Double stars with the naked eye

[Slangers]

My daughter seems to have remarkable eyesight. I can only think of one double star that I can resolve with the naked eye (Alcor/Mizar), but she seems able to spot a whole load more. At first I thought she was making it up, but on my last trip out with her I asked her to show me some more, which she did with 100% accuracy. This list included Castor, Sirius and Capella.

Does anyone else out there have experience of this sort of visual accuity?

[LukeSkywatcher]

I may be wrong, but i dont think the human eye has the ability to split a double star. I know kids have better eyesight then us elders but i still doubt that their eyesight is THAT good.

My 7 yr old niece asked me if she could use a pair or my bins a couple of weeks ago to see the stars.

It was cloudy for god sake. I'm sure my niece does not have inbuilt cloud filters.

[Demonperformer]

If she can split Sirius with the naked eye that is indeed remarkable, as the secondary is, I believe, about mag8. I was out looking at it last night with my 6SE and an eyepiece I had adapted to try to block the glare from the primary and I still could not see it.

[Vega]

Castor?? your kidding!!! They are only separated by 2 arcsecs! Is she superhuman or something?

[Graham Darke]

My understanding is the that the resolution of the unaided human eye is somethng like 1 arc minute if you have 20/20 vision. That said, it is possible for people to have better than 20/20 vision, but not so much better that they could resolve something 2 arc seconds apart!

[DarkerSky]

I would imagine she is familiar with the locations of these double star systems in the sky, which is brilliant that she knows where they are.

[Httetal]

Does your daughter like a good send-up? Sounds like she's got you good and proper!

[brantuk]

Was she pulling at your leg as she rattled them off? lol

[spaceboy]

I have read that the average human eye can see 6 mag stars.(most dark sky maps list up to 6 mag for this reason) So given the right skies and adaption surly in the occasional human 8 mag could be a possibility. Resolving power of the eye could be questionable but who's saying she isn't very long sighted. Slangers dose she have to wear glasses for in the class room?? (based on the assumption she is young to have such good dark adaption) or suffer with headaches?? There is always the chance she is winding you up but even that wouldn't be a bad thing that she can memorized with accuracy where double stars are.

SPACEBOY

[Shibby]

In my experience, the brighter stars can sometimes seem to double up, particularly if your eyes are a little blurry at the time or if one of your eyes is slightly different to the other. Having said that, there are supposedly some people who can resolve the moons of Jupiter with the naked eye! (I read an article recently about this)

[Demonperformer]

The moons of Jupiter can get several arc minutes from the planet and are around mag6, which is about the normal limit.

Mag 8 is only 1/16th as bright and 9 arc-seconds is about 1/20 of the distance from the primary.

[cathalferris]

E1 and E2 are a very good test, ~4 arcminutes.

I can see these as seperate when wearing my glasses, and I can still notice the slight blur as elongated (8-shaped) without my glasses. I'm +0.5 shortsighted and 0.75 in astigmatism, so I'm not far off 20/20 (perfectly average) but I'm verry fussy about my sight. With the glasses I'm about 25/20 or so.

[JamesC]

You mean the double double? This kid will see 4!

[brianb]

Nu Draconis?

[Slangers]

I find it hard to believe myself- she's either telling the truth, or she is a very lucky guesser. Her knowledge of the sky isn't that good. She knows Alcor-Mizar and Albeiro from what I've taught her, but that's all. I'd love to test her on the moons of Jupiter but as she has seen them through the scope this may not be a fair test.

[Hypernova]

I think she had remembered which stars are double/binary and was pointing them out and not actually able to resolve them.

[LukeSkywatcher]

I think she had remembered which stars are double/binary and was pointing them out and not actually able to resolve them.

That sounds more like the case rather then splitting them naked eye.

[meteoriot]

Having read through this is seems that general belief is that it isn't possible but it's an interesting fact that the famous astronomer Gerard Kuiper could actually see stars with his naked eye that were 4x more faint than those visible to anyone else. Quite incredible really!

[Slangers]

Quote:

Originally Posted by Hypernova

I think she had remembered which stars are double/binary and was pointing them out and not actually able to resolve them.

That sounds more like the case rather then splitting them naked eye.

In which case I am delighted that her knowledge of the sky is as good as mine!

[MorningMajor]

I reckon she's downloaded her own copy of Stellarium!

Anyway, encourage her and we've a new recruit!