Jan 25 2022.
article from prior work: ADS-B.pdf
...
Try this: https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/
Nope.
Try this: sudo port install gqrx
had to 'accept' Xcode license- sudo xcodebuild -license
then
sudo port install gqrx
...
Here are references I don't think I saw before:
div-class-title-aviation-and-jet-contrails-impact-on-astronomy-div.pdf
ICRATcontrails_JR050412.pdf
Geophysical Research Letters - 2021 - Bräuer - Airborne Measurements of Contrail Ice Properties Dependence on Temperature.pdf
AI_detection_usingGOES
MergingSatelliteAndADS-B
Tried out using API key access to Flight Aware database. Used old user account under astrostubbs@gmail.com
API key is
1Q0ffUe5VyAsIASAFAwcJiYjs7Mse0nh
...
Flight altitudes depend on vertical separation convention:
Flight levels for northbound vs southbound air traffic over Chile are typically based on the hemispheric rule, also known as the "East/West rule" or "RVSM (Reduced Vertical Separation Minimum) rule". However, since Chile is in the Southern Hemisphere, the rule is applied differently compared to the Northern Hemisphere. Here's how it generally works:
- Northbound traffic (odd flight levels):
- FL290 (29,000 feet)
- FL310 (31,000 feet)
- FL330 (33,000 feet)
- FL350 (35,000 feet)
- FL370 (37,000 feet)
- FL390 (39,000 feet)
- FL410 (41,000 feet)
- Southbound traffic (even flight levels):
- FL280 (28,000 feet)
- FL300 (30,000 feet)
- FL320 (32,000 feet)
- FL340 (34,000 feet)
- FL360 (36,000 feet)
- FL380 (38,000 feet)
- FL400 (40,000 feet)
Key points to note:
- This is the opposite of what's used in the Northern Hemisphere, where eastbound flights use odd flight levels and westbound flights use even levels.
- The actual flight levels used may vary based on specific air traffic control instructions, weather conditions, or other operational factors.
- Below FL290, different rules may apply, and separation is often managed by air traffic control based on various factors including terrain and traffic density.
- Some high-altitude aircraft may operate above these levels, following specific procedures and clearances.
- Local variations or exceptions may exist, especially near major airports or in areas with complex airspace structures.
Tried out using API key access to Flight Aware database. Used old user account under astrostubbs@gmail.com
API key is
1Q0ffUe5VyAsIASAFAwcJiYjs7Mse0nh
this shell script (GetFlights3.sh) worked (after some fussing around)
...
./DoIt.sh | sort -k 8 -n -r
Contrail likelihood:
Now go find winds aloft. The Windy API lets us do this. But its arguments are pressure levels in hPascals, like 300h, which corresponds to about 30,000 feet altitude.
here is APi kee: WindyAPI.txt
this script spits out predictions for Rubin site:
Windy.sh
...
This next script almost works... finds time closest to current one and spits out winds at 30,000 ft
So (u,v) is a vector with x and y components of wind in (W to E, S to N) coordinate system. But our definition of azimuth is from y axis rotating towards x axis.
...
With Preplexity's help generated a shell script that asses ice formation likelihood at 30000 feet:
produces
produces an output file, contrail_predictions.csv, with timestamp, temperature at 300hPa, RH, RH ice, Favorable or Not Favorable for contrail formation:
2024-07-20 21:00:00 UTC,-42.52,28.78,43.45,Not Favorable
2024-07-21 00:00:00 UTC,-42.32,18.62,28.07,Not Favorable
2024-07-21 03:00:00 UTC,-42.98,24.97,37.86,Not Favorable
2024-07-21 06:00:00 UTC,-42.67,14.98,22.65,Not Favorable
2024-07-21 09:00:00 UTC,-42.67,13.93,21.06,Not Favorable
2024-07-21 12:00:00 UTC,-42.41,7.90,11.91,Not Favorable
2024-07-21 15:00:00 UTC,-41.59,7.19,10.77,Not Favorable
2024-07-21 18:00:00 UTC,-42.30,6.49,9.79,Not Favorable
2024-07-21 21:00:00 UTC,-41.90,5.45,8.18,Not Favorable
2024-07-22 00:00:00 UTC,-42.57,9.79,14.79,Not Favorable
2024-07-22 03:00:00 UTC,-43.43,8.50,12.95,Not Favorable
2024-07-22 06:00:00 UTC,-44.64,12.60,19.39,Not Favorable
2024-07-22 09:00:00 UTC,-44.54,16.86,25.92,Not Favorable
2024-07-22 12:00:00 UTC,-43.90,22.23,33.99,Not Favorable
2024-07-22 15:00:00 UTC,-44.21,30.90,47.37,Not Favorable
2024-07-22 18:00:00 UTC,-44.73,28.20,43.44,Not Favorable
2024-07-22 21:00:00 UTC,-45.39,32.17,49.85,Not Favorable
2024-07-23 00:00:00 UTC,-44.45,29.85,45.86,Not Favorable
2024-07-23 03:00:00 UTC,-43.47,18.05,27.49,Not Favorable
2024-07-23 06:00:00 UTC,-43.19,15.87,24.12,Not Favorable
2024-07-23 09:00:00 UTC,-41.43,8.08,12.07,Not Favorable
2024-07-23 12:00:00 UTC,-40.41,6.57,9.73,Not Favorable
2024-07-23 15:00:00 UTC,-39.87,4.99,7.35,Not Favorable
2024-07-23 18:00:00 UTC,-37.32,2.79,4.02,Not Favorable
2024-07-23 21:00:00 UTC,-34.86,1.78,2.51,Not Favorable
2024-07-24 00:00:00 UTC,-34.80,1.40,1.97,Not Favorable
2024-07-24 03:00:00 UTC,-33.19,1.61,2.22,Not Favorable
2024-07-24 06:00:00 UTC,-33.52,2.29,3.18,Not Favorable
2024-07-24 09:00:00 UTC,-35.05,3.55,5.00,Not Favorable
2024-07-24 12:00:00 UTC,-37.39,4.85,6.98,Not Favorable
2024-07-24 15:00:00 UTC,-39.07,12.80,18.72,Not Favorable
2024-07-24 18:00:00 UTC,-39.29,24.85,36.42,Not Favorable
2024-07-24 21:00:00 UTC,-39.32,37.12,54.42,Not Favorable
2024-07-25 00:00:00 UTC,-39.47,44.86,65.85,Not Favorable
2024-07-25 03:00:00 UTC,-40.24,75.56,111.73,Favorable
2024-07-25 06:00:00 UTC,-40.53,53.39,79.15,Not Favorable
2024-07-25 09:00:00 UTC,-40.57,43.91,65.12,Not Favorable
2024-07-25 12:00:00 UTC,-40.95,76.10,113.26,Favorable
2024-07-25 15:00:00 UTC,-41.37,99.20,148.21,Favorable
2024-07-25 18:00:00 UTC,-42.09,85.45,128.51,Favorable
2024-07-25 21:00:00 UTC,-42.78,95.96,145.23,Favorable
2024-07-26 00:00:00 UTC,-43.43,87.28,132.88,Favorable
2024-07-26 03:00:00 UTC,-42.87,54.33,82.30,Not Favorable
2024-07-26 06:00:00 UTC,-44.80,99.82,153.85,Favorable
2024-07-26 09:00:00 UTC,-44.86,91.47,141.07,Favorable
2024-07-26 12:00:00 UTC,-45.18,77.33,119.60,Favorable
2024-07-26 15:00:00 UTC,-45.51,82.50,127.98,Favorable
2024-07-26 18:00:00 UTC,-45.66,91.80,142.59,Favorable
2024-07-26 21:00:00 UTC,-45.26,85.74,132.70,Favorable
2024-07-27 00:00:00 UTC,-45.02,42.92,66.29,Not Favorable
2024-07-27 03:00:00 UTC,-43.85,21.64,33.06,Not Favorable
2024-07-27 06:00:00 UTC,-44.21,31.45,48.22,Not Favorable
2024-07-27 09:00:00 UTC,-44.06,45.86,70.21,Not Favorable
2024-07-27 12:00:00 UTC,-43.10,54.54,82.78,Not Favorable
2024-07-27 15:00:00 UTC,-43.07,50.08,76.00,Not Favorable
2024-07-27 18:00:00 UTC,-43.73,65.04,99.30,Not Favorable
2024-07-27 21:00:00 UTC,-44.71,65.70,101.19,Favorable
2024-07-28 00:00:00 UTC,-44.07,19.24,29.47,Not Favorable
2024-07-28 03:00:00 UTC,-43.68,20.34,31.04,Not Favorable
2024-07-28 06:00:00 UTC,-43.45,19.27,29.34,Not Favorable
2024-07-28 09:00:00 UTC,-42.89,12.38,18.75,Not Favorable
2024-07-28 12:00:00 UTC,-42.44,28.66,43.24,Not Favorable
2024-07-28 15:00:00 UTC,-43.20,80.83,122.80,Favorable
2024-07-28 18:00:00 UTC,-42.73,100.00,151.28,Favorable
2024-07-28 21:00:00 UTC,-41.37,9.94,14.85,Not Favorable
2024-07-29 00:00:00 UTC,-40.79,56.65,84.19,Not Favorable
2024-07-29 03:00:00 UTC,-40.50,85.53,126.77,Favorable
2024-07-29 06:00:00 UTC,-40.08,69.13,102.06,Favorable
2024-07-29 09:00:00 UTC,-39.75,53.80,79.20,Not Favorable
2024-07-29 12:00:00 UTC,-40.37,100.00,148.03,Favorable
2024-07-29 15:00:00 UTC,-40.64,100.00,148.40,Favorable
2024-07-29 18:00:00 UTC,-40.26,100.00,147.89,Favorable
2024-07-29 21:00:00 UTC,-40.74,100.00,148.55,Favorable
2024-07-30 00:00:00 UTC,-42.28,98.65,148.63,.65,148.63,Favorable
2024-07-30 03:00:00 UTC,-43.54,100.00,152.40,Favorable
2024-07-30 06:00:00 UTC,-40.48,52.54,77.87,Not Favorable
2024-07-30 09:00:00 UTC,-40.37,24.82,36.74,Not Favorable
2024-07-30 0312:00:00 UTC,-4340.5400,10068.0020,152100.4061,Not Favorable
2024-07-30 0615:00:00 UTC,-40.4825,5264.5437,7795.8718,Not Favorable
2024-07-30 0918:00:00 UTC,-40.37,24.82,36.74,Not Favorable
2024-07-30 12:00:00 UTC,-40.00,68.20,100.61,Not Favorable
2024-07-30 15:00:00 UTC,-40.25,64.37,95.18,Not Favorable
2024-07-30 18:00:00 UTC,-38.27,36.31,52.71,Not Favorable
So the time difference is 3 hours, eight predictions per 24 hour cycle. Predictions go out 10 days. Wow.
We can validate this using all-sky camera data in daytime.
Let's take 40 m/s as typical wind speed at 30,000 feet ~ 10 km. Angular rate is 40/1e4 = 0.2 degrees per second.
Imagine width is ~100m so that's 0.6 degrees. So if wind is cross-contrail it moves its width in a few seconds. That seems about right.
If wind is cross-contrail then in about 10 seconds is traverses LSST FOV. That's consistent with what is posted above.
But if wind is parallel to contrail it can persist in the sky at fixed alt-az. If we're tracking on the horizon the telescope moves 15 arcsec/sec * 15 sec = 0.06 degrees so 1/10th the width of the contrail.
Tracking is totally subdominant.
SO here is a possible approach:
1) use daytime allsky images in conjunction with Flight Aware to look at contrails. Set a flag for the night, turn contrail avoidance on or off.
2) if contrail avoidance is on, create an avoidance map in alt, az coordinates by:
- run plane-finder every minute or so. Identify any new planes that are above some elevation angle cutoff. Start a data file per plane in a folder for that night
- accumulate track information for each plane above threshold elevation angle.
- Use that track information and winds aloft to create contrail track for each plane. We can also predict this 5-10 min into the future.
- Use wind-aloft direction to determine contrail transport direction- is it along or cross-contrail? Make photometry assessment.
- send contrail mask file to scheduler.
- We can validate all this in daytime with all-sky Canon camera.
...
38.27,36.31,52.71,Not Favorable
So the time difference is 3 hours, eight predictions per 24 hour cycle. Predictions go out 10 days. Wow.
We can validate this using all-sky camera data in daytime.
Let's take 40 m/s as typical wind speed at 30,000 feet ~ 10 km. Angular rate is 40/1e4 = 0.2 degrees per second.
Imagine width is ~100m so that's 0.6 degrees. So if wind is cross-contrail it moves its width in a few seconds. That seems about right.
If wind is cross-contrail then in about 10 seconds is traverses LSST FOV. That's consistent with what is posted above.
But if wind is parallel to contrail it can persist in the sky at fixed alt-az. If we're tracking on the horizon the telescope moves 15 arcsec/sec * 15 sec = 0.06 degrees so 1/10th the width of the contrail.
Tracking is totally subdominant.
SO here is a possible approach:
1) use daytime allsky images in conjunction with Flight Aware to look at contrails. Set a flag for the night, turn contrail avoidance on or off.
2) if contrail avoidance is on, create an avoidance map in alt, az coordinates by:
- run plane-finder every minute or so. Identify any new planes that are above some elevation angle cutoff, say 15 degrees. Start a data file per plane in a folder for that night
- accumulate track information for each plane above threshold elevation angle.
- Use that track information and winds aloft to create contrail track for each plane. We can also predict this 5-10 min into the future.
- Use wind-aloft direction to determine contrail transport direction- is it along or cross-contrail? Make photometry assessment.
- send contrail mask file to scheduler.
- We can validate all this in daytime with all-sky Canon camera.
...
July 26, 2024
For flying weather balloons ourselves, to measure temp and humidity:
Visala downlinks are 403-406 MHz, can read it with SDR radio
High pass and low pass RF filters from Minicircuits: 
ordered July 26 2024.
Rubber duckie antenna:
eventually can use a Yagi:
and this?
a resource: https://overlookhorizon.com/how-to-launch-weather-balloons/inflate-weather-balloon/
From Vaisala:
RS 41 SGE
RI 41 ground check station and associated software
FB 13 weight and clamp
weather balloons from Totex
There is also a contrail predictor avail as a plug-in add-on to Windy. It uses the Appleman criteria for exhaust contrail prediction.
quote from Vaisala, asked Helen to place this order on July 30:
Vaisala_Q-00258333_Harvard University_2024-7-30.pdf
Windows software for decoding Vaisala RS41:
http://escursioni.altervista.org/Radiosonde/
Rubin All-sky camera data and access
software installation on Windows for radiosonde monitoring