#13: First surface images of the moon

17.11.2018

Webcam Moon

New aspect: Taking the first close up surface images of the moon with a modded Logitech webcam

Image acquisition:

When imaging the Mars with the modded webcam in the last session I recognised just how hard it is to get the focus right. So a member of a astro forum (Hi Carole!) pointed me towards the moon. Focusing the moon with its sharp crisp contrast is much more easy than focusing wobbly blurry planets. So I tried the moon as a target for this session. Finding the moon, aligning finder scope and main scope, getting the polar alignment roughly working: all that was done in a minute. Fining the right balance between exposure time, gain, “brightness” and stuff was a completely different story. The Logitech webcam can only be set through the Logitech driver interface and that doesn’t really work smooth with SharpCap, the image acquisition tool I used (and still use). For changing any of the parameters above you have to switch from SharpCap to the driver interface. Gain is called something like “sensitivity” and nobody knows what “brightness” really means… SharpCap has no authority/ability to access the settings of the webcam directly. That’s a shame. So after fiddling around with the settings I tried a few video-files with and without barlow lens. Some were dark, some too bright.

Processing:

Processing the files (~30sec per video file) was a matter of loading them with AutoStakkert!2 and then sharpening the resulting image in RegiStax6. To my disappointment most of the video files turned out too dim or out of focus. Especially the files taken with the barlow lens were useless. Focus is a quite delicate thing. Every feather tip can screw the entire image. On moon and on Mars as well. Never the less some of the images turned out being sharp and I continued with the processing. Some of the chosen settings brought colour aberrations into the image. Which I don’t know but I bypassed the problem by setting the image into black and white. That’s cheating but the colour errors made the images look way too ugly. So a useful BW image was the better deal. Sharpening was also a delicate thing to do. A balance had to be found where artefacts keep low but surface details show up. A higher contrast highlights the shadows of the craters.

Conclusion:

Taking the first close ups of the moon was a difficult, yet interesting new path. The acquisition was like wandering on the moon. Seeing the craters and shadows, the mountains and rims was very nice. Setting the webcam via the drivers was not. All in all the quality of the camera in combination with the barlow under this circumstances and the chosen settings produced images with way to much colour aberrations. This has to bee sorted out before turning to the planets again. All in all I like the craters of my first two images of the moon. Still lots of details are still hidden…

Greetings,
Chris

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