arc minutes ed80 and atik 414ex help

[iwols]

hi all been trying to find  the following

1.......20 percent of my narrowest fov in arc miuntues

2......my largest fov in arc minutes

cheers guys

 

[ronin]

The info I have on the 414EX is that the chip is 9x6.7mm, so 6.7 is the limit.

The ED80 appears to have a 600mm focal length so the Fov is: Ang = tan-1 (6.7/600) (cannot see a superscript option ??)

So that is max FoV=  tan-1 (0.0111666) = 0.63977 deg = 38.38 arc min.

Slight approximation taken in the calc's. So assume a nice round 38 arc min.

Have to be honest do not understand the first question.

[iwols]

Thank s for that im downloading some files for plate solving in sg pro and They are two options i néed to fill in cheers

 

 

 

 

[daz]

From http://astronomy.tools/calculators/field_of_view/ .....

0.86 deg x 0.64 deg

So 0.86 multiplied by 60 (convert degrees to minutes) gives 51.6 arc minutes - your LARGEST field of view

0.64 x 60 (convert degrees to minutes) gives 38.4 arc minutes - now take 20% of that gives 7.768 arc minutes

 

So, when you download the index files (which is what I am assuming you are doing) select the files that are closest but SMALLER than 7.68 and closest but LARGER than 51.6

This will ensure you have the index files that will cover your field of view

 

You answered while I typed - in that case you just need the 51.6 and 7.7 values for SGPro

 

[iwols]

cheers daz ,appreciated