Contains:  Solar system body or event
Seven-Day-Old (First Quarter) Moon, June 28, 2020 (w/ Pixel Shift Resolution), 



Seven-Day-Old (First Quarter) Moon, June 28, 2020 (w/ Pixel Shift Resolution)

Technical card

Imaging cameras: Pentax K-3 II

Date: June 28, 2020

Frames: 4

Focal length: 762

Resolution: 2166x2621

Data source: Backyard


A prime-focus image at ISO 200. The exposure time was 1/250th of a second. However, this is actually four such exposures that were combined in Pentax's Digital Camera Utility (DCU) software. This is a feature Pentax calls Pixel Shift Resolution (PSR) that is available on the K-3II and on all current Pentax DSLRs except the 645Z medium-format model.

When the shutter is triggered in this mode, four exposures are made in quick succession using an electronic shutter. Using the camera's sensor-shift Shake Reduction, each exposure is shifted from the initial position by exactly one pixel such that when the images are combined, each pixel in the final image has complete color information. Hence, the DCU software does not need to interpolate in order to perform demosaicing. (The K-3II can develop a PSR jpeg in the camera, but if you want to use RAW you have to load the image into DCU or another program that supports PSR such as RawTherapee.)

As long as the camera does not move with respect to the scene during the sequence, and nothing in the scene moves, the result is a much sharper image that is also much cleaner with double the signal-to-noise ratio. However, this is difficult to do with the moon. You have to track it fairly accurately and there must be very little atmospheric turbulence.

PSR also avoids shutter shock, which normally blurs fine details at least as much as atmospheric turbulence. Note that a mirror-up shooting mode was used, so there were no vibrations induced from mirror slap.

I had previously tried PSR on the moon and been unsuccessful. You need a little luck. On this night, I got lucky!

The Meade MTS-SN6 is a 6-inch f/5 Schmidt-Newtonian telescope from the 1980's.



Seven-Day-Old (First Quarter) Moon, June 28, 2020 (w/ Pixel Shift Resolution),