Penumbral Eclipse

On the evening of July 3rd, 2020, Richmond Hill resident Ian Shelton captured this image while watching the setting Sun beautifully illuminate the top of a huge distant storm cloud. When sunlight needs to travel horizontally through many additional thicknesses of our atmosphere to reach our eyes or a distant object like the cloud shown here, air molecules can scatter most of the blue sunlight out of the beam, leaving just the yellows, oranges and reds of sunlight to illuminate us or a distant cloud. Contrast this with the unfiltered white sunlight traveling directly through space to reach the Waxing Gibbous Moon seen above and ten thousand times further away than the terrestrial cloud top.

Two days later, Dr. Shelton was joined by several other member of the DDO Defenders to watch the now Full Moon pass into Earth’s shadow. Unlike a more familiar umbral lunar eclipse where a dark circular shadow makes part or all of a Full Moon seem to disappear, a penumbral eclipse is a much more subtle event that is easily missed. Encircling the cone-shaped dark inner “umbral” shadow cast by the Earth is the “penumbra”, a larger outer cone where only partial darkness occurs. On July 5th, the Moon passed 30% of the way into the penumbral cone, causing only about 20% darkening towards the north edge of the Moon.
  By eye, the event went unnoticed. But it was captured photographically, as shown in the image here. A photograph taken just before the eclipse began was subtracted from a photograph taken at mid-eclipse.

-DDO Defenders 🙂

Comet NEOWISE is Here!!

Hi Everyone,

Here is what Comet NEOWISE looked like this morning, July 8th, 2020 (via a camera, not by eye). The image was processed to increase the contrast and darken the sky, which was already getting pretty bright when the comet finally came out from behind the clouds at 4:30 am. The comet is likely going to remain an easy target for cameras on a tripod for the next week or two, as it moves further away from the Sun and closer to Earth. If the sky is clear, it should be visible by eye if you observe between ~4:00 and 4:30 am. Binoculars should reveal its stubby tail. The animation below shows where to look for the comet. And at 4:30 am on July 9th, 2020, the ISS will be seen passing through the same part of the sky (weather permitting). 

-DDO Defenders

More photos from the DDO Restoration

Hi All,

We’ve taken more photos from the DDO! Preparations for restoration are underway, as scaffolding is still being erected. As depicted in these photographs, the Administration building is nearly entirely encapsulated by the scaffolding, which is not yet fully complete (as of the second week of June 2020). Restoration of the facility is currently planned to continue until December 2020. We will continue to bring you updates here!

-DDO Defenders

Venus passes Sun, now entering morning sky

This snap-shot of Venus was taken using a telescope in full daylight on June 7th, 2020, just a few days after Venus appeared to pass just below the Sun*. The planet was just a whisper-thin crescent on this date, with just 0.3% of its illuminated hemisphere visible. It’s during these “inferior conjunctions” that Venus looks biggest to us, because this is when Earth is passing closest to Venus. But Venus still appears at least 30 times smaller than the Full Moon.

One clear difference between seeing a thin crescent Venus through a telescope and seeing a thin (“young”) crescent Moon by eye is that Venus remains very bright, whereas the crescent Moon is much fainter compared to when it is a Full Moon. That’s because we never get to see the surface of Venus, only its very reflective white clouds. In fact, at the time of conjunction, we can catch a glimpse of Venus’ cloudy atmosphere faintly glowing all the way around the planet’s silhouet, making its crescent extend beyond just a half circle like for the Moon. The picture here shows a tiny bit of that extension.


If you want to see Venus for yourself, you will now need to get up just before Sunrise, as Venus has become the Morning Star.

Wishing everyone Clear Skies!

— Dr. Ian Shelton

* Venus was still travelling along its almost circular orbit 50 million km closer than Earth orbits the Sun; but as seen from Earth, Venus was almost perfectly lined up with the Sun 100 million km beyond Venus.

Restoration underway at the David Dunlap Observatory

We hope you all are safe and well! We miss having programs at the DDO and we know you miss them too!

Restorations have begun on the Administration Building of the observatory and they are planned to continue for about 6 months. These restorations will focus on the outer facade (including stonework and paint). We will continue to update you about the work being done as information comes our way.

Hopefully, not too far in the future, we will be back doing our programs at the DDO. When this time comes, the  restoration efforts will not affect our programming.

We look forward to seeing you all again! Until then, please enjoy our online content via YouTube!

-DDO Defenders

Happy 85th Birthday! 🥳 David Dunlap Observatory! ✨

We just finished our second livestream! Thank you everyone for attending! It was lovely to talk with Prof. Stefan Mochnacki and share our memories with all of you! If you missed it, don’t worry! It’s posted on YouTube!

Prof. Stefan Mochnacki

We covered the past ~100 years of Canadian Astronomy History, and got to hear a personal account of what it was like to work at the DDO as a professional astronomer! We hope to hold more interviews in the future, so let us know if you have any topic suggestions or questons!

We’re happy to celebrate together, and look forward to celebrating again in the years to come! Happy 85th DDO!

-DDO Defenders 😁

*Photos by Chris Robart*

Astronomy Nights Online! 🌟

Enjoy a virtual astronomy night on Victoria Day! 🌙✨ May 18th, 2020, 7:30pm EDT! Astronomy Nights Online Episode 1: Venus Going, Going with Dr. Ian Shelton will be broadcast live on YouTube!

Find it here!

Come join us for an evening of Space News and Observing Challenges from the comfort of your home! DDO Defenders welcomes you to participate and ask questions, just make sure to sign in with your YouTube account! Please share and join in on the fun!

Photo by Chris Robart

-DDO Defenders : )

Happy International Astronomy Day!! 🌟⭐🌟💫

Today is a day of celebration! Amidst the seriousness and caution we are all practicing to protect one another, let us take a moment to be thankful for the many achievements that were accomplished within the field of Astronomy.  

We are ever thankful for the three decades we’ve been able to share with the Hubble Space Telescope, generating spectacularly beautiful images and revealing our universe like never before. For example, the Hubble Deep Field image shown below shows galaxies so far away that we are just now seeing the light they released 12 billion years ago. We are seeing them the way they looked 12 billion years in the past, about the same time when our own Milky Way Galaxy was just coming into existence!

This is the 25th anniversary of the landmark SOHO satellite, which has been providing us with a continuous view of the Sun in X-rays, UV and visible light and giving us an advanced warning of approaching solar storms. This feat is even more remarkable when you realize the spacecraft is too far away to receive any repairs and was only intended to last three years! And this is the 30th anniversary of the almost tragic Apollo 13 mission, where dedication and human ingenuity turned a disaster into triumph.

Speaking of weather, two years ago when Mars was last passing nearest to the Earth, an early summer on Mars kicked up a global dust storm that ruined the view. This October, Mars will be passing nearby again and we expect the view to be much better. Mars is already getting brighter in the predawn sky, where you’ll also currently find Jupiter and Saturn. All three planets are rising earlier each morning and will be up all night this Summer. Venus is that brilliant “star” seen high up in the West after sunset, where it is outshining everything except the Sun and the Moon.

Though we are all actively practicing social distancing and have had to give up our usual festivities, the DDO Defenders hope these small reminder of past astronomical accomplishments and upcoming events can bring us all hope for the future. We will continue to plan and prepare for when we can all meet again in person! Until then, stay healthy and intrigued!

~DDO Defenders 🙂

Happy Discovery Day, SN87A!

It’s been 33 years since you first captured our attention! We’ve been learning from you ever since! Can’t wait to see what other new discoveries you will set into motion!

To learn more about SN87A, please visit here and here!

-DDO Defenders : )