This file contains the format and keyword requirements for submission of data to the GBT Legacy Archive.
Last updated: 2024-08-08

- Files need to be in FITS format, either image or table format.
	- Spectra are to be in FITS table format
- Required header keywords for FITS images and spectra in FITS table format
	- `NAXIS` and relevant subsequent NAXIS (`NAXIS1`, `NAXIS2`, etc.)
	- Date information of some kind (`DATE`). If there is a single observation, please use `DATE-OBS`  with a suggested format of YYYY-MM-DD. However, if there were multiple observation dates and/or a date of creation for the data product please provide this information as you see fit in the header keywords with some permutation of `DATE` and detail the date keywords in your README.
	- `RESTFREQ` (when applicable) - rest frequency of your observations
	- `OBJECT` - Object/source name
	- Units
		- For FITS images/cubes, all relevant `CTYPE`s should be defined.
		- For FITS images, `BUNIT` (physical units of the array values) is required. Essentially, what units are your image in? The options are typically K or Jy/beam. If K, then the comments must indicate if these units are in Tmb, Ta*, or Ta where Tmb=main beam temperature, Ta\*=antenna-star temperature, and Ta=antenna temperature. For example if the image is in K where K is the main beam temperature then the comments read as follows: / Tmb
		- For FITS tables for spectra, units of each column need to be specified either in the header or associated with the columns. For example an astropy.unit can be assigned to columns when applicable (see [https://docs.astropy.org/en/stable/units/](https://docs.astropy.org/en/stable/units/)).
	- For FITS table spectra, coordinate information of the observation is required. Coordinates can be either (a) J2000 coordinates in which case the suggested format is `RA` and `Dec` header keywords in degrees, or (b) Galactic coordinates in which case the suggested format is `GLAT` and `GLONG` header keywords. Either way it needs to be clear what the coordinates of the source are and what units the coordinates are in.
- FITS tables with multiple entries
	- It is required to have either a readme with description of column names and units, or  units of each column need to be associated with the columns (again for example an astropy.unit can be assigned to columns when applicable).