across-tools

The across-tools repository is the NASA-ACROSS library to perform specific astronomy-related calculations on the data hosted in the across-server. This repository is responsible for instrument bandpasses, footprint, ephemeris, two-line element (tle) analysis, and observatory/instrument visibility calculations.

Installation

This repository can be installed on python (version >=3.10) environments.

#activate your python environment (conda, mamba, venv... etc)
git clone https://github.com/NASA-ACROSS/across-tools.git
cd across-tools
python -m pip install .

or the latest released version with pip

python -m pip install across-tools

Usage

Below is a small example on how to utilize the tools to initialize a simple footprint, and perform a healpix query on a projected instrument footprint.

from across.tools import Coordinate
from across.tools import Polygon
from across.tools.footprint import Footprint

simple_polygon = Polygon(
   coordinates=[
      Coordinate(ra=-0.5, dec=0.5),
      Coordinate(ra=0.5, dec=0.5),
      Coordinate(ra=0.5, dec=-0.5),
      Coordinate(ra=-0.5, dec=-0.5),
      Coordinate(ra=-0.5, dec=0.5)
   ]
)
footprint = Footprint(detectors=[simple_polygon])

projected_footprint = footprint.project(
   coordinate=Coordinate(ra=42, dec=42), roll_angle=45
)
pixels = projected_footprint.query_pixels()

Contributing

Found a bug? Want to make a feature request? Or create a pull request? Navigate to our Contributing document for more instructions!

Other Links

Open Science at NASA

Notice

NASA Docket No. GSC-19,469-1, and identified as "Astrophysics Cross-Observatory Science Support (ACROSS) System

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.“

The copyright notice to be included in the software is as follows:

Copyright © 2025 United States Government as represented by the Administrator of the National Aeronautics and Space Administration and The Penn State Research Foundation. All rights reserved. This software is licensed under the Apache 2.0 License.