August 21, 2017 Total Solar Eclipse

Like millions of other people, we went chasing the Great American Eclipse. We chose Nebraska, since everybody we knew was going to Wyoming, and the climate models suggested a good probability of clear weather. Our initial camp was at Lake McConaughy, which is just inside the line of totality. My sister Danielle and her husband Edward got there early to start scouting. Our plan was to check weather forecasts and then go mobile the day of the eclipse. The morning of August 19 I got up early and snapped this shot of the moon on its way to its date with destiny:

Sunday morning we checked the forecasts. It was not looking good for Nebraska in general, but east-central Nebraska seemed better than western according to the forecasts. So we packed up camp and headed out to Camp Augustine, a Boy Scout camp near Grand Island, Nebraska:

They had camping spots available, and a large field which would be good for observations. After a rather hot, muggy, sleepless night (dry camping with no electri…

Mars and Saturn near opposition

Mars was at opposition (directly opposite the Sun from the Earth) on May 22, and Saturn was at opposition on June 2.  I've been itching to get some photos of them, and the combination of clear skies, reasonably good seeing (low upper-atmosphere turbulence) and time available made last night a good choice.  Without further ado, the photos:

Although the photos say "June 5" I took them the night of June 4, local time, at about 10:12 PM and about 11:22 PM Mountain Daylight Time, from our back yard in Fort Collins, Colorado.

My equipment was a Meade LX90 ACF 8" f/10 Schmidt-Cassegrain telescope mounted on an iOptron CEM-60.  The camera was a ZWO ASI174MM monochrome camera, with an RGB filter wheel and a 2.4x Barlow, which made the combo a 4800mm focal length f/24 system.

Mars was taken with a 1.9ms shutter and a gain of 280 in FireCapture.  It was a 640x480 ROI, running at 182 FPS.  Saturn was taken with a 6.89ms shutter and a gain of 351, also a 640x480 ROI, but a lowe…

Transit of Mercury, May 9, 2016

Today (well, technically, yesterday now) was the 2016 Transit of Mercury.  These happen much more frequently than transits of Venus.  Mercury transits happen about every 7 years (13 or 14 times per century).  I was watching  the weather anxiously - I wanted this to be a dry run for the 2017 eclipse, but I was not able to travel on Monday so I was hoping that the weather would suffice here in Fort Collins.  I watched the Fort Collins cleardarksky page continuously over the weekend, which helped me stay calm and collect my equipment to prepare for the expedition.

Monday morning started with low clouds which cleared by about 6:30 or so - just in time for me to have all my equipment set up:

From left-to-right, these are:

A Meade 2045 4-inch Schmidt-Cassegrain telescope on a tripod, with a glass front-surface solar filter.  This was for visual use - which turned out handy, since I had about 8 or 10 visitors.A Lunt Solar LS60PT pressure-tuned H-alpha dedicated solar scope, with a Hinode Sol…

Moon, Venus, and Mercury - Feb 6, 2016

I got up really early again this morning to catch the Moon, Venus, and Mercury dancing in the pre-dawn sky.  Here are a couple of my best shots.  The first one was taken from Larimer County Road 38E, where it curves into the foothills.  It was taken at 5:55 AM with a Canon 7DmkII and an EF 100-400 f/4.5-5.6L II lens, at 100mm f/4.5.  It is a 1.6 second exposure at ISO 800:

For the curious, here is a map of the foreground showing what is visible in the 12.8 degree field-of-view of the lens:

I drove home, and snapped one more picture above the neighbors' rooftops.  Same camera/lens/exposure settings:

OK, *now* I can stop waking up early in the morning.

Five Planets and the Moon

I got up this morning very early to make an animation of Jupiter, Mars, Saturn, the Moon, Venus, and Mercury as they rose in the early morning sky.  Here is the finished product:

It was very cold - 7 degrees Fahrenheight - and very early.  This is a 30-minute sequence starting at 5:39 AM and finishing at 6:09 AM.  All of the images have the same parameters: Canon 7DmkII cameraCanon 8-15mm f/4L lens, locked at 10mm (widest useful zoom with this lens on a 1.6x crop camera)8 second exposures at ISO 3200Image sequencing performed by Canon's EOS Utility.  A capture was started every 15 seconds.
That camera/lens combo yields a 180-degree diagonal field-of-view.  Jupiter and Mercury are about 120 degrees apart in these images, so this gives some extra room for animation and cropping.
Capturing all five planets in the pre-dawn skyglow is surprisingly tricky, especially when city light pollution is contributing to a murky lower atmosphere.  I was located at the north end of the parking lot

Total Lunar Eclipse, September 27-28 2015

Jill and I went eclipse chasing this evening.  I did initial research on the Clear Dark Sky site to see what conditions were going to be like.  After digging, I decided that somewhere south and east of Briggsdale was likely to have clear skies.  We ended up on the grounds of an old church called Osgood Church.  We were greeted by this raptor, which we took as an auspicious omen:

We were rewarded with gorgeous skies - only a few wispy clouds floated through occasionally.  Here is an all-sky shot taken with my Canon EF 8-15mm f/4.0L lens on a Canon 5DmkII camera that shows how nice the skies were:

Jill and I are there in the foreground next to the telescopes.  You can see the eclipsed Moon, as well as the Milky Way and the skyglow from Fort Morgan, Sterling, and smaller towns off past the horizon.

For the eclipse photos, I used a Canon 7DmkII camera on an Orion ED80T CF refractor - an 80mm diameter, f/6.0 480mm focal length triplet.  I mounted it all on my handy portable iOptron MiniTo…

Armchair science

I noted with interest this update from the DSCOVR mission:

Cool!  The DSCOVR mission is an Earth-imaging mission that takes a continuous stream of Earth images to monitor it for climate and other changes over time.  It happened to catch the Moon crossing the face of the Earth (go to the link for the animation - you'll be glad you did).  This will happen twice a year, when the plane of DSCOVR's orbit intersects the plane of the Moon's orbit in line with the Earth.

The DSCOVR web page says that the satellite orbits "a million miles" from Earth.  It turns out, you can calculate that distance just from this image and from the known sizes of the Earth and the Moon.  The Earth has a mean radius of 3,959 miles, and the Moon has a mean radius of 1,079 miles.  The ratio between the two is 3.67 - meaning the Earth is 3.67 times as big as the Moon.  But if you open up that image in Photoshop and measure the Earth and Moon in pixels, you will find this:

The Earth is 1595 pi…