNO. I was concerned about some thin clouds moving down from the north, but there wasn't much we could do, so we waited.

Time zipped by quickly and seemingly before I knew it, the disk of the sun became visible in the upper corner of the frame. By the time I determined the correct exposure, it had just touched the mountaintop observatory and I started the timer sequence with an exposure every 4 seconds. Bill, our former club president was worried it wouldn't span the mountaintop and announced he was going to move a few yards - but we assured him all was ok and besides, sunset would be over before he would be able to reacquire the image! And then it really was over. The alignment was perfect, everyone got some great images and all were carrying a silly ear to ear grin. And what was interesting, there was actually a group of sunspots visible - the first in a long time. In the shot here it is just above the University of Arizona's 90 inch telescope - second from the right.


I had read a notice online that the moon and planet Mercury would appear in the sky together, so some of tarried a bit while others packed up the the rapidly dropping temperatures. While we waited Melinda and Jennifer compared silly-looking hats.The moon was almost exactly 36 hours old - a skinny crescent that suddenly seemed to appear out of the darkening sky and a surprisingly bright Mercury less than 5 degrees away. A striking sight with the still orange clouds that glowed after the sunset.


We finally ambled to town and a small subgroup of us stopped for some pizza and beer before finally heading home to download images from our cameras. While my focus and the sunset alignment was great, I inadvertently had overexposed my shots very slightly and the red channel was saturated (since the setting sun is mostly red). It does affect the image some, but it is what it is - will just have to do it again and be a little more careful next time. I did make a quick movie of the exposures I took - we couldn't figure out how to display it here on the blog, but our friend and co-observer Tom Polakis agreed to host the .GIF file on his photo site. If your computer connection can tolerate downloading a 5MB file, take a look at the sunset movie. With the clouds moving in front of the sunset, it is quite incredible.


In the next few days the sun moves a little too far south to align with KPNO, but in a week it will be heading north and the alignment will happen again. The next chance is on Friday 25 December (yes, sunset on Christmas Day). It will be a good pass - if the weather is good I know at least one of our group will be doing it again with me...

(Click on the picture to open and view the .gif file. This is a 5MB .gif file, so it is very large!)

More Sunset Fun!

We certainly hope that all of our regular readers (all 5 or 6 of you!) have gone to Youtube and checked out the spectacular sunset alignment video we posted way back 10 days ago. Partly because of that success, we got to repeat the sunset trip several times, setting a record of 4 attempts this season!

Adam Block, who runs the SkyNights program on Mount Lemmon had a large group going up for the lunar eclipse on the 20th. Unfortunately, while we had some views of the sun while we set up the 5 telescopes (!), the sunset was totally socked in, and other than the view of Kitt Peak telescopes, the group of 25 people were skunked on the sunset observing. At least we tried! I think they had at least partial success on the lunar eclipse observing like we did in town...






Our next try was on Christmas eve the 24th. Friends Tom and Jenn came down from Phoenix to join in the fun with at least 3 other TAAA members. I was thinking that the only way we could improve on our sunset video from the 18th was to do it in the light of Hydrogen Alpha, using a special filtered view that normally shows dramatic activity in the light of a primary hydrogen reaction. When you see images of the sun showing large flame-like structures off it's edge (called prominences), it is likely an Halpha image. Tom is about the only person I know with such a setup, so we supplied Melinda's camera for another video, and he supplied the scope and mount for the partnership. He also shot some white-light shots with a telephoto and through his 10" telescope.

The attempt was partly successful for us. There was indeed a nice prominence that was visible that was just about the last part of the sun to set, but because we needed to use a diagonal in the filter train, the video is flipped left-to-right. Rather than show an inverted video, we show some individual frames here that we flipped in Photoshop. To show the prominence, the disk needs to be overexposed some, and it is hard to coax good views of the prominence so low to the horizon, but I think we did ok (barely visible at the top of the frame). Everyone in the group was successful, even though we were once again shooting through some thin clouds in the west. First timers Jim and Susan O'Connor even had one of their images picked as the solar astronomy picture of the say!

Tom and Jenn stayed the night at our house (we dined on crock pot chili that was waiting for our return from the sunset), setting up Tom's 10" to look for the storm on Saturn in the early morning hours. Unfortunately, the atmospheric seeing was so bad, we could barely tell that the planet had rings!

About the time they took off for Phoenix at noon the next day, another friend Laurie arrived (another Phoenix refugee). She was also interested in the sunset alignment, so we headed up once again. Unfortunately, we were shooting through thin clouds again, and while the video was fine, the blustery wind we had was really shaking the mount, almost inducing motion sickness watching the movie! With the clouds we had more spectacular colors, and we paused at another pullout on the way down to watch the city lights come up against the dimming twilight. Laurie had a great time documenting it all.

So for this December 2010 solstice sunset season, we were 3 successes for 4 attempts. The alignment seems perfect - that pullout at milepost 8.7 seems the perfect place to be when the sun reaches -23.40 degrees declination. It was interesting that none of the 3 "clear" sunsets were actually perfectly clear, but we had great views of each anyway. And even though we got that perfect video on the 18th, well likely do it again a few times next year!