Field of view

[Darron]

Just a quick question, what is the field of view in a 6 x 30 finderscope?

Darron

[FLO]

This is a tricky one to answer as it depends on the eyepiece fitted to the finderscope. Quality finder scopes - such as those supplied by Tal and other Russian manufacturers - use 4-element plossls; simpler three element types are also common.

Generally, you can reckon on around 7 degrees from a 6x30 finder.

To test a finderscope, time how long it takes a star (along the celestial equator) to cross its field. The sky moves 360 deg in 24 hr, or 15 deg an hour, you can work it from there.

Hope that helps

[Darron]

Cheers Steve

Darron

[moondog]

Darron

My TAL 6x30 finder has an 8 degree FOV.

MD

[Darron]

Thanks Moondog

Darron