UFO STS-128, EVA-2 Original and Slow Motion

Very interesting video!

Has anyone offered any explanation as to what the lighted doughnut might represent?

It seems like it might be somewhat out of focus as to the main subjects being photographed....

Thanks for including this!

Hi Rick,

I see those a lot of NASA videos and to me they look out of focus too.

It remind me of looking through a telescope, when the star in question is not sharp, like this example:

http://www.astronomyforum.net/520250-post1.html

The black smaller circle is actually the front of the telescope (Schmidt-Cassegrain telescope (SCT)), with the white area the actual light source you are looking at. The smaller the white circle gets, the closer you are to getting the object in focus.

http://photon-surfing.blogspot.com/2009/10/sct-collimation-tool-collimation-helper.html

As for what they are, well that's a different story.......

Hi Astro!

Thanks for your reply!

Ahh, yes, now I remember those "doughnuts"!

Schmidt-Cassegrain telescope (SCT), also known as a "mirror lens" I believe, were somewhat popular back in the 70's as a compact, long focus lens. I remember not being particularly fond of the out of focus doughnuts compared to the geometric shapes that were common in all-glass, non-mirror lenses.

But I guess where I'm baffled is (I can easily do this to myself!), does/did NASA use (ever) Schmidt-Cassegrain lenses in the shuttle program? I don't remember that type of lens in much favor in a zoom lens design? Sure haven't seen that lens in any photographs of shuttle equipment. Seems like it really never was ultimately used for any other application then fixed focal length telescopes?

SO, taking a leap here, if we are seeing images that ARE NOT taken with a Schmidt-Cassegrain lens, what then explains the "doughnut" shapes? Schmidt-Cassegrain was the ONLY lens to leave that characteristic in out of focus detail.

Hmm, point ponder....

Have a wonderful day, Rick :-)