If you happen to have an iPhone or an iPod Touch the application A Level (cost abt 1 USD to upload) may be of interest, e.g. to calibrate or when using a parabolic dish for moonbounce. The application simulates a spirit-level. I do not know the absolute accuracy and the elevation readout seems to be limited to abt 20 deg or 40 deg dependent how you hold it for readout.
The link to the A-link application is http://www.posimotion.com/index.php?argv=apps&opt=alevel