Basic FOV question

[Catweazel]

Hi, I have a basic question about FOV if anyone can help:

I just got my first scope and before that I had only 15x70 bins. The bins have a 4.4 degree FOV. The scope is f8.33, so by my calculation, with a 25mm plossl the FOV is 1.5 degrees (roughly one third that of the bins) and with a 10mm Plossl FOV is 0.52 (ish) about 12% of bins. Does this sound right

Sorry of this is a dumb question, but I just wanted to get clarification as to what I'm seeing, in order to get perspective when searching the skies.

Cheers

CW

[Chris H]

25mm plossl will give you 1.25 degrees and you're correct about the 10mm. Try this calculator Telescope Field Of View And Power Calculator

Or to calculate it yourself divide the apparent filed of view of the ep by the magnification that ep produces in your scope. For a 25mm Plossl with a 50 degree field of view in a 1000mm focal length scope = 1000 / 25 = 40

50 degrees / 40 = 1.25 degree actual field of view.

[Catweazel]

Thanks Chris, this certainly makes getting around the skies easier to understand. I was swinging the scope around like a pair of bins, wondering why I couldn't pick things out too easily