help

[TJD]

:help:i would like to find the field of view of my 9-50 finder scope i dont know anything else about it


i would also nlike to know how to work out the apparent field of view of my eyepieces i dont know anything about them to.


please help me:D:help:

[jkrah]

Do your eyepieces (EPs) have nothing written on then ?
.. otherwise this might help..

If you know your EP Field of View (FOV) and EP Focal length (FL)
and you know the scopes Focal length .. then I think..

Magnification = Scope FL / EP FL
Apparent FOV = EP FOV / Magnification

[alexch]

Hi Trevor,

You could check with the well known stars. The angular distance between Alpha and Gamma Crucis is 5 deg 45 min, Alpha and Beta Centauri are 4 deg 8 min apart. I measured the angular distance in Stellarium computer program.

If I remember correctly I could just get the Alpha and Gamma Crucis in the field of view of 9/50 Skywatcher finder.

With the eyepieces it is easier to claculate the FOV, I find this online calculator quite useful:
http://www.davidpaulgreen.com/tec.html

Cheers,
Alex

[bmitchell82]

your 9x50 is 5 deg fov. as for your sw ep's they are generally 52 deg afov

[PaulM]

Hi Trevor,
A few years ago I wrote a short article about figuring out the field of view. See here (http://tinyurl.com/ylmulh).

Cheers,
Paul.

[TJD]

i can see what bmitchell is saying as the ep's that can with my new dob were 52':D thanks for the finder fov

[TJD]

thanks my ep's are 52' and i think the finder is 300 arc mins thanks