Shallow Thoughts : tags : eclipse

Saw the Eclipse ... Sort Of

I'm sorry, but I have no eclipse photos to share. I messed that up. But I did get to see totality.

For the April 8, 2024 eclipse, Dave and I committed early to Texas. Seemed like that was where the best long-range forecasts were. In the last week before the eclipse, the forecasts were no longer looking so good. But I've heard so many stories of people driving around trying to chase holes in the clouds, only to be skunked, while people who stayed put got a better view. We decided to stick with our plan, which was to stay in San Angelo (some 190 miles off the centerline) the night before, get up fairly early and drive to somewhere near the centerline.

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Tags: eclipse, astronomy, photography
[ 12:36 Apr 13, 2024    More science/astro | permalink to this entry | ]

Annular Eclipse Party

The path for the Oct 14, 2023 annular eclipse passed right over my house. What luck!

We'd driven a few hours to see the last annular eclipse, in 2012, from Red Bluff, CA. The opportunity to see one from home, without needing to drive anywhere, was not to be missed.

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Tags: eclipse, astronomy
[ 19:22 Oct 14, 2023    More science/astro | permalink to this entry | ]

Total Eclipse

My first total eclipse! The suspense had been building for years.

Dave and I were in Wyoming. We'd made a hotel reservation nine months ago, by which time we were already too late to book a room in the zone of totality and settled for Laramie, a few hours' drive from the centerline.

For visual observing, I had my little portable 80mm refractor. But photography was more complicated. I'd promised myself that for my first (and possibly only) total eclipse, I wasn't going to miss the experience because I was spending too much time fiddling with cameras. But I couldn't talk myself into not trying any photography at all.

Initially, my plan was to use my 90mm Mak as a 500mm camera lens. It had worked okay for the the 2012 Venus transit.

I spent several weeks before the eclipse in a flurry of creation, making a couple of solar finders, a barn-door mount, and then wrestling with motorizing the barn-door (which was a failure because I couldn't find a place to buy decent gears for the motor. I'm still working on that and will eventually write it up). I wrote up a plan: what equipment I would use when, a series of progressive exposures for totality, and so forth.

And then, a couple of days before we were due to leave, I figured I should test my rig -- and discovered that it was basically impossible to focus on the sun. For the Venus transit, the sun wasn't that high in the sky, so I focused through the viewfinder. But for the total eclipse, the sun would be almost overhead, and the viewfinder nearly impossible to see. So I had planned to point the Mak at a distant hillside, focus it, then slip the filter on and point it up to the sun. It turned out the focal point was completely different through the filter.

With only a couple of days left to go, I revised my plan. The Mak is difficult to focus under any circumstances. I decided not to use it, and to stick to my Canon 55-250mm zoom telephoto, with the camera on a normal tripod. I'd skip the partial eclipse (I've photographed those before anyway) and concentrate on getting a few shots of the diamond ring and the corona, running through a range of exposures without needing to look at the camera screen or do any refocusing. And since I wasn't going to be usinga telescope, my nifty solar finders wouldn't work; I designed a new one out of popsicle sticks to fit in the camera's hot shoe.

Getting there

We stayed with relatives in Colorado Saturday night, then drove to Laramie Sunday. I'd heard horror stories of hotels canceling people's longstanding eclipse reservations, but fortunately our hotel honored our reservation. WHEW! Monday morning, we left the hotel at 6am in case we hit terrible traffic. There was already plenty of traffic on the highway north to Casper, but we turned east hoping for fewer crowds. A roadsign sign said "NO PARKING ON HIGHWAY." They'd better not try to enforce that in the totality zone!

When we got to I-25 it was moving and, oddly enough, not particularly crowded. Glendo Reservoir had looked on the map like a nice spot on the centerline ... but it was also a state park, so there was a risk that everyone else would want to go there. Sure enough: although traffic was moving on I-25 at Wheatland, a few miles north the freeway came to a screeching halt. We backtracked and headed east toward Guernsey, where several highways went north toward the centerline.

East of Glendo, there were crowds at every highway pullout and rest stop. As we turned onto 270 and started north, I kept an eye on OsmAnd on my phone, where I'd loaded a GPX file of the eclipse path. When we were within a mile of the centerline, we stopped at a likely looking pullout. It was maybe 9 am. A cool wind was blowing -- very pleasant since we were expecting a hot day -- and we got acquainted with our fellow eclipse watchers as we waited for first contact.

Our pullout was also the beginning of a driveway to a farmhouse we could see in the distance. Periodically people pulled up, looking lost, checked maps or GPS, then headed down the road to the farm. Apparently the owners had advertised it as an eclipse spot -- pay $35, and you can see the eclipse and have access to a restroom too! But apparently the old farmhouse's plumbing failed early on, and some of the people who'd paid came out to the road to watch with us since we had better equipment set up.

There's not much to say about the partial eclipse. We all traded views -- there were five or six scopes at our pullout, including a nice little H-alpha scope. I snapped an occasional photo through the 80mm with my pocket camera held to the eyepiece, or with the DSLR through an eyepiece projection adapter. Oddly, the DSLR photos came out worse than the pocket cam ones. I guess I should try and debug that at some point.

Shortly before totality, I set up the DSLR on the tripod, focused on a distant hillside and taped the focus with duct tape, plugged in the shutter remote, checked the settings in Manual mode, then set the camera to Program mode and AEB (auto exposure bracketing). I put the lens cap back on and pointed the camera toward the sun using the popsicle-stick solar finder. I also set a countdown timer, so I could press START when totality began and it would beep to warn me when it was time to the sun to come back out. It was getting chilly by then, with the sun down to a sliver, and we put on sweaters.

The pair of eclipse veterans at our pullout had told everybody to watch for the moon's shadow racing toward us across the hills from the west. But I didn't see the racing shadow, nor any shadow bands.

And then Venus and Mercury appeared and the sun went away.

Totality

One thing the photos don't prepare you for is the color of the sky. I expected it would look like twilight, maybe a little darker; but it was an eerie, beautiful medium slate blue. With that unworldly solar corona in the middle of it, and Venus gleaming as bright as you've ever seen it, and Mercury shining bright on the other side. There weren't many stars.

We didn't see birds doing anything unusual; as far as I can tell, there are no birds in this part of Wyoming. But the cows did all get in a line and start walking somewhere. Or so Dave tells me. I wasn't looking at the cows.

Amazingly, I remembered to start my timer and to pull off the DSLR's lens cap as I pushed the shutter button for the diamond-ring shots without taking my eyes off the spectacle high above. I turned the camera off and back on (to cancel AEB), switched to M mode, and snapped a photo while I scuttled over to the telescope, pulled the filter off and took a look at the corona in the wide-field eyepiece. So beautiful! Binoculars, telescope, naked eye -- I don't know which view was best.

I went through my exposure sequence on the camera, turning the dial a couple of clicks each time without looking at the settings, keeping my eyes on the sky or the telescope eyepiece. But at some point I happened to glance at the viewfinder -- and discovered that the sun was drifting out of the frame. Adjusting the tripod to get it back in the frame took longer than I wanted, but I got it there and got my eyes back on the sun as I snapped another photo ...

and my timer beeped.

I must have set it wrong! It couldn't possibly have been two and a half minutes. It had been 30, 45 seconds tops.

But I nudged the telescope away from the sun, and looked back up -- to another diamond ring. Totality really was ending and it was time to stop looking.

Getting Out

The trip back to Golden, where we were staying with a relative, was hellish. We packed up immediately after totality -- we figured we'd seen partials before, and maybe everybody else would stay. No such luck. By the time we got all the equipment packed there was already a steady stream of cars heading south on 270.

A few miles north of Guernsey the traffic came to a stop. This was to be the theme of the afternoon. Every small town in Wyoming has a stop sign or signal, and that caused backups for miles in both directions. We headed east, away from Denver, to take rural roads down through eastern Wyoming and Colorado rather than I-25, but even so, we hit small-town stop sign backups every five or ten miles.

We'd brought the Rav4 partly for this reason. I kept my eyes glued on OsmAnd and we took dirt roads when we could, skirting the paved highways -- but mostly there weren't any dirt roads going where we needed to go. It took about 7 hours to get back to Golden, about twice as long as it should have taken. And we should probably count ourselves lucky -- I've heard from other people who took 11 hours to get to Denver via other routes.

Lessons Learned

Dave is fond of the quote, "No battle plan survives contact with the enemy" (which turns out to be from Prussian military strategist Helmuth von Moltke the Elder).

The enemy, in this case, isn't the eclipse; it's time. Two and a half minutes sounds like a lot, but it goes by like nothing.

Even in my drastically scaled-down plan, I had intended exposures from 1/2000 to 2 seconds (at f/5.6 and ISO 400). In practice, I only made it to 1/320 because of fiddling with the tripod.

And that's okay. I'm thrilled with the photos I got, and definitely wouldn't have traded any eyeball time for more photos. I'm more annoyed that the tripod fiddling time made me miss a little bit of extra looking. My script actually worked out better than I expected, and I was very glad I'd done the preparation I had. The script was reasonable, the solar finders worked really well, and the lens was even in focus for the totality shots.

Then there's the eclipse itself.

I've read so many articles about solar eclipses as a mystical, religious experience. It wasn't, for me. It was just an eerily beautiful, other-worldly spectacle: that ring of cold fire staring down from the slate blue sky, bright planets but no stars, everything strange, like nothing I'd ever seen. Photos don't get across what it's like to be standing there under that weird thing in the sky.

I'm not going to drop everything to become a globe-trotting eclipse chaser ... but I sure hope I get to see another one some day.

Photos: 2017 August 21 Total Solar Eclipse in Wyoming.

Tags: eclipse, astronomy, photography
[ 20:41 Aug 27, 2017    More science/astro | permalink to this entry | ]

A Homemade Solar Finder, for the Eclipse

While I was testing various attempts at motorizing my barn-door mount, trying to get it to track the sun, I had to repeatedly find the sun in my telescope.

In the past, I've generally used the shadow of the telescope combined with the shadow of the finderscope. That works, more or less, but it's not ideal: it doesn't work as well with just a telescope with no finder, which includes both of the scopes I'm planning to take to the eclipse; and it requires fairly level ground under the telescope: it doesn't work if there are bushes or benches in the way of the shadow.

For the eclipse, I don't want to waste any time finding the sun: I want everything as efficient as possible. I decided to make a little solar finderscope. One complication, though: since I don't do solar observing very often, I didn't want to use tape, glue or, worse, drill holes to mount it.

So I wanted something that could be pressed against the telescope and held there with straps or rubber bands, coming off again without leaving a mark. A length of an angled metal from my scrap pile seemed like a good size to be able to align itself against a small telescope tube.

Then I needed front and rear sights. For the front sight, I wanted a little circle that could project a bulls-eye shadow onto a paper card attached to the rear sight. I looked at the hardware store for small eye-bolts, but no dice. Apparently they don't come that small.I settled for the second-smallest size of screw eye.

The screw eye, alas, is meant to screw into wood, not metal. So I cut a short strip of wood a reasonable size to nestle into the inside of the angle-iron. (That ripsaw Dave bought last year sure does come in handy sometimes.) I drilled some appropriately sized holes and fastened screw eyes on both ends, adding a couple of rubber grommets as spacers because the screw eyes were a little too long and I didn't want the pointy ends of the screws getting near my telescope tube.

I added some masking tape on the sides of the angle iron so it wouldn't rub off the paint on the telescope tube, then bolted a piece of cardboard cut from an old business card to the rear screw eye.

Voila! A rubber-band-attached solar sight that took about an hour to make. Notice how the shadow of the front sight exactly fits around the rear sight: you line up the shadow with the rear sight to point the scope. It seems to work pretty well, and it should be adaptable to any telescope I use.

I used a wing nut to attach the rear cardboard: that makes it easy to replace it or remove it. With the cardboard removed, the sight might even work for night-time astronomy viewing. That is, it does work, as long as there's enough ambient light to see the rings. Hmm... maybe I should paint the rings with glow-in-the-dark paint.

Update: I have an even simpler design that works perfectly on a camera with a hot shoe, and almost as well on a telescope, pictured here: Camera solar finder made from popsicle sticks.

Tags: astronomy, eclipse
[ 15:25 Aug 14, 2017    More science/astro | permalink to this entry | ]

A Barn-Door Mount for the Eclipse

I've been meaning forever to try making a "barn door" tracking mount. Used mainly for long-exposure wide-field astrophotography, the barn door mount, invented in 1975, is basically two pieces of wood with a hinge. The bottom board mounts on a tripod and is pointed toward the North Star; "opening" the hinge causes the top board to follow the motion of the sky, like an equatorial telescope mount. A threaded rod and a nut control the angle of the "door", and you turn the nut manually every so often. Of course, you can also drive it with a motor.

We're off to view the eclipse in a couple of weeks. Since it's my first total eclipse, my plan is to de-emphasize photography: especially during totality, I want to experience the eclipse, not miss it because my eyes are glued to cameras and timers and other equipment. But I still want to take photos every so often. Constantly adjusting a tripod to keep the sun in frame is another hassle that might keep my attention away from the eclipse. But real equatorial mounts are heavy and a time consuming to set up; since I don't know how crowded the area will be, I wasn't planning to take one. Maybe a barn door would solve that problem.

Perhaps more useful, it would mean that my sun photos would all be rotated approximately the right amount, in case I wanted to make an animation. I've taken photos of lunar and partial solar eclipses, but stringing them together into an animation turned out to be too much hassle because of the need to rotate and position each image.

I've known about barn-door mounts since I was a kid, and I knew the basic theory, but I'd never paid much attention to the details. When I searched the web, it sounded complicated -- it turned out there are many types that require completely different construction techniques.

The best place to start (I found out after wasting a lot of time on other sites) is the Wikipedia article on "Barn door tracker", which gives a wonderfully clear overview, with photos, of the various types. I had originally been planning a simple tangent or isosceles type; but when I read construction articles, it seemed that those seemingly simple types might not be so simple to build: the angle between the threaded rod and the boards is always changing, so you need some kind of a pivot. Designing the pivot looked tricky. Meanwhile, the pages I found on curved-rod mounts all insisted that bending the rod was easy, no trouble at all. I decided to try a curved-rod mount first.

The canonical reference is a 2015 article by Gary Seronik: A Tracking Platform for Astrophotography. But I found three other good construction guides: Optical Ed's "Making a Curve Bolt Barn Door", a Cloudy Nights discussion thread "Motorized Barn Door Mount Kit", and Massapoag Pond Photography's "Barn Door Tracker". I'm not going to reprise all their construction details, so refer to those sites if you try making your own mount.

The crucial parts are a "piano hinge", a long hinge that eliminates the need to line up two or more hinges, and the threaded rod. Buying a piano hinge in the right size proved impossible locally, but the folks at Metzger's assured me that piano hinges can be cut, so I bought one longer than I needed and cut it to size. I used a 1/4-20 rod, which meant (per the discussions in the Cloudy Nights discussion linked above) that a 11.43-inch radius from the hinge to the holes the rod passes through would call for the nut to turn at a nice round number of 1 RPM.

I was suspicious of the whole "it's easy to bend the threaded rod ina 11.43-inch circle" theory, but it turned out to be true. Draw the circle you want on a sheet of newspaper, put on some heavy gloves and start bending, frequently comparing your rod to the circle you drew. You can fine-tune the curvature later.

I cut my boards, attached the hinge, measured about 11.4" and drilled a hole for the threaded rod. The hole needed to be a bit bigger than 5/8" to let the curved rod pass through without rubbing. Attach the curved rod to the top wood piece with a couple of nuts and some washers, and then you can fine-tune the rod's curvature, opening and closing the hinge and re-bending the rod a little in any place it rubs.

A 5/8" captive nut on the top piece lets you attach a tripod head which will hold your camera or telescope. A 1/4" captive nut on the bottom piece serves to attach the mount to a tripod -- you need a 1/4", not 3/8": the rig needs to mount on a tripod head, not just the legs, so you can align the hinge to the North Star. (Of course, you could build a wedge or your own set of legs, if you prefer.) The 3/4" plywood I was using turned out to be thicker than the captive nuts, so I had to sand the wood thinner in both places. Maybe using half-inch plywood would have been better.

The final piece is the knob/nut you'll turn to make the mount track. I couldn't find a good 1/4" knob for under $15. A lot of people make a wood circle and mount the nut in the center, or use a gear so a motor can drive the mount. I looked around at things like jam-jar lids and the pile of metal gears and sprinkler handles in my welding junkpile, but I didn't see anything that looked quite right, so I decided to try a wing nut just for testing, and worry about the knob later. Turns out a wing nut works wonderfully; there's no particular need for anything else if you're driving your barn-door manually.

Testing time! I can't see Polaris from my deck, and I was too lazy to set up anywhere else, so I used a protractor to set the hinge angle to roughly 36° (my latitude), then pointed it approximately north. I screwed my Pro-Optic 90mm Maksutov (the scope I plan to use for my eclipse photos) onto the ball head and pointed it at the moon as soon as it rose. With a low power eyepiece (20x), turning the wing nut kept the moon more or less centered in the field for the next half-hour, until clouds covered the moon and rain began threatening. I didn't keep track of how many turns I was making, since I knew the weather wasn't going to allow a long session, and right now I'm not targeting long-exposure photography, just an easy way of keeping an object in view.

A good initial test! My web searches, and the discovery of all those different types of barn-door mounts and pivots and flex couplings and other scary terms, had seemed initially daunting. But in the end, building a barn-door mount was just as easy as people say it is, and I finished it in a day.

And what about a motor? I added one a few days later, with a stepper and an Arduino. But that's a separate article.

Tags: astronomy, hardware, eclipse
[ 19:25 Aug 10, 2017    More science/astro | permalink to this entry | ]

Lunar eclipse animations

The lunar eclipse on Sunday was gorgeous. The moon rose already in eclipse, and was high in the sky by the time totality turned the moon a nice satisfying deep red.

I took my usual slipshod approach to astrophotography. I had my 90mm f/5.6 Maksutov lens set up on the patio with the camera attached, and I made a shot whenever it seemed like things had changed significantly, adjusting the exposure if the review image looked like it might be under- or overexposed, occasionally attempting to refocus. The rest of the time I spent socializing with friends, trading views through other telescopes and binoculars, and enjoying an apple tart a la mode.

So the images I ended up with aren't all they could be -- not as sharply focused as I'd like (I never have figured out a good way of focusing the Rebel on astronomy images) and rather grainy.

Still, I took enough images to be able to put together a couple of animations: one of the lovely moonrise over the mountains, and one of the sequence of the eclipse through totality.

Since the 90mm Mak was on a fixed tripod, the moon drifted through the field and I had to adjust it periodically as it drifted out. So the main trick to making animations was aligning all the moon images. I haven't found an automated way of doing that, alas, but I did come up with some useful GIMP techniques, which I'm in the process of writing up as a tutorial.

Once I got the images all aligned as layers in a GIMP image, I saved them as an animated GIF -- and immediately discovered that the color error you get when converting to an indexed GIF image loses all the beauty of those red colors. Ick!

So instead, I wrote a little Javascript animation function that loads images one by one at fixed intervals. That worked a lot better than the GIF animation, plus it lets me add a Start/Stop button.

You can view the animations (or the source for the javascript animation function) here: Lunar eclipse animations

Tags: astronomy, eclipse, moon, gimp
[ 12:55 Oct 01, 2015    More science/astro | permalink to this entry | ]

Partial solar eclipse, with amazing sunspots

We had perfect weather for the partial solar eclipse yesterday. I invited some friends over for an eclipse party -- we set up a couple of scopes with solar filters, put out food and drink and had an enjoyable afternoon.

And what views! The sunspot group right on the center of the sun's disk was the most large and complex I'd ever seen, and there were some much smaller, more subtle spots in the path of the eclipse. Meanwhile, the moon's limb gave us a nice show of mountains and crater rims silhouetted against the sun.

I didn't do much photography, but I did hold the point-and-shoot up to the eyepiece for a few shots about twenty minutes before maximum eclipse, and was quite pleased with the result.

An excellent afternoon. And I made too much blueberry bread and far too many oatmeal cookies ... so I'll have sweet eclipse memories for quite some time.

Tags: eclipse, astronomy, science
[ 09:15 Oct 24, 2014    More science/astro | permalink to this entry | ]

Saw the "Ring of Fire" 2012 annular eclipse

I've just seen the annular eclipse, and what a lovely sight it was!

This was only my second significant solar eclipse, the first being a partial when I was a teenager. So I was pretty excited about an annular so nearby -- the centerline was only about a 4-hour drive from home.

We'd made arrangements to join the Shasta astronomy club's eclipse party at Whiskeytown Lake, up in the Trinity Alps. Sounded like a lovely spot, and we'd be able to trade views with the members of the local astronomy club as well as showing off the eclipse to the public. As astronomers bringing telescopes, we'd get reserved parking and didn't even have to pay the park fee. Sounded good!

Not knowing whether we might hit traffic, we left home first thing in the morning, hours earlier than we figured was really necessary. A good thing, as it turned out. Not because we hit any traffic -- but because when we got to the site, it was a zoo. There were cars idling everywhere, milling up and down every road looking for parking spots. We waited in the queue at the formal site, and finally got to the front of the line, where we told the ranger we were bringing telescopes for the event. He said well, um, we could drive in and unload, but there was no parking so we'd just have to drive out after unloading, hope to find a parking spot on the road somewhere, and walk back.

What a fiasco!

After taking a long look at the constant stream of cars inching along in both directions and the chaotic crowd at the site, we decided the better part of valor was to leave this vale of tears and high-tail it back to our motel in Red Bluff, only little farther south of the centerline and still well within the path of annularity. Fortunately we'd left plenty of extra time, so we made it back with time to spare.

The Annular Eclipse itself

One striking thing about watching the eclipse through a telescope was how fast the moon moves. The sun was well decorated with several excellent large sunspot groups, so we were able to watch the moon swallow them bit by bit.

Some of the darker sunspot umbras even showed something like a black drop effect as they disappeared behind the moon. We couldn't see the same effect on the smaller sunspot groups, or on the penumbras. There was also a pronounced black drop effect at the onset and end of annularity.

The seeing was surprisingly good, as solar observing goes. Not only could we see good detail on the sunspot groups and solar faculae, but we could easily see irregularities in the shape of the moon's surface -- in particular one small sharp mountain peak on the leading edge, and what looked like a raised crater wall farther south on that leading edge. We never did get a satisfactory identification on either feature.

After writing and speaking about eclipse viewing, I felt honor bound to try viewing with pinholes of several sizes. I found that during early stages of the eclipse, the pinholes had to be both small (under about 5 mm) and fairly round to show much. Later in the eclipse, nearly anything worked to show the crescent or the annular ring, including interlaced fingers or the shadow of a pine tree on the wall. I wish I'd remembered to take an actual hole punch, which would have been just about perfect.

I also tried projection through binoculars, and convinced myself that it would probably work as a means of viewing next month's Venus transit -- but only with the binoculars on a tripod. Hand-holding them is fiddly and difficult. (Of course, never look through binoculars at the sun without a solar filter.) Look for an upcoming article with more details on binocular projection.

The cast of characters

For us, the motel parking lot worked out great. We were staying at the Crystal Motel in Red Bluff, an unassuming little motel that proved to be clean and quiet, with friendly, helpful staff and the fastest motel wi-fi connection I've ever seen. Maybe not the most scenic of locations, but that was balanced by the convenience of having the car and room so close by.

And we were able to show the eclipse to locals and motel guests who wouldn't have been able to see it otherwise. Many of these people, living right in the eclipse path, didn't even know there was an eclipse happening, so poor had the media coverage been. (That was true in the bay area too -- most people I talked to last week didn't know there was an eclipse coming up, let alone how or where to view it.)

We showed the eclipse to quite a cast of characters --

• The mother with medical problems, obviously feeling quite poorly but still bringing her husband and son out for repeated views.
• the woman who said she didn't want to be in the sun because she'd been drinking too much by the pool.
• The family where Dad kept looking through paper glasses the kids insisted was a "3-D viewer". Alarmed, we took a look, and found it was a perfectly reasonable eclipse viewer marked SAFE FOR SOLAR VIEWING. Whew!
• The teen girl who kept looking directly at the sun despite everyone telling her not to ... I hope she didn't damage her vision.
• The kid who wanted to borrow my binocular to look at some birds circling in the distance. I wanted to let him, but with all the attention on the sun I was too nervous, so instead I changed the subject and showed him how to identify turkey vultures (wings in a V, tipping from side to side) even without binoculars).
• The man who sat in a parking space near us reading a catalog, telling us repeatedly he was just reading his catalog. When Dave insisted he come and take a look, he looked in the eyepiece for about ten seconds, then looked Dave in the eye and informed him solemnly that he was just reading his catalog.
• The family who'd been instructed by their grandmother, in the hospital awaiting an operation, to watch the eclipse and bring back pictures for her. I hope they got some decent ones!

In between visitors, we had plenty of time to fiddle with equipment, take photos, and take breaks sitting in the shade to cool down. (Annularity was pleasantly cool, but the rest of the eclipse stayed hot on an over 90 degree central valley day.)

There's a lot to be said for sidewalk astronomy! Overall, I'm glad we ended up where we did rather than in that Whiskeytown chaos.

Here's my collection of Images from the "Ring of Fire" Annular Eclipse, May 2012, from Red Bluff, CA.

Tags: astronomy, science, eclipse, travel
[ 11:42 May 22, 2012    More science/astro | permalink to this entry | ]

Ring of Fire: 2012 annular eclipse

This Sunday, May 20th, the western half of the US will be treated to an annular solar eclipse.

Annular means that the moon is a bit farther away than usual, so it won't completely cover the sun even if you travel to the eclipse centerline. Why? Well, the moon's orbit around the earth isn't perfectly circular, so sometimes it's farther away, sometimes nearer. Remember all the hype two weeks ago about the "supermoon", where it was unusually close at full moon? The other side of that is that during this eclipse, at new moon, the moon is unusually far away, and therefore a little smaller, not quite big enough to cover the sun.

Since the sun will never be totally covered, make sure you have a safe solar filter for this one -- don't look with your naked eyes! You want a solar filter anyway, if you have any kind of telescope or even binoculars, because of next month's once-in-a-lifetime Venus transit (I'll write about that separately). But if you don't have a solar filter and absolutely can't get one in time, read on -- I'll have some suggestions later even for people without any sort of optical aid.

But first, the path of the eclipse. Here in the bay area, we're just a bit south of the southern limit of the annular path, which passes just south of the town of Redway, through Covelo, just south of Willows, then just misses Yuba City and Auburn. If you want to be closer to the centerline, go camping at Lassen National Park or Lake Shasta, or head to Reno or Tahoe If you're inclined to travel, NASA has a great interactive 2012 eclipse map you can use to check out possible locations.

Even back in the bay area, we still get a darn good dinner show. The partial eclipse starts at 5:17 pm PDT, with maximum eclipse at 6:33. The sun will be 18 degrees above the horizon at that point, and 89% eclipsed. Compare that with 97% for a site right on the centerline -- remember, since this is an annular eclipse, no place sees 100% coverage. The partial eclipse ends at 7:40 -- still well before sunset, which isn't until 8:11.

Photographers, if you want a shot of an annular eclipse as the sun sets, you'll need to head east, to Albuquerque, NM or Lubbock, TX. A little before sunset, the centerline also crosses near a lot of great vacation spots like Bryce, Zion and Canyon de Chelly.

I mentioned that even without a solar filter, there are ways of watching the eclipse. The simplest is with a pinhole. You don't need to use an actual pin -- the size and shape of the hole isn't critical, as you can see in this image of the sun through the leaves of a tree during a 2005 eclipse in Malta. If you don't have a leafy tree handy, you can even lace your fingers together and look at the shadow of your hands. This eclipse will be very low in the sky, continuing through sunset, so you may need to project its shadow onto a wall rather than the ground.

If you have some time to prepare, take a piece of cardboard and punch a few holes through it. Try different sizes -- an actual pinhole, a BBQ skewer, a 3-hole punch, maybe even bigger holes up to the size of a penny. You might also try using aluminum foil -- you can get very clean circular holes that way, which might give a crisper image. Here's a good page on eclipse pinhole projection. What works best? I don't remember! It's been a very long time since the last eclipse here! Do the experiment! I know I will be.

If you do have a telescope or binoculars but couldn't get a solar filter in time, don't despair. Instead of looking through the eyepiece, you can project the sun's image onto a white screen or even the ground or a wall. Use a cheap, low-power eyepiece -- any eyepiece you use for solar projection will get very hot, and you don't want to risk ruining a fancy one.

Point the telescope at the sun -- it's easy to tell when it's lined up by watching the shadow of the telescope -- and rotate the eyepiece so that it's aimed at your screen, which can be as simple as a sheet of paper. Be careful where that eyepiece is aimed -- make sure no one can walk through the path or put their hand in the way, and if you have a finderscope, make sure it's covered. This solar projection method works with binoculars too, but you'll want to mount them on a tripod so you don't have to hold them the whole time.

Of course, another great way to watch the eclipse is with your local astronomy club. I expect every club in the bay area -- and there are a lot of them -- will have telescopes out to share the eclipse with the public. So check with your local club -- San Jose Astronomical Association, Peninsula Astronomical Society, San Francisco Sidewalk Astronomers, San Francisco Amateur Astronomers, or any of the others on the AANC's list of Amateur Astronomy Clubs in Northern California or the SF Chronicle's list of astronomy clubs.

This eclipse should be pretty cool -- and a great chance to test out your solar equipment before next month's Venus transit.

When I went to put the event on my wall calendar last month, I discovered the calendar already had an entry for May 20: it's the start of Bear Awareness Week. So if you head up to Lassen or Shasta to watch the eclipse, be sure to be aware of the bears! (Also, maybe I should get a calendar that's a little more in tune with the sky.)

Tags: astronomy, science, eclipse
[ 21:12 May 16, 2012    More science/astro | permalink to this entry | ]

Getting rid of extra whitespace from Eclipse

Eclipse has been driving me batty with all the extra spaces it adds everywhere -- blank lines all have indents on them, and lots of code lines have extra spaces randomly tacked on to the end. I sure wouldn't want to share files like that with coworkers or post them as open source.

I found lots of suggestions on the web for eliminating extra whitespace, and several places to configure this within Eclipse, but most of them don't do anything. Here's the one that actually worked:

Window->Preferences
Jave->Editor->Save Actions
Enable Perform the selected actions on save.
Enable Additional actions.
Click Configure.
In the Code Organizing tab., enable Remove trailing whitespace for All lines.
Review all the other options there, since it will all happen automatically whenever you save -- make sure there isn't anything there you don't want.
Dismiss the Configure window.
Review the other options under Save Actions, since these will also happen automatically now.
Don't forget to click Apply in the Save Actions preference page.

Whew! There are other places to set this, in various Code style and Cleanup options, but all all the others require taking some action periodically, like Source->Clean up...

By the way, while you're changing whitespace preferences, you may also want the Insert spaces for tabs preference under General->Editors->Text Editors.

An easy way to check whether you've succeeded in exorcising the spaces -- eclipse doesn't show them all, even when you tell it to -- is to :set hlsearch in vim, then search for a space. (Here are some other ways to show spaces in vim.) In emacs, you can M-x set-variable show-trailing-whitespace to true, but that doesn't show spaces on blank lines; for that you might want whitespace.el or similar packages.

Tags: eclipse, android, programming
[ 15:42 Jan 25, 2011    More programming | permalink to this entry | ]

Android/Eclipse Spellchecker is a bit confused

I've been doing some Android development, using the standard Eclipse development tools. A few days ago, I pasted some code that included a comment about different Android versions, and got a surprise:

What do you think -- should I change all the "Android" references to "Undried"?

Tags: humor, android, eclipse, programming
[ 11:09 Dec 07, 2010    More humor | permalink to this entry | ]