> Pentax Astrotracer

  • Posted on: 15 March 2020
  • By: tihomiry

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:

http://www.ricoh-imaging.co.jp/english/products/o-gps1/astrotracer.html

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:

35mm, 120s. Astrotacer On
Milky way center at Sagittarius.

35mm, 500s. Astrotacer Off
star trails

Below is a shot with a 500mm lens:

Reading a new product that claims to be 100x time more powerful then conventional telescope, I realise that this is just an astrograph with a digital camera that is doing stacked images and show them trought eyepiece or App.

I am so impressed with the K5 ability to quickly gather signal from nebulas (Quantum efficiency) and galaxies, so I decide to take one more K5 and to remove the IR-cut Filter of the old one.

Recently I got one very good lens the Asahi Takumar 135mm 1:2.5. This is fast telephoto lens and from my point of view a good lens should be with aperture from 1:1,2 to 1:2,8.

Moon at 45% illumination and 70x magnification. With aperture of 200mm,14,1 stops dynamic range, color depth of 23.7 bits at this image there are slight color variation on the moon surface that reveals it’s structure.

This is the beginning of my research on how dark the sky could be and what is benefit of a dark sky for astrophotography. I was inspired from those 2 sites. First one presents mathematical model of how dark the sky is.

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