> Pentax Astrotracer
Astrotracer is a great way to take advantage of the Pentax DSLR camera in-body shake reduction mechanism. It is available since Pentax k5 and track celestial bodies by moving the sensor. Here is what is it ablout:
It is most suitable for low power panoramic astrophotography with focal lengths from 35mm to 135mm. Thus could be used with longer telephoto lens but it's calibration is a real challenge and it is hard to achieve good tracking result. For wide angle shots this tracking is boosting comma and distortion effects as sensor is going beyond the calculated filed of for the specific lens. Also it is mostly suitable for single shots. After the shot is taken, the sensor is getting back to it's original position and if you need to do a series of shots you need to readjust the camera position. The main advantage of this technology is that very compact and you could have it always with you. Sometimes the best shots are those we do not plan. Here are my examples:
Below is a shot with a 500mm lens:
You can find my last DSLR Astrophotography article in Bulgarian at page 76. I am sharing my last findings for this publication, Specially written for the Institute of Astronomy.
Satellites, cosmic trash or UFOs, the moving spots are everywhere on the sky. Typical satellite behavior is to reflect sun light. It should be yellow or white and could fade and shine due to its rotation.
If you have used DeepSky stacker to stack RAW files, maybe you have notice that the resulting image is poor of color saturation. This is because it has a higher number of bits then the display could show.
Last test from passed night put an end of the questions witch is better CCD or CMOS. My old CCD K-m fall back compared to CMOS K-5.
HDR stands from High Dynamic Range. In short it is the number of tones that compose the image. The larger it is, the best capability we have to see details in the bright and dark regions of a scene.