Monday, May 23, 2016

6D Put Through Its Paces

With a day of practice with the new Canon 6D, it was ready to put to a test at a family event - the Ketelsens at a dinner meeting at Pizza Ranch at Clinton, IA. Some enjoy the pizza, some go for the fried chicken and mashed potatoes, but the food matters little when it comes to catching up on our lives!

I pretty much had the camera out the whole time, trying to avoid getting my fingers too greasy. Stars of the show as always were the 2 great nieces in attendance. At left, Mya provides the smoldering "Ketelsen Look" over the glasses at me. And just to prove that a 9-year-old could operate the 6D, Great-niece Alivia took the photo at right of her great-uncle Dean...

My sister Linda and her husband Lauren had been down visiting us in Tucson last weekend - just returning to their home in the Midwest the day before. About the time we were headed for Chicago, they were on their way to the Grand Canyon and points of interest in northern Arizona. At left, Linda at center shows off photos on her tablet to sister Kathy at right and Melinda at left. They had a great time at the Canyon (Lauren's first trip there), and Sedona on their way back to Phoenix. At left, Alivia makes a cameo appearance between Linda (her grandmother!) and great-aunt Melinda...

So the 6D worked great!  While I was concerned about lack of a built-in flash, it seemed to work well under ambient lighting at an ISO of 6400 as all these shots attest.  The camera was set to aperture-priority, so the f/number was fixes at F/5.6 and chose the correct exposure for the lighting, typically a 60th to 100th of a second.  Autofocus worked fine, and the camera was surprisingly fast and quiet.  At left is another shot by Alivia, this time, of great-uncle Rich (Kathy's husband).

Full Frame, Canon 6D
Full Frame, Canon XSi
So the biggest thing to wrap my brain around and get used to is that the 6D has a much larger sensor that the APS-sized XSi I've been using for 8 years. With a sensor twice as large and almost twice as many pixels, there are a few applications that will affect me, though not particularly the average user. So today I went out looking for some examples of where there are dramatic differences...

I used the macro lens on a couple subjects - first up is a few of the maple seeds that our car (that has been sitting for 6 months) was buried under upon our arrival here. A few seeds were "posed" on a tree stump so I didn't have to kneel on the ground. A tripod was used to hold the camera steady. Note that the setup was exactly the same for both cameras - the 6D and XSi with about 3cm of extension tubes and the 100mm Canon Macro. Lens focus and distance to the seeds was the same for both setups. Both are focus stacks to extend the depth of focus, but that had little effect on fields of view. At left is the full frame of the 6D, and at right the full frame of the XSi. There is a pretty dramatic difference, with the expected result that with the same optical setup, the field would be considerably smaller with the XSi's APS sensor...

Canon 6D - full resolution crop
Canon XSi - full resolution crop
But interestingly, the pixel sizes are not too different. The XSi's pixels are about 5.2 microns, the 6D about 6.5 - about 25% larger. If you look at the above images at the camera's full resolution, they should match to about 25%. Shown here are just that - full-resolution crops of the same area of the above frames to demonstrate the ultimate resolution. At left is the 6D image, at right the XSi. With smaller pixels you would expect a slight advantage in resolution on the image at right, and a little larger scale with the 6D at left which is what is shown. So really for critical work, the smaller pixels of the XSi still give it a little advantage in resolution (though not if field of view!)...

Full Frame, Canon 6D
Full Frame, Canon XSi
Another example came with the full 5cm of extension tubes I have with the macro - the biggest I can make something without new optics or more extension. Here is a dandelion seed pod. At left is the 6D image and at right the XSi - again, distance to the subject and focus setting were the same for both, and both were focus-stacks again to extend the depth of focus. Again, as you would expect, the larger sensor had the larger field of view. Note there are some inherent defects in the image as there was some subject motion in a very slight breeze and the shutter speed of a 40th second, even at ISO 800. With the large extension, this is where having a flash unit would be useful to minimize exposure...

Canon 6D - Full Resolution Crop
Canon XSi - Full Resolution Crop
And similarly, looking at the full-resolution images, the same as above is demonstrated - the smaller pixels provide a narrower field at higher resolution (XSi) as the slightly larger pixels of the 6D.

So I'm loving the camera, though admittedly I still need to crack the manual and learn a few details of basic operations, though at least I've figured out how to zoom in on an image - sure seems a lot more complicated than the earlier generations, though...

Saturday, May 21, 2016

The "BIG SIX"!

It happens so rarely that I don't have a label category for "new Gear"! For the first time since this blog started, I've got a new camera - the Canon 6D! I've mentioned before back in January that I was saving up pocket change for the upgrade, and with the Grand Canyon Star Party coming up, it was time to get it and practice before some good opportunities to image came along. What isn't to like - a sensor that is twice the size of my APS-sized Canon XSi. In addition, there are about 3 generations of improvement in noise reduction (Digic 5+ compared to Digic III), and an associated increase in sensitivity from max ISO of 1600 to 25600. Not that the XSi is no slouch - obtained just before our wedding 8 years ago, it has everything I've ever wanted, and likely some features I've never used. I'll still continue to use it as my primary spare, but 8 years of constant use and it was time for an upgrade.

I decided to have it shipped to St Charles and it arrived yesterday. It is a hefty camera, a good 8 ounces more than the 1 pound XSi - likely as there is more metal construction over the polycarbonate plastic of the XSi. The 24-105mm kit lens is hefty too at F/4, but in initial tests seems a great kit lens for the new camera. There is a huge learning curve in little things like zooming in on an image you've just taken. There are no doubt features I'll be learning about for months - but for now, I've got a couple dozen pictures taken without opening the manual and like what I see. As illustrated above, the sensor size is about twice that of the XSi. Since most of my lenses will work with the new one, that extends the field of view, with very little loss in resolution as the pixel sizes are pretty comparable (6.5 microns for the 6D, 5.2 for the XSi). So nearly twice the number of pixels provide much more freedom to crop and compose an image once taken... Take the images of the flowers on the bush - the full frame shown at left. Of course, since the blog only accepts a max of 1600 pixels, a LOT of data is lost in reducing sampling for the blog. The image at right is a crop of the same frame, showing full resolution with the same number of pixels as at left.

One thing I'm not enthused about is the lack of an on-camera flash... I use the flash on the XSi A LOT! From night-time time-lapses of flowers and sphinx moths to even daytime macro, the on-camera flash is pretty useful, so that will likely be about the first accessory to invest in... That being said, with the high ISOs the 6D has, it should almost work hand-held in the dark! We were visiting sister-in-law Maj this afternoon and I took the image at left of Melinda by the light of the 40 watt bulb adjacent to her. I've got to admit it worked pretty well at 6400 ISO and a 25th of a second.

The same goes for other low-light level shooting - at right is a shot of some ferns in front of our house when we got home about sunset. Resolution is pretty good even as dark as it was getting with the hand-held shot.

So with the first couple dozen images behind me, I'm thinking I'm a happy camper! I'll likely even be happier when I open the manual and figure out basic stuff I used to know on my other cameras, like zooming in on exposures and using live view. I recall some issues on basic stuff like that when using Ken's 6D for some LBT shooting a year ago. I'm sure it is just a matter of training the operator! And if you think that you would get away without an anaglyph of the ferns out front, you would be wrong! At right is a 3D shot of a fern, hand-held at about sunset, assembled in Photoshop. Not bad, say I!

Friday, May 20, 2016

Fifty Shades of Green!

I'm way behind in posting, but have been too busy to think, let along put down electrons on the computer screen!  We've had a good week of medical appointments and relatives visiting, so have been running for days, but finally time to relax some.  We're travelling now - arrived at "Ketelsen East" yesterday, thus the title for today's post.  We've left the desert, where it hasn't rained in weeks, and more is unlikely for another 2 months, and flown to the Chicago area where it's so green it hurts your eyes!  We caught our noon-ish flight (non-stop!), and fortunately, we had a seat with a good window, in front of the wing this time.  As we taxied to takeoff we witnessed something you don't see often - AZ Air National Guard had four F-16s taking off in front of us, and I caught two of them in full afterburner mode!  Click the image to see the center fuel tank and the sidewinder missiles mounted on each wing...

For those who have flown out of Tucson, you might notice also that the F-16s and our plane too took off towards the NW, another rarity! So had another rare chance to cruise around central Tucson as we circled around to head east. We flew right over the UA, so I caught a few pictures of "my" part of campus, which really holds the national headquarters of astronomy and optics within a couple blocks. My workplace, the Mirror Lab is nestled under the east stands of the football stadium. I've included a labeled version to ID some of the more interesting buildings. My 3 workplaces covering the last 40 years are all included in the image (KPNO headquarters, Optical Sciences, and now the Mirror Lab).

I took a lot of images, mostly stereo pairs of objects I knew. We were sitting on the right side, so facing a little up-sun, not ideal, but it was high enough it didn't cause a lot of problems. Moving at 500mph though, it doesn't take long to run out of landmarks for your location reference. We had some nice low clouds that made for interesting 3D images, and took the one at left of the Lordsburg (NM) playa, and another at right a few minutes later of desert near the AZ/NM border. Note that like the SW in general this time of year, there isn't much green - just LOTS of earth tones in browns and greys... Anyway, after these I was mostly lost in the mountains of western New Mexico. I recognized Socorro, but after that, clouds picked up and saw nothing for a couple hours.

Finally we hit a clear spot and didn't know where we were, but were already descending.  Finally, a river valley ahead - I thought it might be the Mississippi, but was the very busy commercial waterway, the Illinois. Barges could be seen plying the narrow channels. Another clue to our location were the dozens if not hundreds of huge windmills for electrical generation. The fields were still bare brown, as it has been a cool, wet Spring and the crops are just getting in now. In a week or two they will be a totally different shade! At left is shown some bare fields (showing drainage patterns), windmills and likely a hay or oats field. One farm pretty looks like the next through central Illinois, so was lost again for a while.

Finally we passed a good-sized town and what do you know - it was St Charles, our "Ketelsen East" home town! The Fox River, spillways and the town's three bridges made for an easy ID. Given our distance from downtown, it was likely we were passing directly over our house! We often know the flight path is over our house with the planes passing over every minute or so, and such was likely the case. At left is a shot of town, and of course, all it takes is another a few seconds later to get a stereo pair, shown at right.

Very quickly I was inundated with clues for our location - St Charles East High School (The Fighting Saints!), the DuPage airport and Charlestowne Mall, but just as quickly moved beyond my local territory of knowledge.  We flew directly into our runway at O'Hare - no circling the city or going out on the Lake.  But once landing, we taxied for what seemed like 20 minutes to get to our gate...

We got picked up by Melinda's buddy Sally Jo, mentioned and pictured just a few posts ago from her Tucson visit last month. Who drove us to another buddy Carolyn, where we park our car in our absence.  We treated them both to dinner and finally got home about 10pm...

Sleeping late this morning, I finally got to see our surroundings. The camp doesn't cut our lawn unless we ask, so has been so far untrimmed this year. As a result we have some foot-tall red trillium, and while we missed the dandelions, there are some seed pods left. Shown at right is a 6-frame focus stack of a dandelion seed pod with the 100mm macro, and at right a 4-framer of some trillium, both in our "lawn". It would be nice to document a few more of our "flower yard" inhabitants before borrowing the neighbor's lawn mower and hacking it all off.

So it will be nice to relax here for a bit and enjoy the green shades and flowers about to come into bloom. We've missed most of the tulips, but have both iris and peony in our yard that will bloom soon. And you just never know what will show up to be documented - stay tuned!

Friday, May 13, 2016

New and Improved!

A week ago I had posted a short time-lapse of my Mammillaria longimamma blooming.  It is an unusual looking cactus with striking flowers, and as I learned, its blossoms last longer than usual cacti and their day-long flowers. After posting the day-long sequence, I started another the next day, then again on the third! The second day the second bud opened, as shown at left. On day three I was looking for something a little more unusual to add, so stopped as they were opening to zoom in on the center of the first flower. Watching the time-lapse later, the vibrations of the flower petals and the interior flower parts seem to be natural and not caused by insects or wind. Since the images were taken every 3 minutes (20/hour), buffeting from outside sources would be herky-jerky, so the gentle swaying seems natural.  Note that all this activity takes place in an 8cm square plastic pot!

Finally, on day 4 I kept an eye on it, but the now-aged buds refused to open, and a snapshot appears at the end of the sequence below. Good thing too, as it was Mercury transit day, and both cameras were busy, and didn't have another to spare!

So without further ado, here is the now-78 second clip.  Feel free to go full screen and hi-def if you have the bandwidth.  Enjoy!

Monday, May 9, 2016

Spots on the Sun - the Mercury Transit!

Today, 9 May, was the latest transit of Mercury, where from the Earth's vantage point, the planet's disk is seen in silhouette against the disk of the Sun.  You would think that it would happen every inferior conjunction as it swings between Earth and Sun, but because of the inclination of Mercury's orbit, it only happens about 13 times per century.  It is always fun to see the inky black disk slide across the sun, much darker than the sunspots, magnetic storms on its surface, demonstrate. 

For us here in Tucson, the transit started about 1.5 hours before sunrise, so of course, we miss that part. I had envisioned shooting the sunrise against the Catalina Mountains so that it could be spotted as soon as it rose, perhaps a few saguaros seen in silhouette too. I spent nearly an hour scouting locations Saturday evening, finally settling on a spot near the east terminus of Roger Road where it meets up with the Rillito Wash near the UA Farm.

Of course, documenting the sunrise means getting up well before sunrise, and since I never use my alarm, actually had to try it to see if it worked! It does, but I ended up waking 10 minutes before it was to go off at 4:50. That gave me plenty of time to set up and be sure of focus, exposure, camera level - all those little details.  My setup consisted of the TEC 140 telescope with a Canon 1.4X converter used with the XSi camera.  The shot at left shows the view where I set up next to the van.  For a few minutes I was thinking it would rise very near Thimble Peak, but ended up rising off the right side of the indicated hill.  In the image at right Mercury just cleared the horizon - the little black round spot at lower left.  Note how much clearer the hillside is than the edge of the sun, only 10 miles away compared to the hundreds of miles of atmosphere the sun's image traversed.

I always find it interesting in the edges of low elevation objects. Most observers know about the atmosphere acting like a thin prism that disperses the light into colors - the upper edge of the setting sun has a green rim, the lower edge is red. Yet, on a black, inky spot, the LOWER edge is blue-green and upper is red! Of course, when you think about it the upper edge of the black disk is really a lower edge of the sun, so should be red like the lower limb of the sun. An enlargement of the effect is shown here at left. The effect holds for the dark sunspot group at top too...

After the sunrise, just as I was starting to shut down, some walkers strolled by and got to see Mercury on my camera's Live View. Finally I shut down and retired to home about 2 miles away for the rest of the transit. Fortunately I had set up the AP1200 equatorial mount in the back yard, and aligned it Sunday night, so was ready to go. Unfortunately, my sleep-addled state didn't realize I had hooked up the wires incorrectly, so spent about 30 minutes figuring why it wouldn't track! The trees in the east side of the yard block the low sun anyway, so didn't lose much important time. At left is shown the setup in the "jungle" part of the yard next to the not-yet-completed observatory...

I set up the timer to take images every 2 minutes for a possible future time-lapse movie - we'll see! In the meantime, I can pick-and-choose images that have the best seeing to show here. At right is a full-frame image that is taken a little after mid-transit. Even though the tracking mount had a "solar" rate, which worked perfectly, BTW in keeping the largest sunspot on one of the camera focus marks, it needed a bit of touchup every 15 minutes or so as the sun continued to track a little northward as we approach Summer Solstice in a month-and-a-half.

While the full-disk views are neat, the resolution of this system is capable of so much more! At left here is a full-resolution picture of the TEC and XSi, taken about 15 minutes after mid-transit. Adjusting the levels of the image you can spot details in Sunspot Group 2542, as well as start to see the granulated surface of the sun.

The transit was a slow-motion event, the entire event lasting over 7.5 hours from some parts of the world.  I was fine with letting the camera run mostly unattended, checking the northward drift every 15 minutes or so.  Finally, it drew to a close about 1140 local time (MST), but before it did, just before 3rd contact I collected upwards of 10 frames in quick succession to make sure I'd get a couple good sharp images.  At right, 2 are stacked just before Mercury meets the edge of the sun.

After putting gear away, I went in to work, and finally looked at some of the images tonight.  The easy ones to do something with are shown here.  Anything more complicated may take some time!

But talk about setting a high bar! Tom Polakis, observing from his back yard in Tempe, AZ used a 4" solar telescope and high-speed video system to record many frames of Mercury. Here he made 31 images of the last 10 minutes of Mercury's egress off the Sun's surface, only keeping about half of the data, using only the sharpest images for highest resolution. In making the time-lapse, the flames and prominences at the edge of the sun are real, recorded in Hydrogen-Alpha. Just an amazing amount of work to get this, and a great achievement too. If you go to his Pbase page on this image, you can poke around his other galleries and find other gems he has collected!

If you had a chance to observe the transit, I hope you had a good one!  The next one is in November of 2019, so not so long to wait!

Saturday, May 7, 2016

TAAA Meeting Night!

Most Tucson amateur astronomers know what happens on the first Friday of the month - the monthly meeting of the Tucson Amateur Astronomy Association (TAAA)! Arguably living in the astronomy capital of the world, we have some pretty good meetings. With the Kitt Peak National Observatory, the Planetary Sciences Institute, Steward Observatory and the Lunar and Planetary Lab all headquartered in central Tucson, we are rarely lacking for world-class lectures about the universe or latest data from spacecraft. We even get great lectures from TAAA members themselves, some of them working at the above institutions!

Last night was the first Friday, so of course, we got together, but our normal lecture hall at Steward Observatory was being used for final exams - it is that time of year! So we arranged to meet across the street at the auditorium of the Lunar and Planetary Laboratory. The location fell into the theme of the evening - celebrating the history of LPL. The traditional Beginner's Lecture was a showing of the great documentary "Desert Moon", a 2014 movie by Jason Davis. Using archival footage as well as interviews with early employees, it tells the story of how LPL played a central role in the space race and eventual landing on the Moon. Gerard Kuiper, who founded LPL in 1960 is at center in the right image, and Ewen Whitaker, one of the main interviewees, is at right.

The movie is a testament to Kuiper's leadership and assembling this team around him, most just barely out of their teens! They played central roles as Kennedy surprised scientists by declaring the Moon as a goal for NASA. Starting with the lunar atlas Kuiper started at Yerkes Observatory, after founding LPL they supported virtually all the lunar missions leading up to the landing. Fortunately, the movie Desert Moon is free for viewing on-line, and at 35 minutes long, is a great watch, even on a computer screen. My favorite scene is the un-narrated final scene when some of the now "old-timers" who played such central roles, put their swagger on and strutted down the University Mall - shown at left!

The main meeting started promptly at 7:30, and after a few announcements and business (Springtime Board Elections!) the main lecture started - given by LPL director Timothy Swindle. He admitted that the first half dozen slides of his normal talk were well covered by "Desert Moon", so modified his presentation somewhat. He also announced that much of what he presented was covered in a recent book, recently published by UA press - Under Desert Skies by Melissa Sevigny. Reading her book would likely be a great addition to the information gleaned from Dr. Swindle's presentation.

Dr. Swindle points to the launch of Sputnik in the 50s, and the 6 week period in Spring of '61 in forming the direction of LPL's mission to the Moon and beyond.  So the developing space race kept funding levels high and the department focused both on the Moon and a fledgling planetary space program.  After the successes in the Moon landings, UA continued involvement in the Pioneer, Voyager, Cassini and Mars missions.

He told the story of Lujendra Ojha, an undergraduate from Nepal working on a student project with data from HiRISE, under the direction of principle investigator Alfred McEwen, and discovered "streaks" on the inner walls of craters and gorges that follow up spectroscopy showed was briny water - one of the first direct indicators of water on Mars.

He also told the story of Richard Kowalski. One of the primary research works of Steward and LPL consists of searching for Near-Earth Asteroids with the Spacewatch and Catalina Sky Surveys. Kowalski is the ONLY observer to discover objects BEFORE they struck the Earth, one exploding over Sudan, the other striking the Atlantic Ocean. He is shown at right holding a small piece of the asteroid/meteor that landed over Sudan.

He closed out his talk with the latest mission coming out of LPL - the OSIRIS-REx mapping and sample return mission to an asteroid. Facing a launch this September, it arrives at Bennu in 2018, and returning with its precious cargo in 2023. Answering questions for a good long time, it was a great talk and enjoyed by all.

After the meeting's conclusion, most stayed to interact outside the auditorium over snacks. Another great meeting!  The next one will be the day before the Grand Canyon Star Party starts the first weekend of June!

Friday, May 6, 2016

A Day In The Life...

On the way out the door this morning, I saw that one of my cactus buds were likely going to bloom today. You might recognize it from the center image of these three bought at the cactus show a couple weeks ago. A Mammillaria longimamma, I had also posted an anaglyph 3d image of the first flower a week or 10 days ago.  This morning, it looked about ready to pop, as shown at right... So what could I do but set up the camera and intervalometer to record it for a possible time lapse? I set it up for an exposure every 3 minutes, so got 20 frames per hour for what turned out to be exactly 10 hours! I had set the aperture to F/9 to keep most of the flower sharp, and guessed what it would look like so the bloom would be centered. I also used a ball cap fastened to the tripod to keep the sun off the camera for the duration. Mostly, it looks like I lucked out!

When I got home from work late in the afternoon, the flower had nearly finished closing, even though the sun was still shining on it. I was expecting it to stay open as long as the sun shone, but that wasn't correct. I let the sequence go on a little more, then after tonight's astronomy club meeting, loaded the images to inspect them. It was a lovely flower, waving perhaps in the strong breeze today,shown at left as open as it attained. And taking only a frame every 3 minutes, only caught one pollinator - a bee shown at right. This image is shown at full resolution to record all the details the macro captured. I may shoot it again tomorrow, as the last flower lasted a good couple days, and a comparison to the first day's bloom might be of interest.

And as promised, I loaded the 200 frames into Moviemaker and made the 20 second time lapse, displaying the images at 10 frames per second.  I ended up running the sequence twice to round it out to 40 seconds long.

There were some interesting things visible in the clip - the flower waving as it opened might be partially due to wind, but seems like it would be more "vibration" than the waving observed.  Also the small fingers and next bud to bloom also move around and wave some during the 10 hour period.  Fun stuff - glad it was able to run unattended - isn't technology wonderful?!