Were you surprised when the SpaceX Dragon capsule didn’t show up on time last night? I was. I waited diligently with camera and tripod in the driveway. The appointed moment came and went. No Dragon. So I decided to hold out for the International Space Station, scheduled to pass 8 minutes later. It was on time, on track and passed directly under the waxing moon. A beautiful sight.
But what about that Dragon? Perhaps the astronauts on board had maneuvered their spacecraft into a different orbit and passed earlier. Or maybe they were behind the space station instead of preceding it. Just as the space station was nearing the end of its pass in the southeastern sky I noticed a fainter object following nearly the identical path but trailing a half-minute or so behind it. Ha! It was Dragon. Fast as I could I reframed picture to capture the wily critter before it passed into Earth’s shadow.
A bunch of satellite watchers expected it to precede the ISS by minutes but instead it followed fairly closely behind. Dragon wasn’t especially bright (magnitude 3) but it wasn’t difficult to see even in moonlight. Sometimes even the best predictions can be off especially when a manned spacecraft or cargo ship launches for the space station. For that reason it’s always a good idea to start watching 5-10 minutes early and stick around an additional 5-10 minutes. I regret not including that caveat in yesterday’s observing instructions. Take it to heart and you’ll keep smiling.
Crew Dragon docked with the ISS this morning and will remain there for the next 30 to 90 days during which time the crew will join the other astronauts in conducting experiments. That means no more Dragon sightings for a month or more unless you’re watching reruns of Game of Thrones. The space station will continue to make evening passes into early June from many northern hemisphere locations. Check Heavens Above for details.
Meanwhile, Venus is approaching the sun from our perspective on Earth and will pass almost directly between the two bodies on Wednesday, June 3. For this reason when we look in the direction of Venus right now it’s lost in the blinding glare of the sun. Don’t even try or you’ll damage your eyes for good. Because our viewing angle is so narrow only the planet’s edge is lit by sunlight, so we see a wiry crescent. Or as my daughter Katherine put it — “a toenail clipping.”
One way to safely view the planet is to use a small telescope equipped with a safe solar filter. With the filter in place you point the telescope at the sun, focus the image and enjoy the view. With the coordinates of Venus and the sun in hand you next offset from the sun to Venus’s location using numbered circles on the telescope mount called “setting circles.” Then remove the filter and look through the eyepiece. If you’ve correctly aligned the telescope you’ll see Venus right in front of your eyes. I tried this yesterday (May 30) and got to see its incredible crescent in the middle of the afternoon when the planet was just 6° east of the sun.
I had to take great care in pointing and moving the telescope to be safe. Today (May 31) Venus is even closer to the sun at 5° and a thinner crescent yet — just 0.3 percent lit — too close for comfort even for experienced observers. On June 3, when closest, it will be less than the width of the full moon from the sun.
Why look at Venus in the glare? I do it for two reasons: to relish the delicacy of the crescent and to see the ends of the crescent extend faintly beyond their tips. Under ideal conditions these cusp extensions reach completely around the planet. Venus has a very thick atmosphere 90 times denser than Earth’s. When the planet lies almost directly between the Earth and sun, the atmosphere and clouds back-scatter sunlight to create a thin layer of glowing haze around the planet’s edge. It’s an amazing sight.
I got up early a couple mornings ago to catch some darkness before the moon returns to brighten pre-dawn sky. When I pointed binoculars at the pair of “eyes” that Jupiter and Saturn now make in the southern sky at that time I also noticed how close they were to two pairs of stars in the constellation Capricornus the sea-goat. Both split into duos with any pair of binoculars. The stars are Alpha and Beta Capricorni and lie just 5-7° — about a binocular field of view — to the upper left of the planets, making for a trio of celestial doubles at dawn.
Alpha is an optical double star masquerading as a true double. It’s really two stars viewed along nearly the same line of sight, similar to how we see Venus and the sun right now. The fainter star, called Alpha-1, is 690 light years away, while Alpha-2 is just 109 light years. Beta’s the real thing, located 330 light years from Earth. The two stars are at least 21,000 times the Earth-sun distance apart and take at least a million years to orbit each other.
Nature, always abundant, seems to me to have more time than anything. I wish I could negotiate for a bigger piece of it.