It’s quite rare for my location to have the right conditions for observing the Moon and planets, and it’s actually very rare to have those superb conditions with stable atmosphere when you can glimpse details normally visible in images produced from intense processing of many hundreds of frames.
Well, on the morning of October 14 I had just one of those very rare moments at the eyepiece of my C11 telescope while observing the Moon. At a magnification of 600x the details near the terminator where just breathtaking.
Of course I didn’t just look through the eyepiece since the +4 degrees Celsius temperatures demanded for something “solid” to take back home, beside the cold I’ve successfully managed to catch. That something was around 100Gb of data acquired over a two hour period.
The equipment used for the acquisition of the images was my trusty C11 (280mm in diameter) working at F/20 and F/25 via two TeleVue Powermates (a 2x and a 2.5x one), and the ASI120MM camera with a Baader Red filter. The seeing conditions varied from 6/10 to an memorable 8/10. It seems that October may be the month of choice at my location for good lunar images.
I start with one of the “beautiful” (for me) images, showing the Aristoteles and Eudoxus craters. Aristoteles (up) has a diameter of around 90km, while Eudoxus is around 70km wide.
Another “nice” image shows the lunar rougher terrain around crater Abulfeda (around 60km in diameter), just below the center of the image. An interesting feature near-by is the chain of craters that go away from Abulfeda towards the upper left corner of the image, properly named Catena Abulfeda. Another very interesting feature is the deformed-floor crater in the upper part of the image, named Abenezra; it looks like the meteorite that form the crater just didn’t stop spinning after it impacted the lunar surface (just a funny observation of course).
An interesting volcanic area is presented below, showing the Hyginus (left) and Ariadaeus rimae. The Triesnecker Rimae is visible just below Hyginus, and also the Sosigenes Rimae can be seen in the right part of the image, together with a very interesting volcanic feature crossing it.
Another very interesting and eye-catching area at the eyepiece is the Lamont region presented in the images below. Lamont is the large (~80km) submerged crater surrounded by many complex ridges in the lower part of the images.
The region immediately around Lamont is perhaps better presented in the following image, which shows the Arago domes near crater Arago (below and right of center) and also the volcanic feature mentioned in the Hyginus-Ariadaeus image above.
Using the LROC (Lunar Reconnaissance Orbiter Camera) QuickMap measuring tool I’ve measured the height of some of the domes present in the above images. The yellow lines show my selected measuring paths while the blue lines in the graphs show the approximate diameter of the domes.
The Moon has many areas where signs of volcanic activity are present, and perhaps none is more famous than the feature named Ina. The image below shows the entire imaged area which also includes Rima Hadley (upper part of the image) and part of the Appenninus mountains. The landing spot of the Apollo 15 mission was near Rima Hadley, so this is an historic area for the Moon but also for the humans.
And since Ina is a rather small feature but of a big importance in our understanding of the Moon’s history, I had to compare my images of this area (in terms of resolution) with the “master” of all lunar images, the Lunar Reconnaissance Orbiter. My smallest details imaged with the 280mm scope are a few 800m-wide craters marked in the LRO detailed images from the mosaic below.
Speaking of the resolution achieved in that morning’s session…
Bellow is an image of the well-known crater Plato. The detection of the many craterlets on it’s floor represents a good test for the telescope’s optics but also for the seeing conditions. The main image below shows both Plato (left) and Vallis Alpes (right) with it’s inner rima which is another not-so-easily imaged feature. Also, a lot of rimae are present in the image, some extending many hundreds of kilometers on the lunar surface.
And the resolution test image, a re-processed image from the above one, showing only Plato and around 56 marked small craters onto it’s floor. I’ve only marked those craters which show the tiniest amount of inner shadow, so many other bright spots are ignored, despite being also the signs of small craters.
And yet another test-image, showing Rupes Recta (the Straight Wall) and crater Arzachel (upper right of center) with it’s inner rimae system. The very delicate rima perpendicular to the Straight Wall is just visible under this illumination, but (again) this shows that the seeing conditions were indeed very good.
Another interesting area, towards the North Pole this time, captures the Lacus Mortis area just before the Sunset. Crater Burg is visible with it’s illuminated rim on the terminator, and also some of the rimae system onto Lacus Mortis floor are visible. Rimae Daniell (center) seems to continue itself in the lunar highlands (towards the left) for quite some distance.
And continuing with the imaging session, I’ve stopped for a while at some of my favorite craters…
Clavius and Tycho:
But almost as my laptop battery was getting very low (after two continuous imaging hours in the middle of a field), I’ve decided to acquire some last images of a not-so-often imaged area (by me), the lunar North Pole, with crater Anaxagoras very sharply defined (just above center) and crater Timaeus (lower part of the image) with it’s rather large central peak.
What a night for lunar imaging and observations at the eyepiece! I will remember this one for at least a year, until the next “almost perfect” seeing conditions in October 2015…
(October 15, 2014)
I’m starting to reprocess some of the above images from zero. This time I’m trying to process the images to get the smallest details visible and thus to see the actual resolution on the lunar surface.
For now I’ve processed only the two mosaics showing the Lamont area; both are resized to 150% due to a 1.5x drizzle. Some of the smallest craters detectable area around 650-700 meters(!).
One of the above images was selected and commented by Chuck Wood as an LPOD for October 22, 2014.