Alex Koukarine Apps
PolarDrift Calculator 1.0
PolarDrift calculator is a simple polar alignment assistant toolhelping astrophotographers to solve the question of optimum polaralignment sufficient to minimize the effects of field rotation. Itis targeting typical auto-guiding setups. By understandingallowable error in polar alignment, field rotation can becontrolled to be under the minimum visible threshold. A number ofdetails increase or decrease the requirement for precision. Factorsthat require higher precision include: longer exposure duration,increased distance between the guide star and the edge of theimaging field, and declinations that approach the pole. Factorsthat tolerate more error include: shorter duration exposure,centering of the guide star and a smaller imaging field, anddeclinations that approach the equator. Drift polar alignment via aguide camera and guide scope allows a precise measurement of therate of movement of a guide star. By using tools to measure thedrift rate during ALTITUDE and AZIMUTH adjustment phases of thedrift procedure, a value of error can be calculated. Some driftalignment tools report this error in pixels or arc seconds. Afterentering the values in the Imaging setup parameters menu, thenentering the values of Declination and Exposure Duration on themain screen, the maximum allowable error is displayed. During driftalignment, the speed star movement should be recorded and enteredas Measured Drift to determine current conditions. Note: You cantap the parameter's description on the main screen to see a moredetailed explanation for the corresponding value. This tool allowsan astrophotographer to better understand the limits of theirsetup, so that they can determine if a configuration is feasible.The idea, calculations algorithm, and instructions text by StephenMigol. Calculations are provided from: Hook, R.N., Polar axisalignment requirements of astronomical photography, Journal of theBritish Astronomical Association, vol. 99, no. 1, p. 19-22 (Feb.1989) http://adsabs.harvard.edu/full/1989JBAA...99...19H Barrett,Frank, Determining Polar Alignment Accuracy, 2009http://celestialwonders.com/articles/polaralignment/PolarAlignmentAccuracy.pdfYou may find more information and contact the developer directly athttp://app.kukarin.com
