remarkable eyes?

[alan plummer]

Hi all

I pointed out the planets last night (wed 1st) to someone who would not have known venus from the moon. She imeadiately exclaimed, of 'the bright one', 'wow, it's a cresent!' Which of course it was. And this with 50+ year old eyes.

This is new to me - anyone else got eyes like that?

Alan P

[pgc hunter]

Highly doubt it. Maximum resolution of a healthy human eye is about 1 arc min. Venus currently has an angular diameter of 33 arc seconds which is only half that.

[Meru (Michael)]

I can also see that the shape is crescent, I know this to be true because it was the first time before I looked at the planet through a scope and didn't know Venus had phases! That being said I am in my mid-20s and definitely have better than 20:20 vision

[N1 (Mirko)]

Originally Posted by alan plummer

She imeadiately exclaimed....'wow, it's a cresent!'

Sounds like she'd never noticed Venus in the sky before (otherwise she'd have noticed the phases with her keen eye then). How likely is that I ask, given that she's obviously excited by making discoveries.

[alan plummer]

Thanks Meru - Your answer is helpful. I never would have thought.....

[Allan]

Well the ancients studied the sky for thousands of years before the telescope finally revealed Venus has phases. I have heard similar accounts of people being able to see the Galilean moons with the naked eye (I don't believe that either).

[LewisM]

The ancients also had 100% NIL light pollution save maybe some oil/tar lamps, nor any atmospheric pollution! Of course under those conditions, which NONE of us have ever experienced nor ever will (regardless of how dark a site it is), anything is possible.

Seeing Jovian or Saturnian moons - I HIGHLY doubt it. I have my doubts about Venus phases being visible too, due, more than anything, to Venus' extreme albedo which saturates the receptors in the eye. Try using an artificial star at say 100 yard, with a crescent blackened off - I guarantee you will NOT see any visible "phase" of the artificial star.

[N1 (Mirko)]

Lewis, the trick for bright objects is to "stop down" your pupil by looking through a pinhole, which you might even create crossing your hands. Works surprisingly well. I'll be trying this on Venus between now and Inferior Conjunction. Can't positively see the crescent shape now (but I do see that it's non-stellar), but Venus will get bigger in the next few weeks.

[LewisM]

But I doubt SHE did that Mirko.

[N1 (Mirko)]

Same. But hey, maybe her eyes were just really good! Or maybe her pupils didn't dilate beyond 1mm

[astroron (Ron)]

I also get people who can see Alpha Centurii is a double star after looking through an eyepiece for the first time.
I doubt that too.
I would say this lady squinted and saw a distorted bright light.
Cheers

[Geoff45 (Geoff)]

Crescent of Venus with the naked eye--lots of reports, nothing absolutely convincing. Just try google for lots of hits.

The visibility of Jupiter's moons is more authenticated. They are around mag 5 and would be easily visible away from the glare of Jupiter. Callisto can get as much as 10' from Jupiter and reports suggest that hiding Jupiter behind a convenient pole is the best way to spot it naked eye. Interesting article here about the best time to try for a naked eye hit http://astroblogger.blogspot.com.au/...ers-moons.html
Geoff

[N1 (Mirko)]

Originally Posted by astroron

I would say this lady squinted and saw a distorted bright light.
Cheers

I haven't investigated this myself, but I think that is actually the most likely scenario. I've taken overexposed photos/videos of the solar crescent during eclipses (especially when starting out) and found that the shape of the crescent could influence the shape of the overexposed blob and the lens flare rays emenating from it. So even though the crescent itself was not visible, its effects possibly were - and in a bigger format than the actual target; and (importantly) as a non-symmetrical shape. I don't see why the same couldn't happen when using the naked eye on a high-contrast object.

[AussieTrooper (Ben)]

Whenever I look at Venus I see the non symmetricalness of it, but this is caused by the rays always favouring the side the sun is on. There's not a chance that the actual crescent could be seen.
I used to have vision much better than 20-20, and I couldn't see it then.

It's probably just a lucky guess. With millions of people seeing Venus for the first time at some stage, one of them is sure to say it's a crescent, after being used to seeing the moon that way.

[multiweb (Marc)]

Originally Posted by ghsmith45

The visibility of Jupiter's moons is more authenticated. They are around mag 5 and would be easily visible away from the glare of Jupiter.

I tend to agree with this as well. If the moons are aligned on one side you'll make up a little "spike" and you can easily see that something is lopsided, but that's with a lot of imagination IMHO. Venus crescent happens all the time though after a bottle of shiraz. oh no... wait... it must have been the moon.

[andyc (Andy)]

Yeah, not convinced myself (Venus crescent without optical aid). I looked several times in the mid-1990s with a teenager's good eyes, and despite a lot of effort when Venus was a thin crescent of 50" or more and well up, day or dusk, I couldn't convincingly see it. This was after reading an S&T report suggesting that it was just about possible when Venus was near it's maximum 60"-ish diameter. So it may be just about possible naked-eye with superb eyes and right around inferior conjunction... but now, at <35", I really doubt it without optical aid!

[Nico13 (Ken)]

I was told on a number of occasions by optometrists that I had way better than 20:20 vision it was just the lens at the front was the problem
They used to doubt I could detect a less than .25 diopter shift until they put me to the test.
With my now sixty year old eyes I do believe I can still detect the lop sidedness of a crescent Venus from the flair but as for seeing it as a crescent even when the eyes were good I don't believe I could have unaided.
You'd have to put the lady to the test I guess.

[ZeroID (Brent)]

No, I'll have to say I've seen Venus crescent naked eye just a few weeks ago. Early evening so the contrast wasn't quite so strong and could see a definite crescent shape to it. Glared out a bit later it was not so apparent but it didn't look 'round' either.

[scoperboy (Stuart)]

This reminds me of when my son was only 3 or 4 and I pointed out Venus and he said it was shaped like the moon.

I definitely notice it to be 'lop sided' as someone else put it, but cannot see a crescent.

[Steffen]

Maybe the trick is to stare at the Moon for a while to get the iris stopped down, then at Venus...