2 sunsets

I see that I've presented evidence for what Ski and I have been saying. I don't see any evidence presented for your side of the argument.

1:0

Tom, you only think you have presented evidence.  In the same way as a theist quotes back passages of the bible, you have submitted to us your own ancient "scripture".  Your faith in that scripture in just that, "faith".

I see that I've presented evidence for what Ski and I have been saying. I don't see any evidence presented for your side of the argument.

1:0

Rowbotham's claim is that the apparent dip in the horizon viewed through surveying equipment is caused by magnifying lenses.  Not all modern surveying equipment uses magnifying lenses.

That's beside the point however.  If you, along with forum user Ski, are indeed claiming proof of Rowbotham's 'laws of perspective' the ball is still on your side of the court.  Rowbotham appears to have neglected to provide data regarding collumation to back up his claims.  In addition to my earlier post I also make the following points:

- Why does the amount the horizon 'dips' below the level-line in a levelled theodolite increase with altitude.  If the horizon is level with your eye at any altitude, errors present in the equipment would alter the image in the same fashion regardless of altitude.

- Transiting theodolites have been around since the 1850's and allow the surveyer to identify any error along the horizontal axis - if a dip in the horizon existed as a result of equipment miscalibration, transiting or flipping the theodolite along the trunnion axis would place the horizon  the same distance above the level-line, giving Rowbotham the means to gather further data regarding the inherant errors of the equipment.  Rowbotham could have proven his point by simply rotating his telescope 180 degrees and re-aiming it at the horizon.

Quote from: ThinkingMan on August 24, 2012, 10:05:30 AM

What is your evidence for this? This is false. Horizon does not move. Your eyes are simply drawn to it because of the sharp contrast between land and sky. Your eyes will be drawn to any sharp contrast.

The horizon moves to stay at the level of your eye when you ascend or descend.

In Zetetic Cosmogony by Thomas Winship we read a real world test:

AERONAUTICS.

If the world be a ball, as Sir R. Ball gravely informs us,
the aeronaut should be one of his most ardent supporters, as
the highest part of the "surface of the globe" would be
directly under the car of a balloon, and the sides would fall
away or "dip" down in every direction. The universal
testimony of aeronauts, however, is entirely against the
globular assumption, as the following quotations show. The
London Journal 18th July, 1857, says: --

"The chief peculiarity of the view from a balloon at a con-
siderable elevation was the altitude of the horizon, which remained
practically on a level with the eye at an elevation of two
miles, causing the surface of the earth to appear concave instead
of convex, and to recede during the rapid ascent, whilst the
horizon and the balloon seemed to be stationary."

Tom. This says two miles. That's 10,560 feet. The average modern airliner flies at 35,000 feet. That's ~6.63 miles. Very slight curvature can be seen from this altitude. The circumference of earth at the equator is ~24,901 miles. This means that from less than seven miles in the air, it's not gonna look all that different.