transit – The Amazing Sky

November 17, 2019November 18, 2019

The Great Transit Expedition of 2019

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On November 11, I traveled to the near-flung corners of my backyard to observe the rare transit of Mercury across the Sun.

History is replete with tales of astronomers traveling to the far corners of the Earth to watch dark objects pass in front of the Sun — the Moon in eclipses, and Mercury and Venus in transits.

On November 11, to take in the last transit of Mercury until 2032, I had planned a trip to a location more likely to have clear skies in November than at home. A 3-day drive to southern Arizona was the plan.

But to attend to work and priorities at home I cancelled my plans. Instead, I decided to stay home and take my chances with the Alberta weather, perhaps making a run for it a day’s drive away if needed to chase into clear skies.

Transit of Mercury Selfie with Sun

As it turned out, none of that was necessary. The forecast for clear, if cold, skies held true and we could not have had a finer day for the transit. Even the -20° C temperatures were no problem, with no wind, and of course sunshine!

Plus being only steps from home and a warming coffee helped!

As it turned out, the site in Arizona I had booked to stay was clouded out for the entire event. So I was happy with my decision!

For my site in Alberta, as for all of western North America, the Sun rose with the transit in progress. But as soon as the Sun cleared the horizon there was Mercury, as a small, if fuzzy, black dot on the Sun.

Low Sun with Mercury in Transit

As the Sun rose the view became sharper, and was remarkable indeed — of a jet black dot of a tiny planet silhouetted on the Sun.

The Transit of Mercury Across the Sun (10 am MST)

I shot through two telescopes, my 4-inch and 5-inch refractors, both equipped with solar filters of course. I viewed through two other telescopes, for white-light and hydrogen-alpha filtered views.

I was able to follow the transit for three hours, for a little more than half the transit, until Mercury exited the Sun just after 11 a.m. MST. The view below is from moments before Mercury’s exit, or “egress.”

The Transit of Mercury Across the Sun (11 am MST)

I shot still frames every 15 seconds with each of the two cameras and telescopes, for a time-lapse, plus I shot real-time videos.

Mercury at Mid-Transit (November 11, 2019)

At this transit Mercury passed closer to the centre of the Sun’s disk than it will for any other transit in the 21st century, making this event all the more remarkable. That point is recorded above, from a shot taken at 8:19 a.m. MST.

Stacking a selection of the time-lapse frames, ones taken 1-minute intervals, produced this composite of the transit, from just before mid-transit until Mercury’s egress.

Transit of Mercury Composite Across the Sun v2

I assembled all the best images and 4K videos together into a movie, which I narrated live at the telescope as the transit was happening. I hope this provides a sense of what it was like to view this rare event.

The Transit of Mercury from Alan Dyer on Vimeo.

We won’t see another until 2032, but not from North America. The next transit of Mercury viewable from here at home is not until 2049! This was likely my last transit, certainly for a while!

Transit of Mercury Trophy Shot

This was my trophy shot! Bagged the transit!

P.S.: For my video of the previous transit of Mercury in May 2016, see my blog post which includes a similar compilation video.

P.P.S.: And for tech details on the images and videos in this blog, please click through to Vimeo and the video description I have there of cameras, scopes, and settings.

Clear skies!

June 9, 2012

Venus: 6 Degrees of Separation

This was my first look at Venus following Tuesday’s transit. Here, it’s just six degrees west of the Sun as a thin crescent in the afternoon sky. It was a beautiful sight in the eyepiece, far enough away from the Sun to not be in its glare but close enough to still appear as a razor-thin backlit crescent.

Each day now Venus is widening the gap between it and the Sun, shortly to become a brilliant morning star in the eastern sky before dawn through the rest of June, July and August.

I shot these images in broad daylight through a 130mm f/6 refractor. The big image is a full-frame shot with the Canon 60Da and a 2X Barlow lens, for an effective focal length of about 1500mm. The inset is a single frame grabbed from a 30-frame-per-second movie shot with the Canon in its Movie Crop mode, which yields a high-magnification view suitable for planet shooting, but only 640 x 480 pixels. But this mode is certainly ideal for capturing planets, though none ever appear as large as Venus is here. This is an uncommon instance of Venus as close and as large as any planet gets.

June 5, 2012

Transit of Venus: From One Cloudy Planet to Another

The day looked hopeless with not a chance of clear skies. But a small hole opened, revealing Venus on the Sun.

I had seen this sight before, in 2004 from Egypt. But my first reaction upon seeing it again, albeit briefly, was [Expletive Deleted]!!! No photos really provide the visual impression of just how enormous Venus appears on the Sun. We’re used to sunspots (and there were lots today) and some quite large. But nothing we ever see on the Sun matches the size of Venus. The eyepiece impression is of something much larger than the photos show. It’s like Moon illusion at work on the Sun.

It had been hopelessly cloudy all day in Calgary. Interpretive obligations over at the science centre (where we showed the NASA webcast from Hawaii), I hit the highway in search of a clear hole … and found one northeast of the city, one at first that seemed to be wide and stable. I stopped, looked with the filtered naked eye, then drove on seeking slightly less cloud, getting greedy! I should have stopped sooner. By the time I did stop and hurriedly set up the little 80mm refractor telescope, I had about 30 seconds for a great clean view, then switched to the camera. By the time I got it set, clouds were coming out of nowhere and thickening fast. I couldn’t shoot through the solar filter. This is a filterless shot, at 1/8000th second! Clouds provided the natural filtration. Fine! At least I got the camera focused, for a crisp view of Venus next to the clusters of sunspots, something no one alive has seen — in 2004 the Sun was virtually spotless.

So, not a view or photo under the best of conditions, but an experience I am happy to settle for. Now, I just want clear skies in Australia for November’s total solar eclipse. Please!!

May 30, 2012May 30, 2012

Venus Descending

A wonderful sight tonight, as I caught Venus in its last days before the transit, shining as a glistening crescent low in the evening twilight.

Venus was visible to the unaided eye after sunset, but not for long. It set soon after the Sun. But for a short while it put on a beautiful show as a large crescent (large for a planet that is), easily resolvable in binoculars and stunning in a small telescope. One could almost make out, for brief moments, the sight of the backlit atmosphere going all the way around the disk. But I suspect it was more imagination at work than reality shining through.

The inset blows up the boxed area, to reveal the crescent-phased disk of Venus, despite this shot being taken with no more than a 200mm telephoto lens. I used a Canon 60Da camera at ISO 100. A plane is flying just below Venus.

So this was May 30, 6 days before the June 5 transit, with Venus 9.5° east of the Sun. How far up to the Sun can we catch it, before it crosses the Sun on Tuesday?

May 28, 2012May 28, 2012

Venus Sinks Sunward

Here’s a last look at Venus before its historic transit across the face of the Sun on June 5.

I took this Monday evening, May 28, with the Sun still up and Venus about 13 degrees east of the Sun but low in my evening sky. Venus appears as a razor-thin crescent, like a tiny “new Moon.” Most of the daylight side of Venus now faces away from us; on the side of Venus turned toward us now all but a sliver of a crescent is dark — we’re looking at the night side of Venus. On June 5, all we will see is this dark side of Venus, appearing in silhouette in front of the Sun’s brilliant disk as Venus moves across the Sun in a transit not to be repeated for another 105 years.

This is a single still-frame grab from a movie shot I shot with the Canon 60Da camera, set in Movie Crop Mode, for a movie 640 x 480 pixels wide. This mode magnified Venus considerably on the frame. I shot this through a small 80mm apo refractor at its f/6 prime focus, so with only 480mm of focal length. But Venus is now so large it doesn’t take a lot of extra magnification to show its disk and phase.

The view through the eyepiece was stunning. The rippling image and sparkling colours, though from distortion in our atmosphere, added to the beauty of Venus, fitting for the goddess of love.