For each my optics- scopes and SLR Photolenses - I have determined the Field-of-View.
I used my FOV measuring method to find out the real Field-of-View per optics in combination with my cameras and made the following table.
Please note that I made this table for my own use and it might not be applicable for your setup, so I strongly recommend that you make your own table !

I use the table to select the appropriate optics for a celestial object, depending on the size of that object.
Note: meanwhile I have made a similar table based on my Canon EOS 1000D DSLR Digital Camera

Meade Bresser Skylux 70mm f/10 Telescope [Lidl]
Meade LX200 10" f/10 Telescope
SLR Photolenses
William Optics Zenithstar 80 ED II APO
Focal Length Width in arc minutes
with SC3 and/or ATK16IC camera
Height in arc minutes
with SC3 and/or ATK16IC camera
ToUcam lens5.8mm28072105
TV Zoom lens at 10mm10mm13571017
TV Zoom lens at 40mm40mm441331
SLR Photolens 29mm
Note for myself: use 7mm extension ring (T2<->M42) to reach focus with filterwheel/ATK16IC combo.
29mm542407
SLR Photolens 35mm35mm465349
SLR Photolens 50 mm50mm313234
SLR Photolens 35mm with 2x teleconverter70mm232174
SLR Photolens 85 mm85mm193.85145.37
SLR Photolens 135mm135mm125.4894.11
SLR Photolens 200 mm (SOLD)200mm83.4962.62
ATK16IC camera + WO Zenithstar 80ED with Meade 3.3 FR240mm67.8450.88
William Optics Zenithstar 80ED II APO with Mogg 0.6 FR245mm66.4549.84
SLR Photolens 135mm with 2x teleconverter270mm6649
SLR Photolens 300 mm (SOLD)300mm57.1342.85
William Optics Zenithstar 80ED II APO with Meade 3.3 FR290mm56.1442.11
Coronado PST with Trust WB-5400 webcam400mm46.236.96
SLR Photolens 400 mm (SOLD)400mm40.730.5
Meade Skylux 70mm f/10 'Lidl scope' with 0.6 Focal Reducer435mm37.4328.07
William Optics Zenithstar 80ED II APO Prime Focus545mm29.8722.41
TAL-2M with Focal Reducer (SOLD)690mm22.5516.91
Meade Skylux 70mm f/10 'Lidl scope'700mm23.2617.44
LX200 10" f/10 with f/3.3 Focal Reducer
SC3 camera in combination with Scope Teknix Filter Wheel
912mm17.8513.39
LX200 10" f/10 with f/3.3 Focal Reducer
SC3 camera mounted with custom made M42 ring
and extra spacer ring
1015mm16.0412.03
LX200 10" f/10 with f/3.3 Focal Reducer
SC3 camera mounted via 1,25" eye piece adapter
1030mm15.8111.86
LX200 10" f/10 with f/3.3 Focal Reducer
SC3 camera mounted via 1,25" eye piece adapter and Astronomik H-Alpha filter
1140mm14.2810.71
LX200 10" f/10 with f/3.3 Focal Reducer
ATK16IC camera in combination with Scope Teknix Filter Wheel
1270mm12.829.61
LX200 10" f/10 with f/3.3 Focal Reducer
SC3 camera mounted with custom made M42 ring
(distance between optics and CCD too small)
1420mm11.478.60
TAL-2M Prime Focus (SOLD)1200mm13.5710.18
TAL-2M 2x Barlow (SOLD)2400mm6.785.9
LX200 10" f/10 2500mm6.414.88
LX200 10" f/10 with Trust WB-5400 in 1280x1024 pixels frame format2500mm7.395.91
TAL-2M 3x Barlow (SOLD)3600mm4.523.39

Field-of-View with Canon EOS 1000D DSLR
[Tested values: verified on the stars]

Optics Focal Length Width in arc minutes
with Canon EOS 1000D DSLR camera
Height in arc minutes
with Canon EOS 1000D DSLR camera
William Optics Zenithstar 80 ED II APO with William Optics 0.8 Focal Reducer Type III435mm175116
William Optics Zenithstar 80 ED II APO in 'Prime Focus'545mm14093