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Using one eye to find daytime planets - known method?

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#1 freestar8n

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Posted 03 December 2021 - 04:29 PM

There was a recent thread about finding Venus in daylight and I mentioned how easy it was to spot when it was next to the moon.  At the time I thought it was because my eyes were better *focused* on infinity by having the moon as a reference.  But in recent attempts to find Venus I realized that it was almost invisible until I spotted it, at which point my eyes *aligned* on it stereoscopically.  So I wondered if the main benefit with the moon was that my eyes were aligned on infinity so that both views of Venus matched up.  Even if your eyes are focused on infinity, if they aren't aligned your brain just doesn't see it because the two separate images don't match.

 

So I tried finding it with one eye shut - and it seemed to help greatly.  Is this a known method?  Give it a try and see if it works for you, since Venus is pretty far from the sun now but will sink soon.

 

Frank


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#2 JohnBear

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Posted 03 December 2021 - 05:20 PM

Sorta like (or maybe the opposite) when I use a binoviewer the floaters in my eyes tend to not be very visible anymore. Our cerebral image processing system can be rather awesome.



#3 Barlowbill

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Posted 03 December 2021 - 05:21 PM

I will try it.  I search for Venus virtually every night in summer/fall.  I try when the sun is approaching setting.  Always trying to find it when fairly "light" out.  Not had any luck with what I consider light out.  I always know about where it should be because I do it nightly.  Next time I don't have clouds, I'll try the one-eyed trick.  Thanks



#4 Astrojensen

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Posted 03 December 2021 - 05:24 PM

Very interesting! I'll try it out. Never heard of it before. 

 

 

Clear skies!

Thomas, Denmark



#5 jmillsbss

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Posted 03 December 2021 - 05:32 PM

I have a running challenge with the 7 year old as to who can see the planets first when it's close to sunset.  I've had a lot of trouble and his young eyes find it quicker.

 

To the two-eyed approach, if I can't find it naked-eye, the binoculars are a great help.  Once spotted with binos, it's quite easy to see from there.  I've spotted Venus and Jupiter before the sun had fully set before and it's amazing how much less glare that you see, particularly on Venus.  With your eyes contracting from the brighter sky, It's quite easy to see it in it's "phase", like the moon.

 

And, in like fashion, Luna isn't nearly as bright in the morning sky for those first few days after a full moon.  The eyeballs are doing what they're made for and it's amazing how we're made!


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#6 TOMDEY

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Posted 03 December 2021 - 06:06 PM

Hi, Frank --- Intriguing!

 

I've pondered that conundrum a lot and just sorta guessed that being focused rather randomly was the culprit. And that would be as you mention regarding the proximate moon as a focus-setting target. But your additional point regarding ~binocular collimation~ also sure makes sense. I sometimes look at a star at night or a distant plane in the day... cover one eye for a few seconds, and then flip to the other eye. In that ~relaxed~ state, my R eye consistently points about 15 arc-min above and to the left of where my L is fixated. Not only that, but the R image is several % bigger than the L one. Yikes! But with both eyes uncovered, the two images fuse and scale almost immediately, comfortably, and acutely. All I can figure is that my ability to subconsciously auto-merge all pertinents (parfocal, V and H fusion, perceived equal scale) must be within the "normal range" of comfortable/functional adaptation. PS: I always look for the "first star" as the sun is going down. Do that exercise a lot and it gets easier/practiced... also a great way to learn the constellations. I guess we all have some prism and differential focus, but at levels within comfortable capture without glasses.    Tom


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#7 clearwaterdave

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Posted 06 December 2021 - 04:50 AM

I have been observing Venus for the past few weeks and I have gotten to see it right on the meridian the other day.,long before sunset.,same with Jupiter.,Having the scope pre-focused at infinitely is key.,and having some idea where in the sky the target is.,I still haven't gotten Saturn though.,not till it's almost naked eye visible.,

  I am using a 70x600mm refractor w/ a 23mm ep.,and my simple homemade angle gauge.,I'm sitting in my recliner viewing through a thermal pane window.,all cozy and warm.,lol.,Works all good.,.

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#8 ButterFly

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Posted 12 December 2021 - 02:01 PM

Delightfully easier yesterday!

 

Venus was at transit against a sky with some haze.  It was disappearing two eyed, but held steady one eyed.  It was much easier to spot one eyed, even against the side of the scope.

 

It could have to do with vergence as well as focus.  Relaxed infinity focus with my "good" eye comes fairly naturally to me.  I could feel my eyes struggling to not cross two eyed.  It took about fifteen-twenty seconds for it to disappear into the haze.

 

I want to try it again on a clear day.



#9 freestar8n

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Posted 12 December 2021 - 05:24 PM

Hi-

 

I've been trying it here in Melbourne, Australia and I'm pretty sure it does work.  It may require eyes of a certain age, but once I find Venus with one eye and I know where it is in the sky, I can then re-find it with two eyes.  But when I first see it with two eyes it is slightly double and then snaps into view.  So I think with two eyes I really am just not seeing it because the stereoscopic view doesn't overlap.  I have astigmatism and wear progressive lenses so that may be a factor and younger eyes might not have the problem.  But if this really does work I think it's fairly rare 'new' thing in the world of visual observation techniques.  Something new, literally under the sun.

 

Frank


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#10 gmiller123456

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Posted 13 December 2021 - 04:03 PM

With your eyes contracting from the brighter sky, It's quite easy to see it in it's "phase", like the moon.

 

From what I understand it's actually the extra light is activating the cones in your eye which can see greater detail. Someone in our club mentioned this trick near a Mars opposition a while back, and I still remember how dramatic it was the first time I tried it.  Just shine a flashlight on something just in your field of view, but at a steep enough angle that it doesn't cause glare on the eyepiece.  It also helps see some color too.  I had not tried it on Venus, but it works wonders on Mars, Jupiter and Saturn.



#11 spaceoddity

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Posted 13 December 2021 - 04:51 PM

I remember Venus being visible in the middle of the day when it was straight overhead a few years ago but I thought that was a very rare occurrence. 



#12 ButterFly

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Posted 13 December 2021 - 06:45 PM

I remember Venus being visible in the middle of the day when it was straight overhead a few years ago but I thought that was a very rare occurrence. 

 

Not at all rare.  It's near -5 magnitude right now, and still fairly far away from the Sun.  When to look is near when it's the brightest around this time in its orbit.  Knowing where to look is the key.  Apparently, how to look make a difference too.

It's pretty easy, when you know where to look, on a clear day.  It can be extremely hard to find without help, though.  I use a "Last Alignment" on my AVX, hunt around with an eyepiece if I have to, then sight along the side of the scope.  There is it.

 

Another trick is to wait until it transits, point toward actual South, then scan upward from the horizon.  It's hard.  This is what I want to try one-eyed on a clear day.  The haze was making it impossible two-eyed when I tried.

 

As it gets closer to the Sun, there will be glare from sky glow.



#13 doug mc

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Posted 13 December 2021 - 10:15 PM

I find it by first scanning the sky with binoculars set at infinity.  Once you have the place in the sky I use the optical viewfinder on my scope and scan. Bingo.


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#14 byi

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Posted 15 December 2021 - 04:12 PM

I wonder if a related set of effects is at play when I look at the night sky with an eyepatch on. I like to keep one eye covered to maintain dark adaptation when looking at charts or under adverse lighting conditions, and I find that it's generally a lot harder to focus on or even see stars with one eye.

#15 freestar8n

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Posted 16 December 2021 - 05:10 AM

I had another good test today in Melbourne.  With clear skies Venus was nearly directly overhead and the sun was at altitude 63 degrees and I was able to find Venus easily with one eye by viewing from an area shaded from the sun by a roof, but with a view directly overhead.

 

When I switched to two eyes initially I couldn't see it anymore and it took some time to bring both images together so I could actually see it - knowing then exactly where to look.

 

TheSkyX says Venus was 32 degrees from the Sun, Mag -4.6, 15% phase, and 50" diameter.

 

Frank


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#16 Rutilus

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Posted 16 December 2021 - 01:05 PM

I use a one meter measuring stick  held at arms length, to measure the off-set from due south

from my location. Today using this method I found Venus at 12 degrees altitude at 13:30 GMT. 

With my 8x44mm binoculars, Venus showed a brilliant silver looking crescent. Here is a photo

I took at 14:00 GMT with my 80mm refractor at 17.5x power with a simple point and shoot digital

camera held at the eyepiece. 

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Edited by Rutilus, 16 December 2021 - 01:05 PM.

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#17 freestar8n

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Posted 16 December 2021 - 09:12 PM

Another clear afternoon - this time spotted with one eye near noon with sun at 75 alt and venus 52 alt, and 31 degrees from sun.

 

I just use the size of my fist and outstretched arm to estimate 30 degrees and then visually sweep slowly in the general area.

 

Once spotted with one eye it was fairly easy just to look up and recover it again with both eyes open.

 

Frank


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#18 freestar8n

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Posted 31 December 2021 - 01:06 AM

Still able to find it with one eye in bright daylight with the sun about 50 degrees up.  Two days ago the sun was high and Venus was around 15 deg away from the sun I found Venus with the one eye method in just a few seconds - while standing under the eaves of a roof to block the sun.

 

Today Venus is now about 14 degrees away and could not initially find it by eye, but with binocs I did find it and then could find it by eye.  It helped to have a few high clouds passing nearby to use as a reference.

 

It is getting much harder to see as it moves into the broad skyglow around the sun - but so far I can still see it unaided, but I couldn't find it unaided today.

 

I don't know what the record is, either for finding it unaided or seeing it unaided - but I assume people have done well with very clear and transparent skies as the main factor, plus good eyesight.

 

Frank



#19 Bill Weir

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Posted 31 December 2021 - 01:26 AM

As you’ve noticed it can be difficult to focus on infinity without a reference. I used to try to place something in the foreground like the roof of a building or tree so my eyes would have to focus past it. Then one day when nothing was handy and wanted to try I thought I’d try using my actual hands. On that day what I like to call “Finger Binos” were invented. They work well at 1X magnification but do have a narrow FOV. 

 

Bill

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#20 freestar8n

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Posted 01 January 2022 - 02:16 AM

Here's an example of what I've been looking at.  It will end soon - at least until the next evening apparition - because I am not a morning person.

 

get.jpg?insecure

 

Click the link for full image.

 

Frank


Edited by freestar8n, 01 January 2022 - 02:17 AM.


#21 yeldahtron

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Posted 01 January 2022 - 11:09 AM

Here's an example of what I've been looking at.  It will end soon - at least until the next evening apparition - because I am not a morning person.

 

get.jpg?insecure

 

Click the link for full image.

 

Frank

What camera/lens combination did you use to take this cool photo?



#22 csrlice12

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Posted 01 January 2022 - 11:21 AM

This morning I found the daytime planet called Earth....it is 1*F and crystallized hydrogen dioxide atmosphere.  Not a fit place for man nor beast.wink.gif


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#23 freestar8n

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Posted 01 January 2022 - 05:59 PM

What camera/lens combination did you use to take this cool photo?

Hi-

 

That was with a Canon EOS 5Dii with 300 mm f/4 image stabilized lens on tripod, f/11.  And then I cropped the central part of the image as a form of magnification.

 

For visual or imaging when it is close to the sun, make sure to be under eaves or some kind of overhang so there is no way accidentally to point at or glimpse the sun.

 

A separate topic is if anyone can see the crescent shape with the unaided eye.  I remember thinking I could when I was younger but even though my prescription now is good and my vision is I think better than 20:20, I don't think I can see it.

 

Frank


Edited by freestar8n, 01 January 2022 - 06:18 PM.

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#24 WeatherCat

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Posted 04 January 2022 - 12:07 PM

As you’ve noticed it can be difficult to focus on infinity without a reference. I used to try to place something in the foreground like the roof of a building or tree so my eyes would have to focus past it. Then one day when nothing was handy and wanted to try I thought I’d try using my actual hands. On that day what I like to call “Finger Binos” were invented. They work well at 1X magnification but do have a narrow FOV. 

 

Bill

I honestly can't tell if your are joking. All I know is my neighbors are going to be even more confused lol



#25 freestar8n

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Posted 04 January 2022 - 05:22 PM

I honestly can't tell if your are joking. All I know is my neighbors are going to be even more confused lol

I think he’s doing that to avoid focusing on a near object in view that would then blur the view of Venus. I think that also plays a role in finding it in daytime. But for this thread I’m talking about the binocular effect of two eyes being the problem - if they aren’t aligned on infinity so the two images of Venus match in the brain. So I would shut one eye and then block the view around the open eye if need be. 
 

But if you have nearby clouds to focus on they should help both with focus and binocular vision. 
 

frank




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