Shallow Thoughts : tags : eclipse

Akkana's Musings on Open Source Computing, Science, and Nature.

Tue, 22 May 2012

Saw the "Ring of Fire" 2012 annular eclipse

[Annular eclipse 2012] 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

[early stage of annular eclipse 2012, showing sunspots] 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. [black drop at end of annularity] 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.

[pinhole eclipse viewing] 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.

[binocular projection for eclipse] 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 --

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: , , ,
[ 10:42 May 22, 2012    More science/astro | permalink to this entry | comments ]

Wed, 16 May 2012

Ring of Fire: 2012 annular eclipse

[Solar annular eclipse of January 15, 2010 in Jinan, Republic of China, by A013231 on Wikimedia Commons.] 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.

[eclipse viewed through leaves] 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.

[Solar projection with a Dobsonian] 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: , ,
[ 20:12 May 16, 2012    More science/astro | permalink to this entry | comments ]

Tue, 25 Jan 2011

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: , ,
[ 14:42 Jan 25, 2011    More programming | permalink to this entry | comments ]

Tue, 07 Dec 2010

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:

[The word 'Android' is not correctly spelled. Change to 'Undried'?]

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

Tags: , , ,
[ 10:09 Dec 07, 2010    More humor | permalink to this entry | comments ]

Syndicated on:
LinuxChix Live
Ubuntu Women
Women in Free Software
Graphics Planet
DevChix
Ubuntu California
Planet Openbox
Devchix
Planet LCA2009

Friends' Blogs:
Morris "Mojo" Jones
Jane Houston Jones
Dan Heller
Long Live the Village Green
Ups & Downs
DailyBBG

Other Blogs of Interest:
DevChix
Scott Adams
Dave Barry
BoingBoing

Powered by PyBlosxom.