Friday, 29 December 2017

The Raspberry Pi camera module as a LunaCam

Lunar imaging with the Raspberry Pi 3 and the Pi Camera module.

The Pi camera module was fitted with a C/CS mount and a scope adapter, and was placed at the Newtonian focus of an f/5, Skywatcher Explorer 130 P-DS OTA Newtonian on a Star Discovery AZ, GOTO mount.

Using Python software that I have been writing for the past couple of weeks. I captured Flat frames against a grey sky and later, 100 bmp images at 800 x 600 resolution. (100 images were also captured at 1024 x 768). The images were registered, flatfield corrected and stacked in lnxstack. The resulting image was processed in the Gimp and Pinta, all native Linux programs, on the Raspberry Pi 3 running Ubuntu MATE.

A Waveshare 5Mp Raspberry Pi camera module with a OV5647 CMOS sensor was used because the lens assembly can be unscrewed and replaced by a C/CS mount, or the lens itself can be unscrewed and a standard webcam scope adapter attached. A 1m ribbon cable enabled the camera to be mounted on the scope.

Raspberry Pi camera module

C/CS mount attached to Pi Camera module board

Scope adapter attached to Pi Camera module

Pi Camera module at the Newtonian focus 

The imaging setup 

Semi-transparent mode for setting up captures

Fully opaque mode for setting camera brightness & contrast
Click on the image to get a closer view.

Final 800 x 600 image

Final 1024 x 768 image

The Pi camera module will be implemented in AstroDMx Capture for Linux. However, Nicola is currently sorting out an issue with the ZWO SDK with USB2 and long exposures before a new version is released implementing the QHY cameras. QHY is already implemented, but the release is delayed until the issue with the new ZWO SDK is resolved.
Meanwhile, my simple Python program is showing that the Picam module has potential as a prime focus Lunacam.