Note that there are three ICE destinations in Hamburg: Hamburg main station, Hamburg Altona and Hamburg Dammtor. You will be able to reach DESY with public transport by any of these stations in a reasonable time. However, closest stop to the DESY campus is Hamburg Altona.
Update: The meeting will take place in seminar room 204, building 49a. You can find this in section C1 on the campus map. You may enter DESY at the main gate (via Notkestr.) or - actually closer to the seminar room - at the side gate (via Luruper Chaussee). Registration of visitors is not necessary at DESY. If you need help to find your way, our colleagues at the gate will be there for you.
Accomodation: If you stay over night and did not make a reservation at the DESY hostel, we recommend one of the following hotels - without any special offers, however. Of course, there are much more hotels in Hamburg.
Mercure Hotel Hamburg am Volkspark
Albert-Einstein-Ring 2
22761 Hamburg
Phone: +49 40 899 52 0
E-Mail: h1659@accor.com
www.mercurehotel.de
Sylc. Apartmenthotel
Kronsaalsweg 88
22525 Hamburg
Phone: +49 40 537 513 3700
www.sylc.de
B&B Hotel Hamburg-Altona
Stresemannstr. 318
22761 Hamburg
Phone: +49 40 851 806 0
www.hotelbb.de/de/hamburg-altona
NH Hamburg-Altona
Stresemannstr. 363-369
22761 Hamburg
Phone: +49 40 421 060 0
Res.: +49 30 223 805 41
E-Mail: nhhamburgaltona@nh-hotels.com
http://www.nh.de/nh-hamburg-altona
Superbude Altona
Paul-Dessau-Str. 2
22761 Hamburg
Phone: +49 40 855 070
E-Mail: altona@superbude.com
www.superbude.com
InterCity Hotel Altona
Paul-Nevermann-Platz 17
22765 Hamburg
Phone: +49 40 380 340
www.intercityhotel.com