Manufacturer

Astrophotographers
Astro-Physics Robert Gendler
Santa Barbara Instruments Group Johannes Schedler
Carl Zeiss Germany Daniel Verschatse
  Ray Gralak

Dealer

 Loke Kun Tan
Baader-Planetarium (German) Chris Hetlage
Fernrohrland (German) Steven Juchnowski
  John P. Gleason

Discussion-Groups

 Capella-Observatory
Yahoo: AP-UG Gerald Rehmann (German)
Yahoo: AP-GTO Thierry Legault
Yahoo: SBIG Ed Grafton
  Dietmar Hager
   

Miscellaneous

Sources
Spaceweather Astronomy Picture Of The Day
Heavens Above SOHO
Astromart Ron Wodawski: CCD Calculator
Excelsis - Astronomy AstroInfo (German)
Cloudy Nights Astro Corner (German)
Scope Rewiews ESO Online Digitized Sky Survey
Sternwarte Welzheim (German) Ephemeris Generator
Sternwarte Höfingen (German) Aladin sky atlas
   

Software

Weather
Giotto (German) Astrowetter (German)
AstroArt (MSB Software) Wetterspiegel (German)
  wetter.com (German)

Search Engines

 Wetter24 (German)
Google Wetterzentrale (German)
  WetterOnline (German)