The Wahweap Wow

Glen Canyon dam

Glen Canyon dam

Last weekend I was in Page Arizona to visit my parents and catch the May 20th 2012 annular solar eclipse. Page is a little town that owes its existence to the construction of the Glen Canyon dam in the early 1960’s. The reservoir behind the dam, Lake Powell, has appeared in so many movies that it should collect royalties. Charlton Heston crashed his spaceship here in the first and only good Planet of the Apes movie.  John Travolta nuked the place in Broken Arrow. Even Jesus Christ used Lake Powell as a Dead Sea ringer in The Greatest Story Ever Told.

Page, the dam and Lake Powell did not disappoint. I had a great time toodling around shooting pictures. I only had one day which was partly devoted to the eclipse but I saw enough to give Glen Canyon an unqualified thumbs up. If you’re into rocks, desert and water this place is bucket list material. Like MacArthur I will return.

Wahweap Overlook eclipse fans

Wahweap Overlook eclipse fans

While pleased with Glen Canyon I was surprised by the large number of people who turned out for the annular eclipse. The US park service in conjunction with local amateur astronomers set up viewing grounds on Wahweap Overlook and ran full size shuttle buses from the nearby Carl Hayden dam visitor center. At least four busloads of eclipse fans were carried to the overlook where they joined more amateur astronomers and serious eclipse photographers that had set up dozens of telescopes and cameras for the big show. There must have been at least four hundred people on Wahweap Overlook and Wahweap was only one of many sites where people set up to watch the eclipse. It’s gratifying to see that when a real star puts on a show the audience is huge.

Before the eclipse started, and during the early phases when the Moon was creeping on the Sun’s disk, I walked around looking through telescopes. Two scopes stood out. One expensive large aperture Hydrogen Alpha scope served up gorgeous high-resolution views of the Sun. In Hydrogen Alpha light solar prominences , filaments  and photosphere mottles are clearly visible. The big Hydrogen Alpha scope put on a good show but bang for the buck went to a 15 dollar light funnel that a 14-year-old made by hand and attached to a small refractor. His makeshift funnel projected the brightest and clearest white light image of the Sun. I told him his projection was the best; he was happy to hear it.

iPhone image captured by holding eclipse shades over the lens.

As the eclipse approached the annular phase I set up my camera. I didn’t have the right filter, only a 4D neutral density, but I thought I’d give it a try. When the light ring formed I fired off a few shots. The filter didn’t cut enough light so I immediately gave up and went to plan B. Plan B consisted of covering the lens of my  iPhone with eclipse shades and Phd’ing it.  I took a few frames and managed to catch the ring. It was a minor triumph of iPhoneography.  After that I just gawked through my eclipse shades while the Sun and Moon wowed the masses with their dance. The crowd burst into applause when the ring broke but, sadly, the performers declined an encore.

Lake Powell houseboats

Lake Powell houseboats

As I have already said, annulars are not in the same awe-inspiring class as totals but this annular, falling where it did, was special. From the overlook you could see the lake, the dam, towering red rock formations and of course the sky. The perfect ring of light was just the icing on the cake of a Wahweap wow!

GPX from Google Maps KML J Script

In preparation for my Arizona jaunt to watch the May 20th annular eclipse I spent a few hours on Google Maps selecting locations to visit.  Here are my prime targets.

After selecting targets the next step is to load them onto my “GPS device.” Currently my GPS device is the MotionX GPS iPhone app.  MotionX can read GPX files in many ways but you need GPX files not Google Maps KML files. Converting KML to GPX is a recurring nuisance. I’ve used online converters for this chore but today, after being annoyed by this problem for the zillionth time, I dashed off a J script that transforms Google Maps KML to GPX.  The main verb gpxfrmapkml is shown below. The entire script is available here and in the files sidebar. Browse to the J Scripts directory. Happy KML to GPX’ing my friends.

gpxfrmapkml=:3 : 0

NB.*gpxfrmapkml v-- gpx from Google maps kml.
NB. monad:  clGpx =. gpxfrmapkml clKml
NB.   NB. download Google map waypoints as kml
NB.   kml=. read 'c:/temp/arizona annular eclipse.kml'
NB.   NB. convert to gpx and save
NB.   gpx=. gpxfrmapkml kml
NB.   gpx write 'c:/temp/arizona annular eclipse.gpx'  

NB. parse kml form waypoint table
dname=. ;'name' geteletext '<Placemark>' beforestr y
wpt=.   ;'Placemark' geteletext y
wpt=.   ('name' geteletext wpt) ,. <;._1&> ','&,&.> 'coordinates' geteletext wpt
hdr=.   ;:'phototitle longitude latitude'

NB. format gpx header 
gpxstamp=. 'Waypoints: ',(":#wpt),' GPX generated: ',timestamp''
gpxheader=. ('/{{headername}}/',dname,'/{{headerdescription}}/',gpxstamp) changestr GPXFRKMLHEADER
gpxtrailer=. GPXTRAILER

rvarbs=. idx htmlvarbs pkml

NB. all row varibles must exist in data header
assert. *./ rvarbs e. hdr
rows=. (#wpt) # ,: pkml
rows=. ((hdr i. <'phototitle'){"1 wpt) (<a:;(rvarbs i. <'phototitle'){idx)} rows
rows=. ((hdr i. <'latitude'){"1 wpt) (<a:;(rvarbs i. <'latitude'){idx)} rows
rows=. ((hdr i. <'longitude'){"1 wpt) (<a:;(rvarbs i. <'longitude'){idx)} rows


2012 Venus Transit and Annular Eclipse

I’m gearing up for two big eminent celestial events. On May 20th I’ll be near Page Arizona observing an annular eclipse of the Sun and on June 5th, weather permitting, I’ll be in St. Louis watching Venus creep on the disc of the Sun for the last time in my lifetime.

Eclipses and transits are spectacular events for amateur astronomers and innocent bystanders. Of the two eclipses offer the greater spectacle. In fact, for sheer unbridled awesomeness, it’s hard to beat a total eclipse of the Sun! You can add up all the World Cups and Super Bowls ever played and they would barely register on the logarithmic total solar eclipse spectacle scale. The one total solar eclipse I saw easily ranks as the greatest thing I’ve ever seen and I’m including the births of my children. The May 20th solar eclipse is annular so it’s not in the same galaxy as a total but annular’s have their charms. At maximum eclipse the Sun appears like a perfect blazing ring of light. In Page it will be 10 degrees above the north-western horizon: a good altitude for composing solar landscape pictures.

By comparison the June 5th transit of Venus will not be a big show. Without proper equipment you won’t be able to see it at all. During transit Venus looks like a little black dot on the Sun. The best way to see this event is with telescope or binocular projection. Under no circumstances should you look directly at the Sun without proper eye protection!  For safe transit viewing techniques look here. In 2004 I used binocular projection to view the last transit of Venus from Ottawa Canada. Transits of Venus come in pairs, eight year apart, followed by over a century before the next pair.  After 2012 you will have to wait until 2117 to see another transit of Venus. This is our last chance people. Yeah mortality seriously blows.

2004 transit of Venus from Ottawa Canada. I used 10x50 binoculars to project an image of the Sun. The little dark spot on Sun's limb is the planet Venus.