Excel - A useful tool for choosing eyepieces

[Moonshane]

Hi all

I was thinking about eyepieces for a change at work this lunchtime and I have a spreadsheet which creates calculations for field of view, magnification and exit pupils for the scopes/eyepieces I have and the possible future purchase and 'the competition' focal lengths.

The figures themselves are of course useful but I got to thinking about a more visual representation of the field of view in particular.

Therefore based on the FOV figures my spreadsheet calculated, I created a series of circles, resized to match the sizes of the FOV for each eyepiece I have and am considering and this allowed me to see clearly which give a more 'natural' progression.

I then made the circles for the 'best' options bold and this is what is attached with labels.

Based on this I should consider :

35mm Panoptic (got this)

26mm Nagler (one on the way)

20mm Nagler (borrowed one)

13mm Ethos (got one)

10mm Ethos (want one! but might have to 'settle' for a 10mm Radian first for a while!)

8mm Radian (got one - not sure I can justify an 8mm Ethos too)

6-3mm Nagler zoom(got one)

So I am not too far from my 'perfect' set up with well spread eyepieces and a couple of wonderful dobs. I know how lucky I am too - it was not long ago that we had literally no money for luxuries and I'm making the most of this period when we do!

I thought this idea might help others in their own decision.

Cheers

Shane

lenses_2.pdf

[Nick P]

I use the FOV pane in starry night pro to do exactly the same thing I find it absolutely indispensable for eyepiece selection when plotting views and what can fit in the viewing field.

Did you try using the pie chart function btw? I think there's one that plots concentric circles to scale

[Moonshane]

cheers Nick

I'll try the pie chart function I bet that will be even better!

[starman345]

Thanks for this Shane, I have only the 13 mm Ethos and a meade 18mm, at some point very soon I"m going to have to get a low power eyepiece and probably a couple more to fill the gaps. Your chart helps me see how big those gaps are right now.