View Full Version : Now another silly question...

2003-Jun-16, 03:04 PM
Hope I'm not too bothersome. ;)

Anyway, the other night my fiancee and I were observing the nearly full moon. It was a little cloudy and humid that evening. I began to notice something strange: the moon looked just fine through our telescope, but when I'd start looking at it with just my eyes, I was seeing the moon in a weird sort of double-vision. The moon kinda looked like a Venn diagram, two overlapping circles.

I thought of three possibilities for the effect: either

a) The moon was reproducing asexually (just kidding);
b) It was a trick of the atmosphere (although my fiancee didn't seem to pick up on it at all);
c) It was a trick of my eyes (I have mild astigmatism and don't tend to wear my glasses often).

I'm leaning toward the third possibility, but I was just curious if anyone else had ever experienced anything like it. Thanks! :)

2003-Jun-16, 03:36 PM
First of all, welcome to the BABB. Secondly, I would lean toward your third explanation as well, since I've never experienced this phenomena, and your finance didn't either. :)

And there are no really "bothersome" astronomy questions around here. :wink:

2003-Jun-16, 04:48 PM
I agree with Gethen; I can't think of any atmospheric or astronomical basis for what you described. Since your fiancee saw nothing unusual, looks like your eyes were having a bit of fun with you!

Welcome to the board.

Pi Man
2003-Jun-16, 04:52 PM
And there are no really "bothersome" astronomy questions around here. :wink:

Except maybe "What's astronomy?" :lol:

2003-Jun-16, 05:07 PM
A telescope is generally monocular so there is no chance of double-vision as there would be in the event you looked at Luna out of focus. Because Luna is so bright at Full Moon, it's easy to have troubles focusing on it properly so you get double-vision.

2003-Jun-16, 06:50 PM
I've had trouble focusing my eyes after looking through binoculars for a long time. It gives exactly that double-vision effect. But then, they were some pretty bad binoculars!

2003-Jun-16, 10:47 PM
Temporary double vision can be caused by simple eyestrain.

If you have constant double vision, you should read this and then see an opthamologist.

Warning, scholarly doctor-type article chock-full of appalling things that could be wrong with your eyes--not for hypochondriacs... :eek: :D


2003-Jun-16, 11:26 PM
Welcome aboard Miusheri:

I have bad astig and can tell you that it is very possible to have the overlapping effect from a bright object as you describe. I get the same effect looking at street lights, headlights, etc. when I don't wear my glases or contacts. I did not know the cause of this until I asked my opthamologist about it and he duplicated the effect for me in his office.

Congratulations on your impending nuputuals. :D