Slooh. Position Sensors. Position sensitive device. A Position Sensitive Device and/or Position Sensitive Detector (PSD) is an optical position sensor (OPS), that can measure a position of a light spot in one or two-dimensions on a sensor surface. Principles[edit] PSDs can be divided into two classes which work according to different principles: In the first class, the sensors have an isotropic sensor surface that has a raster-like structure that supplies continuous position data. The second class has discrete sensors on the sensor surface that supply local discrete data,. Isotropic Sensors[edit] The technical term PSD was first used in a 1957 publication by J.T. Wallmark for lateral photoelectric effect used for local measurements. On a laminar semiconductor, a so-called PIN diode is exposed to a tiny spot of light.
And in the electrodes, the location of the light spot is computed using the following equations. The are simple scaling factors, which permit transformation into coordinates. 2-D tetra-lateral Position Sensitive Device (PSD)[edit] Astrogene1000 Stuff. DIY Autoguider (Part 1: Introduction) « Night Sky in Focus. Very long exposures requiring precise tracking needed for imaging deep-sky objects may now be achieved through an advanced imaging technique called autoguiding. This article provides a brief introduction and how one could construct a do-it-yourself guider that delivers equally satisfying results for a fraction of the cost of ultra expensive commercially available counterpart. Guided Imaging Guided imaging simply involves active monitoring of the telescope’s tracking accuracy by observing a reference object (any bright star) and making the necessary adjustments to nudge the telescope to the east or to the west so that the reference object remains stationary for the whole duration of an exposure.
The simplest example is a setup involving an imaging telescope (equipped with a finderscope) on a tracking mount. After the object to be imaged has been properly framed and focused, the imager adjusts the finderscope and centers its cross hair to the brightest star in its field. Image 1. Image 2.