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Posts Tagged ‘SPIE’

SPIE 2016 – Poster Done Too

Posted by Tom Benedict on 09/06/2016

And now the poster’s in the bag, too.

SPIE 2016 Astronomical Instruments and Telescopes - Poster

It’s not my most visually appealing poster, but the subject matter doesn’t really call for a lot of elaboration. It’s mostly a data dump of all the spectra I took over the past several months. Just for grins, the bar at the bottom is a gallery of all of the samples photographed with my NIR-converted A2200 point ‘n shoot. (Yes, this actually factors into the paper.)

The two columns on the left contain spectra from all of the samples, scaled from 0-50% reflectivity. The two columns on the right are where the good stuff is: With the exception of the bottom two graphs, it’s only the materials that reflected less than 10% of the light across the whole spectrum. That’s where the useful materials are.

So why include the others? Those are the ones to avoid! The paper wouldn’t be complete if I didn’t include them. Unfortunately, some of the materials we’ve been using for years for stray light control fell into the “avoid at all cost” columns. Bummer. But now we know better.

The poster is printed, and I shoved it in the mailing tube with all of the other posters from our group this morning. All that’s left now is to get my butt on a plane to Edinburgh and present the thing.

Hip hip hooray! Scotland, here I come!

Tom

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SPIE 2016 Manuscript Done

Posted by Tom Benedict on 30/05/2016

Last week didn’t turn out quite the way I’d intended. Right after writing my last post I got a call from my sister to tell me my father had to go to the emergency room. Neither of my siblings were in a position to fly in to help him, so I offered. I spent last week helping him get back on his feet, get to all the doctor’s appointments my sister set up for him, and figure out his next move. This meant I wasn’t spending that time making further edits on my SPIE paper or flying kites and cameras for World Wide KAP Week, but I wouldn’t have wanted it any other way. WWKW rolls around once a year, and I knew I could submit the manuscript to SPIE remotely no matter where I was in the world. I needed to be at my father’s side, so that’s where I was.

Turns out I didn’t need to submit the manuscript remotely, though. I got back two nights ago, a couple of days before manuscripts were due. I gave the paper one last looking over just in case. Just… In… Case… Yeah.

Here are some lessons I learned from “just in case”:

  1. No matter how many times you check your spacing, there’s always a space somewhere you don’t want it. (Yes, I’m using this to justify how anal I am when editing.)
  2. When proofing a paper, also check captions and figure titles. I had one graph labeled “Diffuse Reflectance of Bulk Materiaw 1.5ls”. Um… What?! (Global search and replace can be a real bitch at times.)
  3. Be sure to catch all your little place-holders and fix them. One sentence included “…overall reflectivity between 6-?% across the full range…” In three rounds of editing by multiple people, no one caught that. Not even me.
  4. I always put in too many commas when writing a first draft.
  5. I always leave too many in during subsequent edits. There’s always one more comma to kill.
  6. Above all else, listen to the input from your co-authors. Right before flying out to be with my father I had a frenzied text conversation with one of the co-authors on the paper who insisted on a particular change in the paper. I disagreed, but I had to drop it when I got on the plane. When I got back I found I agreed with him. I made the change, and the paper was stronger for it.

That last one really applies to all forms of writing, not just technical and scientific papers. Listen to your editors. Listen to your co-authors. Listen to people who tell you something doesn’t make sense, doesn’t flow, or is just plain wrong. Even if it means a complete re-write it means you’re connecting with at least one more person when you finally publish.

I submitted the manuscript this morning. I’ll start designing the poster tomorrow.

Tom

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SPIE 2016

Posted by Tom Benedict on 08/04/2016

Turns out I’m going to the SPIE Astronomical Telescopes and Instrumentation 2016 conference in Edinburgh, Scotland, from June 26th through July 1st! I’m holding out hope my neck will have healed by then and I can do some kite aerial photography while I’m there. Either way I’m planning on bringing sound gear so I can play in a new environment and come home with some fresh sounds to play with.

I’m still writing the manuscript for my paper, and the poster hasn’t even made it to the sketch pad yet, but the research has been underway for a couple of years. As boring as this may sound, the paper is all about black stuff.

Whether you’re building an optical experiment on a workbench, modifying or building a telescope for your own use, or working at an observatory, at some point you’ll need some way to control stray light. The bulk of stray light control happens in the design: adding baffles and stops, planning light traps, or controlling the output cone of any light source. But inevitably least one of those will involve making some surface black.

The question is: What does “black” mean? And once you define it, what materials fit the definition?

From the standpoint of stray light control, “black” means “doesn’t reflect much”. But what’s “much”? 5%? 1%? 0.01%? And what range of wavelengths do you care about? CCDs can detect light well outside the range of human vision. What about infrared arrays like the H2RG? They can see well past human vision into the near edges of the thermal infrared.

At first glance the obvious answer is that it shouldn’t reflect anything at any wavelength. Unfortunately such as beast doesn’t exist.

The next best thing would be that it shouldn’t reflect much at all (0.01%?) at all the wavelengths we care about. For the sake of making it a tractable problem let’s say from the UV to K-band infrared, or about 250nm out to 2500nm. The problem is that 0.01% is tough to hit. It’s possible to get close using an exotic surface like carbon nanotubes, but such surfaces are fragile and tough to impossible to clean without damaging them. Let’s face it: astronomy is an outdoor sport. We try to close the domes when it rains, but things do get dirty. They do occasionally get wet. Eventually they’ll need to be cleaned. Ultra fragile exotic surfaces simply aren’t practical much of the time.

But maybe we don’t need 0.01% reflectivity. If we’re careful with our design we can make sure that any stray light has to reflect off of at least two surfaces. Let’s say we’re even more careful with our design and make it so light has to reflect off of at least three. That was the design rule I used when I designed the optical baffle for the Megacam Wide Field Corrector, shown here without its outer skin.

Megacam Baffle Internals - Rendered

If light has to bounce off of at least three surfaces, that means each reflection has the opportunity to absorb light. If each surface reflects a whopping 5% of the light, by the time you’ve bounced off three surfaces you’re down at the 0.01% level. 5% on three surfaces is a heckuvalot easier to deal with than 0.01% on one surface, and it brings our material selection into the realm of common off-the-shelf materials.

Now that we have a good working definition of a practical, workable “black”, that leads us to the second half of the question: What materials fit the bill?

At work I have the good fortune of having a spectrophotometer at my disposal. I’ve used it to scan instrument filters, optical assemblies, even the odd pair of sunglasses. But I’ve also scanned a bunch of stuff that looks black. In the process I’ve run into some surprises. Some years back we made a wrap for one of our instruments in an effort to keep light from LEDs and motor encoders from encroaching on the beam. Out of our own ignorance we used a synthetic black cloth that looks extremely black to the human eye, but turns out to be blindingly reflective above 690nm. We hadn’t fixed the situation at all. We’d made it worse! We replaced the wrap with a different fabric that’s absorptive out past 1100nm (the limit of what a CCD can see), and that solved it.

Over the years our growing catalog of things that are and aren’t black has come in handy. We’ve added paints, papers, tapes, and bulk materials like plastics. We figured it was time to share.

Of course we’re not the only ones doing this. Two years ago a group from Texas A&M published a paper at the SPIE Astronomical Telescopes and Instruments 2014 conference on exactly the same topic. They covered a number of metal treatments – anodizing, black electroless nickel plating, oxide treatments, etc. – in addition to a number of paints and a handful of other materials. But as it turns out our catalogs have almost no overlap, so our paper will be a good follow-up to theirs.

I’m in the process of finishing off the last of our scans over the next few weeks, and finishing the manuscript over the next month. Then it’s on to poster time!

Now I just need to figure out a way to make a visibly engaging poster that’s mostly… black.

Tom

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The Good and The Bad

Posted by Tom Benedict on 09/07/2010

The 2010 SPIE Astronomical Instrumentation conference was a blast.  We worked some seriously late hours, and all of us were dragging our tails by the end of it.  But the amount of information I came home with was…  for want of a better term, it was astronomical.  But that’s a post for another day.  This one is about the KAP I managed to do while I was there.

“Managed” is the right word to use in this case.  Sunset was at 8pm, and the only full day I had to do KAP was the Saturday before the conference.  I had some problems with my flight, so most of that day was lost.  Even so, it was the most productive day I had, from a KAP standpoint.  I wound up staying at the Porto Vista Hotel in Little Italy.  I highly recommend it for a couple of reasons:  1 – It’s a nice hotel.  That’s tough to beat.  2 – Close proximity to a lot of good KAPing.  3 – It’s in Little Italy!  As it turns out it’s also close to a camera store, which I didn’t visit, and a Blick Art Supply, which I did.  Twice.  It’s about a two minute walk to the nearest trolley station, and it’s only a few blocks from the Maritime Museum, which boasts some outstanding KAP subjects.  Unfortunately none of the KAP I did there really worked out.  This is the best of my efforts:

Maritime Museum

Further down, there were a number of other good subjects.  Some I wound up photographing with a pole, others with a kite.  By far the best KAP I had in San Diego was at the marina at Seaport Village:

Seaport Village Marina

The wind was steady enough to let me do some panoramas as well, one of which turned out nicely:

Seaport Village Marina Panorama

Heading back toward the hotel is the USS Midway and the statue, “Welcome Home”, which I photographed using a carbon pole:

Welcome Home

If you’re already taking framed kites with you, I highly recommend bringing a lightweight pole as well.  The carbon pole I use is a collapsible fishing pole intended for breem fishing.  It’s far from ideal, and the performance isn’t up to that of the higher end carbon fiber carp poles.  But it’s light, it’s portable, and it only cost me $20 at K-Mart.  I had no problems transporting mine, but even if it did take damage, it was cheap insurance against poor wind or restrictions on flying.  It also let me do some night photography in and around Little Italy:

Fountain in Little Italy, San Diego

Little Italy at Night

The only time I flew once the conference began was on a day when there weren’t any afternoon sessions I really wanted to attend.  Instead I grabbed my gear, got on the trolley, and headed over to the SDSU campus.  The wind was plenty strong, the weather was clear, and it should’ve been a fantastic KAP session.

It wasn’t.  The wind was strong but turbulent, and before I even got a camera up, my Dopero inverted.  I was in the middle of setting up my rig, so everything was clipped off.  I frantically tried to unclip my winder and line in time to let line out and try to save the kite, but I was too late.  The line came down across the Malcom A Love Library.  My heart sank!  I had no way of telling if the kite had hit the roof, or the glass dome just beyond.  I felt like an idiot.  Overwhelmed with dejection, I packed up my gear, reeled in the line, and walked over to see what the damage was.

Lo and behold, there was my kite dangling about halfway down the side of the building.  It was out of reach of my pole, but to my immense surprise it had inverted again just before landing, so it was sitting nose up!  In case you’ve never seen a Dopero, one attribute of this beautiful kite is that it is extremely stable.  Once it’s pointed in a given direction, it really likes to go in that direction.  It’s a little sluggish on reacting to changes in wind direction, which is one of the things that makes it an excellent kite for KAP.  I knew if I put some tension on the line, it would try to fly.  More to the point, it would try to fly straight up and off the library.

I went back out to where I’d been standing, took up all the slack I could, and heaved.  The tension in the line built as it stretched, then I felt two distinct yanks as the kite cleared the far side, and then the near side of the building.  A little shaken, a little wiser (I hope) I brought my Dopero down, packed it away, and sweated for a little while.

In the end I changed winders and switched to a 6′ rokkaku.  It wasn’t enough to lift the camera reliably, but I got some decent low-altitude KAP:

Flower Bed Outside Hepner Hall - SDSU

Love Library Plaza - SDSU

Love Library - SDSU

Shortly after I packed everything up, jumped back on the trolley, and got back to the conference for the evening session and poster presentations.  By the time I got back to the hotel, I was beat.  But a KAP session isn’t complete until the gear is checked, so I examined my line for fraying (surprisingly none!) and checked my Dopero for dings.  It got a small tear in the sail, which I opted to fix once I got home.  Other than that, I got away unscathed.

More to the point, I got away lucky.  The lesson was still learned:  If the conditions aren’t right, it’s better to walk away than to risk hurting someone, damaging property, or damaging your own gear.

Posted in Astronomy, Engineering, Kite, Kite Aerial Photography, Photography, Weather | Tagged: , , , , , , , , , , , , | Leave a Comment »

SPIE Poster

Posted by Tom Benedict on 08/06/2010

As with most of the projects I do for work, the SPIE poster didn’t work out 100% as expected.  Once I started going through the photographs and diagrams I wanted to stick on the poster, and figured in the size everything had to be in order to be readable at a distance, that 36″x45″ started to look awfully small.  And no matter how neat I tried to make it, that background texture of snow was just distracting.  So out went the theme of “cold” and in came the theme of “I have no clue what I’m doing.”

So I ran with it.

SPIE 2010 - Espadons PCC Poster

I really didn’t know how I wanted to lay the poster out, so I gave up and didn’t.  The text blocks were set on a page I tore out of a notebook and scanned on our Xerox Workcentre printer.  The photos were set in Polaroid-like frames I’d used for the KAP talk I gave a couple of weeks ago.  (True Polaroid frames are taller than they are wide.  These were tweaked to fit the aspect ratio of the photos.)  The graph and diagram were superimposed over the graph paper letterhead we use at work, likewise scanned on the Xerox.  The only traditional object on the poster is a JPG reconstruction of our monitoring web site for this cryosystem.  If the poster looks scattered, it’s because I was, too.

But in talking to people around the company, the feedback I got was that the approach actually worked.  The whole job of the poster at a poster session is to draw someone’s interest long enough for them to come over and talk.  Even if they come over to ask what the @#$^ I was drinking when I made the poster, that’s good enough for me.  If they want to talk cryocoolers, that’s fine.  If they want to talk poster layout, that’s ok, too.

The best part was when I brought my 11″x17″ test print of the poster home last night.  One of my kids asked what it was.  “It’s…  It’s my science fair poster!”  And know what?  It’s true.

– Tom

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