Ssos

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* Including preprocessing steps: Certain FITS header keywords stop SCAMP from computing the astrometric solution. If FIX_HEADER is set to True, these keywords are removed from the original images. Further, the projection parameters CTYPE are changed from ZPN to TAN if necessary
* Started switching to f-strings. This requires python3.6 but improves readability and maintainability of the code
* Improved console output: The progress bar on the SExtractor runs and others now display time estimates. The tqdm package is used and added as requirement
* Some changes to the default settings of ssos and scamp
* Bugfixes

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* Bugfix in fixed aperture extraction method

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* Inspection mode added: using `ssos -i|--inspect path/to/analysis`, SSO candidates can quickly be visually inspected and quickly classified into SSO / Unknown / Artifact using the arrow keys
* FOV_DIMENSIONS can now be set automatically by pipeline
* The DATE-OBS keyword can now be passed in either ISOT or MJD format
* edited the GREETING to point to correct documentation
* no longer creating target directory if the images cannot be found
* Fixed a bug in the SWarp cutout creation where it would chose the wrong image extension if SCI_EXTENSION is 0
* Fixed the cutout images filename scheme so that they are now correctly ordered by epoch when calling from the command line
* Revisited the SkyBoT query: It is now executed at the beginning of the pipeline and states the amount of all known SSOs in the image. A brief overview is printed to the console.

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* default.ssos is now properly included in the pip install

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* SCAMP does not properly compute the proper motion of sources without a reference source association when choosing INCLUDE_ASTREFCAT to false. It is now always set to true while the bug is being investigated
* SExtractor catalogue header files are not adjusted anymore when SCAMP has not been run since the last time they were changed
* Excluded the HYGCAT from the package, it can be retrieved from http://www.astronexus.com/hyg

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* Included the option to remove source detections within 1" of the reference catalogue sources in SCAMP before the pattern matching. This is turned on using the REMOVE_REF_SOURCES parameter. Random associations of SSOs with stars and galaxies are effectively removed this way. Note that the importance of the choice of reference catalogue increases.
* The pre-configured SExtractor and SCAMP config files were updated to the latest versions (2.25.0 and 2.7.7 respectively)
* Renamed several output parameters to better match common standards
* Code restructured, leading to major speed ups in SExtractor catalogue look-ups