Skip to main content

Take a bite out of TESS Full Frame Images using HTTP range requests.

Project description

Take a quick bite out of TESS Full Frame Images using HTTP range requests.

pypi

tess-bite is a user-friendly package which provides fast access to sections of TESS Full-Frame Image (FFI) data. It uses the HTTP range request mechanism to download only those parts of an FFI that are required to obtain a cut-out image.

Installation

python -m pip install tess-bite

Example use

Obtain a Target Pixel File for a stationary object:

>>> from tess_bite import bite
>>> bite("Alpha Cen", shape=(10, 10))
TargetPixelFile("Alpha Cen")

Obtain a Target Pixel File centered on a moving asteroid:

>>> from tess_bite import bite_asteroid
>>> bite_asteroid("Vesta", start="2019-04-28", stop="2019-06-28)
TargetPixelFile("Vesta")

Obtain a cut-out image from a single FFI:

>>> from tess_bite import bite_ffi
>>> bite_ffi(url, col=50, row=20, shape=(20, 20))

Quickly download the header of an FFI:

>>> from tess_bite import bite_header
>>> bite_header(url, ext=0)
FitsHeader

What are HTTP range requests?

Tess-bite is powered by the HTTP range request protocol. This is a mechanism which allows a client to request specific bytes from a file on a web server. For example, downloading a 3-by-3 pixel square of 4-byte pixel values from a TESS image can be done very quickly using a HTTP request as follows:

>>> import httpx
>>> url = "https://mast.stsci.edu/portal/Download/file?uri=mast:TESS/product/tess2019142115932-s0012-2-1-0144-s_ffic.fits"
>>> resp = httpx.get(url, headers={"Range": "bytes=80000-80012,80020-80032,80040-80052"})
>>> print(resp.text)

--00000000000000000103
Content-Type: application/octet-stream
Content-Range: bytes 80000-80012/35553600

D?A@DLR½DW˜oD
--00000000000000000103
Content-Type: application/octet-stream
Content-Range: bytes 80020-80032/35553600

³D .]D?ªJD
--00000000000000000103
Content-Type: application/octet-stream
Content-Range: bytes 80040-80052/35553600

D-aöD+W/D?R?D
--00000000000000000103--

Of course the difficult part is to translate pixel coordinates to byte positions, and to convert bytes to pixel values. Tess-bite takes care of these steps for you!

Documentation

Coming soon!

Similar services

TESScut is an excellent API service which allows cut outs to be obtained for stationary objects. Tess-bite provides an alternative implementation of this service by leveraging the HTTP range requests mechanism to download pixel values directly from FFI files.

Compared to TESScut, the goal of tess-bite is provide an alternative way to obtain cut-outs which does not require a central API service, but can instead be run on a local machine or in the cloud. At this time tess-bite is an experiment, we recommend that you keep using TESScut for now!

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for tess-bite, version 0.1.0
Filename, size File type Python version Upload date Hashes
Filename, size tess_bite-0.1.0-py3-none-any.whl (6.0 kB) File type Wheel Python version py3 Upload date Hashes View
Filename, size tess-bite-0.1.0.tar.gz (6.0 kB) File type Source Python version None Upload date Hashes View

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring DigiCert DigiCert EV certificate Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page