After complaining about cloudy skies the other day I got a break last night and had very clear skies. As a result I was able to capture a sequence of images of the ISS flying over my part of the world. I use the Starry Night Pro program to simulate the flight path of the ISS so I can determine where best to aim my camera. My technique is basically to use a wide angle (18 mm) lens and once I determine the appropriate F-stop and shutter speeds I lock the tripod and wait until the ISS appears. Then I take pictures either manually from the laptop or with a digital cable release set to take a sequence of pictures. My preference, however, is to use the utility program that came with the camera. I connect the camera with a USB cable to the laptop and this gives me a real-time view on my laptop computer screen as well as remote control of the camera settings and picture taking. The camera is on a tripod several feet away to reduce any camera jitters.
   During the fly-over the ISS was traveling toward the southeast and crossed the ‘Square of Pegasus’ asterism, and then past the ‘Circlet’ asterism in Pisces coming within a few degrees from the planet Uranus. The images are each 3.2 second time exposures – long enough to capture the dim stars making up the ‘Circlet’ – but also so long in the sense that in 3.2 seconds the ISS has moved enough to show up as a streak of light, like star trails in longer time exposures. This animated graphic is slightly faster than the actual event but I have set it to give a sense of how quickly the ISS moves and how its brightness increase, peaks, then fades.
   Looking toward the east were the stars of the Pleiades and, lower toward the horizon were Jupiter and the Hyades. Obviously I couldn’t resist!
   And then this morning there was a neat contrast between the reds and pinks toward the west, the setting waning gibbous Moon, and some high thin cirrus clouds.
   
   
Click here to go to the Qué tal in the Current Skies web site for more observing information.