my bar for the 560 (large image)

Started Sep 27, 2012 | Discussions thread
Taffy Veteran Member • Posts: 5,006
Re: my bar for the 560 (large image). WOW just a few..............

extra mm reach on that outfit of yours, and I think we'd be able to see Neil Armstrong's footprints there. Briilliant, thanks for showing us.

lpammann wrote:

This image represents my bar for the 560, an image I took tonight of the moon using my Televue 85 APO refractor + 1.7AFA + K5. This image has been cropped to 2400x2400. Previous moon images I've posted here were taken with a 0.8x field flattener/focal reducer added to that combo, but I decided to take it off for this shot. Many moon images from the astronomical community use stacks of multiple images to reduce noise and increase resolution, but this image is just one shot taken by the K5. This combo produces a 1020mm f/11.9 lens (1530mm equivalent for FF). This scope is not a Petzval design like the TV102, but it does have a very high quality APO doublet 600mm f/7 objective. I have no idea what the lens design of the 560 is, but starting with a similar objective that is 700mm f/7 combined with a 0.8x FF/FR farther back in the light path, with a couple of lenses added for AF across the designed focus range would give the same specs as the 560. That design should be capable of images which are somewhat sharper than this one with better contrast.

The moon is now 4 days past 1st quarter, so there is not as much relief visible in this image as there is around 1st quarter. Here is a key to some of the more prominent features visible in this image. The large crater in the south with rays emanating out from it is Tycho. Left of Tycho is a small mare, the Sea of Humors with the large crater Gassendi on its NW edge. Below and to the left of Tycho is the elongated Schiller crater. The large crater by itself near the middle west area around the lunar equator is Copernicus (who never saw this or any other lunar crater since telescopes weren't invented until after his death), and the crater to its southwest almost to the terminator is Kepler. The bright crater in the northeast with wedge-shaped bright ejecta is Proclus. The darker area southwest of Proclus is the Sea of Tranquility, Neil Armstrong's landing site.


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Have a good day.
Regards Allan

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