High Resolution lunar images – Just how High ?
In 2015 I’ve been able to acquire some High Resolution (HR) lunar images due to some excellent seeing conditions from September to December. I must say that I’ve been very lucky with such conditions, and moreover, been lucky to have the 355mm F/5 Newtonian ready for such imaging sessions, since I’ve been working for almost one year to have it prepared for this period of the year (when I usually have very good seeing at my location).
Now I can show a few results regarding the ability of such a scope to resolve small details of just a few hundred meters on the Moon.
I’ll post the measurement results for some of the September images, measurements done using the LROC interactive map.
The following images show just some areas from the original mosaics, with only a few details (craters, rimae) measured, in order to have a fairly clean presentation. One can easily compare my measurements with other details in the images, thus evaluating other details and their sizes.
Three results already presented on this blog:
And three new measurements:
These last three images were measured using a new reprocessed version of the September 5th Ptolemaeus/Alphonsus/Arzachel mosaic.
This time the processing was performed only in AutoStakkert!2 (aligning) (A BIG Thank you Emil Kraaikamp for this fantastic software!), AstraImage 4.0 (wavelets, deconvolution, multiscale contrast, noise removal) (A BIG Thank you Stuart Hodgson from Astra Image Company, another superb piece of software!) and for the final mosaic I’ve used the very good Microsoft ICE. Usually I also use Photoshop CS2 (“old-school”) for the final result, but for this specific interest (measurements) all processing was kept to a minimum to show only the actual data, with no artifacts or cosmetic post-processing.
Now, the reprocessed version of the above mentioned mosaic, enlarged to 140% (it was processed at 140% from the start):
This result might not be very “pretty”, with a lot of blurry crater rims, but the important details (the smallest detectable craters) show a little better compared to the initial result, which is shown below (it does not have the Rupes Recta “glued” with the rest of the image):
Now, as a general conclusion, it can be observed that in excellent seeing conditions, and using good equipment (ASI 120MM-S camera in my case with a Baader Red filter and the superbly good Baader 2.25x Barlow) it can be possible to acquire lunar images that show details as small as 350 meters wide! They might be hard to observe in the end result, but they are detectable. This is pretty good news I hope for any amateur not having a large 1 meter scope in his backyard.
For me, it’s a good motivation for getting a much larger mirror, like a 500mm one 🙂
I’m already saving my money…
I should perhaps find myself a buyer for this 14 inch scope, that looks more like a radio-telescope…
…but not just yet 😉