Brief explanation

My situation with this blog has been a bit silly.  Not only have I not been finding time to write new posts, but I have not made time even to edit and publish the several long blog posts that I wrote more than a month ago about my experiences traveling in Chile -- and that trip is now more than two months ago.  I am going to post all of those blog updates in quick succession now, in the hopes that they will make interesting reading even though they describe events that are now more than two months past.

Living Kin of Long-Dead Stars

As I write this it is April 9 (though it will only be posted much later after editing), and I am on the train home from Jamaica Station: the last leg of a journey that began over twenty-seven hours ago when I departed from Cerro Tololo Inter-American Observatory in Chile.  Many interesting things happened to me in Chile, but in the next few posts I want to describe my first three nights at Cerro Tololo.  I will try to give some sense of what the actual experience of astronomical observing – something very few people have a chance to do at the professional level – was like for me.

March 28, 2014: I woke up early in a peaceful dorm room within the AURA (Associated Universities for Research in Astronomy) compound in the seaside town of La Serena, Chile.  I had to hurry to catch the Carryall – a big white van – up to Cerro Tololo, where I will be using the 4 meter Blanco Telescope.  The one and a half hour drive from La Serena to the observatory runs first through pastures and vineyards and then up into desolate, beautiful mountains where few have reason to be except the miners who exploit Chile’s wealth of minerals and the astronomers who exploit the wealth of her skies.

The 4m Blanco was built as a twin of the Mayall telescope at Kitt Peak, which I have often seen but never yet used. However, because the Mayall dome is on a huge tower that dominates the north end of Kitt Peak, it looks much more imposing than its southern sister.  From a few hundred yards away, with perspective somewhat lost, the Blanco dome could be mistaken for that of a much smaller telescope.  It is only on a few occasions at closer range – especially at night – when I will look up at the dome looming above me and appreciate the grandeur of the instrument I have come to use. I should say there is one other view that shows the true size of the Blanco dome: the view from many miles away in an airplane, when the observatory is dwarfed to a tiny silvery dot amid the vast and endlessly varied red-brown mountains – but it remains a dot one can see, when the smaller domes have faded into barely noticeable specks.

I have come up to the observatory early: my observations do not actually start until tomorrow night.  I plan to spend the intervening 24 hours getting some familiarity with the telescope and instrument.  I hope to meet tonight’s observer at dinner and ask permission to be present in the control room.  It turns out that tonight’s observations will be part of a long-term campaign monitoring and searching for light-echoes from ancient supernovae and other huge stellar outbursts. As this campaign requires many widely-spaced, single nights of observations, it would be silly for the main astronomer in charge to fly from the US to Chile every time.  Instead he has entrusted the observations to a local colleague, who readily agrees to let me tag along.

One of my favorite things about visiting observatories is talking to other astronomers about the interesting research they are doing, and tonight turns out to be especially good in that respect.  In addition to tonight’s observer and the telescope operator, another astronomer spends much of the night in the control room. Both astronomers have fascinating things to say.  We talk about light-echoes from Eta Carinae’s Great Outburst, and from the supernova observed by Tycho Brahe.  We talk about spectroscopy of extremely metal-poor stars that were born in the early universe. Such stars are metal-poor because they were born so early in cosmic history that few of the massive stars whose explosions release metals into the galaxy had yet had time to form and die.  It turns out that some of these metal-poor stars have unusual patterns of elemental abundances – patterns that suggest the explosion of just one earlier massive star may be responsible for all their heavy elements.  Thus we should imagine a wild, brand-new galaxy with stars just beginning to form, and in a given region of the galaxy there has probably only yet been one supernova.  The low-mass stars that form in that region, some of which survive to this day, bear in their elemental abundances the unique signature of that specific supernova.  As the exact elements produced by a supernova depend on the mass of the star that exploded, studying these unusual low-mass stars allows us to do something remarkable: estimate the masses of long-dead giant stars that exploded when our galaxy itself was newly formed.

The actual operation of DECam, the instrument I have come to use, turns out to be very simple, though different from most astronomical instruments.  In general, when I take an astronomical image I give a computer command to move the telescope to the precise location I want, and then another command (often on a separate computer that runs the instrument) to take the image.  If I want to change something, such as the filter that defines the colors of light being observed, or the image exposure time, or the telescope focus, I execute another set of computer commands (or for the focus, sometimes even analog commands using a hand paddle).  Not with DECam.  With DECam I must make a set of observing scripts ahead of time, specifying the coordinates, filter, exposure time, and other parameters of each image.  If I have set the script up properly, all I have to do is command the computer to run it and then sit back, relax, and watch the telescope work for me.  In principle, a whole night’s observations could be put into a single script.  In practice, I will want perhaps a dozen scripts each night, and will make some of them ‘on the fly’, only minutes before they are needed – in order to give me flexibility to adapt to changing conditions or implement new ideas I have thought of to optimize the final set of images I will obtain.  I like using DECam, once I have got used to it. The discipline of having a new script fully ready before the old one is finished takes some getting used to at first (and this is very important, to avoid the wasteful and embarrassing situation of having the huge, powerful telescope sit idle while I am finishing a script).  However, the fact that I can write a script and check it over in several different ways before running it undoubtedly makes for fewer mistakes and a more organized set of final observations.  It also makes some of the observing skills I have carefully honed over years of practice – the skills that help prevent me from making mistakes – unnecessary.  I can live with this, however.

Not all those who wander are lost...

It's been a long time since I've posted anything here because there has been so much to write about that I haven't had time to write! I've been traveling a great deal. Also, for the sake of my family's security, I haven't wanted to post anything that revealed my absence from home as long as I was still absent. Now (April 10) I'm back home at last, and I'm planning to make several posts about interesting experiences I had while traveling. Some of these were actually written (although of course not posted) while I was still abroad – including the one that follows this introduction. It was mostly written over a week ago in Chile, hence its references to my April 6-7 observing run as still in the future. It gives an outline of my travels over the past several months. Here it is:

My last post was written from Canada, in late January. My former boss had moved there, and had invited me and my wife and children to come and stay with him and his family for a couple of weeks while he and I worked on astronomy papers we are writing together. We had a very good time with them. Our children played well together, and were sad to leave.

Less than two weeks after we got home, I had to leave again – this time on a astronomical odyssey spanning two continents and two hemispheres. The barely-possible scheduling was born of writing too many telescope proposals, and having them be too successful (actually, that's impossible, but anyway...)

I flew to Tucson, Arizona to observe from February 17-20 with the 2.1 meter telescope at Kitt Peak, and then on Feb 21 I flew out from Tucson on my way to South America to observe with the 8m Gemini telescope in Chile. There was no time to go home to New York in between: I was scheduled to observe February 23 and 24 at Gemini. Since it takes about 24 hours to get from the Tucson (or pretty much any place in the US) to La Serena, Chile, there was only one day to spare – a pretty small error margin for an intercontinental journey and the most important observing run (at least, the one using the largest telescope) of my life up to now. I had a few adventures on the journey (which I may have time to write about later), and was very grateful to arrive at Gemini. The observations went well, and I flew home by way of Tucson – an illogical route that required two consecutive red-eye flights, but was dictated by the fact that one-way airtickets are so much more expensive than round trips.

I arrived home February 27 – and then flew out again March 5 to observe at Kitt Peak from March 6-13. I got back late March 14, and was able to stay home almost two weeks that time, before flying back to South America on March 26, this time to observe with DECam on the 4m Blanco telescope at Cerro Tololo. I have two runs scheduled with DECam: March 29-30 (the observations went well) and April 6-7. Thus, I'm in Chile as I write, in between the two DECam runs.

You may ask what my dear wife is doing, left at home with four children (and a fifth on the way) while I fly all over the Western Hemisphere using telescopes. She is a very capable and courageous woman, and all of these plans (including the initial telescope proposals) were made with her approval. So she is handling things very well – but will be very glad to have me back. The baby is due May 1, and I have not submitted any telescope proposals for the second half of 2014 – so after this I will be home for a while. This crazy schedule has been sort of a 'last hurrah' of observing for me before the baby comes and such things become much more difficult for a while. That will do for this post for the present – but I hope to post again soon with some highlights from my various trips.

Brief musings on a long journey

Travel can be a microcosm of life, bringing into sharper focus the absoluteness of lost opportunities, the brevity of the time between greeting and farewell, the swiftness of change both in ourselves and our situations – and the reality that today is all we have for sure. I like it: I like the things that remind me that life is for real, decisions are momentous, and we play for keeps.

AAS press release

A bit silly to wait almost two weeks to post this, but I had a great time at the American Astronomical Society meeting (January 5-9), and a press release I helped give wound up on the BBC front page on Jan 7: http://www.bbc.co.uk/news/science-environment-2564765...7

As well as lots of other places:
http://www.nbcnews.com/id/54005662
http://www.sciencedaily.com/releases/2014/01/140107170600.htm
http://phys.org/news/2014-01-stormy-stars-spitzer-probes-weather.html
http://www.astronomy.com/news/2014/01/spitzer-probes-weather-on-brown-dwarfs
http://www.popsci.com/article/technology/brown-dwarfs-racked-planet-sized-storms-molten-iron
http://www.space.com/24192-stormy-weather-brown-dwarfs-aas223.html

Pictures with new camera

The blizzard beat the guarantee, but the new camera did finally arrive.  Thanks to everyone who gave me money to buy it!  Here are a couple of pictures we took last Sunday.  For security reasons I won't post any of the adorable pictures we took of the children on this publically accessible website -- however, the children did help me choose these and optimize the display parameters.

Reeds at a frozen pond, Cathedral Pines County Park



Frozen pond near sunset, Cathedral Pines County Park

Walking home on the night of Jan 2

I start at 11:30pm.  There wasn’t much choice: I had to work late, and there’s no way our car could handle this blizzard: I couldn’t ask Jane to pick me up.  I’m well prepared: a hat and a long scarf tightly wrapped across my face, and a spare, hooded coat in case my usual denim and fleece jacket isn’t enough.

The storm is wild, and I delight in it: the dry, powdery snow whipping off the ground in swift flurries, blowing behind my glasses and stinging my face.  Is frostbite a possibility, I wonder? My shoelace breaks and unexpected hazards occur to me: what if my hands are too cold to fix it?  What if when I get home, my hands are too cold to unlock the door?

There’s about 5 inches of snow on the ground.  I find it much easier to run than to walk, because my running stride gets my feet higher, clear of the snow.  None in my shoes so far.  I cross the major road and start climbing a long hill.  I knew this would be hard, but I’m feeling frightened now by the exhausting snowdrifts and the strangeness of it all.

Stop.  I’m actually hot now from running, and being hot tends to make me anxious.  My earlier concern about frostbite is laughable now. I suddenly realize that stress level about deadlines at work is feeding an unrealistic reaction to my current situation.  Everything is going fine.  I am easily strong enough to do this.  I take off my denim fleece, button it down so no snow will get inside, and tie it by the sleeves to my backpack.  Now I am only wearing two layers.  The wind cuts icily though my sweater, but I welcome it.  Now I can run without fear of overheating.

I pass the fire station.  Its illuminated sign reads 12:16 AM, 16 degrees F.  I have seen snow drifts before, but not snow dunes: I have never seen snow that so perfectly imitates sand.  Fascinating to see this on Earth.  On the icy satellites of the outer planets, ice always acts like rock.

I pass our church: 3 miles down now, two to go.  In places the roads are well-plowed, and I run on them rather than the sidewalk, delighting in the blessed feeling of my feet not sinking in snow, but mindful of the possibility of being hit from behind by a snowplow I was too muffled to hear coming.  I look over my shoulder often.  Only one of my boots has snow inside it.  I would prefer zero.

I’m relaxed and calm now.  I thank God for this.  Everything is going to be fine.

I’m almost home, approaching Port Jefferson Harbor.  There will be no protection there from the wind.  I put my denim fleece back on, and re-wrap the scarf across my mouth.  The outside is liberally encrusted with ice from my breath.  I’m not careful enough in the cold and wind to tell if I’m getting the scarf backwards or twisted, but with every wrap I find the icy part goes outward, as it should: a small blessing but a very real one.

The wind off the harbor is every bit as cruel as I thought, but I delight in its power.  Then I see the water: the most amazing vision of the night.  No, it isn’t frozen, it’s… high.  I’ve never seen a normal tide this high.  The wind must have raised the tide in Long Island Sound.  It looks like if it were two feet higher it would be flooding the lowest part of the street.  That suggests a somewhat stronger wind could have made my walk home... very interesting indeed.  I walk along the water front, checking my initial impression that the water is ridiculously high.  Yep.

Edges of the boardwalk and wooden plank boarders of flowerbeds near the waterfront are blown clear of snow.  If I ever own any sizeable piece of land in an area where it snows like this, I will build walkways made of wooden planks two feet above the ground and only eight inches wide.  The blowing snow won’t stick to them and on a night like this they will be absolutely delightful to walk on, and worth their weight in gold if I need to do anything outside.

I wish I had the new digital camera I ordered with my Christmas money, but it will only be delivered tomorrow.  That is, it’s guaranteed to be delivered tomorrow… we’ll see who wins, the guarantee or the blizzard.  I could have taken fantastic pictures with it tonight.  On the other hand, I would have spent a lot of time taking those pictures... and getting very cold.  In fact, it’s possible that a good digital camera is the only thing that would have made my walk home tonight truly dangerous.

My little house is covered with pure white snow and still lit up for Christmas.  It looks like Heaven.  My hands are not too cold to turn the key.  As I step inside, the clock is just striking one.  I must have run faster than I thought.  Thank you, my Lord -- I’m home.