bytran -|- spectral calculations for portable devices using the HITRAN database

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Planned for bytran 1.5

August 13, 2021:   We plan on deploying an alternative combinational Voigt function algorithm as the default https://doi.org/10.1016/j.jqsrt.2021.107797.  
(Note: The algorithm coefficients in the Fortran supplementary file need to be rewritten with a 'd' instead of 'e' in the exponent or else the calculated values will be limited to single precision;  Typos: Value "1." should be "1.28" in Table 3,  in the supplementary files "Kuntz" is misspelled as "Kunz" in several places.)

August 9, 2021:   Version 1.5 update is not yet ready.   Apologies to those who would like to see it released.   Over the last >2 years we have had several other tasks to address with higher priority which has slowed down the bytran development.   We will try to complete version 1.5 update as soon as we are reasonably able to.

Version 1.5 lineshape options window
Version 1.5 sensors selection window

The features planned for bytran 1.5 update include:   (1) The implementation of the Hartmann-Tran and a couple of other optional lineshape profiles,   (2) Experimental support of the authenticated access to HITRAN Online using the HAPI API key,   (3) as well as some slight improvements to the desktop versions.   (4) The support of the new SensorTag is planned for bytran version 1.5.   Custom ''bytran firmware for Texas Instruments'' (BFF-TI) is planned to enable the use of the new SensorTag with bytran (please read below for a short overview of the new SensorTag features).

The Texas Istrumnents has issued a new Wireless MCU Launchpad development kit and a new version of SensorTag LPSTK-CC1352R which is significantly different from its predecessor SensorTag CC2650STK (alternative link) bytran currently supports.   Unlike its predecessor the new SensorTag has fewer built in sensors but it combines multiple wireless communication protocols in one device and includes the TI's LaunchPad Microcontroller Development Board thus providing wide options for customization and addition of new sensors and hardware.

The new SensorTag LPSTK-CC1352R lacks an on-board pressure sensor but it can be added by interfacing with a pressure sensor development board (see examples at Mouser and Adafruit) or else with a to be discontinued booster pack BOOSTXL-SENSORS plugin module which also includes other sensors.   As an alternative to the SensorTag the BOOSTXL-SENSORS may also be used with the new Wireless MCU Launchpad development kit.

Mobile versions

Android™ 4.4 and above, iOS 8 and above, or Windows 10 (ARM & x64).
The iOS version will be updated with the relase of bytran 1.5.

Desktop versions

Desktop versions currently do not include and installer and contain unmodified mobile interface. Additional information about previous releases is available in the   Archive
  (1) Linux versions are currently unavailable due to the issues linking SSL libraries to access HITRAN over secure socket layers.   This issue will most likely be addressed with the release of bytran 1.5.   (2) The serial port profile Bluetooth connectivity used for remote control may not work (or requires additional setup) under Ubuntu and Mac OS.

Raspberry Pi board

Startng with version 1.3 bytran supports the Sense HAT add-on board.   To run bytran under Raspbian (tested on Stretch with Raspberry Pi 3) a script file supplied should be used as outlined in the readme file within the archive.

Source code

Distributed under the MIT license.   Cross-platform source code, written in Qt/C++.   Mobile and desktop operating systems supported.

Latest Version 1.4

Read this note to compile the source code for Raspberry Pi.


Distributed under the MIT license

bytran source code and binary are provided under the terms of the MIT license. The bytran binary distribution also includes dynamically linked Qt libraries it relies on which are distributed under the LGPL (Version 3) license, more information is available here.

Original bytran operation video

Example usage of the original bytran version 1.0 Alpha on a cell phone
(May 12, 2016)

About bytran

bytran is an application for calculating atmospheric and molecular absorption spectra using the HITRAN database and the line-by-line method.   The concentrations of molecules, optical pathlength, total pressure, temperature, and other input parameters are used to model the gas mixture optical transmission spectra as a function of wavelength.

bytran can be controlled remotely and supports optional usage of SensorTag, Sense Hat, and cell phone sensors for calculations using empirical readings of ambient total pressure, temperature and humidity (H2O vapor concentration) .   For more information read the overview of bytran, the bytran publication and the change log of the bytran releases.

Radiance now viewable as "separate molecules"
Coordinate rulers added (activated on zoom)

The usage of cell phone sensors is currenly limited to the Android operating system due to the limitations of the Qt environment.

Thermometer, Barometer & Humidity sensors

Line-by-line calculations using measured meteorological data -|- Sensors may be used to provide empirical values of total pressure, temperature and water vapor concentration as input instead of manual entry -|- SensorTag, Cell phone built in sensors, Sense HAT


NOTE: The new SensorTag model LPSTK-CC1352R and the Wireless MCU Launchpad development kit are not yet supported by bytran, its support is planned for bytran version 1.5.

SensorTag (model CC2650STK) is a keychain size coin battery operated bluetooth device containing temperature (TMP007 and BMP280, ~ ±1 °C accuracy), pressure (BMP280, ~ ±1 hPa accuracy) and humidity (HDC1000, < 3% accuracy) sensors.   Starting with version 1.2 bytran is able to connect to SensorTag and access its sensors.   The SensorTag may be purchased directly from Texas Instruments or its distributors.


Cell phone sensors

Bytran is able to access cell phone built in sensors however this support is limited to the thermometers and barometers under the Android operating system due to the present limitations of the Qt environment.   Future bytran editions will likely include custom code to suppport the iOS operating system and the humidity sensor.   A search of cell phones with a barometer, thermometer and/or humidity sensor may be performed here.


Raspberry Pi's Sense HAT

Starting with version 1.3 bytran supports the Sense HAT add-on board for Raspberry Pi to measure ambient total pressure (LPS25HB, accuracy of 10 to 100 Pa), temperature (HTS221, < 0.5 °C accuracy) and humidity (HTS221, < 3.5% accuracy) for input into the line-by-line calculations instead of the manual entry.

Though not currently supported by bytran, alternatives to the Sense HAT board are emerging which are compatible with the Raspberry PI.   One such board is the Environmental Sensor Board by Coral.

To report a bug or suggest a feature please email us:


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