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!

Friday, March 28, 2014

End of an Era!

Today was Melinda's last treatment!  She made it through the two weeks of daily whole-brain radiation with flying colors.  No serious symptoms to speak of, minor headaches, and some dizziness - enough that they gave her a liter of fluids after yesterday's treatment.  They offered a steroid to lessen some of the effects of brain inflammation, which she started last night, and she thinks it is a little better today.  As a prize for making it through the latest round, they presented her with her "head cage" and a carnation...  The cage is what holds her head absolutely still during the 5 minute treatment, and was form fitted to her when she first started.  She demonstrated its use at right against the wall.  The mesh helps with claustrophobia since you can see and breath through it, but still, being bolted down to the table has got to feel strange...  Evidently the radiation stimulated her olfactory nerves, and told the techs that she could smell ozone or an electrical smell.  They told her that it was normal and some also see blue light from the optic nerve being similarly stimulated (which she didn't see).

At left, our cat Annie comes to investigate the cage.  Since I'm such a fan of moiré fringes, the shot shows the start of fringes formed by the mesh holes lining up, or blocking each other... 

So our adventure from the last 7 months is ending! No more treatments on the horizon!  She's got more doctor appointments weeks and months away, along with PET scan and MRI monitoring on a quarterly basis or so.  But otherwise she is declared cancer free!  It is interesting to be suddenly over the treatments after weeks of waiting for the end to come.  We've sort of forgotten what "normal" is like, but hope to find out in the weeks to come.  For those of you who have showered your prayers and good wishes upon us, thank you so much for your support!  For those of you in Tucson that would like to tip a celebratory beer with us, we'll be at Barrio Brewery about 5:30 tomorrow (Saturday)!  Happy Times!

Monday, March 24, 2014

A Scouting Adventure!

One of the engineers at work, and fellow photographic adventurer Steve West is fond of telling me that "Luck rewards the well-prepared".  I guess that is true as experience goes a long way towards a successful conclusion.  This last weekend, the Large Binocular Telescope (LBT) had another ARGOS run, which uses a laser to help correct the atmospheric distortion of the telescope image.  I had some fortune in imaging the laser beams from a distance the last observing run in November, and wanted to improve on it.  I consulted with another staff photographer and the implication was that we weren't welcome at the Observatory this run, so decided to check out Heliograph Peak (HP) - shown at left here when I last visited the LBT last October.  If we had a good view of HP from LBT, conversely there should be a good view of LBT from there!  Time for a scouting reconnaissance run...

Fortunately the 2 day run fell on a weekend, but clouds early on Saturday delayed my plans - we decided to take in a movie instead of the road trip, even though it cleared late...  Oh well, that left Sunday.  Even though thick clouds were moving in, I decided to hit the road to scout out the situation.  Actually, there had been some homework to do first.  I checked with the Forest Service about access to Heliograph Peak earlier in the week.  No permits were needed, but unfortunately, there was a locked gate where the access road met the main road - motorized access for the antennas and fire lookout only.  I also wanted to run a couple cameras and a small telescope from a single tripod to save weight, so tried and found that one of my adaptors would hold both the little Meade 80mm APO plus hold the 70-200 zoom with my wife's camera.  The setup is shown at right.  So I figured the tripod, pair of cameras and optics would be packable.  Good to go!

It is a good 3 hour drive to get to the top of Mount Graham.  While it had been weeks since we last had rain, I was a little surprised to see snow on the upper elevations of the mountain, given the warm temperatures we've had lately.  I got to the locked gate about 45 minutes before sunset, loaded the lil' scope and zoom in a backpack with a water bottle and snacks, made a sling from some webbing for the tripod and had 2 cameras in a lightweight case.  Hitting the trail, I was immediately hit with the quadruple whammy - first, I'm not in that great of shape, second, the hike started at over 9,000 foot elevation and the mile-long hike included over 600 feet of elevation gain, third, the hike was over mud and slushy ice and snow, and fourth, I was humping about 30 pounds of gear.  Let me tell you - that hour-long hike to cover that mile was the closest thing to real work I've done in recent years!  My heart rate climbed faster than the elevation, and even stopping frequently, like every 40 yards, it was hard to get the heart rate to drop or catch my breath. 

By the time I got to the switchback that provided the view I was after, I was soaked in sweat and just about exhausted.  And it was so dark that there was barely enough light to use live-view for focusing the 2 cameras - but it has potential to be a great vantage point!  The view to the left is the wide-field view with the zoom set to 200mm.  Besides the Large Binocular Telescope, the Sub-Millimeter Telescope (radio telescope), and the Vatican Advanced Technology Telescope are labeled.  While it looks pretty light yet, it is a 16 second exposure!  At left is the view with the 80mm F/6 (480mm equivalent).  I'm thinking if it was possible to drive to the site, it is just about perfect as there are very few places where there are good vantage points of the Observatory on the Mountain because of the forestation.  For about the first time since leaving the main road, there was also good cell reception, so was able to check in with Melinda, and also with fellow photographer Ray who was shooting the ARGOS from San Pedro Vista on Mount Lemmon.

I had planned to stay a while in case it cleared, and while there were some stars visible, there seemed to be some low clouds hanging over the Mountain.  But I had also started shivering, and knew I needed to get back down, as the temperature was dropping below freezing and my sweaty clothes weren't helping me much.  I repacked and headed down by flashlight - fortunately going down was much easier, though the mud and slush was starting to freeze.  There were a couple slippery spots, but was mostly good going.  Reaching one of the western switchbacks, I got a text from Ray, who had heard from LBT that they were going to shoot the laser shortly.  By then it had nearly totally cleared (of course, since I was headed down), but my decision was made and it had been a good choice.  Rounding a corner to head towards the NW towards the LBT, bam - there was the ARGOS beam!  While from my previous observations from tens of miles away the beam was at best barely visible, from here at only 4 miles distant there was no mistaking this beacon.  I stopped, too tired to even set up the tripod, but mounted the fisheye lens (the only lens I had packed besides the zoom and little scope), leaned it on a rock and exposed for 30 seconds.  It looked very much like the picture - the brightened areas are evidently where there were a thin layer of clouds to better scatter the light.

Even stopping to take a few exposures, the hike down was faster than the trip up.  I waited to get back to the van to munch on my snack and ran the heater on the drive down.  It was an uneventful trip back to Tucson, arriving about 12:30.  But even with the death march, it had been a good evening, and I learned a lot about the area.  I need to see how many hoops I need to jump through to get access past the gate next time!