The horizon dip measurement is the angle between the horizontal (the line perpendicular to the vertical at a specific point) and the apparent horizon.

On a globe, we would expect this angle to increase with increasing altitude, because the horizon would drop away with the curve.

On a flat earth, we would expect the horizon to always "rise to eye level".

This page is a gallery of photos showing the measured dip of the horizon from horizontal.

Instructions

If you want to submit your own image, email dip@mctoon.net Please include the following details with your submission:

1. A clearly visible horizon (ideally, no clouds at, or near the horizon)

2. An instrumented graphic overlay showing true horizontal

3. The name of the device generating the graphic overlay

3. Altitude at time of photo

4. Image Source/Credit. Please indicate if you want to be credited and how. We do not wish to dox anyone but we do want to appropriately give credit where it is due.

Gallery

Note:
Some photos are cropped due to the size limit for uploaded files.


Source/Credit	Globular EPIC Bikini @FlatSlugbrains on Twitter
Altitude	11074 m
Dip	3.3°
Device	Theodolite


Source/Credit	@Tylerthepilot_ on Twitter
Altitude	35820 m
Dip	4.8°
Device	Theodolite


Source/Credit	McToon
Altitude	35091 ft
Dip	~4°
Device	Theodolite


Source/Credit	@dwolfman54 on Twitter
Altitude	33709 ft
Dip	>2°
Device	Theodolite


Source/Credit	BK, flight from Newcastle to Brisbane, in Australia:
Altitude	36706 ft
Dip	~2°
Device	Theodolite


Source/Credit	Wolfie6020
Altitude	46000 ft
Dip
Device	cockpit display