Wednesday, April 23, 2014

It Can Now Be Revealed...

I can tell you now about what I got from Melinda for Christmas!  It was/is a trip to Ebertfest - the film festival organized and run by Chicago film critic Roger Ebert for 15 years!  Of course, this is the 16th year, and the anniversary of his passing was just a couple weeks ago.  So while I actually swapped e-mails with him a few years ago, there is no way to turn back the clock and shake his hand.

Many of us became fans of his when he and Gene Siskel had a give-and-take movie review show that stretched back to the 70s and made them media stars.  Over the years Gene died of brain cancer in '99, and Roger had thyroid and salivary gland cancer, which in 2006 required surgery that left him unable to speak, eat or drink.  Like a blind man's developing extraordinary hearing, the loss of his ability to speak and depend on the written word (he had been a newspaperman his entire lie) improved his writing skills further.  It was during this time that I became a big fan of his writing, looking forward to frequent posts on his journal.  It is still on line and easy to lose hours in his reading.  I've got favorites among his posts - his entry on Steak 'n' Shake is a classic - years after his feeding tube was installed, he describes the emotions and tastes of a burger and fries he enjoys in his dreams...  Another is his perfect description of growing up in a small town in the Midwest.  I contributed occasionally to his comments - just about the happiest day in the last 5 years was when he responded to one of my comments (rare for him) in my response to some of his complaints of 3D movies.  Anyway, Melinda and I had talked of going one of these years, and she surprised me with festival tickets for Christmas!

Fortunately, his widow Chaz stepped up with festival organizers and an army of volunteers and picked out the slate of this year's movies.  Melinda and I are looking forward to a couple of the classics that are already favorites, and expect to enjoy the rest as well.  Directors Spike Lee and Oliver Stone will be here to introduce the 25th anniversary showings of their movies "Do The Right Thing" and "Born on the 4th of July" in the coming days.  There are 12 movies over the 5 days, so it should be a great time!

After arriving in Champaign, IL late yesterday, we stopped by the Virginia Theater this afternoon for our passes, and took the obligatory pictures and noted the honorary street renaming.



The Virginia Theater is a REAL theater, not a little multiplex like you see these days!  Built in the 1920s, it served as a vaudeville stage, legitimate theater and movie house.  Seating nearly 1500, it is HUGE and underwent a massive restoration in the early 2000s.  It has served as the home of Ebertfest for many years, if not its full 16 year run.  The first offering was tonight, and we got into the Virginia for the first time.  Arriving 90 minutes before showtime, we got in a block-long line, which grew to 2 blocks long before they opened the door 60 minutes before the 7:30 screening.  After talking to a fellow next to us in line (a 12-time veteran!), we decided to join him in the balcony and take in the show from the front row.  We enjoyed an organ recital with the old Wurlitzer pipe organ (from memory w/no sheet music!), while ads from supporters and images from Roger and Chaz' life were projected.

Appropriately enough, tonight's opening offering was a documentary about the life and career of Roger Ebert named "Life Itself", based on his autobiographical memoir.  Director Steve James was given unrestricted access to film Roger and Chaz, unknowingly only 4 months before his untimely death.  While his daily life and medical struggles towards the end of his life were shocking, the archival footage and interviews with friends, family and cinema insiders made for a very entertaining feature.  Of course the entire house, being Ebert fans, loved it - there were lots of laughs and tears flowing, and afterwards there was a panel discussion with Chaz (who also greeted us and introduced the movie at left), director Steve James (who won a "thumbs up" award), and a coworker and lifelong friend whose name I've unfortunately forgotten...  It was interesting to hear some of the behind-the scenes info and be able to ask questions to the principles involved - one of the traits of the film festival - interactions with the directors or actors after the showing.

Enough for now, but likely more as the week progresses...

Sunday, April 20, 2014

TAAA Springtime Kitt Peak Star-B-Que!

Last night was our springtime Star-B-Que at the Kitt Peak picnic area.  We've had some spectacular ones in he past - great skies and a nice venue with a pavilion and tables for a sizable group to socialize and picnic.  Since the Tucson Amateur Astronomy Association (TAAA) assists Kitt Peak National Observatory with some of their outreach events, they even let us use their grill for the cookout.  Unfortunately, the weather leading up to the weekend was not promising, but the Clear Sky Chart was hopeful for late clearing, so always the optimist, I prepared for clear, but always enjoy the trip, rain or shine!

Sure enough, the promised clearing was a hoax, but there were some spectacular cloud buildups and long lines of rainstorms visible out in the desert, so lots to watch for.  Of course, clouds and vegetation always looks more impressive with my IR-modified camera, so used it for the 3-frame mosaic of the radio dish and mountaintop shown at left here.  The radio antenna is part of a 10-dish array scattered over the hemisphere, the Very Large Baseline Array.  Using the signals from all of them, they can synthesize maps of an object as if they had a dish nearly the size of the earth!  It was stowed when this picture was taken, but a little later it came to life and was working in the eastern part of the sky, as shown at right.

It is an interesting time of year on mountains of southern Arizona.  The vegetation is dominated by scrub oak trees - considered evergreen, they keep their leaves through the winter, and the old leaves die off and are replaced by new growth this time of year.  When pointing this out to the attendees, most thought the trees were stressed by drought, but in fact in a close examination you can see both old green leaves, some yellow/brown leaves, and the new growth of grey-green leaves.  It was always interesting to get our "Fall" colors in the springtime on mountaintops!



And while I admit knowing little about lichens, I do admire the variety we saw yesterday - it was easy to capture at least 3 different types (of different colors, anyway) a fraction of an inch apart on the bark of an oak tree...

The threat of clouds cut in to our attendance some, but still folks came for the socializing and the chance to get out of town.  We had a nice discussion with Michael Turner regarding his new Canon 60Da, a camera model specifically modified for astronomical imaging.  Joining into discussions was Mary at left and Paul Lorenz at right.  The dark clear sky and bright vegetation is a characteristic of the Wood effect of infrared wavelengths - vegetation readily reflects IR light and the blue sky is naturally dark in IR. 

Since we didn't have telescopes to set up with storms within 15 miles of us, we set up the grill, and in fact, gathered around it to get warm with the cool temperatures and blustery breeze.  You could tell we were all thinking alike as a majority brought brats to grill and potato salad as a side dish!  After dinner we mostly played a waiting game to see what the weather would do.  At right a couple attendees keep an eye on  storms towards Sells and beyond to the west.

Finally I set up my small Meade 80mm triplet APO scope (480mm focal length), and shot some time-lapse of the storms, which morphed into imaging the sunset.  Though watching "live" you need to pay close attention to see the rain falling to the ground, the time lapse amplifies the effect.  Note also that on the first part of the time lapse below, I utilized unsharp masking techniques from Photoshop to accentuate the rain features in the images.  It does introduce some artifacts, like the halo effects near high contrast edges shown here at left, but it works so well in bringing out the sheets of rain, I put up with it.  By the time I've panned over to catch the sun setting, I turn off the sharpening.

Here is the time-lapse of some of the desert rain and sunset.  You can watch it in this viewer or go to the YouTube site to watch it, or click it for full-screen.  Watching it full-screen, likely requires going to the highest quality setting.



As I returned to the van from the outlook after the sunset, it started sprinkling, and by the time optics and cameras were put away, it started drizzling in earnest.  All had left by this time, so we did the same.  As I was locking the picnic area gate in the rain, I looked up and was able to see Jupiter high in the sky over the setting Winter Milky Way!  We were THAT close to having clear skies, but the rain generally increases the humidity enough to cause dewing problems even if it had magically cleared right away.  So it was an early evening at home, though the cats were glad as we got home to feed them at 9pm...

Friday, April 18, 2014

Puerto Peñasco Mirage and Fata Morgana!

On our last trip to Puerto Peñasco at Christmas, we observed several mirage effects over the Sea of Cortez, and I was looking forward to our return to see if any more could be seen.  While the sun and moon were rising and setting too far north to be seen over water, I was not disappointed!  We were able to spot several instances of Fata Morgana - a mirage effect caused by layers of air at different temperatures.  In the cases below, I believe cooler air is trapped near the Sea of Cortez or the ground with an inversion layer and warmer air above.  The effect of this is a vertical magnification or stretching caused by bending of light rays by the temperature differences.

The first instance was on our first evening there, on eclipse night.  After taking the picture mosaic of the rising full moon in our last post, I whipped over and took a shot of Bird Island to the southeast (shown at left), about 25 miles (40km distant).  So far, so good...  About 2.5 hours later, just before the eclipse started, I went looking for Bird Island again to try imaging it by moonlight (shown at right).  Wait a minute - they appeared much higher from the exact same viewpoint!  Even though they are reproduced at the exact same scale here, they appear at least twice as tall!  I'm thinking that a cool layer of air formed over the water, and magnified the height of the island vertically.  At Christmas I observed them to float over the Sea (see link above), in a more complicated mirage effect, but this version was interesting too!  Both of these pictures were taken with the William Optics 11cm diameter F/7 APO (770mm focal length), with the moonlit image a 10 second exposure.



The next night found us near downtown Puerto Peñasco, at a popular restaurant with a spectacular view of the harbor and sea.  From our vantage point, even a casual look to the north showed an interesting mountain range.  The distant mountains were stretched vertically into a nearly impossible profile.  This shot was taken with the 70-200 zoom (set to 200mm), and is another example of Fata Morgana.  Taken again, shortly after sunset, it slowly dissipated over 20 minutes.


After taking the above mountain picture, I noticed another example to the west over the Sea of Cortez.  Here, with just the horizontal line of the sea marking the horizon, the vertical displacement due to the Fata Morgana is easily identified.  I actually took a time lapse of it, but likely won't display it (I didn't get the frame very level), but at right show how it dissipated in 30 minutes time - nearly, but not totally back to normal.

The interesting thing about all these examples of Fata Morgana is that they depend on stable layers of air at different temperatures, but for nearly our entire stay in Mexico the wind was blowing pretty steadily, and I would have predicted there would be too much mixing of the air to produce these effects.  But I'm glad I was able to see and document them.

Some of the finest examples of Atmospheric optics, as well as written explanations for their cause is at the excellent website by Les Cowley - Optics Picture of the Day.  He has some great images of Fata Morgana shown here and here...

Thursday, April 17, 2014

Mexican Lunar Eclipse!

We just got back from a short trip down to Puerto Peñasco  to visit our friend Margie at her home there, view the lunar eclipse Monday, and just relax a couple days.  We were out of cell range and lacked internet access, so have been out of touch for most of the week.  We left early enough on Monday (mid-morning for the 4-hour drive) to get settled in well before sunset.  Watching from her "astronomy deck" on the roof, we had a great view of moonrise over other houses and condos down the beach a few minutes before sunset.  I was hoping to get a time-lapse of the moon rising over the Sea of Cortez, but it rose too far to the north and the sky was hazy enough it would have been tough - plus I was late and didn't see it in time.  Sharp-eyed Melinda was first to spot it.  This shot at left is a 4-frame mosaic with the William Optics 11cm F/7 telescope (770mm focal length).


While I didn't capture it, the moon was sitting just above the "Belt of Venus", the shadow of the earth rising into the eastern sky.  It was quite spectacular as the sky darkened.  Watching the moon rise in the telescope (I swapped between eyepiece and camera on the W.O. scope most of the night), we were also able to observe "notches" in the edge of the moon from it rising through temperature layers in the atmosphere.  Also interesting as the moon neared the earth's shadow was that there were absolutely NO shadows visible around the edge of the moon.  Normally, even near full phase, the sun isn't directly behind us and one edge of the moon usually shows some crater's shadows.  But not this time.  At left is the moon shortly before the eclipse started, so shows the moon as full as it can get outside of eclipse.  At right, about an hour later, the penumbral phase of the eclipse had started, and the partial shading of the earth's shadow was spotted.


Finally, right on time about 11pm local time, the hard edge of the earth's shadow touched the moon and started its march across the moon's disk.  While it looks similar to crescent phases of the moon we see during the month, notice there are no crater shadows available.  During a lunar eclipse such as this, the dark edge is caused by the earth's shadow, not the phase of the moon!



As a smaller and smaller part of the moon was illuminated, the stars started to come out, yet, the camera exposures needed to stay short to keep from overexposing the moon still in sunlight.  It wasn't until a full hour after the shadow first contacted the moon that it was fully engulfed, and no longer illuminated by direct sunlight.  The photo at right was taken  3 minutes before totality and I could expose long enough (1/4 second) to start showing the red illumination caused by light refracted into the earth's shadow by our atmosphere.  The blue rim inside the earth's shadow is evidently real, explained as an effect of ozone in the upper atmosphere of earth.  The star shown at the upper left corner is 76 Virginis, bright enough to show up on many shots of totality.


Finally with the moon entirely within the earth's shadow, we reveled in the dim orange orb of the moon, only slightly brighter than the orange spot of Mars a few degrees to the west.  Shown at left with the wider view of the 70-200 zoom (set to 80mm), the moon is shown with the bright blue Spica to its lower right, and orange Mars to upper right.  It was quite amazing to see the clouds of the Summer Milky Way rising in the east with the ruddy eclipsed moon to our due south.  The view through the telescope had a 3D effect with stars visible around the moon - a rare sight since it normally drowns out any stars in the field.  Because I didn't have a tracking mount for the telescope, I was limited to exposures of about a half second before trailing became objectionable.  In fact, we had a bit of a blustery wind during all phases of the eclipse, so I had to go to a bit of trouble for all the totality images.  The shot at right is one of these half-second exposures and is about my best shot.  Taken right at mid-totality at 1245, you can tell from the illumination that the moon passed south of the earth's shadow center.  Next time I'll set up with a sturdy tracking mount in a dark site, but this one, spent with friends at an exotic location made it a special event too.

Like our Christmas trip, I've got lots of posts waiting for me in the 1500+ pictures taken this trip.  Stay tunes for some interesting stuff!

Tuesday, April 8, 2014

Coming Soon To A Sky Near You!

It has been a long time coming, but this next Monday night, 14 April, there will be a total lunar eclipse!  This occurs during the full moon when it passes into the shadow of the Earth - totally safe to observe, unlike a solar eclipse.  You might rightfully ask why there isn't a lunar eclipse every full moon.  It is because its orbit is inclined about 5 degrees to the ecliptic, the sun's apparent path across the sky.  A total lunar eclipse only occurs when the moon is full and is at the ascending or descending nodes, where the moon's path crosses the ecliptic.

While they typically happen a couple times a year, in the Americas, our astronomical fates have not shown us a total lunar eclipse since December of 2010!  The pictures shown here were taken on 21 December of that year, through the thin clouds that came and went.  At left is a partial phase, where the moon was moving towards the lower left into the Earth's shadow.  The right picture was taken during totality - even though entirely in the Earth's shadow, it was still illuminated by light diffused by the Earth's atmosphere.  One analogy I've heard is that the moon is lit up by all the simultaneous sunsets and sunrises around the world.

The only disadvantage of this eclipse is that it occurs very late on a school night (again, Monday night, Tuesday morning).  In Arizona time, the partial phase starts about 11pm, and totality just after Midnight.  Mid-totality is at 12:45 and totality ends about 1:30am.  Again, that is Arizona, Mountain Standard Time...  Central Daylight is 2 hours different (later - mid-totality at 2:45am), and Eastern Daylight 3 hours later (3:45am for mid-totality).  We'll be out hopefully with better conditions than 2010 where these were our best shots.

Ironically, we're in the front row seat for the next 4 (!) lunar eclipses.  At about 6 month intervals, we should be able to observe all of them the next 2 years!  So if you miss this one, there is another in October, though that is on a school night too...

Saturday, April 5, 2014

Streaks in the Sky!

I've long advocated using Heavens-Above for tracking not only the appearances of satellites in the sky, but it is helpful for making star maps for a particular date and time, and for tracking the location of planets and comets.  This weekend I'm helping out at Kitt Peak National Observatory's intro class in astrophotography, and when I saw there were a couple satellite appearances, of course I had to try to capture them!

First up, about an hour after sunset, was an Iridium Flare - a glint of sunlight off the antenna of one of the Iridium constellation of satellite phones. Since they maintain an accurate orientation in space, Heavens-above can calculate when their flat, shiny antennae shine a shaft of sunlight across a narrow path of the earth. These glints can become quite bright and for brief periods become the 3rd brightest thing in the sky. From Kitt Peak last night, we were about 6 miles from the center line, but was still to be nearly as bright at Venus at -4 magnitude, and just above Polaris. I found a vantage point looking north that included the 4-meter telescope, the flare and the Big and Little Dipper asterisms. Right on schedule (you can set your watch by these!) it flashed the sun down on us, and fortunately, the shutter was open! I had anticipated a longer exposure to get more of the Iridium's trail, so turned down the ISO and F-stop a little and ended up only getting the flare. It was ok s the stars came through fine, as well as some of the lights along I-10 and the lights of Tucson reflected in the clouds. Besides the bare-naked image at left, an annotated one at right shows the asterisms.

After the Iridium flare, I had 20 minutes to find another vantage point for a pretty good International Space Station (ISS) pass.  ISS, the largest satellite assembly orbiting the earth, is easily seen shortly after sunset or before sunrise when it is dark at the observer's location, but the sun still illuminates it circling overhead.  I decided to hike up around the 4-meter to record it passing to the south of Kitt Peak.  Once there, I realized the moon couldn't be in the shot, so set up in the shadow of the 4-meter dome for the passing.  Again, like clockwork, ISS appeared and passed with its contingent of astronauts on board.  The clouds added an interesting element to the image, and rather than the single vertical frame, I decided to take 2 more images and combine them into a horizontal mosaic.  So this image is a combination of 3 frames with my wide-angle 10-22 zoom set to 12mm.  Assembling the 3 frames with Microsoft's ICE (Image Composite Editor), there is naturally some distortion, but shows the ISS pass below Canis Major past Jupiter over the 4-meter dome past Auriga to Perseus, as well as a few of the moonlit domes on the mountain.  I've got to admit that ICE did a great job assembling the frames - even with the 3.5 minute exposures (plus 3.5 minute in-camera darks), I don't see any errors, artifacts or gaps given the time gaps between frames...

Another classroom session tonight - I give my presentation on time-lapse imaging.  We'll see if another imaging opportunity crops up...

Wednesday, April 2, 2014

A Spring Long Sprung!

It has been a warm, dry Winter!  While it didn't break 80F until the end of January, there were 22 days that month over 70F, and lots more days in the 80s in February and March.  And dry!  We've only had .6" of rain this year, that back the first 2 days of March, so it has been dry, even for the desert.  As a result, we had a pretty dreadful wildflower season, and we're coming up fast on the cactus flower season, which will bloom even if we've had no rain, though not as plentiful or long-lasting as if we'd had more substantial moisture.  And I'm always looking to show off more examples of the focus stacking technique in macro shots, so was about time to get out looking...  I've got a number of posts on focus stacking, check out some of those results too!

These first shots were actually taken a month ago in March after the little rain we got.  The plant is Desert Globemallow, a native plant to the local desert that while considered a weed in most yards, I let it grow in our pea-gravel front yard...  I give the plants a squirt of water when I think of it, otherwise just leave it along and it gives a bit of color even with it as dry as it has been.  It was also a month ago that I went chasing after it with the macro lens and tripod, and even though it was a windy day, got a couple decent shots.

While the flower looks pretty big in the shots here, they are moderately small, about 1.5cm, 3/4" in diameter.  With the meager wildflower season we had, what few flowers there were around were heavily trafficked with pollinators.  With Arizona now populated by "killer bees" that moved up from South America, you have to assume bees and colonies are of the Africanized versions and you need to be careful not to upset groups of them.  This one in particular was small, and totally zoned-out on the pollen in this flower.  I took a couple multi-shot sets (several frames-per-second while cranking focus slightly) for focus stacking.  Since the 2 shots are clearly different, he was clearly paying no attention to me.  while I didn't quite get the full range of focus for every detail, sharpness is pretty good.  I think the wind was more of an issue rather than pollinator motion!


Now in April we're approaching cactus flower
season, and my neighbor Susan's prickly pear are covered with buds about to pop.  I had a few minutes before heading in for an afternoon shift at work, so again got out the macro and tripod for some focus stacking.  Wind was substantial, but affected the prickly pear less than wildflowers, so didn't have any issues.  With focus stacking, you don't need to stop way down to increase the depth of field, in fact, doing that increases diffraction which decreases overall resolution.  Keeping it at a moderate f-stop, in this case, F/8, taking several shots at different focal positions to get everything in focus, then combining them in Photoshop gives some excellent results!  At left is shown one of the subframes, and you can see the 2nd bud from the right is in focus, but the others are less sharp.  Loading all 6 frames and following the workflow (I follow the YouTube tutorial by Tony Northrup), only the sharpest part of each frame is combined into the final image, shown at right.  I didn't go too extreme and get the background parts of the cactus in focus, but all the buds along the pad shown here are shown in sharpest focus.

While the full-frame of the camera is shown in the above examples, the focus stacking technique seems to work right down to the finest resolution.  At left here, you can look pretty closely and I don't see any artifacts or defocus, which is very close to the resolution limit of the camera from the focus-stacked shot above.

I continue to be amazed with the technique, and once learned, comes second nature - easy to both take the exposures as well as run them through the software.  I can't wait to continue to apply what I've learned to my macro imaging!