My Eyepiece Collection

[Don Pensack]

2 hours ago, Louis D said:

I always go by lowest power (25x to 40x), mid power (65x to 90x), and highest power (150x to 220x) and then do the math for the particular telescope to figure out what eyepieces make sense.  Certainly, there is plenty of room to fill in the blanks at the higher end of the power range when poking at the limits of seeing.

That works fairly well for 3-5" apertures, though the range is a bit low for larger ones.

If you tailor it to magnification per inch of aperture, you adjust for aperture, say:

4-10x/inch--low power

10-20x/inch--medium power

20-30x/inch--high power

>30x/inch--ultra high power

For a 4" refractor, that would be 16-40x, 40-80x, 80-120x, and 120-240x and beyond, so right in line with your magnifications.  You did leave out a very useful range, though.

For my 12.5" reflector, it's 50-125x, 125-250x, 250-375x, and 375-750x, and that pretty much works for me at my observing sites.