stellarium ocular plug-in. help!

[bmc]

has anyone used the Stellarium ocular plugin? if so, did you input your 'field stop' value for your EP's ? and/or is it necessary ?

i researched my EP's field stop values, and i got the following:

GSO super Plossl  (aFOV - 52 degrees )

12mm - 0.420

15mm - 0.495

20mm - 0.671

sky watcher

32mm - 1.055  (aFOV - 50 degrees)

but when i entered these values into stellarium, the visuals i got were mental. either i have the Hubble strapped to my mount, or stellarium thinks i have.

when i left the value as zero, the visual i got was more realistic. 

any advice would be grateful.

thanks

[bingevader]

You have to add the field stop in mm.

So for my ES 82^o 18mm, I  put the field stop in as 25.3.

Using the field stop allows a more accurate measure for the true field of view.

Cheers

[bmc]

so are the values i have in cm?

therefore times them by 100?

[bambuko]

I didn't put the field stop values (left as 0) and it works fine?

[bmc]

that's what i've done. left them at zero.

but the puritan ocd in me is screaming in my ear to do it right!

[bambuko]

google is your friend   oculars plugin wiki

btw - I don't think it was a good idea to start the same topic in two different places on the forum

[Dude_with_the_tube]

as above,i left them on 0 and works fine.

[bingevader]

Looking at your numbers, I don't think they're values for the field stop of your EPs, they look more like the (approximate) true field of view in degrees.

My 11mm plossl has an apparent FOV of 50^o, a field stop of 9.1mm and a true field of view of 0.43^o.

As the others has said, probably easier to just enter 0! 

Cheers

[astronymonkey]

These dont look like field stop sizes, id have another go of finding out what they are.

cheers

[AlexB67]

has anyone used the Stellarium ocular plugin? if so, did you input your 'field stop' value for your EP's ? and/or is it necessary ?

i researched my EP's field stop values, and i got the following:

GSO super Plossl  (aFOV - 52 degrees )

12mm - 0.420

15mm - 0.495

20mm - 0.671

sky watcher

32mm - 1.055  (aFOV - 50 degrees)

but when i entered these values into stellarium, the visuals i got were mental. either i have the Hubble strapped to my mount, or stellarium thinks i have.

when i left the value as zero, the visual i got was more realistic. 

any advice would be grateful.

thanks

Looks like you are using the wrong data, as Astromonkey said. Field stops are not expressed in number < 1 as in you examples, but multiples of mm. Typically the field stop is a bit larger than the focal length, and for wider FOV eyepieces  the values get bigger still above that value.  Ideally, always use the field stop values where available, it will give a better estimate of the resulting eyepiece FOV.  I use the field stop in the ocular plugin for eyepieces where I know them, it works fine against my own calculations where I get the same values.  If you fill in the field stop value field in stellarium plugin with a non zero value,  it will use that value and use the field stop formula. If left at zero it will ignore that field and simply calculate the FOV using the focal length of the eyepiece  and telescope, and apparent FOV you specify for the eyepiece ( the latter being a less accurate approach).

[AlexB67]

Forgot to add, since I do not know the eyepieces you have.  If for your eyepieces happen to find field stop values less than the focal length, sure this is possible, but it is quite rare, perhaps some orthos  come to mind , eyepieces with an apparent FOV of less than 45 degrees or so.