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!

Alan, November 17, 2019 / © 2019 Alan Dyer / amazingsky.com

 

Transit of Mercury


Transit of Mercury near Sunrise

On May 9, a last-minute chase into clear skies netted me a view of the rare transit of Mercury across the Sun.

The forecast called for typical transit weather – clear the day before, and clear the day after. But the day of the transit of Mercury? Hopeless at home in Alberta, unless I chanced the prospects of some clearing forecast for central Alberta.

As the satellite image below, for 8:30 a.m. MDT on May 9, shows, that clearing did materialize. But I headed west, as far west as I needed to go to be assured of clear skies – to central BC. Kamloops in fact.

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I stayed at the Alpine Motel, got a great room as the end, and set up in the parking lot away from traffic. Not the most photogenic of observing sites, but I was happy! I had my clear skies!

IMG_8037

I set up two telescopes, above: a 130mm refractor to shoot through, and an 80mm refractor to look through. Both with dense solar filters!

Both worked great. However, low cloud prevented me seeing the Sun as soon as it cleared the eastern hills. So this was my first good look, below, at the transit as the Sun rose above the clouds.

Transit of Mercury near Sunrise
The May 9, 2016 transit of Mercury taken about half an hour after sunrise, as the Sun emerged from low horizon cloud. Taken from Kamloops, British Columbia, where the transit was well underway at sunrise. Mercury appears as the circular dot at lower left, with a sunpot group above centre. I shot this with the 130mm Astro-Physics refractor at f/6 prime focus with the Canon 60Da camera at ISO 100. Shot through a Kendrick white light solar filter. The low atltitude added much of the yellow colouration.

There it was – the fabled “little black spot on the Sun today.” Mercury is the dot at lower left, with a sunspot group at upper right. This was the first transit of Mercury since November 8, 2006. We see only about 13 Mercury transits a century, so in a lifetime of stargazing (the Sun is a star!) even the most avid amateur astronomer might see only a handful. This was only my third transit of Mercury.

Transit of Mercury in Clouds
The May 9, 2016 transit of Mercury taken about 45 minutes after sunrise, as the Sun emerged from low horizon cloud. I shot this with the 130mm Astro-Physics refractor at f/6 prime focus with the Canon 60Da camera at ISO 100. Shot through a Kendrick white light solar filter.

This was the view, above, a little later, as the Sun entered more assuredly clear skies. From about 7 a.m. PDT on, the Sun was in the clear most of the morning, with just occasional puffy clouds intervening now and then.

I shot still images every 30 seconds, to eventually turn into a time-lapse movie (after a ton of work hand registering hundreds of frames!).

But for now, I’ll be content with this composite of 40 frames, below, taken at 7-minute intervals. It shows the progress of Mercury across the Sun over the last 4.5 hours or so of the event, until egress at 11:38 a.m. PDT.

This motion is due to Mercury’s movement around the Sun. A transit is one of the few times you can easily see a planet actually orbiting the Sun.

Transit of Mercury (May 9, 2016) Composite with Arrow
For all images I used the 130mm f/6 Astro-Physics refractor with a 2X Barlow for an effective focal length of 1560mm and the Canon 60Da camera (at ISO 100) to yield an image size with the Sun just filling the frame. Exposures were 1/250th second through a Kendrick white light Mylar filter. Yellow colouration of the solar disk added in processing.

In this composite, the disks of Mercury are not all perfect dots. The wobbly seeing conditions distorted the images from frame to frame. But I used the actual images taken at that moment, rather than clone some perfect image across the disk to simulate the path.

To wrap up, here’s Mercury Transit: The Movie! I shot several HD and zoomed-in “crop mode” movies at the beginning of the transit and again at the final egress. Commentary is from me talking live into the camera mic as I was shooting the clips. Background noise is courtesy Pacific Drive and the Trans-Canada Highway!

Enjoy, and do enlarge to HD and full-screen for the best look.

 

The next transit of Mercury is November 11, 2019. If you are hoping for a transit of Venus, good luck. The next is not until December 10, 2117!

– Alan, May 15, 2016 / © 2016 Alan Dyer / www.amazingsky.com