Re: Magnification needed to split tight doubles

It all depends on how good your eyes are.
Ras Al ~3.6" at 31X produces an apparent separation
to your eye of 111 " or 1.85' The normal "young eye"
IIRC can separate about 2'.
It seems you have good eyes.
I would need about 60X to see the split.

d.

Ioannis wrote:

I have often seen people here write about "how much magnification a tight
double requires to split, with this or that scope".

One curious phenomenon which I have observed with my surgically modified
Tasco, is that if the Tasco IS able to split the double I am looking at, I
perceive it as split on ANY magnification the Tasco zoom EP provides.

For example, Ras Algheti (~3.6") is at the practical separation limit of my
60mm/700mm Tasco. On VERY clear nights, I see it split even at
magnifications of 31x. Increasing the magnification with the zoom, only
increases the separation between the components, but the components ARE
visible as distinct, even at the lowest magnification. They are really close
to each other, but my eye clearly sees two separate stars there.

Since resolving power is dependent only on aperture theoretically, shouldn't
this be true for any scope? If for example your scope resolves epsilon
Lyrae, shouldn't it resolve it even at its lowest magnification?

I know the opposite is true: If your scope's HIGHEST magnification cannot
resolve a certain double, certainly no lower magnification will be able to
do it.

So I wonder, what exactly is the meaning of "my scope requires magnification
x to split double y". Maybe related to a more "subjective" perception where
the viewer requires the split to be "clean" and "comfortable"?
--
Ioannis

.

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