Exposure data
Telescopes: 4.5" Newton f=440mm + Vixen R200SS (8" Newton f=800mm)
Camera: SBIG ST2000XM
Filters: SBIG LRGB
Exposure times: L:30x3min+12x5min R:8x3min+2x5min G:8x3min+2x5min B:10x2min
Exposure time total: 3h 58min
Mount: Vixen New Atlux
Location: Erdweg/Germany (500m)
Date: 2005-07-04 + 2010-07-02
Object data of M 20
Object type: Emission and reflection nebula
Size: 28'
Magnitude: 6.3 mag
Constellation: Sagittarius
Distance: 5200 Ly
Object data of M 21
Object type: Open cluster (l 3 m)
Size: 13'
Magnitude: 6.5 mag
Constellation: Sagittarius
Distance: 4250 Ly
