Hoping to catch a glimpse of ATV Johannes Kepler in orbit? One good option for calculating when ATV will be visible from your location is NASA’s SkyWatch tool, via spaceflight.nasa.gov.
I just spoke with Rainer Kreskin, a flight dynamics at ESOC, ESA’s European Space Operations Centre, in Darmstadt, Germany. Rainer is also a keen amateur astronomer, and he explained that the NASA tool linked above is quite good. It is updated with ATV’s actual orbit; remember, Johannes Kepler is manoeuvring these days to ‘phase’ – or match – its orbit to that of the ISS so its orbit changes regularly. So SkyWatch provides a fairly accurate prediction of when you can see ATV based on your location -clouds and weather also have an effect! More details and a worked example after the jump (thanks, Rainer!).
Rainer explained an example of how to use/understand SkyWatch.
First, go to the base web address (http://spaceflight.nasa.gov/realdata/sightings/) and select your location, say, Germany, from the drop-down list.
Next, select the city/town nearest your actual location – say, Darmstadt.
Now, you’ll be at this page:
Which shows you this (scroll down for the ATV section below the ISS section):
THE FOLLOWING ATV2 SIGHTINGS ARE POSSIBLE FROM FRI FEB 18 TO THU FEB 24
|ATV2||Tue Feb 22/07:55 PM||< 1||17||17 above SW||17 above SW|
|ATV2||Wed Feb 23/07:59 PM||< 1||27||17 above WSW||27 above WSW|
|ATV2||Thu Feb 24/06:46 PM||4||35||15 above SSW||15 above E|
What this page tells you is that we have one reasonable opportunity to see ATV-2. On Tuesday, 22 Feb, ATV disappears into the Earth’s shadow too early to reach a useful elevation above the horizon. Basically, 17º is just too low to see it – also, it will be in the direction (from Darmstadt) of SW – towards the setting Sun. If its clear, it’ll be all but impossible to see.
Also, on Thursday, 24 Feb, ATV will have docked to the ISS at the time (18:46 CET) of an otherwise favourable pass (just watch the ISS). This leaves Wednesday, 23 Feb, at 19:59 CET as the only good viewing opportunity. First, you’ll see the ISS and four minutes later, the ATV will pass into view – just for a minute or so (note that the ISS reaches a significantly higher elevation due to its higher orbit).