SkyWatch NASA

SkyWatch NASA

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:
http://spaceflight.nasa.gov/realdata/sightings/cities/view.cgi?country=Germany&region=None&city=Darmstadt

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

SATELLITE LOCAL DURATION MAX ELEV APPROACH DEPARTURE
DATE/TIME (MIN) (DEG) (DEG-DIR) (DEG-DIR)
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

Rainer says:

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).

Thanks Rainer!