Pear Tree Observatory

I got up fairly early to see if I could get a decent image of Venus before the Sun rose high enough to ruin the seeing. The sky was very clear with Orion standing astride the meridian. Unfortunately, clouds moved in well before Venus cleared the tree line and the attempt to image it was thwarted.

However, while waiting for Venus I imaged Reiner Gamma on the waning crescent Moon. The feature is located in Oceanus Procellarum (Ocean of Storms).

Over time, lunar surface material darkens due to the constant impact of the solar wind. This means newer material on the surface looks brighter than older material. Obvious examples are the bright rays extending out from one of the Moon’s youngest craters – Tycho.

Reiner Gamma is classified as a lunar swirl. There is no crater there, the markings making up the feature are all just brightness differences in the surface material. Orbiters circling the Moon have detected relatively strong, highly localized, magnetic fields associated with lunar swirls. Solar wind is made up of electrically charged particles and their paths of motion are subject to magnetic field influence. The current theory is the magnetic fields associated with lunar swirls act somewhat as force fields that deflect the solar particles and reduce the darkening effects.

Also visible in the image upper left is the Marius Hills volcanic dome field. This location was one of the proposed landing sites for Apollo 15. A volcanic dome is thought to be a low relief shield volcano formed by thicker lava than formed the mare. The area is also home to the recently discovered “Marius Hole” which is thought to be a skylight into a subsurface lava tube.

Reiner Gamma[(V)C:1655×0.48ms]

Reiner Gamma[(v)C:1655×0.48ms]

I am beginning to document my procedures that will be used to capture the upcoming total solar eclipse (08 Apr 2024). To that end I purchased a small refractor telescope to match with my Nikon D-90. This will give me a broader field of view (FOV) than any other configurations that I can set up. Regular camera lenses that I have give me a very small Moon in the FOV. I’m not sure of the level of detail that will be visible with any of those. Using my portable telescope gives me a view of the Moon that, at best, totally fills up the FOV. That will not be large enough to capture the Sun’s corona during totality. So, I needed something in between my camera lenses and my current telescopes. I could have purchased a long camera lens but an equivalent focal length telescope was much cheaper. Plus, I get to use it as a telescope at other times. One can never have too many telescopes.

So, since the apparent size of the Moon matches the apparent size of the Sun, I used the nearly full Moon last night as a stand in. Properly centered, this will capture all of the corona with a large enough scale to see fine detail.
 

Below is a slightly stretched Moon cropped from the above image. The very bright small spot towards the top is the recently formed crater Aristarchus. Also easy to see at middle left is the crater Tycho with its extensive system of rays ejected during impact, some measured as long as 930 miles. Tycho is even younger than Aristarchus estimated to be only 108 million years old.