Astronomical Brain-Teaser

[Gary Fox]

Pinched from gCaptain, the answer is obvious when you don't think too hard..

You are standing on a hilltop and, at sunrise, you aim your sextant at the middle of the Sun. This forms a line.
You return to the same hilltop at noon, and again aim your sextant at the middle of the sun, forming another line.

Q: Where do these two lines cross?

 

[Sticky Fingers]

Where you are standing?

 

[Gary Fox]

Where you are standing?

On top of your favourite hill. Not a pole or the equator.

 

[Sticky Fingers]

So am I right? Can’t see any alternative

 

[JumbleDuck]

Since both lines go from where you are standing to the middle of the sun, the obvious answer is "Either where you are standing or the middle of the sun, depending on the axis system used".

 

[Sticky Fingers]

Deleted, total bollocks

 

[bignick]

Wherever you are standing.

 

[Skylark]

……… when you don't think too hard..

I’m probably guilty as charged. ?

I don’t understand the context of the question. It seems superficial to the point of being either misleading or wrong ?

No mention of (artificial) horizon. Why use a sextant to obtain two bearings, why not a simple compass.

Why aim at “the middle of the sun”. A position line derived from a sextant angle (position circle of infinite radius) will be at a tangent to the bearing of the sun. No mention of any sight reduction.

A local noon will always be due south, in northern hemisphere, and sextant angle will enable latitude to be derived.

The simple question is too vague and confusing for me, yep, I’m probably over thinking it ?

 

[SimonKNZ]

Surely the lines only cross at the centre of the sun? Your position has changed in the time between sightings (due to earth rotation on axis and earth orbit around sun). The only point they both go through is the sun

 

[john_morris_uk]

Surely the lines only cross at the centre of the sun? Your position has changed in the time between sightings (due to earth rotation on axis and earth orbit around sun). The only point they both go through is the sun

That’s my thinking too.

 

[chrisclin]

But presumably the sun is moving too

 

[laika]

Why aim at “the middle of the sun”.

I think that was Roger Waters's suggestion

 

[Gary Fox]

Yes, the middle of the sun is the answer they give.

 

[ithet]

Surely the lines only cross at the centre of the sun? Your position has changed in the time between sightings (due to earth rotation on axis and earth orbit around sun). The only point they both go through is the sun

Yes, the starting points of the two lines will be a quarter the way around the earth and the lines diverge at the earth.

 

[JumbleDuck]

But presumably the sun is moving too

That's why the axis system used matters!

 

[Biggles Wader]

They probably only meet at infinity as both Sun and sextant are moving.

 

[ithet]

That's why the axis system used matters!
[/QUOTE

Well, if we take the sun's movement into account the the lines will cross at roughly the centre of the galaxy.

 

[179580]

Only one answer, 42.

 

[[3889]]

But th

Yes, the middle of the sun is the answer they give.

But both lines are defined as having an end point at the middle of the sun so they don't cross at all, do they?

 

[john_morris_uk]

But th
But both lines are defined as having an end point at the middle of the sun so they don't cross at all, do they?

I’m not sure ‘aiming at the middle of the sun’ defines the line as ending there. If you aim your rifle at a paper target the line the bullet follows goes straight through and carries on.