Exit Pupil Comfort Level

As we move up in magnification and down in exit pupil, floaters in our eye become more and more annoying. For lunar and planetary viewing, I find my "comfort" levels ends at around 1.0 to 0.8 mm. If the exit pupil is much smaller than 0.8 mm, the floaters are just too bothersome.

What do you find?

Clear skies, Alan

I agree, Alan, I find an exit pupil of .8 or so to be about as small as I can go without those bothersome little fellows showing up. Based on Todd Gross's findings I did switch to a binoviewer for all my higher magnification planetary work and bingo--no more floaters. That was really a pleasant discovery!
Larry Seguin
Taos, New Mexico

Alan,

I find I can go down to about .4-.5mm before floaters begin to really annoy me. It may be that I am simply tolerant to them, because I do notice them at exit pupils around .7-.8. I am 56 years old.

At 56 I'm like Randy. I notice them at .7 or .8 but they don't become really annoying until about .4. The binoviewer approach does work.
Also, as someone recently stated in another thread, floaters tend to settle to the bottom of your eye if you keep your head still and don't make quick movements. I find that if I sit down and keep my head as close to upright as possible for a little bit, the floaters tend to settle toward the bottom of my field of vision. As long as I don't move my head quickly or look straight down, they tend to stay in the lower 1/3 or more of my field of vision. It helps keep them out of my primary field of vision.
Clear Skies, Bill

Alan French said:

As we move up in magnification and down in exit pupil, floaters in our eye become more and more annoying. For lunar and planetary viewing, I find my "comfort" levels ends at around 1.0 to 0.8 mm. If the exit pupil is much smaller than 0.8 mm, the floaters are just too bothersome.

What do you find?

Clear skies, Alan

Floaters are mainly a lunar observation problem with me. I only go down to around 1.0mm exit pupil on deep sky, and then only rarely. My favorite deep sky exit pupil is between 1.5mm to 3.0mm. Floaters are not an issue then. Luna filling the EP gives floaters nowhere to run. Then I use a binoviewer and an exit pupil well below 1.0mm, usually 0.7mm to 0.3mm.

Same here. I generally consider a 1.0mm exit pupil to be my limit. My 59 year old eyes see them above that, but they only become really bothersome at or below 1.0mm.

I guess I'm going to have to do the binoviewer thing if this keeps up.

Jim in Texas

>>>What do you find?

Clear skies, Alan
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Alan:

As I have grown older, floaters have become a problem for me. Not only do I see them at small exit pupils but of course once I started seeing them, I notice them when driving and even just working at the computer.

For lunar and planetary, my experience is similar to yours, I am happy with my 80mm at 125x which is an 0.64mm exit pupil but in most larger scopes I prefer closer to 1 mm.

At low magnifications, my astigmatism shows up as spikes so an eyepiece which produces a 7mm exit pupil will be rough and nasty no matter how good the it might be. I think 5mm exit pupils are nice for low power viewing.

And I do calculate the exit pupil, it is a good guide as to what to expect, not only when dealing with floaters and astigmatism but other factors like background darkness, central obstuction effects during the day. When moving from one scope to another of different size, it is a good way to compare views.

One example would be the background sky darkness from my light polluted back yard. 80x in a 4 inch scope is a 1.25 mm exit pupil and the sky wil look quite dark and contrasty. 80x in a 10 incher from my backyard and while targets may be bright, the background sky is an ugly gray and indeed one might suspect the scope.

But crank the power up to 240x and that same 1.25 mm exit pupil and suddenly the background is quite black and the view quite attractive. It is not the scope, just the conditions.

jon