The contrail shots were digiscoped using a Sony compact digital with a Swarovski scope @ 20X.
You wouldn't be far off that if you could get a decent result at 400mm with a 2x teleconverter 
Cheers.
Ahhh that's right, I remember now, you posted some stunning shots a while ago where you had used the telescope

Heres a few more of my shots from last weekend. I've been abit lazy and still havn't got around to editing them all. Sorry for the overload of pictures.
Detla's 767-400, seems to be a regular at Dublin Airport these days.

One of Delta's 2x daily 757's touching down.

Always nice to catch a Star Alliance livery, looks great on the MD80.

The only A330 to depart during the morning hours. All departed later in the day.

Having been in Dubrovnik a month earlier, it was nice to see this airline again.

With the tail winds quite high, several aircraft seemed to have difficulties touching down.

I've seen many photos of this bird but never caught it my self until now.

Always nice catching an airline you've not seen before.

Something for the Heli fans.

I thought this would have been a Lockheed Electra... turns out it was a completely different airline


Dublin seems to be blooming at the moment.

Remember this one from the Bombardier Centenary Celebrations?

Talk about luck! Lights, Smoke, Action!

All the way from Luxemburg

Definately looking forward to the next trip down to Dublin. We also had a great lunch at a restaurant located beside the Travelodge near by, which we always seem to end up when spotting at Dublin.
EDIT; to remove dead link