Sun Altimeter/Barometer Tutorial

[@markharrington1947]

Good tutorial for the barometer; but, how about an overview on it's use as an altimeter? Perhaps, with examples for hiking, e.g. using in conjunction with a compass and topographic map.

[@LedokolDX]

The black needle gives the altitude and the orange needle gives the mean sea level pressure. You can use the altitude to infer the MSL pressure (if you know the altitude, as in this video), or you can use the MSL pressure to infer the altitude. To find the altitude / elevation, you need to know the real-time MSL, which you can look up on the internet. In the example in the video, you can see that his ambient barometric pressure was 28.3 inHg. However, the MSL reading for his location was 28.86 inHg (see 1:22). Therefore, he rotated the outer ring so that the orange indicator was at 28.86 inHg. When this is done, the black needle rests at 450ft, which is his altitude. A compass or a topographic map is not required for this exercise.

[@hilaryjacobs8716]

So this contraption does not give you your elevation, you have to know it and use it to correlate pressure?

[@LedokolDX]

The black needle gives the altitude and the orange needle gives the mean sea level pressure. You can use the altitude to infer the MSL pressure (if you know the altitude, as in this video), or you can use the MSL pressure to infer the altitude. To find the altitude / elevation, you need to know the real-time MSL, which you can look up on the internet. In the example in the video, you can see that his ambient barometric pressure was 28.3 inHg. However, the MSL reading for his location was 28.86 inHg (see 1:22). Therefore, he rotated the outer ring so that the orange indicator was at 28.86 inHg. When this is done, the black needle rests at 450ft, which is his altitude.

[@turboturd7954]

@@LedokolDX your answer is no, if you need to hook to internet first.

[@noggler6211]

​@@turboturd7954If you have a topographic map, and you know where you are on the map. You will set it to your elevation, and it will tell you the air pressure.

[@belowmars]

So, if I need to know my altitude to calibrate the barometer to sea level, and need to know the sea level pressure level to calibrate the altimeter.... am I not going around the endless cycle of unknowing? This is like I must know A to find B and I must know B to find A... which I will never find either.. Say if I am going into a strange place where I will get no cell tower communication at all to the outside world, which means I cannot obtain the atmospheric pressure at sea level, what tool can I use to find my altitude? Can digital GPS give me real-time altitude since GPS doesn't rely on sea level pressure instead it uses light wave signals(and gyroscopes and accelerometers etc.) so it should be able to find real-time altitude without relying on another unknown data right? What other tools are there and any analog tools?

[@BackYardGardeningTip]

Kinda sucks when you don't finish the tutorial. How about the altimeter? Thumbs down!

[@dc5189]

I bought this $85 altimeter and it's clear it's just a barometer. That's fraud.