Sunday, September 20, 2015
Some Bright International Space Station Passes and Saturn (21-28 September 2015)
|The ISS passes near Saturn, as seen from Brisbane on the evening of Wednesday September 23 at 19:15 AEST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.||The ISS passes near Saturn, as seen from Adelaide on the evening of Tuesday 22 September at 19:35 ACST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.||The ISS passes through Scorpius, above Saturn, as seen from Perth on the evening of Tuesday 22 September at 19:37 AWST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.|
|All sky chart showing local times from Heavens Above for Wednesday September 23 for Brisbane.||All sky chart showing local times from Heavens Above for Tuesday 22 September for Adelaide.||All sky chart showing local times from Heavens Above for Tuesday 22 September for Perth.|
Starting tommorow night (Monday) there are a series of bright evening passes of the International Space Station lasting a week. For many places in Australia this series has the ISS gliding either through or under the Southern cross, depending on where you are, and coming close alpha Centauri or Alpha Crucis. Some of the passes are very short although bright as the ISS enters Earth's shadow, but it is interesting to see the ISS wink out abruptly. Several do not get very high above the horizon, but are interesting nonetheless.
As a further treat in many place the ISS passes very close to Saturn on either the 22nd (Tuesday) or 23rd (Wednesday). In Brisbane and Adelaide, the IS passes so close together that the ISS and Saturn may be (briefly, for less than a second) visible together in the filed of view of a widefield telescope eyepiece (25-30 mm)
When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky to get site specific predictions for your location (I'm using Brisbane, Adelaide and Perth as examples, for example, the view from Brisbane is radically different from that of Adelaide and Perth on the night of the 22nd). Even the difference between the city centre and the suburbs can mean the difference between seeing the ISS go very close to Saturn or above or below it.
Start looking several minutes before the pass is going to start to get yourself oriented and your eyes dark adapted. Be patient, on the night there may be slight differences in the time of the ISS appearing due to orbit changes not picked up by the predictions. The ISS will be moving reasonably fast when it passes near Saturn, so be alert to catch the fleeting moment when the pair are close..