With a bit of luck and clear skies on the night of 5/6 June, backyard astronomers in W. Europe have a pretty good chance to spot ATV-4 during the vessel’s second orbital pass after lift off.
Launch is set for 23:52 CEST, and shortly afterwards ATV will pass high over the UK, the low countries and northern Germany on its first orbit (still attached to the Ariane EPS upper stage – this will happen before final separation).
This pass will not be visible, however, due to the lack of illumination (ATV will be there, it’ll just be in shadow so not visible).
However, during the next orbital pass (after separation from the EPS), between about 01:46 and 01:49 CEST, ATV will be nicely illuminated by the Sun and should be quite visible, given clear skies.
Observers located 1000 km from the ground track would see ATV just 10° above the horizon, 500 km from the ground track it will be 25° and within 250 km, ATV rises higher that 45° and should be quite visible to the naked eye.
Obviously, if you are located north of the ground track, you would see ATV somewhat to the south, and if you are south of the track, expect ATV to pass across the northern sky.
Sky chart and more info after the jump…
The sky map below shows how ATV will move across the sky as seen from Darmstadt, Germany.
At 01:47CEST, it passes the Big Dipper; half a minute later it flies 3° above Polaris and at 01:48CEST it moves high over Cassiopeia – all objects that are easy to spot in the sky (if there are no clouds).
The next orbit, at 03:20 CEST, is also visible – but we’re guessing most folks will be in bed at that time…
And if we have clouds on the evening of 5/6 June, don’t worry: there will be additional passes on 6/7 June. On the next evening, shortly after midnight, there will be a nice pass and the ground track is shown below.
Of course, more passes after 6/7 June until docking will be visible, but we can wait until we get the actual launch / orbit injection results to provide further predictions (ATV’s actual orbit may vary somewhat from that planned due to slight launcher over/under performance, etc.).
You’ll also be able to track ATV’s orbit via Heavens-Above.com and – of course – right here in the blog.