Flexure is the error in telescope pointing due to the non-rigidity of the telescope mount and tube. For PCTCS and TCSng flexure correction also includes polar alignment and other issues not generally considered flexure. To correct flexure in TCS we must build a flexure map. This is done by measuring the error in pointing across the sky and analyzing those measurements with tpoint ( http://www.tpsoft.demon.co.uk/).

In order to create a flexure map using the methods mentioned in this wiki you will need a linux (preferably ubuntu) computer and some software. First you will need astropy (http://astropy.org) for fits image manipulation.

Then you will need some python modules located on the mogit repository.

• astro (Classes to handle coordinate data)
• astrometry (Classes to submit data to astrometry.net for astrometric solutions)

The best way to gather data for building a flexure map is to take images all over the sky in a dithered alt-az pattern and solve the astrometry of the image using http://astrometry.net or some other astrometry engine. If the telescope camera uses AzCam we can utilize AzCam scripts to take a