2024-05-28, 12:11 PM
I have no experience but read this on Lumicon's site:
"As filter bandpass decreases, optimum exit pupil size tends to increase. To determine the best eyepiece focal length to use with a given filter, simply multiply the Exit Pupil value shown above by your telescope's focal ratio. For example, if you are using the Lumicon H-Beta filter at a dark site and your telescope has an f/6 focal ratio, the best range of eyepiece focal lengths to use with this filter is [(4 to 7) x 6] = 24 mm to 42 mm."
chart in the middle of this page
https://www.lumiconinc.com/uses
I guess this would come into play with people with smaller telescopes trying to push high magnification with an H-Beta filter or something like that. they are recommending it's not optimal...maybe it gets too dim?
"As filter bandpass decreases, optimum exit pupil size tends to increase. To determine the best eyepiece focal length to use with a given filter, simply multiply the Exit Pupil value shown above by your telescope's focal ratio. For example, if you are using the Lumicon H-Beta filter at a dark site and your telescope has an f/6 focal ratio, the best range of eyepiece focal lengths to use with this filter is [(4 to 7) x 6] = 24 mm to 42 mm."
chart in the middle of this page
https://www.lumiconinc.com/uses
I guess this would come into play with people with smaller telescopes trying to push high magnification with an H-Beta filter or something like that. they are recommending it's not optimal...maybe it gets too dim?