Observation by Nick James: Polarised Moon
Uploaded by
Nick James
Observer
Nick James
Observed
2025 May 31 - 21:25
Uploaded
2025 Jun 01 - 07:22
Objects
The Moon
Equipment
- Lucid PHX050S1 + Celestron 0.15m, f/10
Exposure
40ms
Location
Chelmsford
Target name
Moon
Title
Polarised Moon
About this image
I'm doing some experiments with a Lucid polarisation camera which I've bought for use to do some polarimetry on the solar corona at the next total eclipse. The camera uses a Sony IMX264MZR sensor. This has a grid of polarisers implemented over the pixel sensors, similar to the colour filters in a Bayer array but sensitive to 0, 90, 45 and 135 degree linear polarisations. This means that you can do simultaneous imaging in all linear polarisations and then synthesise parameters such as degree and angle of polarisation (DOLP and AOLP).
Light reflected from the lunar maria is fairly strongly linearly polarised and this can be used to determine information about the lunar regolith (see the work reported here). This image is a single frame from the camera processed to show DOLP in false colour. It shows that light from the highlands is nearly unpolarised but that light from the maria is polarised with a DOLP of around 20%.
Files associated with this observation
Like this image
Comments
Excellent stuff.
Did you stack frames at all?
Also, what did the AOLP look like?
This was just a single shot since I was really playing around last night. I do have a way of presenting DOLP, AOLP and luminance in the same colour coded image. I'll post that later.
Excellent, interesting, exciting - calibration using manufacturers data I guess - do you plan to calibrate separately later? look forward to seeing results.
Will be very interested to see the result.
No calibration as yet, not even a flat field. I've only just got the camera and have a lot to learn before the August 2026. There are loads of papers around with techniques for accurately calibrating these micropolariser CMOS imagers, e.g, this one, and also lots for visualisation including some nice Python libraries, e.g. this one. I'm giving a talk on this at the Solar Eclipse Conference coming up in a couple of weeks so will be learning quickly!
Copyright of all images and other observations submitted to the BAA remains with the owner of the work.
Reproduction of work by third parties is expressly forbidden without the consent of the copyright
holder. By submitting images to this online gallery, you grant the BAA permission to reproduce them in
any
of our publications.
