----

* Fix 'catalog already exist' when trying to do single-image magnitude calibration,
but the existing catalog contains only astrometry.

* Add a possibility to always use either wget or curl, not both! ???

* Test with bad images
./diffphot /mnt/usb/MSU_Obs/2021_09_30/alternative_mffC_morning/fd_TOI2025_C_10sec_run01-*.fit
default.sex 10 10 10

* For file already exist in ms and md add check that the directory is actually writable.

* Add ZTF periodic variables catalog support
http://variables.cn:88/ztf/
https://ui.adsabs.harvard.edu/abs/2020ApJS..249...18C/abstract

* Add support for "bias + scaled dark" CCD image calibration strategy

* Specify image center for plate solver.

* Write warning in sextract_single_image that with the default settings 
a measurement will be dropped.

* Do a range check for all STAR*[Pos*[i]]

* Transfer to double-precision star positions

* First try to plate-solve with guessed coordinates and retry without them if failed...

* Support long filenames in ./lc display.

* Print amplitude in ./lc display.

* Do not try to guess gain if 'photocurve' is used for magnitude calibration???
Unless it is explicitly requested by user.

* Image arithmetics with floating point images

* util/ccd/mk - do robust sigma-clipping before MEDIAN-combining images???

* Ignore JD keyword if there is a comment "/Julian Date at start of exposure"

* Correct for differential extinction/flat-fielding problems while performing
absolute magnitude calibration using APASS.

* Make sure the narrow-field CCD test images can be plate-solved automatically

* Even more clear interpretation of the command line
