ADS-B and Contrails

Jan 25 2022.

article from prior work: ADS-B.pdf

Signals are broadcast (unencrypted) from aircraft at 1.090 GHz, can be directly monitored with software defined radio on the ground.

Preamp/filter combination: https://v3.airspy.us/product-category/preamps/

software needed is some SDR (software-defined radio) control stuff plus a module called dump1090 (https://github.com/MalcolmRobb/dump1090)

OSX installation instructions: https://web.stanford.edu/class/ee26n/Assignments/Dump1090.html

OK that didn't work, try this:

https://github.com/mxswd/dump1090-mac

and/or

OK that didn't work due to some library access issue. Used this link

https://inst.eecs.berkeley.edu/~ee123/fa12/rtl_sdr.html

That downloads OSX executables. Need to overcome OSX security with System Preferences → Privacy and then allow these to run. That seems to work, for rtl-sdr. Still need to fix dump1090

See https://harvard.zoom.us/j/98577694028?pwd=MXdISGhMN0dDZ0U4S3g5dzlKeUR0QT09

OSX application CubicSDR seems to work with RTL-SDR v3 hardware. From https://github.com/cjcliffe/CubicSDR/releases

Nope- can't get rtl_tcp running.

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

Jan 29, 2022

Trying again to get dump1090 on Big Sur mac laptop.

Following instructions here: https://www.hfunderground.com/wiki/index.php/RTL-SDR

sudo port install libusb

cd rtl-sdr/

/Users/cstubbs/desktop/OldDesktop/projects/ADS_B/rtl-sdr

autoreconf -i
./configure 
make
sudo make install
sudo ldconfig

last thing, ldconfig, didn't work, not found. Try it anyway! 
Nope. Evidently in Big Sur OSX the dynmica library functions changed radically. Great. 

From https://discussions.flightaware.com/t/using-on-a-mac/61904/21 

sudo port install sox

brew install librtlsdr


I give up. We'll use a mac mini (with old OSX) or a raspberry pi or generic Linux box

Raspberry Pi's are out of stock everywhere. Bought two old Mac Mini's on Amazon with Catalina version of OSX. That ought to work.

Getting old version of Mac operating system: https://support.apple.com/en-us/HT211683

Steps:

don't upgrade operating system!
install Xcode
install macports
follow rtl-sdr and dump1090 instructions
hope

Connectorization:

ADS-B antenna has Female type N connector.

Uputronics preamp has SMA F on both ends.

Coax cable- LMR400-UF is ultra-flexible version of LMR400 cable, 4.7 dB/100 feet at 0.9 GHz.

cable spec sheet: LMR-400-UF.pdf

Preamp:

This is a SAW based units which is cost effective and gives excellent performance gains.

All our preamps are compatible with most USB SDR Dongles such as the RTL USB, Airspy, Fun Cube. You can power them from either bias tee (This item is 100% compatible with the Airspy bias-tee) or a simple USB Mini B cable (Not Supplied - See related items for a suitable USB Type A to Mini B Cable).

A regulator is fitted as standard which means the bias-tee voltage input range is 5V to 26V. USB input is 5V.

This unit is a small filter and preamp designed to go between a software defined radio receiver and an antenna. Using a SAW bandpass filter and a low noise amplifier (LNA), it stops out of band intermodulation while providing additional gain for increased sensitivity. The LNA is before the SAW filter in this design to reduce the noise factor of the unit. This particular model is tuned for use with ADS-B frequencies (1090MHz).

The LNA used is a MiniCircuits PSA4-5043+ which provides about 16dB of gain @ 1090MHz.

The insertion loss of this filter is approximately 2.3dB, which does increase the overall noise figure of the unit to 0.75dB, and gives effective gain of 13 dB or so. This will help accommodate cable attenuation.

Since March 2020 we have fitted improved SMA female connectors for antenna input and radio output to address the issue of the SMA barrels coming away. Also the Bias Tee regulator kit is now fitted as standard. At this time a ceramic filtered version of this unit is no longer available.

Datasheet here :

1090MHz ADS-B SAW Filter & Preamp For Dongles Datasheet (Outdated needs revising for Match 2020 design)

OK, got older version of Mac OSX on a mac mini, Catalina circa 2014, used on Amazon

steps:

made user ads with pwd ADSB
upgraded to Catalina 10.15.7 from 10.15.1, with software update tool
install Xcode tools (compilers, etc) version 12.5.1 from developer.apple.com, also command line tools for 12.5.1
1. nope, that didn't work. Try an earlier version of Xcode - need 12 or 12.1 . Also command line tools for xcode 12
2. Xcode 12.1 seemed to install OK. Double-click on it and allow it to install components.
3. command line tools for 12 installed OK too
install macports (catalina version) from guide.macports.org
install homebew package manager

attempt to execute brew install instructions above failed due to library linking issue- 'library not found for lusb-1.0'
This is in ~/SDR/rtl-sdr/build

Try using the Berkeley OSX version:

get 'failed to open device #0'

---------------------

this seemed to partially work:

make LIBRARY_PATH=/usr/local/lib
sudo make install

in ~/SDR/rtl-sdr/build

at least it seems to have found a receiver!

tried dump1090 from flightaware but Makefile has a conditional error

so try dump1090osx. Nope.

Try

in dump1090_2

git clone https://github.com/antirez/dump1090.git

cd dump1090

make LIBRARY_PATH=/usr/local/lib

./dump1090 --interactive

seems to work!! (after plugging in the antenna)

sudo port install wget

then

wget -O - -q http://myreceiver.30003 > foo.txt

---------------------------

for a map with planes:

./dump1090 --enable-agc --aggressive --net --net-http-port 8080

then

browser to http://127.0.0.1:8080 gives a map with planes on it!

also

wget -O - -q 127.0.0.1:8080 > foo.txt

gets html source code for this panel.

in ~/SDR/dump1090_2

mkdir public_html/data/

nope, the installed version does not seem to have write-json.

But the data do go somewhere.... where does the html source file reside?

netcat (nc) is a useful tool for snagging info from the http port.

-----------------

OK, this works for both terminal output, web page, and data capture:

./dumnp1090 --enable-agc --aggressive --net --interactive

then point browser to 127.0.0.1 for web map and moving planes

and also (in another window) do

nc 127.0.0.1 30003 > datafile

(default port seems to work, not 8080)

this also seems to work

wget 127.0.0.1:30003/data.json

message formats described here: http://woodair.net/sbs/article/barebones42_socket_data.htm

Need to parse and aggregate the various messages, need at least 3 to get flight ID, lat, long, airspeed, heading.

This looks useful for parsing into a database: https://github.com/yanofsky/dump1090-stream-parser

cute tool to prepend a timestamp in ISO format:

brew intall moreutils

then for any output stream | ts '%Y-%m-%d.%H.%M.%.S%z'. will prepend a timestamp in UT

Satellite data access: (2/6/2022)

updated CLASS access for NOAA

NOAA COMPREHENSIVE LARGE ARRAY-DATA STEWARDSHIP SYSTEM

        A SERVICE OF:
OFFICE OF SATELLITE DATA PROCESSING AND DISTRIBUTION
---------------------------------------------------

Congratulations!

You have successfully registered with the Comprehensive
Large Array-data Stewardship System (CLASS).

Your user name/ID will be: stubbs1
(Please save this ID, as you will not be able to change
it in the future.)

You may now log into CLASS as a Registered User.
http://www.class.noaa.gov/

Please forward any questions to the following:

     NOAA/CLASS User Assistance
     email: class.help@noaa.gov

Again, Thank you for registering with CLASS.

-The CLASS Staff

-----------

pwd=cact4class

ESO page on contrails: https://www.eso.org/gen-fac/pubs/astclim/contrails/

AVHRR is in sun-synch orbit, get data twice per day. 1 x 1 km pixels

GOES is in geosynch orbit, multiband. GOES East is GOES-16. Image archive at Wisconsin: https://www.ssec.wisc.edu/datacenter/archive.html

GOES South America: https://www.star.nesdis.noaa.gov/goes/sector.php?sat=G16&sector=ssa

detection from GOES and other geosynch data: https://www.eumetsat.int/contrails-when-do-we-see-them-satellites

night-time microphysics images have a color plane (red) that is 10.4 - 12.4 micron difference. See https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&sector=ssa&band=NightMicrophysics&length=240&dim=1

ESO shows wind field at 200 mb. That's an altitude of around 12km or 40,000 feet. That should be the wind at contrail altitude. ESO data page is at http://wxmaps.org/pix/sa.00hr

forecasts of 200 mbar wind field out many days is at http://wxmaps.org/pix/sa.jet

GOES data access- http://cimss.ssec.wisc.edu/goes-r/data.html

AMDAR data of winds aloft collected by commercial aircraft. Provides along-track data for wind speed and direction: https://climatologia.meteochile.gob.cl/application/requerimiento/producto/RE5030

Chilean weather service has an ice cloud map, derived from GOES-16 data. One could imagine there being a couple of contrails in the center of this image:

wind speed of 30 m/s at an altitude of 10 km is an angular rate of 30/10000 rad/s, or 0.17 degrees/sec. This is way higher than sidereal rate. In 15 sec a contrail moves one LSST field width in one exposure, so it's like high cirrus of low optical depth, where optical depth is width of contrail divided by field width. At higher zenith angles the angular rate is (v/30 m/s)*0.17 deg/s /sec(zenith). But if a contrail is within the image at either the start or the end of the frame, we'll get a weird edge of obscuration. How well-defined that edge is depends on transverse dissipation. Frame subtraction residuals will be a clear indicator of something being amiss, so we will have a quality control opportunity. In fact the variance in fixed-centroid photometry for a set of indicator stars, and the spatial structure of the residuals, is a good metric to use.

July 20 2024.

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

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)

#!/bin/bash

curl -v -X GET "https://aeroapi.flightaware.com/aeroapi/flights/search?query=-latlong+%22-40.953469+-60.045360+-20.962321+-90.046577%22" \
-H "Accept: application/json; charset=UTF-8" \
-H "x-apikey: 1Q0ffUe5VyAsIASAFAwcJiYjs7Mse0nh" \

this returns a JSON object, which can be nicely formatted using jq:

./GetFlights3.sh > foo.txt
cat foo.txt | jq

to strip out just the flight IDs

cat foo.txt | jq ".flights[].ident"

Lat Long for Rubin is -30.2446, -70.7494

What is decent size of bounding box in lat long?

Let's assume we want some advance warning for flights that are headed to us, as well as tracking for projections.
lat from -35 to -20 goes from Santiago to Peru. long -74 to -68 is very generous in EW direction.

For flights directly overhead, let's go to 100 km x 100 km.

The range of latitudes and longitudes that span a 100 km by 100 km area around the point (-30.2446, -70.7494) is approximately:

Latitude range: -30.6951 to -29.7941
Longitude range: -71.2696 to -70.2292

Made DoIt.sh that runs two other shell scripts, that produce a row per airplane with azimuth and elevation from Rubin!

Need to install jq utility.

Here are the scripts:
DoIt.sh
AllFlights.sh
ProcessFlights.sh

running ./DoIt.sh gives

flight ID, lat, long, alt in meters, heading in degrees of azimuth, airspeed in knots, az (degrees N to E) , elevation angle (deg)

./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

produces this:

christopherstubbs@Christophers-MacBook-Pro-2 FlightAware % ./Windy.sh

{

"ts": [

1721509200000,

1721520000000,

1721530800000,

1721541600000,

1721552400000,

1721563200000,

1721574000000,

1721584800000,

1721595600000,

1721606400000,

1721617200000,

1721628000000,

1721638800000,

1721649600000,

1721660400000,

1721671200000,

1721682000000,

1721692800000,

1721703600000,

1721714400000,

1721725200000,

1721736000000,

1721746800000,

1721757600000,

1721768400000,

1721779200000,

1721790000000,

1721800800000,

1721811600000,

1721822400000,

1721833200000,

1721844000000,

1721854800000,

1721865600000,

1721876400000,

1721887200000,

1721898000000,

1721908800000,

1721919600000,

1721930400000,

1721941200000,

1721952000000,

1721962800000,

1721973600000,

1721984400000,

1721995200000,

1722006000000,

1722016800000,

1722027600000,

1722038400000,

1722049200000,

1722060000000,

1722070800000,

1722081600000,

1722092400000,

1722103200000,

1722114000000,

1722124800000,

1722135600000,

1722146400000,

1722157200000,

1722168000000,

1722178800000,

1722189600000,

1722200400000,

1722211200000,

1722222000000,

1722232800000,

1722243600000,

1722254400000,

1722265200000,

1722276000000,

1722286800000,

1722297600000,

1722308400000,

1722319200000,

1722330000000,

1722340800000,

1722351600000,

1722362400000

],

"units": {

"wind_u-300h": "m*s-1",

"wind_v-300h": "m*s-1"

},

"wind_u-300h": [

24.22140821109733,

45.67694476108432,

26.15707247470207,

30.043442280527792,

24.343856929972674,

24.81776313087928,

32.15345826668342,

27.16441444399631,

33.57549464289517,

24.071630971919397,

21.406358770933146,

21.100554747236817,

18.758246338509004,

46.72930464172967,

30.560141978342415,

36.80756882891751,

25.876902179351646,

26.328882009317844,

32.88687948596759,

32.506398691676864,

29.610422935577784,

21.270457640901185,

26.97290295288333,

19.914941848991933,

25.1720805743376,

26.351126153750176,

31.752745893408928,

26.854373440408065,

17.71308932367991,

31.300130516458996,

28.231285980771332,

15.412091468897916,

50.33094939882112,

26.341804797988036,

16.08502980022546,

22.654255273588756,

48.114267443887584,

27.533349468081607,

25.924674127632596,

23.535653015596775,

26.636168975976236,

33.01367110923204,

32.289253472218064,

22.282460288076436,

40.15563033947998,

26.436607223068776,

21.327127246955026,

25.509026400239293,

31.47681257795039,

38.50426742662025,

20.902581861788835,

31.20066741349722,

33.59403142992215,

24.763741637257844,

15.385716269070981,

34.08075449500166,

27.087089560969474,

35.557341987321394,

36.24892303017331,

20.016523441899697,

40.318012593836286,

31.902417208089542,

28.82605203309381,

12.951783170181272,

28.56071116736487,

21.70665472077012,

20.212483761899087,

27.91277101739929,

24.807170681149593,

33.71256094239741,

26.56647065675487,

18.860463478400586,

27.08984359789921,

25.090095013429757,

29.525577413242917,

23.676002974515267,

18.94064832285445,

16.783813708893636,

12.288378043610379,

44.93865101492452

],

"wind_v-300h": [

21.67038570056732,

-44.167596586850415,

14.43023573422853,

8.266897932007364,

-8.604653818346838,

-3.17833327161586,

-37.1686990977489,

-3.080649389966576,

5.018336500676773,

-49.94954751521067,

11.532725752574809,

6.537874147932964,

-32.83445382164311,

-40.554437698817395,

24.264446045964963,

14.983809528379352,

-32.4371360803648,

18.077832006319614,

-39.68548996645143,

13.917204566738828,

-37.74526294607695,

-28.270975764674972,

-40.83785450778204,

3.2151912556244553,

14.584297715540577,

6.562104329514016,

-4.576720010967273,

5.453144247314613,

24.80037187321626,

-49.17341854929458,

-50.78892297871797,

7.864428892282743,

-2.545772901287695,

-40.96415671413319,

-5.044248042180982,

23.326146573404717,

-43.2361655122186,

10.954254015933362,

3.3702071810931993,

7.275559164332855,

-41.674845110897515,

-5.84622889474445,

4.14471444194283,

-46.23011924811781,

6.316177525908829,

-4.877593998000108,

-0.854048333741531,

-34.13582444025509,

-52.94350125110988,

-39.318698438188456,

-41.21809664865491,

8.80435006990943,

8.981497499814289,

12.789737967898816,

-34.646184564105994,

16.089621594861555,

-28.362363614889702,

-5.1943988524503855,

2.892376552986794,

3.077632508223905,

-46.270566480363186,

-6.6053776546707095,

22.097084921872934,

-34.795763007881376,

-1.6606081182572967,

7.784297583117384,

-10.285312633675,

-19.6873862424124,

-42.590822290190324,

35.256267591894066,

10.518396930723105,

12.722580299264957,

5.777676049434401,

-49.635318309983575,

-5.114362937700698,

-5.737383866461483,

1.3860033350933993,

-6.119629290063447,

8.861777508144622,

6.3908713533808434

],

"warning": "The trial API version is for development purposes only. This data is randomly shuffled and slightly modified."

}

-------------------

This next script almost works... finds time closest to current one and spits out winds at 30,000 ft

Windy6.sh

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.

Produces:

christopherstubbs@Christophers-MacBook-Pro-2 FlightAware % ./Windy6.sh

Wind data for approximately 30,000 feet (300hPa):
Time: 2024-07-21 03:00:00 UTC
Wind speed: 36.0 knots
Wind direction: 65.1
U component: 16.783813708893636 m/s
V component: 7.784297583117384 m/s

I upgraded to Windy professional version, now gives repeatable and sensible results. API key is the same.

OK so now we have airplanes, alt-az to airplanes, wind speed and direction at 30,000 feet. Let's think about how to use this information.

BTW this is a good resource for Pachon conditions including jet stream

https://www.meteoblue.com/en/weather/outdoorsports/seeing/Cerro+Pachon_-30.238N-70.734E2698_America%2FSantiago

With Preplexity's help generated a shell script that asses ice formation likelihood at 30000 feet:

Contrails.sh

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,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 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, 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.

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