Floating Islands? Yea - They Have Those In Mexico!

Growing up in the Midwest and now living in the Arizona desert, I don't spend much time around large bodies of water.  I mention that because of some astronomical observations that are more apparent near water.  The Green Flash, for one, is argued to be only visible with mirage effects, which are much more prevalent around bodies of water...

Anyway, I was on the lookout for mirage effects, caused by bodies of water, like the Sea of Cortez, where we visited over Christmas.  Particularly this time of year, the water temperature is warmer than the air temperature, and these layered temperature gradients can lead to a variety of interesting observations.  Margie's house is about 120 meters away from shore and perhaps 20 meters above sea level to the top of her "astronomy deck".  Many of the effects would be amplified if we were closer to sea level, but the convenience of leaving gear set up on the deck is too good to be true!

We didn't have long to wait - 2 hours after our arrival, I had the William Optics scope set up to photograph the sunset.  While I hadn't unpacked the intervalometer, I took a few pictures - hey I had 6 sunrises and sunsets, the first one was practice!  It started like an ordinary sunset, but towards the end, the disk of the sun took on a distinctly non-round shape!  It looked more like the profile of an old WWI doughboy helmet...  And a few seconds later, while in Arizona the last glimpse of the sun is ususally a point of light, the last glow of sun over the Sea was a flattened line composed of bright spots - we definitely weren't in Arizona any more!

We tarried a bit into the evening, observed brilliant Venus for a bit and watched Orion rise, but an insistent wind off the desert made it feel a lot colder than it was, putting a stop to any serious observing.  The next morning, I slept through sunrise, climbing to the roof about 5 minutes too late, but dutifully set up the scope and used the last quarter moon's craters to get an accurate focus.  To the southeast, Bird Island looked interesting - through the viewfinder, it appeared to be floating over the Sea!  In a previous trip to Rocky Point, I imaged Bird Island from roof, ground level and sea level to demonstrate the curvature of the earth, but you need a mirage effect to explain floating islands!

What is even more interesting is not that they were appearing to float over the water, but they were changing over a time frame of minutes as the apparent warming sun and breezes affected the stratified air temperatures.  I took a few separated by a few minutes, then headed off to the beach, then went into town for some shopping before having another chance to reimage.  So there is a big gap in the center.  Shown here at right is the series of pictures, the label showing the local time in hours and minutes.

The top image, as above, shows the three main peaks, and if you look carefully you can just see the tip of the fourth at right.  Twenty minutes later you can make out a second peak and by afternoon the full extent of the archipelago can be seen.  If you click to see the full size, what is also of interest is that the distance from the peaks to the water is a constant for all the images except the last, where there is little-to-no mirage effect seen (I worked to maintain a constant scale for all images).  Evidently a vertical magnification was in place for all the frames except the last...  The explanation is given by acquaintance Les Cowley, who maintains the excellent website on atmospheric effects called Optics Picture of the Day.  My interpretation of the above effect is that of an inferior mirage, explained and diagrammed in his entry on a miraged ship in the Baltic.  The air gap seen under the upper images is actually the sky bent by the warmer air layer near the sea.  The rounded bottoms of the peaks is actually a compressed inverted view of the peaks themselves...  The rough-looking waves on the water are actually the lower boundaries of the mirage and do not reflect water conditions.  I especially like the sunlight reflecting off the waves during the part of the day that it was behind the island.  Go to the latter link for a top-notch explanation.

After the taste of hunting mirage effects, I went after more sunsets.  On Christmas eve, looking for a repeat of the above sunset, it was disrupted by the effects of distant low mountains over on Baja 120 miles away.  Finally, on our last morning, I awoke in time to set up gear well before sunrise.  Sunrises are harder to catch than sunsets as you don't quite know where they'll appear with the telescope, but managed to catch this one.  Interestingly, it popped up above the sea's level!  As it rose further, the lower part filled in, and like the above explanation, as the sun cleared the horizon, a compressed, inverted inferior mirage image set back under the water.  As above, some captures are assembled into the image at left, with the image time stamp noted on each exposure.  Unfortunately I didn't pack any filters on this trip and I was exposing at minimum ISO and fastest shutter of 1/4000 second, and the exposures are well overexposed, so no green flashes caught, but it was still amazing to catch these effects.  Note that while it takes almost exactly 2 minutes for the sun to set in Arizona once it touches the horizon, from the first glimpse of the sun to when the inferior image disappeared took 3.63 minutes!  Les Cowley has an abundance of these "Etruscan vase" or "Omega" sunset images as well as some great explanations.

And, of course, what sort of a blogger would I be without providing the time-lapse for you to watch of the sunrise?  You can see from the above paragraph why the images are overexposed...  I used an intervalometer to take images about every 2 seconds, then assembled them with Windows Moviemaker.  Unfortunately, I had to translate the scope about halfway through to keep it visible throughout the sequence.  I used my Canon XSi, and the William Optics 11cm diameter F/7 triplet APO refractor, so 770mm focal length.  They are played back at 5 frames per second.  You can play it in the viewer below, or click the "Youtube" icon below the player to go watch it there.  Enjoy!

It was amazing to look out for these little unusual "extras", and know what causes them...  We're thinking of repeating our visit again later in the Spring, but by then the water will likely be cooler than the air and different effects may be in play - something to look for!

Kitt Peak From The "Wrong Side!"

I figure I've made the trip to Kitt Peak National Observatory nearly a couple thousand times in the last 35 years... That includes 5 years of working on the mountain full time, 20 some years of volunteering and observing, and the last few working there part time.  But virtually every trip is from Tucson about 40 air miles to the northeast, so we're always seeing it from the same vantage point.  The view we're used to has the 4-meter Mayall Telescope dominating the north, right side, and the McMath-Pierce Solar Telescope the south.  The other 24 or so telescopes are scattered between these two bookends, with a few at a lower level on the western side of the mountain.  The view here shows the "standard view" we normally see from the east, taken a few miles south of Three Points, the approximate halfway point.

Going to and returning from Puerto Penasco, Mexico, we continue considerably past the Observatory, so get a great view from the west.  It looks strikingly different, since the telescopes at the lower western slopes are visible, as is the "new" (finished in the mid-60s) road and it's scars from its excavation and blading.  While the sacred mountain Baboquivari is the center of the universe to the Tohono O'odham, due in some part to its being visible throughout the range of the reservation, Kitt Peak was also spotted shortly after turning east from Why, from a good 60 miles or more away until it was obscured by the 4,000 foot elevation Quijotoa Mountains.  Crossing the pass the Observatory stayed in view and grew steadily, the 2-image mosaic at left taken a few miles east of Sells with the 200mm zoom lens.  Continuing past the observatory on Ajo Way, Route 86 we had a majestic view from the northwest, with the Quinlan Mountain (where Kitt Peak is located) foothills blocking the view occasionally.  That view is shown at right...  Be sure to click on the images for the full-size view..

And of course, what sort of stereo photographer would I be without shooting some stereo frames from the moving car (while Melinda drove)!  Shooting with the 70-200 zoom, I'd shoot frames when lack of trees along the road would allow, and the moving vantage points allowed a good baseline for hyperstereo images (where the baseline is much further apart than your eyes.  This pair is likely nearly a half mile separation, and is presented in a "cross-eyed" view.  Cross your eyes slightly to view the right image with your left eye and vice-versa.  You should see 3 images, the center one showing depth.  The thumbnails is easier to practice on, then load the full-size image for more detail.

These last few pictures are rarely seen by those who don't wander past Highway 386, the Kitt Peak access road, so presents a view rarely seen by even long-term visitors or staffers.  Perhaps their appearance will inspire a few folks to wander a few miles further to investigate some new views!

Venus! Go! Look! Now!

Enjoying all the sunsets looking out over the Sea of Cortez the last few days reminded me that we'll not have Venus in the evening sky for much longer.  Long-visible the last few months as the brilliant "evening star", it is swiftly moving between us and the sun in a couple weeks.  But the good news is that even the modest magnification through binoculars will reveal it to be an impossibly skinny crescent during the half hour or 45 minutes after sunset. The reason even binoculars will reveal the disk is that Venus will be at the closest part of its orbit to the Earth.  The picture at left is a cropped shot from the William Optics 11cm F/7 triplet refractor I had on the trip.  This shot was actually taken before sunset and was one 1600th of a second in the daylight sky (I knew where to look from where it was the day before).  Another week and it will be too close to the sun to see easily, so if it is near sunset, go - look - NOW!

Feliz Navidad de Puerto Peñasco!

We're just returned from a spectacular 3 days in Rocky Point, Mexico!  Our friend Donna joined us in paying a holiday visit to Margie, who has part-time interest in a house there.  Even though there was an apparent drug-related shootout 5 days before we arrived (killing 5), we decided not to change our plans, though perhaps many did, as beaches, streets, restaurants and fish markets were deserted while we were out-and-about.

We've posted about visiting Margie many times before. Her house is about a block from the Sea of Cortez, leaving the shore and seabirds visible with slight optical aid from her vantage points. The house layout is pretty much ideal - a trio of bedrooms on the ground floor, living room and kitchen sharing an open-air outdoor table on the second level, and an upstairs "astronomy" deck up on the roof.  I left tripods on the roof and spent most of the sunsets, sunrises and many hours of the day viewing a number of items that will appear here the next few days.

We made a number of short walks down to the
beach.  Temps were pretty nice for the end of December - reaching nearly 70F most days, though the water temperature was quite a bit brisker, but not too cold to get your feet wet.  Unfortunately for this trip, the moon phase was at 3rd quarter so the tides that can reach upwards of 6 meters near new or full moon were only about 1.5 meters, still an impressive range.  At left Melinda is shown enjoying some beach time at low tide.  Since we are budding birders, I attempted to document a few of the new ones to us.  And even while we've seen scads of brown pelicans in many locations, it is always amazing to watch these birds - the way they dive while fishing, and soar for seemingly hundreds of yards a few inches off the water.  You could actually see their wingtips splashing the water when they did flap to gain some altitude.

On Christmas Day we had reservations at Casa del Capitan, a restaurant atop a hill adjacent to a lighthouse overlooking the city.  Reservations were hardly needed as there were few other diners, and unfortunately it was too windy to sit outside and enjoy the view.  The mosaic at left was taken before sunset from the deck showing the development at Sandy Beach to the upper left, to the old town section below center.  Off in the far distance to the right is the extinct Pinacate volcanic range, which I'm told has some amazing crater fields.  The food was great, and we had a good time socializing with Margie and some of her friends from Cottonwood who were also down for the holiday.  At right is Donna and Margie after dinner.

But mostly is was a quiet time to unwind - we didn't have internet access, Margie's TV satellite plan only had Spanish language channels, and the international roaming charge was $1 per minute so I had my phone off the entire time...  It was fun to sit and watch the world spin, and you will see some of that the next couple posts.  And of course, we celebrated Christmas!  Margie had decorated the outside table area with Christmas lights that I suspect will remain up through the year - it was a very nice ambient glow for eating and conversing while enjoying the views.  Between friends, osprey, dolphins, the resident cat Amigo, and some of the celestial wonders you'll see the next few days, it was a memorable time!

Seeing The Light!

I've been entranced with astronomy for what, 45 years now, and one of the most amazing things is that it is one of the few sciences, if not THE only science, where you cannot touch or examine up-close what you are studying.  Sure these days, we are sending probes to Mars and have samples from the moon and we're working on asteroid samples, but as far as stars-and-galaxies astronomy, examining them through a telescope is the best you can do. 

But wait - while we can't get a piece of a distant star in the lab, we know what elements they are composed of, their temperature and how fast they are moving and rotating - how do we know that?  The answer is in analysis of the light using spectroscopy.  Break the light into a spectrum using a prism or diffraction grating converts it into a rainbow of colors.  So far, so good...  The image at left shows what happens with luminous bodies - a hot object such as a tungsten filament or a star will produce a pure continuous spectrum.  Add an atmosphere to the star and the atoms and molecules of gas absorb particular wavelengths of the light and produce an absorption line spectrum.  A hot gas cloud will produce an emission spectrum - again, the atoms and molecules emitting certain wavelengths of light.  While beyond the scope of this blog, elements absorb or emit very specific wavelengths as the electrons move between energy levels.  We can observe a particular red emission line in the laboratory spectrum of hydrogen, and see the very same wavelength in a cloud of hydrogen thousands or millions of light years away, or if the star has hydrogen in its atmosphere, it might appear dark against the star's spectrum at the same wavelength.  By inference then, we can identify the elements in distant stars and galaxies from these spectral signatures.  Add to this that motion towards or away from us can produce Doppler shifts - slight wavelength shifts to the blue as the object approaches, to the red if it is receding, and we know a LOT more about the universe!

I've posted some of these before - spectra of stars taken with a glass prism and telephoto lens.  It was good enough to show a few dozen absorption lines in a spectrum of a star in the Hyades star cluster with my camera's zoom lens.  I was thinking that with a longer focal length, it might have higher spectral resolution.  When I made the prism mount for the post above back 3 years ago, I left space to use my little Meade 80mm F/6 scope, a 480mm focal length lens, shown at left.  I'm still amazed that a sloped slab of glass (cut, ground and polished myself over a couple weekends) shows the makeup of distant stars.  Perhaps I'm just easily impressed!

Anyway, the other morning when I went up early to image C/2013 R1 Lovejoy, I tried the combo for the first time.  Since the prism introduces a considerable shift to where the scope needs to be aimed, it took some practice to find some objects, first up being the bright star Arcturus rising in the east.  Once the offset was taken into account, the spectrum was focused to a point using live view, and some exposures tried.  The spectra look better when widened a little bit, so I moved the scope at a slow rate while taking the 15 second exposure.  The absorption lines came out well - and the cool giant star, spectral class K1.5III,  cooler than the sun, but slightly larger and much more luminous.  Identifications of the lines are not straightforward because the prism has a non-linear dispersion.  The dark line near the red limit is likely Hydrogen-Alpha, and the doublet line in the yellow is likely the sodium doublet, but I'd have to work to identify others...  Don't forget that the element helium was discovered on the sun in the solar spectrum before it was discovered on Earth!

As a demonstration of different types of spectrum, I swung over and took a shot of  the Orion Nebula, a mostly-hydrogen gas cloud and star formation area.  Of course, the resultant spectrum type is an emission nebula, since the gas is heated to fluorescence by hot stars inside the cloud.  Since the nebula has a considerable diameter, monochromatic images of the nebula occur along the spectrum.  Since the cloud is mostly Hydrogen, line identification is easier!  The left-most red image of the nebula is the H-alpha line - the principle hydrogen emission in the visible part of the spectrum.  Of the three greenish-blue images in the center the rightmost is H-beta, the left 2 from triply ionized oxygen.  The faint image to the very far right is likely H-gamma hydrogen line, and the faint orange image to left center is likely a helium line.

And then, of course, the reason I practiced earlier in the evening before the comet rose, getting a spectrum of Comet Lovejoy itself!  While the comet was still too low to image, I took a dozen frames of the spectrum from 1.5 to 3 minutes and stacked them to improve the signal.  Since a comet is a "dirty snowball" at most a mile or two in diameter, the part that we see is mostly sublimated gas from the sun-melted ices from the nucleus.  The solar radiation dissociates the molecules (breaks up) and an emission line spectrum results.  Instead of single wavelength emission though, the larger, more complicated molecules have emission bands shown here.  The green, aqua and blue emission bands are from diatomic carbon molecules, the much fainter bands in the orange and red are from ammonia.  I was hoping to catch some of the tail features, but the brightness wasn't quite high enough to detect it...

So it was a great evening to tryout the new scope/prism combo and it came out fine.  Of course, I'm spending much more time manipulating and describing the images than what it took to take the 3 spectra!  Anyway, hope you enjoy!

A Great Alignment and Spectacular Sunset!

Last evening was our first opportunity this year

to observe the sunset alignment of Kitt Peak National Observatory.  About 4 or 5 days before and after the Winter Solstice, it can be observed from a broad pullout on the outside of a curve just below milepost 9.  There is an unimpeded view of the Observatory to the SSW, and though sometimes the cars passing on the road are pesky, it is a safe place to observe the alignment.  It seems a tradition leading up to the holiday season to observe or shoot it and it would seem strange not to chase it - any excuse to get out and observe!  While it can be quite cold here in December above 5,000 feet elevation, yesterday we set a high temperature record of 83F in Tucson, so it was comfortable in long sleeves even without a jacket...

I always have fun trying new imaging options every year, and there was no exception this year.  Our friend Roger, a telescope maker of some renown, built a 5.75" F/8 diameter triplet apochromat a few years back, and I talked him into joining us, and running Melinda's T1i on it.  The 1170mm focal length was perfect for the sun's diameter on the APS sensor.  I quickly adapted his mounting plate to a massive tripod I've had for decades, and the combination was quite robust.  The pictures were taken shortly after we arrived with the sun still a good 10 degrees off the horizon.  Yes, we had some thin clouds, but perfectly clear skies usually make for boring sunsets!

We had a few friends joining us this year from the Tucson Amateur Astronomy Association (TAAA).  Alan Strauss,director of the Mount Lemmon Sky Center, joined us with some small scopes, one for white light and another for H-alpha viewing.  In the image at left, Alan is standing at right talking to Roger, behind his blue telescope, with Melinda sitting in the back of the van.  Jim Miller and his wife Elaine also joined us, setting up his 10" telescope - the picture at right shows him focusing for the sunset.

Jim O'Connor and wife Susan also came along, Jim attempting to take video of the event with laptop and Imaging Source camera (shown at left image).  We all arrived in plenty of time to get our equipment setup, and had a chance to socialize a bit before the sun hit the horizon.  We even had a couple of normally speeding cars stop and ask what was going on...  The picture at right shows the wide-angle view with the spare camera once the button was pushed and pics came crashing in...

Our observing setup is shown in a little more detail at left.  Roger's APO is the blue scope at left.  It has an older Thousand Oakes glass solar filter - a type 2 filter designed for imaging with short exposures.  Not entirely safe for visual observing (a little too bright), but perfect for shooting a dimmed sun on the horizon!  You can also see the kludged saddle plate mount atop my binocular mount to hold the telescope...  We also observed the sunset visually with a C5 telescope with Mylar filter and roof prism diagonal to give a correctly oriented view.  Through trial and error, I found I could shoot a full-size jpeg every 2 seconds with Melinda's T1i without problems, so that is how I shot it.  While the images were quite sharp when we set up, the seeing got quite mediocre a little before sunset.  I'm thinking it was the inversion layer that was very near the level of Kitt Peak, Roger thought it was cooling air falling down the slopes of the mountain we were on.  Effects of the seeing can be readily seen in the time-lapse below...

As soon as the sun entered the field of view, I
checked the exposure to make sure it wouldn't be overexposed, then started the exposure-every-2-second sequence.  Running manually, each was about a 2000th of a second.  As soon as the sun set below the mountain, I switched it to aperture priority automatic, and even through the solar filter, an adequate exposure was about a 16th of a second.  The image at left shows the sun perfectly centered on the Observatory outline.  Yes, the clouds made the pictures a little more interesting, and fortunately, there was a clear zone at the level of the telescope domes above Kitt Peak.  The sun always seems to move a surprising amount from left to right as it sets (because we're in the northern hemisphere).  It also seems to happen so quickly through a telescope, but takes about 2 minutes, telescope or not!  The last piece of sun set between the 4-meter telescope at right and the Steward Observatory scopes to the sun's left, the last bit bifurcated by the flat-topped dome of the 90".

Of course, we get some spectacular sunsets in
Arizona - something about the clarity of the air and the normally clear skies of the drier, more desolate desert to the west.  And did we have a spectacular sunset.  While normally the show is over once the sun sets, it just got more and more spectacular for the next 10 minutes!  While some of the first color shows up in the wide shot above while the sun was still above the horizon, a few minutes later with the sun illuminating the underside of the clouds, they just glowed...  I took a couple different styles of images - at left is an HDR (High Dynamic Range) which combines 3 exposures of different lengths to preserve details in both shadows and highlights of the image.  I wanted to preserve the purple illumination of the front side of the mountains, as well as the bright colors in the clouds.  At right is a 4-frame mosaic with my zoom's maximum 200mm focal length to preserve details of our view to the west from Thimble Peak at right to the south past Kitt Peak.  Of course, I'm limited to the 1600 pixel wide frame here, but it is a good representation of the spectacular sky.  I'm sure you might think that I've photoshopped in the colors, but check out Alan Strauss' post of the sunset and you will see that I'm not pulling your leg!

So finally, the 173 images collected, of both the sun setting and a minute of twilight skies afterwards, were assembled into a movie using Windows Moviemaker, then uploaded to Youtube.  It makes a very nice 30 second sunset time lapse, showing not only the motion of the sun, but also the slight motion of the clouds past the mountaintop.  You should be able to play the movie right here in the blog post, or you can hit the youtube icon at the bottom of the viewer to go to that site for viewing.  Enjoy!

Lovely Lovejoy - First Look!

While the potential "Comet of the Century", C/2012 S1 ISON got pulverized as it passed over the Sun's surface on Thanksgiving and has disappeared, there has been another with greater staying power - C/2013 R1 Lovejoy.  Discovered by Terry Lovejoy in Australia just 3 months ago, it is currently barely visible to the naked eye from a dark site ( I mean that - barely imagined from a really dark sky!).  While I've spotted it from the back yard in binoculars knowing exactly where to look, nothing beats the view of these things from a dark sky, but as it is a pre-dawn object, I've not gone for any early-morning drives...

But with the nearly-full Moon upon us, this morning was the last chance to have a dark sky for an hour after moon set and before twilight starts, so pulled the trigger and drove up Mount Lemmon north of Tucson to San Pedro Vista with a clear, dark sky in the northeast.  Leaving the house at 1am reminded me of the "olden days" when as a pup of 43 years of age, I would head up the mountain about every third or fourth morning to shoot Hale-Bopp in the morning sky with a Schmidt Camera back in the spring of '97, and believe me, I felt it in my bones these 17 years later!  Arriving well before moonset, I set up 2 mounts and 3 cameras running 80mm to 480mm focal length.  Here are some quick-and-dirty results.

Interestingly, it was also the peak of the Geminid meteor shower, and the skies really were ablaze with meteors.  I was sticking to the task at hand, so never set up a camera with a wide-angle lens, but believe me, would have been like shooting fish in a barrel!  While not even looking away from the quadrant of the sky where the comet was located, I'd see 2 or three over 5 or 10 seconds!  I'm thinking it was easily a couple hundred per hour over the entire sky...  The dark sky really helps with that.  Interestingly, 2 of my early shots with the wide-field 80mm caught Geminids on consecutive frames, so stacked them here.  Comet Lovejoy is sporting a very nice tail (also visible in binoculars) just south of the Keystone of Hercules.  The grand globular star cluster M13 is visible on the left side as well, and made a nice contrast to the comet.  I'm thinking the comet was just brighter than the cluster, but not by a great amount...  Since the comet is so low, the fast lens (Canon 80mm @F/3.5) also caught some airglow (the greenish tints), and possibly some very thin cirrus.  North is at the upper left corner...

One of the other rigs I set up was the little Meade 80mm F/6 triplet APO lens (480mm focal length).  Shown here is a stacked set of nine 150second exposures. Taken with a Canon XSi (my normal go-to camera), north is approximately up in this exposure, whose field of view is small enough that it doesn't even show Xi Hercules at the left of the comet in the wide-field above...  The comet is moving pretty quickly, and I stacked the picture on the overexposed head of the comet, so the multiple-star trails demonstrate how far it moved in the nearly 3 minutes between exposures.  The colors are real - the greenish glow in the coma is from dissociated carbon molecules from the nucleus, and the bluish glow of the ion tail is from the fluorescence of water vapor and carbon monoxide driven back by the solar wind.

The hour of darkness between moonset and start of twilight passed all too quickly, and I packed up all the gear and drove back down the mountain to Tucson, arriving home just after sunrise.  It made for a long night, and sleeping till 1pm, but it was worth it to see this stand-in for Comet ISON do such an admirable job as substitute.  And this fellow isn't going anywhere soon - it will stay at the limit of naked-eye brightness for another month in the morning sky, and even into the Spring and the Grand Canyon Star Party, a dedicated hunter with a C-14 might be able to show it to tourists as a barely-visible speck.  In the meantime, I'll look at these exposures more carefully and see if I can get out something a little more interesting...