This is a two shot mosaic of Mare Nectaris taken last Tuesday night. The large crater at the bottom of the mare is Fracastorius. I found a great on-line Moon map that helps me find these details.

The two images were stacked in Registax, 400 frames each, then combined in Photoshop. All other processing was done in PixInsight. Both images were shot through a C-8 at f10. Seeing was not good as the Moon was low in the sky, maybe 2-3/5. I could see the image swirling in the AVI. I used 4 align points in Registax for each image.

In processing this image, I learned, from a practical rather than mathematical perspective, the differences in resampling algorithms. I upsample the image by 2x at the start of processing. Bilinear increases noise, Bi-cubic is better, cubic has less noise but softens part of the image.

Thanks for looking.

--Andy

Attached Images

Mare-Nectaris-080311-01v04sm.jpg (122.0 KB, 19 views)

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Observatorio de la Ballona

Very very marked contrasts as one would expect at the terminator. Interesting that you are using 4 points as I often try and use twice that on DSOs, far fewer images to process. Excuse my ignorance but what is meant by upsampling? Good clarity despite the seeing. I might set up in webcam mode tonight but the moon is low here too. Thanks for sharing

Kind regards
Matt

Matt,

Thanks for the kind comments.

For DSO imaging, I use 3-5 stars in CCDStack. It does a very nice job aligning the images and I find that it gets confused with too many points. Once its got the basic geometry correct, the whole image is aligned.

Alignment in Registax is really a different animal. You are really doing two things: Trying to find the best images and align the images you select. I have only used multi-point alignment in Registax for Lunar images; planets I generally just align on the whole planet.

Upsampling is increasing the number of pixels in the image. My ToUCam is 640x480 pixels. When I upsample the image, I double the pixel dimensions to 1280x960, doubling effective resolution of the image. Of course, you can't create information where there isn't any, so the image really has no more information than the original. It probably has less because some information is lost in the interpolation of the new pixels, but I'm not sure about that. It does let me more effectively use the tools in PixInsight for sharpening and contrast adjustment, because there are more pixels to build the contrast gradients on.

HTH,

--Andy

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Observatorio de la Ballona

Thanks Andy.

Kind regards
Matt

You have a great photo with many details, At the floor basin the riles,depressions and the fine surface are sharp and could be easily be seen. What was your equipment used?. Clear Skies

Efrain, thanks!

I was using a C-8 at f10 -- no barlow, no focal reducer. The camera was a Phillips ToUCam Pro, shooting at 640x480 and 15 frames per second. It was taken near Anza, California, at about 3400 feet/1040 meters.

--Andy

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Observatorio de la Ballona