You know it is cold when the very air starts to freeze.
This is what happens in a Martian winter when no sunlight reaches the polar region. It grows so cold that the atmosphere, mostly carbon dioxide, begins to freeze and fall to the ground as snow. Frozen carbon dioxide, dry ice, accumulates into a permanent polar cap. While the extent of this polar cap waxes and wanes with the Martian seasons, there is always some ice.
The image below, taken by the HiRISE camera aboard the Mars Reconnaissance Orbiter shows of a section of the southern permanent polar cap. Late summer has caused much of the polar cap to sublimate (convert back to gas), exposing some of the rock under the ice.
Here much of the terrain is shaped by the annual freeze and thaw cycles. These pits are probably the result of these cycles and are about 60m (200ft) across. Soon the region will return to the darkness of winter and the pits will be re-buried in the ice.
Pits in the southern Martian polar cap exposed by late summer sunlight, image taken July 29th 2011, credit: NASA/JPL/University of Arizona
Mike Brown did more than give a lecture while in Hawai’i. He just finished a four day observing run using Keck 2 with AO and OSIRIS, as well as gathering data with NIRSPEC. The target? Among other things Mike and his team observed Neptune and the large moon Triton. Triton is thought to be a captured KBO (Kuiper Belt Object). These objects, including well known Pluto, and lesser known, but just as large objects like Eris, Haumea, Makemake and Quaoar, are Mike’s area of expertise.
It is always nice to see a system I help maintain operating well and producing images like this…
A Keck AO / OSIRIS photo of Neptune and the large moon Triton, credit Mike Brown/CalTech
We were doing more engineering tests with the K1 laser Sunday night. And as usual, Dan Birchall, working the night over at Subaru, took advantage of the opportunity to do some time lapse photography. Enjoy…
I do not usually post random YouTube vids here. But sometimes I just have to. I seriously suggest you select 1080pHD and expand to full screen now.
The shot starts over the west coast of North America heading south. This particular orbit went right down Central and finally South America. You can pick out a lot of major metropolitan areas, Los Angeles, Phoenix, Mexico City, etc., by the lights. Also spectacular is the lighting in several storm complexes along the coast of Mexico and further into South America.
Planning a night of observing is a challenge. There is the choice of equipment, setting up observing lists of objects to target. And then there is deciding where to go.
Finding a dark spot can be a challenge in Hawai’i. Almost every bit of land is gated and tied up in bureaucratic rules. We often use the area around the Mauna Kea VIS to observe. Located at 9,000ft on the south side of Mauna Kea the area has much to recommend it for amateur astronomy. This land is under the administrative control of OMKM, who actively support astronomy, both professional and amateur. But the area does have a number of lights, and there is regular vehicle traffic, even in the middle of the night. Thus I have been actively looking for other places.
The 18″ setup at 9000ft on the side of Mauna KeaThe area around the MK VIS is state land, under the control of the State of Hawaii Department of Land and Natural Resources. Just below the VIS is the start of a back road that almost entirely circles the mountain, R-1, also part of the Na Ala Hele trial system, a road designated for public access. Perfect! All I need is a place just enough out of the way to avoid any lights or activity in the night.
State land is an interesting issue in Hawai’i. No camping is allowed outside of designated sites, period. But, according to the DLNR administrative rules it is not camping unless you are… “in possession of a backpack, tents, blankets, tarpaulins, or other obvious camping paraphernalia, any time after one hour after sundown until sunrise in a forest reserve” (Section ยง13-104-2 Hawai’i Division of Forestry and Wildlife). I made certain I had no “camping paraphernalia” with me. I am merely picnicking… in the middle of the night.
With four days of observing scheduled starting tonight, the pressure was on. Both Keck telescopes, four nights, lost for something I am responsible for? Not an attractive prospect. Everyone in the department has a helpful hint or two, some of them even made sense, most we had already tried. Phone calls and emails fly as everyone chimes in, even the guys at JPL who built the cameras get involved.
It was not until three in the afternoon that I found it. Comparing oscilloscope traces between the two FATCAT instruments I note something amiss in the video signal. Most of the waveforms makes sense, even look OK if viewed alone. The colored trace on the screen isn’t the same as the working camera. Now I recall a couple other waveforms I had looked at earlier and wondered about, even to the point of making some notes about. Realization dawned with an enormous sense of relief. Those clock edges are not supposed to be rounded like that!
I pull the clock driver board out of the working camera and install it in the problem child… The noise goes away!
I stole a spare clock drive card from the instrument guys, from the spares for LRIS. I suppose I will hear about raiding their precious stash Monday when they find my note.
I need both cameras and two good clock boards. The spare has to be configured correctly, which takes another hour of logic and good guesses in the absence of decent documentation. Only two hours before dark we perform the final checkouts on the system, the mood notably lighter as we realize it is going to work.
As I write this the FATCAT cameras are on-sky, detecting fringes of interfering light from some distant star.
Yes, it is broken. Worse, I do not know how to fix it.
Specifically it is the primary fringe tracking camera, FATCAT, that has unacceptable levels of noise. We are due to be observing with it tomorrow night. No fringe tracker, no interferometer. After several days of troubleshooting I still have no idea what is wrong. I do know about a lot of things that are working, having painstakingly checked many parts of the system. The level of frustration is building.
Back to the summit tomorrow. Which sucks. I was supposed to be helping out with the Planet Walk tomorrow. Setting up a solar telescope to allow kids to see our star. Instead, it is back to the frustration of a broken camera.
Any day that starts with two flat tires is bound to be an interesting day.
Waiting for another spare tire to fix the second flat on Mauna KeaYes, not one, but two flat tires in a matter on moments. I felt the first tire blow out and as we inspected the damage a hissing could be heard from the opposite side. The summit road is known to be a problem, and flat tires are not an uncommon event. We do get practice changing tires on this road. Fortunately other Keck vehicles were coming up behind us, and we could ask for another spare to be brought down from the summit. In the meantime we spent a pleasant half hour waiting for the second spare. The weather was beautiful, and so was the view from high on the side of Mauna Kea.
I had planned on working on one of the cameras in Interferometry. The camera has been having trouble automatically filling with liquid nitrogen. In addition I had a list of smaller issues that needed to be dealt with. Unfortunately one of those minor issues turned out to be not so minor.
The Keck-Keck Interferometer fast delay linesThus I spent much of the day troubleshooting Fast Delay Line #5. Used to compensate the optical path between the two telescopes, the delay line is a cart that runs on rails, carrying a set of mirrors. The cart should track very smoothly, changing the path length on the order of micrometers (a few ten thousandths of an inch), instead it visibly jittered and jumped along the rail, something wrong in the motor control software or circuitry. It took much of the day, but in the end it was tracking smoothly.
The entire day was busy from beginning to end. I attempted to finish the last few tasks on my list as the last few minutes of the day sped away. The rest of the guys were ready to leave about a quarter to five, while I was still connecting a few last metrology cables. “Yes, I am coming!” I answered on the radio for the second time. I grabbed my tool bag and headed to the door as the clock hit 17:00.
One of those days I return home exhausted. I will have to head up again, quite soon, to deal with other problems still unfinished. Hopefully a somewhat less complicated day.
Four previous times we have attempted to do this, hold a star party for the students of Waikoloa Elementary School. Four times it has been either cloudy, or outright raining. Yes, raining in one of the driest areas of the island, a place that gets, maybe, ten inches of rain each year.
We even had clear skies!
It was a great event, perfect skies, several big telescopes, and hundreds of eager eyes.
Students of Waikoloa Elementary School enjoying the night with Mr. OEarly in the evening I was worried that it was all for naught. About 7:30pm we were all set up and had a total of two guests, a mother and her daughter. They were getting a private showing of the sky at my telescope, with good views of Saturn, star clusters and nebulae. But where was everyone else? Classroom announcements had been made. Flyers had been sent home with every student. Two people?
They hit us just after 8:00pm, a steady stream of students and parents drawn to see the sky. I would guess that well over two hundred folks came by the star party. The skies in Waikoloa are wonderful for this sort of thing. Nice and dark, with the summer Milky Way glowing brightly overhead. We slewed from globulars to nebulae, to binary stars. Steady lines of folks waiting to look through each telescope. I have never gotten tired of the reaction when someone sees something spectacular through the eyepiece for the first time.
Cliff used his 24″ ‘scope to hunt down the new supernova in M101, visible as a small star like object at the edge of a faint halo. I was wondering which star was actually the supernova. Examining some photos afterwards I realized we were looking at the correct object. It will be interesting to observe this event over the coming week, as a nearby Type 1A supernova it should get quite bright.
My thanks to the guys from WHAC who supported this event. Mr. O, our school contact had everything perfectly arranged, from the flyers, to insuring the lights and sprinklers were off for the night. It was a great event, I expect we will do this again.
I get email. Unlike some more controversial folks on the web, this does not normally contain hate mail. My messages are usually fun to read. A regular feature of my mail are astronomy newcomers asking the usual questions…
Hi,
I found your site while hunting around Google for an answer to a question. I wonder if you can help.
My telescope was bought during the winter of 2011. I’m new to hunting and finding stars and planets. This morning like many mornings I was out and about around 5:38 am. I live in the northern hemisphere, on a farm. As always I look around for any stars that might still be out before the Sun rises fully. If I look hard enough I can find a few. One always sticks out. It is to the south, high in the sky and very bright. At first I thought it was Saturn, but my star chart tells me Saturn would be closer to SSW at 5:35 in the morning. Being I’m not using a compass, I wonder if indeed I’m not facing true south. I’ve read it could be Sirius, but I don’t believe it is, maybe I’m wrong.
Are you able to give me some idea’s as to what star I’m looking at?
Thanks, and I hope you don’t mind the crazy question.
One more question. In the spring when I was looking at Saturn I could have sworn I was able to see the rings of Saturn tilting, or better stated moving up and down for lack of better wording. Am I correct in that? I am using a Celestron AstroMaster 114. Not the best but it was affordable, just in case star gazing was not for me.
Cheers,
[Name withheld]
Saturn with Titan above, Philips ToUcam PCVC740K on a C-14 w/2x barlow, stack of 550 frames selected from 1200With a message like that I just have to respond…
[Name withheld],
Looking up whenever you walk outside is a good sign that you are indeed a stargazer at heart. I find myself doing the same any time I am under the night sky, even when walking across a supermarket parking lot I look up to see what stars or planets are visible.
Learning the sky simply takes a curious mind and a little experience. The patterns of the sky are regular and predictable. Keep learning and you will be able to recognize any bright star any time you step outside.
A remarkable early morning star could indeed be Sirius this time of year. This is the brightest visual star in the sky and can be quite striking. A quick look at the brightest star in the constellation Canis Major will also reveal the bright constellation Orion just to the north.
Each morning a fixed star like Sirius will rise about four minutes earlier, about one degree higher in the sky each day. The cycle repeats each year with the same stars visible in the same positions in the same season. By fall Canis Major and Orion will be in the evening sky and they will disappear into the Sun’s glare come spring.
Your description of Saturn is interesting… The angle of Saturn’s rings does change, but only over the months and years as the the Earth and Saturn orbit the Sun and the angle from which we view the planet changes.
It may not have been your imagination either. You may have been experiencing what astronomers call poor seeing. This is due to the air above, through which we view the heavens, distorting the light. the effect is the same thing that gives stars a twinkle or can cause the image to shimmer over a hot road. Normally the effect will blur the image slightly, coming and going with moments of clarity. When really bad the image of a star or planet can move about in the eyepiece. I have seen Jupiter look like a bouncing rubber ball under bad seeing conditions.
