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  1. Rory

    Observations of Brighton from Worthing Pier

    Not as far as I can tell. But it could be part of a related field of study.
  2. Rory

    Full-Disk HD Images of the Earth from Satellites

    Thanks; they're all in this search result here: http://inventory.ssec.wisc.edu/inventory/?date=2011/12/6&time=&satellite=GOES-15&search=1#search&start_time:2015-07-06 14:30;end_time:2015-07-06 23:59;satellite:GOES-15;type:Imager;coverage:NH;schedule:ROUTINE; Basically the same as the imgur gif...
  3. Rory

    Photos of Planes and Contrails (That you took yourself)

    Anybody know the "most live" source for zoomed GOES-17 images? This one posts images about 12 minutes after they're taken: https://weather.msfc.nasa.gov/cgi-bin/sportPublishData.pl?dataset=goeswestabifulldisk&product=dayLandCloud.jpg&stamp=20190128_0915&loc=#image And this one after about 3...
  4. Rory

    Debunking Humor...

    Road sign in Ibiza yesterday.
  5. Rory

    Earth curve calculator for obstructions

    Here's a diagram showing 'the simplified trig': This doesn't factor in the tilt, nor the difference between 'base to base' and 'peak to peak' distances. It's accurate enough, though, and useful as a verifier to show that the more complex methods achieve pretty much the same result.
  6. Rory

    Earth curve calculator for obstructions

    I've been working on a calculator that outputs the predicted visible amount of a distant landmark when there's an obstruction above the horizon, such as a view over terrain with a ridge or intervening mountain. It seems to be working pretty well, and I'd say it's just about finished, but I have...
  7. Rory

    Debunk: The horizon never falling as proof of flat Earth theory

    A few shots from the Hunter theodolite on an iPhone SE over the last few days, first calibrating at sea level and then going up a 1500 feet hill. Predicted dip to the horizon from that height is 0.6°. The theodolite app claims accuracy to 0.1°, so I suppose the range in those pictures...
  8. Rory

    Water Level Showing Mountain and Horizon Dip Due to Curvature

    I posted my water level pics in a video on YouTube and quite a few commenters responded that I should have had holes in the bottoms of the bottles to ensure air pressure wasn't playing a part in where the levels are set. Seems like a reasonable request/proposal, so I shall do that next time -...
  9. Rory

    Simulating Atmospheric Refraction

    Amazing work, Mick! I love stuff like this 'cos it makes me realise my place in the grand scheme of things. ;) Coupla questions: do the red and blue lines of the 60 foot target signify anything? Being the same colour as the refraction lines there's a sense that they're related. Also, in the...
  10. Rory

    How to Take a Photo of the Curve of the Horizon

    One or two trees in the way doesn't seem to matter either. ;) I just screenshotted the horizon at that altitude from Walter Bislin's site and it matches up really nicely. I'd be interested in seeing how the P900 fares with the grid above.
  11. Rory

    How to Take a Photo of the Curve of the Horizon

    1500 feet. It's a pretty sweet spot with 180° views to a horizon and, I discovered, driveable to the top, so easy enough to go up with better gear. I might do the full set of parallel lines, water level, theodolite, curve of the horizon, actual eyes, and the new pipe one that the YouTube crowd...
  12. Rory

    How to Take a Photo of the Curve of the Horizon

    iPhone SE: Looks good right around the centre of the frame. Interestingly, more of an upward curve in the lower portion, and downward above centre. Analysing closer, a little over 7% of the horizontal field is showing pretty much perfect straight lines, which equates to pixels 1403-1621 in...
  13. Rory

    Water Level Showing Mountain and Horizon Dip Due to Curvature

    Finally got around to doing my own water level observation today up a hill at around 1500 feet elevation. Here's the levels lined up: Also took a shot from a few centimetres higher, to line up the far bottle with the horizon: The colour of the water is due to a mixture of curry powder...
  14. Rory

    Need debunking: Writings in the sky

    Where in the video are the images in the OP?
  15. Rory

    Need debunking: Writings in the sky

    Where are the words? Where was the claim posted?
  16. Rory

    How to Take a Photo of the Curve of the Horizon

    Barrel distortion on two phones, a Moto G3 and an iPhone 6: The distortion on the Motorola is so evident I can even see it in the viewfinder. (iPhone image rotated slightly: this compression technique is also useful in showing how poor I am at aligning a camera perfectly parallel to a...
  17. Rory

    Measuring the Curvature of the Horizon with a Level

    I posted a video on youtube briefly summarising how to take shots of the curvature of the horizon, and hopefully it will inspire some people to do this. A few responses, however, have shown that some don't think it's possible, given that the general understanding is that the horizon is 'flat'...
  18. Rory

    How to Show the Horizon is Below Eye Level, Using Actual Eyes

    What y'all think of these photos, with regard to using parallel lines to establish the vanishing point, and therefore eye level? (Hint: the sides of the pool and the markings on the runway all converge at a point some way above the horizon.)
  19. Rory

    Measuring the Curvature of the Horizon with a Level

    Indeed. Lots of convincing proofs of the curve of the horizon - but what I mean is the ol' straight edge 'n' compression technique, which is kind of lovely. :)
  20. Rory

    Measuring the Curvature of the Horizon with a Level

    Two and a half years and still no convincing shot of the curve of the horizon? :( I'm in a great spot to do it but I've never owned a good enough camera.
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