Floaters and telescope used for viewing
Howard Lester
floaters to sink to the bottom of the eyeball, clearing the view. This can
only? be accomplished using newtonians. With refractors and SCT's that use
star diagonals, one has to look down, keeping floaters in view. Comments?
Howard Lester
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Stephen Paul
news:3e136...@corp.newsgroups.com...
> It occurred to me that looking "horizontally" through an eyepiece allows
eye
> floaters to sink to the bottom of the eyeball, clearing the view. This can
> only? be accomplished using newtonians. With refractors and SCT's that use
> star diagonals, one has to look down, keeping floaters in view. Comments?
>
> Howard Lester
Simply turn the diagonal.
Stephen Paul
James Cook
eye
> floaters to sink to the bottom of the eyeball, clearing the view. This can
> only? be accomplished using newtonians. With refractors and SCT's that use
> star diagonals, one has to look down, keeping floaters in view. Comments?
>
My experience of viewing the moon with a newt during last years (2002)
perseids didn't bear this out. The whole sky was still fairly bright when I
started observing and with a very bright image in the eyepiece the floaters
remained very obvious. I guess you would have to keep the eyeball
unnaturally still for a very prolonged period to see any noticeable
difference.
Richard G Amirault
: It occurred to me that looking "horizontally" through an eyepiece allows eye
: floaters to sink to the bottom of the eyeball, clearing the view. This can
: only? be accomplished using newtonians. With refractors and SCT's that use
: star diagonals, one has to look down, keeping floaters in view. Comments?
My floaters "float". I've never seen them sink. But then I've got worse
problems to deal with when viewing :-(
Richard in Boston, MA, USA
Howard Lester
"Richard G Amirault" wrote
>
> My floaters "float". I've never seen them sink. But then I've got worse
> problems to deal with when viewing :-(
They do float, but if you just keep looking ahead, not moving the eye much,
you will see them sink toward the bottom. If I look at the daytime sky, they
are seen at their worst, of course, and you will at first see them rapidly
ascend.. then slow... then sink.
Stephen Paul's idea of rotating a refractor's diagonal will work, yes, if
the tripod is extended high enough.
William Hamblen
<heyl...@dakotacom.net> wrote:
>It occurred to me that looking "horizontally" through an eyepiece allows eye
>floaters to sink to the bottom of the eyeball, clearing the view. This can
>only? be accomplished using newtonians. With refractors and SCT's that use
>star diagonals, one has to look down, keeping floaters in view. Comments?
You always can turn that diagonal to the side.
Chris L Peterson
wrote:
>It occurred to me that looking "horizontally" through an eyepiece allows eye
>floaters to sink to the bottom of the eyeball, clearing the view. This can
>only? be accomplished using newtonians. With refractors and SCT's that use
>star diagonals, one has to look down, keeping floaters in view. Comments?
Floaters don't really sink. They are trapped in vitreous, which does not allow
much free movement. Over any reasonable time span, their movement will be quite
small, less than a mm. So if you actually have one right in the center of your
FOV, you can tip your head and it will move slightly, possibly enough to help
with viewing. Of course, it is just as likely that one which is slightly out of
your central FOV will float into it.
If gravity actually drove floaters to the bottom of the eye in a short time,
many of us would have a lot fewer problems with them.
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
Etok
eye
> floaters to sink to the bottom of the eyeball, clearing the view. This can
> only? be accomplished using newtonians. With refractors and SCT's that use
> star diagonals, one has to look down, keeping floaters in view. Comments?
>
> Howard Lester
I have an astronomer's centrifuge set up in the back yard.
It's a 3 phase 10hp electric motor driving a truck differential with the
axle oriented vertically.
On the upper hub, I've affixed a playground swing to one point, and
opposite, a 185 pound counterweight on a chain.
I get into the swing, and the wife operates the variable frequency drive to
spin me up. After about 5 minutes at 5-6 g's, she lets it coast down and
all my floaters have disappeared. This effect seems to last about 1-2 days,
longer in the winter, for some reason, shorter in the summer.
About the only adverse effect we've noticed is my shoe size has increased
from a 10 to a 12.
A happy and prosperous new year to you all at SAA!
Etok
______________________________________________________________________
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Lunar-Observing
Maybe we can get Meade or Celestron to market these for those unable to
build their own!
--
Chuck Taylor
Do you observe the moon?
Check out the Lunar-Observing Group at
http://groups.yahoo.com/group/lunar-observing/
Home of the Lunar-Feature-of-the-Month,
and in-depth preparation for your observing.
"Etok" <hell...@bogusnet.net> wrote in message
news:3e1395f1$1...@news3.uncensored-news.com...
Rich N.
Howard Lester wrote in message <3e136...@corp.newsgroups.com>...
>It occurred to me that looking "horizontally" through an eyepiece allows
eye
>floaters to sink to the bottom of the eyeball, clearing the view. This can
>only? be accomplished using newtonians. With refractors and SCT's that use
>star diagonals, one has to look down, keeping floaters in view. Comments?
>
>Howard Lester
I find tilting my head back and looking up for a few seconds
repositions my floaters for a little while.
Using a binoviewier makes a big difference for me. I don't
notice my floaters nearly as much when using a binoviewer.
Rich
Jan Owen
Definitely the hardest, longest laugh of the week!!!
"Etok" <hell...@bogusnet.net> wrote in message
news:3e1395f1$1...@news3.uncensored-news.com...
>
Curtis Croulet
--
Curtis Croulet
Temecula, California
33° 27' 59"N, 117° 05' 53"W
Howard Lester
"Curtis Croulet" wrote
> I have floaters and I've seen no difference with any type of scope.
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Paul Kammueller
> floaters to sink to the bottom of the eyeball, clearing the view. This can
> only? be accomplished using newtonians. With refractors and SCT's that use
> star diagonals, one has to look down, keeping floaters in view. Comments?
To me the only thing that has made a difference is sheer aperture. It
seems to me like floaters 'disappear' as the size of the scope
increases. Floaters seem to be very obtrusive to me at 3 inches or
less but not noticeable at 10 inches. I wonder if it has to do with
the size of the exit pupil relative to the size of the floaters.
Robert Pollard
I've got floaters in my right eye and they definitely do sink out of
view if I keep my eye fairly steady. The actual sinking for me occurs
quite slowly, whereas eye movement tends to move them around quite
rapidly.
>Floaters don't really sink. They are trapped in vitreous, which does not allow
>much free movement. Over any reasonable time span, their movement will be quite
>small, less than a mm. So if you actually have one right in the center of your
>FOV, you can tip your head and it will move slightly, possibly enough to help
>with viewing. Of course, it is just as likely that one which is slightly out of
>your central FOV will float into it.
>
>If gravity actually drove floaters to the bottom of the eye in a short time,
>many of us would have a lot fewer problems with them.
>
>_________________________________________________
>
>Chris L Peterson
>Cloudbait Observatory
>http://www.cloudbait.com
--
Robert Pollard
Jan Owen
eventually, intrusive.
"Paul Kammueller" <pkamm...@usfamily.net> wrote in message
news:364c0c2e.03010...@posting.google.com...
Coppy Littlehouse
Chris L Peterson
wrote:
>Hi,
> I've got floaters in my right eye and they definitely do sink out of
>view if I keep my eye fairly steady. The actual sinking for me occurs
>quite slowly, whereas eye movement tends to move them around quite
>rapidly.
Vitreous is strange stuff. I used to make surgical instruments for cutting it-
you can't just suck it up like a liquid. It is really a protein matrix. Floaters
can freely drift around in a very small volume- probably a few tenths of a
millimeter on a side. That is more than enough to allow their shadows to move
off your fovea, and of course, gravity will tend to move them downwards. Bear in
mind, however, that downward drift induced by gravity will cause the floaters to
appear to move upward in your view. If you are actually seeing them drift
downwards, you are seeing the effects of buoyancy (also a gravity effect, of
course.)
I have lots of floaters, and when I hold my eye very still, I see some drift up
and some drift down. They don't go very far, but it is not easy to detect them
once they are off the fovea, unless they move. I find that holding my eye very
still is just as likely to allow a floater to drift into my field as it is to
allow one to leave it. And as you note, if you move your eye at all everything
gets mixed back up (even normal, saccadic movements do this, and they are nearly
impossible to control. Just looking around the field in an EP will have far more
effect on floaters than gravity.)
Wayne Hoffman
Kammueller) wrote:
>To me the only thing that has made a difference is sheer aperture.
<snip>
>I wonder if it has to do with the size of the exit pupil relative to the size of the floaters.
Bingo! And to *really* see how the exit pupil affects the visibility
of floaters, try a short F/L eyepiece (high power) to get the exit
pupil down below 1mm.
Wayne Hoffman
http://home.pacbell.net/w6wlr/
33° 49' 17" N, 117° 56' 40" W
"Don't Look Down"
Bill Becker
Best regards,
Bill
"Howard Lester" <heyl...@dakotacom.net> wrote in message
news:3e136...@corp.newsgroups.com...
William Hamblen
Kammueller) wrote:
>To me the only thing that has made a difference is sheer aperture. It
>seems to me like floaters 'disappear' as the size of the scope
>increases. Floaters seem to be very obtrusive to me at 3 inches or
>less but not noticeable at 10 inches. I wonder if it has to do with
>the size of the exit pupil relative to the size of the floaters.
That's it. The narrower the beam of light entering your eye the
easier it is to see the structures inside your eye.
Yuri
> It's a 3 phase 10hp electric motor driving a truck differential with the
> axle oriented vertically.
> On the upper hub, I've affixed a playground swing to one point, and
> opposite, a 185 pound counterweight on a chain.
> I get into the swing, and the wife operates the variable frequency drive to
> spin me up. After about 5 minutes at 5-6 g's, she lets it coast down and
> all my floaters have disappeared. This effect seems to last about 1-2 days,
> longer in the winter, for some reason, shorter in the summer.
> About the only adverse effect we've noticed is my shoe size has increased
> from a 10 to a 12.
>
> A happy and prosperous new year to you all at SAA!
> Etok
>
Side effects like double images may occure. (-:
A question, what if your wife got the call and will be back not in 5
minutes, but in a halh an hour?
Yuri
Jan Owen
"Yuri" <yp...@attbi.com> wrote in message
news:6ea29974.03010...@posting.google.com...
G.Tom
> Using a binoviewier makes a big difference for me. I don't
> notice my floaters nearly as much when using a binoviewer.
>
> Rich
lx200 and the clarity is unbelievable compared to mono viewing.They
have opened up a whole new experience for me.Floaters are a non issue
now:-).Do you belong to this group?
http://groups.yahoo.com/group/Binoviewers/
Good folks to talk to about all things binoviewers.
Clear Skies......Tom Munroe
Howard Lester
"Bill Becker" wrote
> Shame on you for saying the "f" word.
>
> Best regards,
> Bill
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Cathy Crawford
Bender
I tend to agree. My floaters stay in pretty much the same position
unless I move my head or eyes suddenly. Then the whole glob of
vitreous fluid seems to move/bend slightly - taking all the floaters
with them - but then they slowly (2-3 sec) move back into their
original position.
This could account for some of the movement that is noticed when
looking "sideways" - the whole of the vitreous fluid moving, due to
its non-symectrical shape and hence the center of gravity not being in
the center of the optical path. Just a guess, as I've not had a chance
to try this yet.
I'm lucky that in my primary eye I only have one slightly annoying
floater. I originally took it to be scar tissue on my cornea due to an
accident whilst de-soldering - I flicked molten solder into my eye -
not recommended.
My optometrist told me that there is no damage to the front of my eye
and that it is a floater - told you I was lucky.
Now I wear safety glasses when de-soldering.
Tom L.
Han Sibot
> Vitreous is strange stuff. I used to make surgical instruments for cutting it-
> you can't just suck it up like a liquid. It is really a protein matrix. Floaters
> can freely drift around in a very small volume- probably a few tenths of a
> millimeter on a side. That is more than enough to allow their shadows to move
> off your fovea, and of course, gravity will tend to move them downwards.
One degree of visual angle corresponds to 0.3 mm on the retina. So if
a fluid cavity of 0.3 mm is close the retina, it corresponds to 1
degree of visual angle. That is 5 times smaller than the fovea. When
looking through a pinhole I see floater shadows with a length of 10
degrees (or even more) of visual angle. I think such small fluid
cavities are inadequate to explain the mobility of floaters. In
addition, I was slightly puzzled why gravity off course moves the
floaters in any direction.
The idea of the matrix structure surprised me because I had the
impression that floaters are drifting in a fluid medium, but given
your experience the matrix must be true. At first thought the matrix
seems to prohibit floaters to drift up or down.
I wonder if the matrix fibres have some excess length before they pull
tight, allowing laminar flow like behavior during short time
intervals, because that would explain my own observation of sinking
floaters. Most of my floaters behave as if they are part of a layer
parallel to the retina, which never maintains its central position,
but always descends to a lowest position at about 20 degrees below the
horizon (while my eye is gazing towards the horizon). Consequently
other floaters come into view when I tilt my head to the left, and
others when I tilt my head to the right, and others when my head is
upside down.
This description represents what I see, although I have to guess why
gravity forces that layer with floaters to move up or down. The
inversion of the eye implies that this layer, close to the retina, is
drifting upwards. To close the circulation, there should be a layer
somewhere near the lens moving in the opposite direction. Does anyone
know if the eye lens has a higher specific density than the vitreous?
That might explain it.
Now that I think of it, it would be a better idea that the suspension
of the lens is suddenly pulled tight, instead of the matrix of the
vitreous. Less risk of retinal detachment.
Chris L Peterson
>One degree of visual angle corresponds to 0.3 mm on the retina. So if
>a fluid cavity of 0.3 mm is close the retina, it corresponds to 1
>degree of visual angle. That is 5 times smaller than the fovea. When
>looking through a pinhole I see floater shadows with a length of 10
>degrees (or even more) of visual angle. I think such small fluid
>cavities are inadequate to explain the mobility of floaters. In
>addition, I was slightly puzzled why gravity off course moves the
>floaters in any direction.
If you watch the motion of floaters, you see that most of them move in concert,
with a small degree of independent motion on top of that. My thinking is that
most of the motion is caused by the movement of the vitreous body, with the
smaller drift caused by limited free motion within the vitreous. When you move
your eye, muscles around the globe distort the entire structure, including the
internal vitreous. If you change the orientation of your head, gravity also will
distort the vitreous slightly.
It may be that at low enough rates, floaters can drift significant distances
through vitreous. Like I said, it is strange stuff. Very viscous, but also with
a structure. You can dissect the vitreous from an eye (pig eyes work nicely for
this experiment) and hold it in your hand as an object- it won't flow away, no
matter how long you wait. A little like a gel, although technically it isn't
one.
>I wonder if the matrix fibres have some excess length before they pull
>tight, allowing laminar flow like behavior during short time
>intervals, because that would explain my own observation of sinking
>floaters. Most of my floaters behave as if they are part of a layer
>parallel to the retina, which never maintains its central position,
>but always descends to a lowest position at about 20 degrees below the
>horizon (while my eye is gazing towards the horizon). Consequently
>other floaters come into view when I tilt my head to the left, and
>others when I tilt my head to the right, and others when my head is
>upside down.
>
>This description represents what I see, although I have to guess why
>gravity forces that layer with floaters to move up or down. The
>inversion of the eye implies that this layer, close to the retina, is
>drifting upwards. To close the circulation, there should be a layer
>somewhere near the lens moving in the opposite direction. Does anyone
>know if the eye lens has a higher specific density than the vitreous?
>That might explain it.
I don't believe any such circulation exists within the vitreous body. Chemicals
(and floaters) move about by gradual diffusion.
>Now that I think of it, it would be a better idea that the suspension
>of the lens is suddenly pulled tight, instead of the matrix of the
>vitreous. Less risk of retinal detachment.
Traumatic retinal detachment is normally caused by tension between the vitreous
and the retina. A large acceleration or distortion of the globe is transmitted
through the vitreous body to the retina. The lens is very firmly supported by an
annular structure of fibers and muscle.
Jan Owen
I can speak to that!
I just got my final release from my surgeon after recovering from retinal
reattachment surgery. The detached retina was a really scary event, and
recovery after surgery kept me from doing a lot of my favorite things for
the better part of a year, all told... Of course, that was still a small
price to pay versus the alternative... I just got my new glasses, and it
appears, with correction for the effects of the surgery, I have recovered
100% of my prior vision... Which was actually a bit better than 20/20...
But I do seem to have somewhat more floaters now than prior to the
separation...
"Chris L Peterson" <c...@alumni.caltech.edu> wrote in message
news:m9rg1v48av1gri2ug...@4ax.com...
> On 5 Jan 2003 07:45:16 -0800, han...@freemail.nl (Han Sibot) wrote:
SNIP!
>
> >Now that I think of it, it would be a better idea that the suspension
> >of the lens is suddenly pulled tight, instead of the matrix of the
> >vitreous. Less risk of retinal detachment.
>
> Traumatic retinal detachment is normally caused by tension between the
vitreous
> and the retina. A large acceleration or distortion of the globe is
transmitted
> through the vitreous body to the retina. The lens is very firmly supported
by an
> annular structure of fibers and muscle.
SNIP!
Han Sibot
wrote
> When you move
> your eye, muscles around the globe distort the entire structure, including
the
> internal vitreous. If you change the orientation of your head, gravity
also will
> distort the vitreous slightly.
External distortions may cause an immediate velocity field throughout the
eye, but it should immediately stop when the distortion disappears. Floaters
may continue to flow for many seconds. Do you think external distortions
need many seconds to relax?
> It may be that at low enough rates, floaters can drift significant
distances
> through vitreous.
1) I think you imply that the specific density of floaters is different from
the vitreous. Do you?
2) Large and small floaters move "in concert", that is at the same speed.
They would not so when moving through the surrounding vitreous.
> I don't believe any such circulation exists within the vitreous body.
With "circulation" I mean a velocity field with circular streamlines that
exist for a short time. That's no problem. The floaters do not move through
the matrix. Afterwards, the center of the vitreous has rotated over small
angle.
> >Now that I think of it, it would be a better idea that the suspension
> >of the lens is suddenly pulled tight, instead of the matrix of the
> >vitreous. Less risk of retinal detachment.
>
> Traumatic retinal detachment is normally caused by tension between the
vitreous
> and the retina. A large acceleration or distortion of the globe is
transmitted
> through the vitreous body to the retina. The lens is very firmly supported
by an
> annular structure of fibers and muscle
Not absolutely rigid, I suppose. The muscle structure may have some
flexibility. Anyway, the lens is flexible. If its specific density is
different from the vitreous, its shape might change due to gravity, moving
its center of mass up or down.
Rich N.
Dittos here. They injected a bubble of air into my eye to press the
retina against the freeze burns on my eye as a way to form scar tissue
where my retina could attach. The bubble of air moved easily, no as if
it was in thick fluid.
Rich
Jan Owen wrote in message ...
Chris L Peterson
>External distortions may cause an immediate velocity field throughout the
>eye, but it should immediately stop when the distortion disappears. Floaters
>may continue to flow for many seconds. Do you think external distortions
>need many seconds to relax?
Possibly. I'm just trying to think of mechanisms that support the observed
behavior of floaters. They clearly don't float freely, since the same floater
will persist in the same area of the eye for many months, or even longer.
>1) I think you imply that the specific density of floaters is different from
>the vitreous. Do you?
I expect that in general, floaters have a higher specific density than the
vitreous.
>2) Large and small floaters move "in concert", that is at the same speed.
>They would not so when moving through the surrounding vitreous.
They would move this way if my suggestion that most of the motion is due to
movement of the vitreous body as a whole is correct.
>With "circulation" I mean a velocity field with circular streamlines that
>exist for a short time. That's no problem. The floaters do not move through
>the matrix. Afterwards, the center of the vitreous has rotated over small
>angle.
I don't think any permanent rotation of the vitreous is likely. The outside of
the body is attached to structures in the eye, including the retina. I can
believe that torques cause a short term relative rotation of the inner vitreous
with respect to the outer, however. Is that what you are suggesting? There is,
in fact, a slight difference in the density of the interior and exterior parts
of the vitreous body.
>Not absolutely rigid, I suppose. The muscle structure may have some
>flexibility. Anyway, the lens is flexible. If its specific density is
>different from the vitreous, its shape might change due to gravity, moving
>its center of mass up or down.
The lens and it's support system are considerably more rigid than the vitreous.
I doubt that either gravity or local torques result in any perceptible
movements. I can tell you that in removing a lens surgically, it is necessary to
apply fairly large forces to it, and in so doing, the entire eye moves around. I
haven't seen any movement of the lens with respect to the rest of the eye,
however.
Han Sibot
From: "Chris L Peterson" <c...@alumni.caltech.edu>
> >With "circulation" I mean a velocity field with circular streamlines that
> >exist for a short time. That's no problem. The floaters do not move
through
> >the matrix. Afterwards, the center of the vitreous has rotated over small
> >angle.
>
> I don't think any permanent rotation of the vitreous is likely. The
outside of
> the body is attached to structures in the eye, including the retina. I can
> believe that torques cause a short term relative rotation of the inner
vitreous
> with respect to the outer, however. Is that what you are suggesting?
I think that the core of the vitreous always tries to follow the rotation of
the eye, over the same angle except for a kind of hysteresis. That's
possible if the matrix is sloppy. Some eye motions make the core of the
vitreous rotate 20 degrees less than the eye, some other eye motions make it
rotate 20 degrees more. The rotation deficit or its excess might be called
semi permanent, or perhaps remanent like in magnetism. When lying in bed on
my left side, the supposedly heavy eye lens sinks a little, down to the
point where the maximum remanence is reached. The vitreous core rotation
follows the heavy lens. When lying on my right side, the opposite remanence
is reached. In my idea, the floaters have fixed positions in the vitreous
core.
> The lens and it's support system are considerably more rigid than the
vitreous.
> I doubt that either gravity or local torques result in any perceptible
> movements. I can tell you that in removing a lens surgically, it is
necessary to
> apply fairly large forces to it, and in so doing, the entire eye moves
around. I
> haven't seen any movement of the lens with respect to the rest of the eye,
> however.
Why doesn't nature just listen to my ideas?
Andre Berger
> the eye, over the same angle except for a kind of hysteresis.
> In my idea, the floaters have fixed positions in the vitreous core.
If that hypothetical core is rotating as a whole, not all of its
floaters would appear to sink down: one half of the sphere is sinking
down, the other half is moving up at the same time. In practice I
don't see many floaters in the opposite direction.
Han Sibot
"Andre Berger" <avbe...@netscape.net> wrote
> If that hypothetical core is rotating as a whole, not all of its
> floaters would appear to sink down: one half of the sphere is sinking
> down, the other half is moving up at the same time. In practice I
> don't see many floaters in the opposite direction.
You will see them if you reduce your pupil size. Take a look through a very
very small pinhole (diameter of 0.1 mm, made with pin & paper) at a bright
light source, like the surface of a light bulb. You can get a wide field of
view if both the pinhole and the light bulb are close to the eye. Move your
eyes to stir the floaters up. On the one hand you will see the familiar
floaters sinking down. Due to the pinhole you can see them and in more
detail. On the other hand you'll see magnified (about 3x) floaters moving
up.
Their shadow on the retina is presumably magnified because they are closer
to the pinhole.
jerry warner
-Jerry
Howard Lester wrote:
> It occurred to me that looking "horizontally" through an eyepiece allows eye
> floaters to sink to the bottom of the eyeball, clearing the view. This can
> only? be accomplished using newtonians. With refractors and SCT's that use
> star diagonals, one has to look down, keeping floaters in view. Comments?
>
> Howard Lester
>
Cathy Crawford
3x. Then have his wife say " YOU'RE NOT GOING TO THE CONVENTION YOUR
GOING TO THE MOUNTAINS WITH ME'