Archive for the ‘Eclipse’ Category

h1

Observing Report: Total lunar eclipse on April 4, 2015

April 5, 2015

April 2015 lunar eclipse composite

I stayed up late Friday night to catch the beginning of the lunar eclipse early Saturday morning. The penumbral eclipse started at 3:16 AM local time, and it was still going on when the sun rose. The umbral or ‘total’ eclipse was very brief, just five minutes between 4:58 and 5:03. Just like last October, I got London up to see it. He was kind enough to loan me his 60mm Meade refractor for the event, and he used his XT4.5. The little Meade refractor made photography easier by cutting down the light level without sacrificing contrast. I took all of these photos with my iPhone 5C shooting through a Celestron 8-24mm zoom eyepiece. As usual, I processed and composited the photos in GIMP.

Full moon 2015-04-03

I’m particularly happy with this shot of the full moon. I really need to do a composite image with all of my best full moon shots. One of these days.

Previous lunar eclipse reports:

Previous full moons:

 

h1

Our eclipse viewing got a nice, free-to-read newspaper story after all!

October 31, 2014

IMG_2079

When I first blogged about last week’s partial solar eclipse, I mentioned that a reporter had come out from the local paper, but that the story was unavailable behind the paper’s paywall. It turns out that I was mistaken. I had thought the story was paywalled because clicking on the front page link didn’t lead to anything more extensive, just the same short blurb and a link to subscribe. But that was because the main story hadn’t been written yet, not because it was paywalled. The full story was only published today. Here’s a link to the story online, and I’ll post a scan of the print version as soon as I get around to making one.

It’s a nice writeup, with lots of detail and just about everything correct. The only thing I’d change is in the last paragraph–the telescopes at the Claremont Public Library are not for rent, they’re free to check out, just like a library book. I haven’t blogged about our library telescope program yet because frankly it doesn’t need any additional exposure; we’re more than two years in, with two telescopes in circulation, and the wait list is still four months long. If and when the program gets to a point where it can handle more interest, I’ll see what I can do to fire some up!

Anyway, this gave me the opportunity to post a couple more photos: above, London drives the Sun Funnel, and below, some mid-eclipse sun dapples on the sidewalk.

IMG_2088

h1

Observing Report: Partial solar eclipse on Oct. 23, 2014

October 27, 2014

IMG_2099

Last Thursday afternoon I went to London’s school to show the eclipse to the students. I was rolling with the Astroscan-plus-Sun-Funnel combo, veteran of the 2012 annular eclipse and transit of Venus, and the GalileoScope that David DeLano built for me, now sporting a Baader solar film filter from AstroMediaShop.co.uk.

IMG_2053

The eclipse started here at 2:11 PM, Pacific Daylight Time.

2014-10-23 eclipse in filtered scope

I’m still struggling to get good digiscoping photos with the iPhone. This one, shot through the filtered GalileoScope, is the least wretched of the lot. The immense sunspot group is AR 2192, the largest seen in 24 years. At nearly the size of Jupiter, It was easily naked-eye visible with eclipse glasses. There’s a nice video of it from before the eclipse at APOD.

IMG_2076

Oh, I also passed out a lot of eclipse glasses. The best deal I have found on them is this pack of 30 for $33 from Amazon. Of that 30-pack, two got mailed off to relatives (along with our entire previous stash of eight), London and I each brought home a pair (London promptly disassembled his to see how they were put together–that’s my boy!), and the other 26 went home with other excited kids.

Incidentally, my favorite view of the eclipse was through the glasses, with no magnification. There is something awesome and terrible about watching another world come between you and sun, even partly.

IMG_2072

I wanted to do an activity with the kids so I brought a pack of index cards and had them make pinhole projectors. That succeeded beyond my wildest dreams. The kids were completely occupied for a solid 20 minutes, and we could do the projections indoors and save our UV exposure for the scopes (which I brought inside, of course–you don’t leave a solar scope set up and unattended).

IMG_2069

London’s school is Oakmont Elementary and ‘BLAST’ stands for Best Learning After School Time.

IMG_2077

We also looked at pinhole projections of the eclipse cast by trees.

IMG_2092

Just a bit after max eclipse, which was at 3:30.

IMG_2122

The last of the wine, at 4:40. Unless I get really rich in the next couple of years, rich enough to go on eclipse cruises, my next solar eclipse will be in August of 2017. A total solar eclipse will cut a path from the Pacific Northwest to the Southeast US. My tentative plan right now is to fly to Oklahoma, see the relatives, and then drive up to northern Kansas for the event. Kansas in August should be hot and sunny, and on the Great Plains you can usually see bad weather coming hundreds of miles off, which will let us adjust our targeting on the fly.

Eclipse story in Claremont Courier

A guy from the Claremont Courier came out to interview me and some teachers, parents, and kids. Thanks to the paper’s paywall, I haven’t seen any more of the story than this web preview, which at least features two of London’s best friends. If anyone out there has a hardcopy they’d be willing to scan or pass along, I’d be very grateful. Update Oct. 31: Whoops! The story wasn’t paywalled; it was unavailable because it wasn’t done. Here’s the full story, and here’s a post with a couple more eclipse shots.

All in all, I think about 90 people got to see the eclipse through my scopes. The kids were mesmerized–so were the adults, actually–and I was very, very happy. Can’t wait until the next one!

h1

Observing Report: Total lunar eclipse on Oct. 8, 2014

October 11, 2014

London watching the Oct 2014 lunar eclipse 1

It had been six and a half years since I had actually watched a lunar eclipse (back in February, 2008), so I stayed up late Tuesday night to watch the lunar eclipse early Wednesday morning.

London watching the Oct 2014 lunar eclipse 2

London didn’t stay up that late, he went to bed at the usual time and I got him up about 3:00 AM. We spent about half an hour together, watching the Earth’s shadow gradually overtake the moon until the moon was entirely eclipsed. I had set up my pimped-out GalileoScope (it’s on the second tripod in the background), but after a lot of scope- and eyepiece-swapping, the setup I settled on was my 4-inch refractor and 8-24mm zoom eyepiece.

Oct 2014 lunar eclipse composite

My Nikon Coolpix 4500 gave up the ghost last year. I got a Canon S100 to replace it, but I dropped it out in the field this spring, and I haven’t gotten it repaired yet. So other than the DSLR Vicki uses at work, my only camera is the one in my iPhone 5C, and I used it for all of my eclipse photos. For most point-and-shoot photo purposes, it’s all I need. As an astronomical camera, it leaves much to be desired. There are apps out there that let you control the exposure and shutter speed, but I haven’t investigated them much yet.

When you first hold the iPhone camera up to the eyepiece, all you will see of the moon is an undetailed spotlight. The trick is to tap and hold on the moon for a few seconds to kick in the exposure lock and focus lock. That will gear down the exposure to the point that you can start getting decent photos. The focus lock is a little squirrelly – sometimes one part of the image is better-focused than another (for example, because the camera is not perfectly parallel to the light beam coming through the scope), and the camera will seize on the out-of-focus portion for the focus lock. In that case, you can usually get things back to good by tweaking the focus of the telescope, using the image on the camera screen to tell when the image is best focused.

All of the photos above have been rotated, resized, and lightly sharpened in GIMP. Max eclipse was at 3:55. The moon was entirely in Earth’s umbra, but it wasn’t centered in the umbra, so the northern limb was definitely brighter than the southern one, and the photos record that.

In sum, it was a lot of fun. Even the fussing about with the camera was rewarding – the iPhone may not be a replacement for a decent point-and-shoot camera when it comes to digiscoping, but it was still satisfying to learn how to use it for that purpose.

Now we’re getting prepared for the solar eclipse in a couple of weeks, and keeping our fingers firmly crossed for clear skies. Stay tuned.

h1

October 2014: two eclipses and my favorite star party

October 5, 2014
Eclipse end 8x10 sharpened

The end of the February 2008 lunar eclipse, as seen from Merced, CA.

Some big things coming up this month, especially for observers in the western US and in SoCal and the Southwest specifically. In chronological order they are:

A total lunar eclipse early in the morning on Wednesday, Oct. 8. These are the PDT timings for Los Angeles, from TimeandDate.com.

  • 1:17 AM – penumbral eclipse beings
  • 2:18 AM – partial eclipse begins
  • 3:27 AM – total eclipse begins
  • 3:55 AM – maximum eclipse (moon is farthest inside Earth’s shadow)
  • 4:22 AM – total eclipse ends
  • 5:32 AM – partial eclipse ends
  • 6:32 AM – penumbral eclipse ends
DSCN7707

An early phase of the May 2012 annular eclipse, photographed at Page, Arizona.

A partial solar eclipse in the afternoon of Thursday, Oct. 23. Again, these are PDT timings for LA, from NASA’s eclipse website, especially this table.

  • 2:08 PM – eclipse begins
  • 3:28 PM – max eclipse
  • 4:40 PM – eclipse ends
AASP 03 London and Daddy at dusk

London and me at the 2010 AASP.

On the two days right after the solar eclipse, the 2014 All-Arizona Star Party will be taking place at the Hovatter Road airstrip in western Arizona. London and I have been three times now, in 2010, 2012, and 2013 (click on links for my observing reports), and we’ve always had a fantastic time. See the star party webpage for details.

 

h1

Earth-moon distance and the diameters of the planets

June 15, 2014

A few days ago Mike sent me this:

Earth-moon distance and planetary diameters

I was surprised to see so many people calling BS on this–it’s simple enough to double-check. So I did. Here are the results.

Mean radii in km, from Wikipedia:

  • Mercury – 2400
  • Venus – 6100
  • Mars – 3400
  • Jupiter – 69,900
  • Saturn – 58,200
  • Uranus – 25,400
  • Neptune – 24,600
  • Total – 190,000

Doubled, to convert to diameters – 380,000 km

Average Earth-moon distance, also from Wikipedia: 384,000 km.

Yep, this checks out. With the proviso that the Earth-moon distance actually varies from 363,000 to 405,000 km, so sometimes you’d have to leave out Mars and Venus, and other times you’d have to clone them to fill the extra space.

If you want a remarkable coincidence, the moon formed maybe only 10,000 miles from Earth and has been gradually receding ever since. So we are living in the tiny slice of Earth history when the moon is at just the right distance to appear the same relative size as the sun, and thus produce total eclipses as we know them. Annular eclipses have only been around for a few tens of millions of years, and in another few tens of millions of years, they’re all we’ll ever get, because the moon will be too distant to completely block the sun.

Anyway, after I sent Mike this reply, he said, “That is a whole lot of awesome, which clearly ought to be a 10MA post”. And now it is.

UPDATE October 13, 2014: A much more detailed explanation of the end of total solar eclipses in the distant future can be found on this page, under the “Final Totality” heading.

h1

Observing report: the 2012 annular eclipse

May 21, 2012

Today rocked. It would have rocked a lot less if things had gone the way I wanted them to. I put off ordering a solar filter for my telescope until last week, and of course everyone was sold out and even the manufacturers were backordered. One is on its way to me, hopefully, but it didn’t arrive in time for our eclipse trip, so I fell back on the sun funnel I built a couple of months ago, and my son’s Astroscan. This turned out to be the perfect combo. In the photo above I was testing the sun funnel in the hotel room, after our long drive from SoCal to Page, Arizona (spread out over 2.5 days, so very civilized and enjoyable, but still a lot of miles).

For the eclipse we set up on the lawn of the Courtyard Inn here in Page. Here’s first contact, when the moon first starts crossing the solar disk. Click for the big version and look at the sunspots–this is the sharpest sunspot photo I got all day.

In addition to the sun funnel I brought a piece of #14 welder’s glass for naked-eye viewing. The eclipse glasses London is wearing were supplied by the hotel when we checked in–I thought that was an awesome thing for them to do, and I told them so.

The middle group of sunspots is getting devoured by the moon.

Almost to second contact, when the trailing limb of the moon crosses the edge of the sun. I like the meta-ness of this photo of a photo-in-progress via a projected image of a projected image.

Just after second contact–we have annularity!

Annularity. This was incredible. I would write more about it, but words fail me.

And here’s why it’s a good thing that my solar filter didn’t arrive on time. If it had, I would have brought my 5″ Mak and left the sun funnel at home. And when the tour bus pulled up 50 feet away and disgorged all these people 5 minutes before totality, they would have missed the eclipse. Thanks to the sun funnel, we had a nearly constant stream of visitors coming by during the first half of the eclipse, and we made some new friends. There’s no way all those folks would have had time to see the eclipse at the eyepiece if I’d been rolling with a solar filter. So from here on out, I’m a sun funnel man. Oh, I will probably also set up a filtered telescope nearby for observing at the eyepiece, but the sun funnel is a key piece of gear, and I don’t intend to voluntarily be without it for future solar events (like the transit of Venus coming up in two weeks).

Third contact–the leading edge of the moon hits the far edge of the sun. See the little points of light between the ‘horns’ of the moon sun? Those are Bailly’s beads, the last rays of sunlight shining through valleys on the limb of the moon. They’re visible at second contact, too, I just failed to capture them in pixels.

I was afraid that the second half of the eclipse would be boring–like the first half run in reverse. It turned out to be a blast. Precisely because we’d all seen it all before (or thought we had–keep reading), we felt free to goof around a bit. Here I removed the sun funnel and put in a regular eyepiece to project the eclipse on my t-shirt. This is a hairy operation–you don’t want to be the projectee and the one pointing the scope at the sun, or you’ll be tempted to glance down into–what? Oh, that’s right, the blindingly intense beam of concentrated sunlight shining out of the telescope. Fortunately I had the presence of mind not to do that, but after this shot, we didn’t let anyone get on the eyepiece side of the scope without eclipse glasses on. This led to some modest hilarity of trying to guide the effectively blind subject to kneel just so beside the scope.

More second-half fun: the sun goes behind an antenna on the next ridge over, maybe a mile away. I suppose a purist might not want anything man-made screwing up the eclipse, but we all thought this was super-cool.

People farther west got to see the entire eclipse, but here the eclipse was still in progress when the sun started to set. Again, some folks might have been bummed but we thought it was crazy-cool to see the sun blocked by both the moon and the Earth. Check out the electrical towers on the distant horizon, much farther away than the antenna in the previous pic. All three sunspot groups are still visible, too.

Moonset at sunset. I don’t even know what you call this…third-and-a-half contact, maybe? Whatever the actual name, we all thought it was the highlight of the second half of the eclipse.

The last sip of sunlight. Good times.

Stay tuned, we’ll do it all over again in a fortnight, only with a much smaller (in apparent size, anyway) object blocking the sun. There’s still time to build a sun funnel and scare up a cheap scope if you’re so inclined. Clear skies!