Visiting one of the world’s great observatories is always a highlight for any astronomy enthusiast. Most of us “collect” observatories, and try to get to as many as possible in our lifetime of travels and explorations. This last week provided me an opportunity to visit a place of legendary status in astronomy, the Arecibo Radio Observatory in Puerto Rico. This is the world’s largest single-dish radio telescope, and consists of a 1000-foot metal dish suspended in a natural bowl in the island landscape.
In this shot, our tour group, part of the “Cosmic Trails” Caribbean cruise I was on that week, is standing underneath the metal mesh dish, looking up toward the antennas suspended high above the dish. This is a rare and privileged place to stand — driving down into and under the dish isn’t on the usual tourist tour. Had they been beaming powerful radar signals out to some solar system target that afternoon we would not have been able to stand here. As it was, they were listing to signals from pulsars. We also got into the main control room to talk to the observers and technicians at work that afternoon.
I won’t provide all the background about this remarkable observatory (you can read about it yourself at Wikipedia or visit the telescope’s webpage). However, movie fans will know this location from its appearance in the movie Contact and in the James Bond film Goldeneye. And it is well-known for its role in broadcasting signals to potential aliens and for listing to signals from extraterrestrials. However, one of its main roles these days is bouncing radar signals off passing near-Earth asteroids, and producing radar “images” of those asteroids. Arecibo also discovered, back in the 1960s, the true rotation rate of Mercury, now visible at its best in the evening sky.
– Alan, March 13, 2011 / Image © 2011 Alan Dyer
For the past week I was on a cruise ship in the Caribbean, on a “cruise and learn” voyage, serving as one of the guest speakers to a group of astronomy enthusiasts who wanted an immersive vacation learning about the latest in astronomy research and, in my presentations, about the hobby side: choosing a telescope and doing astrophotography. The cruise was organized by Insight Cruises and by Sky and Telescope magazine.
The trip went great, with fabulous weather all along, and a welcome break to an awful winter in the north. However, a cruise ship is not the best place to actually do astrophotography!
This is a shot taken on Friday, March 11, from the upper deck and bow of the ship, the Holland America Line’s “Nieuw Amsterdam,” as we sailed on a northwest course back to Fort Lauderdale from our most southerly port of call in St. Maartens in the eastern Caribbean. The Moon is overexposed at right, and is directly ahead of us, making it look like we were sailing toward the Moon. At left is Orion and Canis Major, tipped over on their sides compared to our northerly view. This was from a latitude of about 20° North.
To keep the stars looking like stars (and not seagulls) and freeze the rolling of the ship, I had to bump the camera up to ISO 6400 and use a 5 second exposure at f/2.8 (wide open) with the 16-35mm lens. Not the best combination of settings, but it’s what it took to capture the “seascape” night scene.
— Alan, March 13, 2011 / Image © 2011 Alan Dyer
What an awesome spacecraft it has been — launching the Hubble Space Telescope, Ulysses and John Glenn! It returned NASA to manned spaceflight following both the Challenger and Columbia accidents. And now this week, we say goodbye to Space Shuttle Discovery. On Sunday night, Feb. 27, I took a look at it (perhaps my last), and the ISS, as they flew over together in an ideal pass across our sky. Even in binoculars you could see the shape of the ISS — or at least that it had a shape and was not just a star, as all other satellites appear. A great sight was watching the craft fly into Earth’s shadow and go deep red then fade out. That’s why the bright streak the ISS/Shuttle left on the frame during the time exposure fades out at left, as they fly to the east and experience sunset.
To the west (right) note the Zodiacal Light glow reaching up from the western horizon. Orion and Canis Major are at bottom in the south. To the northwest is my house. I purposely left the porch light on around the other side of the house to light up the yard and the photogenic old house on the property. It features in many of my backyard shots.
This shot is a two-image stack of 4-minute exposures, with the Canon 5D MkII at ISO 800 tracking the sky on an equatorial mount. The lens is one of my favourites, the Sigma 8mm full-circle fish-eye lens. Some haze in the sky knocked back the contrast, so the Milky Way doesn’t pop out as well as it should. Still, this was the first clear night in a while when it wasn’t -25°C!
– Alan, February 27, 2011 / Image © 2011 Alan Dyer
My previous post was a profile of Perseus. Right next door in the current evening sky is Auriga the Charioteer, embedded right in the middle of the Milky Way. This is a 50mm “normal” lens shot of all of Auriga showing its distinctive pentagon shape with the bright yellow star, Capella, at top. It’s the bright star shining high overhead on winter nights, at least if you live in the northern hemisphere at latitudes like the US and Canada. What is not obvious (because it can’t be resolved through a telescope) is that Capella is a close double star, made of twin suns orbiting each other at about the same distance apart as are the Sun and Venus. A planet orbiting the pair would definitely see a Tatooine-style double-Sun sunset. Not to say Luke Skywalker was from the Capella system — remember Luke’s tale took place in a Galaxy far, far away! Capella is just 42 light years from Earth.
What shows up here just below centre is some of the wisps of red nebulosity in the middle of Auriga (tough to see visually but easy for the camera to see), as well as the trio of star clusters first catalogued by Charles Messier in the 18th century and that are great objects for any telescope. Notice how the Milky Way brightens through Auriga, partly by way of contrast to the lanes of dark nebulosity to the right that weave through Taurus and Perseus. The streak of nebulosity at right is the California Nebula in Perseus. Flip back to the previous blog to see more of Perseus, in a shot taken the same night.
I took this shot on January 23, 2011 (just about the last decent night we’ve had!) with the Canon 5D MkII set at ISO 800 and the 50mm Sigma lens set at f/2.8. It’s stack of five 4-minute exposures, plus three 4-minute exposures with the Kenko soft filter to add the star glows. The blog “Fuzzy Constellations” a few posts back gives some more details about my technique.
– Alan, February 2011 / Image © 2011 Alan Dyer
One of the tenets of my astrophotography “philosophy,” if there can be such a thing (my university degree is in Philosophy after all), is to not spend an enormous amount of time and money chasing after the same images others do, knowing they will likely get far better results than I might achieve, given my location and choice number of clear skies. I don’t live in Arizona, New Mexico or Chile.
Yes, there are certain showpiece objects one is obliged to shoot, to add to the portfolio. But rather than go after many of the usual galaxies and nebulas, I often prefer to shoot wider-field targets that others often bypass.
Simple shots of constellations are often more in demand by publishers than closeups of deep-sky objects, and yet are usually in short supply, as many astrophotographers dismiss them as being “just for beginners.” But good constellation shots still take the right gear, techniques and skies to stand out. Only now am I getting the results I’ve long sought.
With new techniques now in hand, one of my goals is to accumulate a complete portfolio of constellation portraits, though not all of these star patterns stand out as being photogenic. But this one does.
This shot is a recent favourite of mine, of the constellation of Perseus, a rich area of sky. Modern digital cameras show it as the old film cameras never could, laced with reddish dark nebulas of different densities. The Milky Way through this region takes on such a variety of subtle hues achieving correct colour balance is tough.
At top is the loose collection of hot blue stars known as the Perseus Association. At bottom is the most famous tightly bound cluster of stars, the Pleiades. Between is the finger of glowing hydrogen gas called the California Nebula. This photo is an example of how “simple constellation” shots can take on a beauty of their own.
– Alan, February 2011 / Image © 2011 Alan Dyer
Now and then I have the opportunity to test new equipment for astrophotography. That can be both a blessing and a curse — I get to try out new gear before I buy it to see if it really works first, which is nice. But if the equipment doesn’t work well, I might have wasted some valuable nights with little to show for it but some poor photos and lots of frustration. Not so with the gear pictured here. The Celestron CGEM mount, tested for SkyNews magazine, worked great, tracking very well and serving as the platform I used in late 2010 for a lot of astrophotos over two dark of the Moon periods. At about $1500 this is a superb entry-level mount for anyone serious about astrophotography.
I also can praise the Celestron NexGuide autoguider (with the glowing screen at right), shown here on a William Optics 66mm guidescope. It, and its near twin, the Synta SynGuider, worked very well — these are autoguiders to provide exact tracking of the mount over long exposures, a necessity even in the digital age. Unlike many autoguiders, these units are “stand-alone,” requiring no additional computer and able to run for many nights off a typical 12-volt power pack. They are great for use in the field. What’s more, the new autoguiders are quite low cost (~$300) compared to the $1000+ cost of previous models with similar capabilities. I reviewed these units for Sky and Telescope and for SkyNews.
The scope shown here is a favourite of mine, the A&M (now Officina Stellare) 105mm f/6 apo refractor, a beautiful Italian-made “designer scope” with first-class optics. It is a terrific visual and imaging telescope, though a little large for its aperture.
For more details about recommended autoguiders, see the website I developed to support The Backyard Astronomer’s Guide and follow the links to the Chapter 13 entries on astrophoto gear.
– Alan, February 2011 / Image © 2011 Alan Dyer
While I took this image a year ago in early 2010, I thought I’d post this up now, with the new blog now underway. This is a mosaic of what surely ranks as one of the most amazing areas of sky — the vast panorama of the night sky visible in the northern hemisphere each winter. Here we see more bright stars than at any other season of the year, in the constellations (in clockwise order) of Orion, Canis Minor, Gemini, Auriga, and Taurus. Canis Major and its luminary, Sirius, are just off the bottom of the frame.
This is a 4-panel mosaic, each panel consisting of four 4-minute exposures plus two 4-minute exposures with a soft diffuser filter to add the star glows. Each was taken at ISO 800 with the Canon 5D MkII and a 35mm lens at f/4. Slight haze, changing sky fog, and changing elevation of the fields make it tough to get consistent colours across the sky during the couple of hours of exposure time needed to grab the images for such a mosaic, especially from my home latitude. But this attempt worked pretty well and records the wealth of bright red and dark nebulosity throughout this area of sky, a region of the Milky Way in our spiral arm but a little farther out from the centre of the Galaxy than where we live.
– Alan, January 2011 / Image © 2010 Alan Dyer