The Moon and the Pleiades, Edited

As a follow-on to my last post, I've taken my first pass at using some of the shots I took that night at differing shutter speeds to create a composite image with a higher dynamic range, representing both the sunlit and Earthshine portion of the Moon similar to how it appeared to the human eye. Combined with the stars of the Pleiades, this is close to what I had in mind for the image. A lot closer than the raw image in the previous post. 😃

As always, click on the image to see large. 

The Moon and the Pleiades

There are plenty of interesting sights in the night sky each year. Headlines right now are touting the 5 planets that'll be visible this week, unique because it will be easier than usual to spot Uranus (though you might still need binoculars for it and possibly for Mercury). Unfortunately, I don't expect to see that given the current forecast for cloudy weather in North Texas. 

A sight that didn't get much press but that I looked forward to was a conjunction this past Saturday evening (March 25th) between the Moon and a star cluster called the Pleiades, also known as the Seven Sisters, or Messier 45, or Subaru in Japan or many other names across time and cultures. If you ever stared up into the night sky on a winter or spring night and saw what looked like the Big Dipper but almost so small you weren't sure that's what you were seeing, that was probably the Pleiades. 

The Pleiades is located in the sky just shy of 5 degrees off the ecliptic. As that's the path that the Sun, planets and the Moon generally follow across the sky, it's not uncommon for the Moon to pass near this star cluster. But many times it occurs during the daytime, or when the Moon is full or nearly full or the Moon doesn't pass close enough to the Pleiades to appear in the same telescopic view. So seeing a conjunction of the Moon as a crescent (just five days after its New phase) and the Pleiades is not that common. I've been told this occurs about every 12 years though I haven't been able to find a concrete source for that. 

To capture this event, I drove out to Terry Park on the east shore of Lake Ray Hubbard so I would have less light pollution to deal with than at home and so that I had a clear western horizon to allow the longest amount of time to shoot between the end of twilight and when the Moon set. For this session, I used my Evostar 72ED refractor telescope, Nikon D750 camera and Star Adventurer star tracker. 

Here is a raw, unprocessed image from my session on Saturday night. 

5 day old waxing crescent Moon with Earthshine passing near the Pleiades

This is not entirely what I had in mind but it's just one of the many shots I captured. I'm working with the full set of images to come up with a shot that addresses the challenges in taking this shot. 

• In this image, the sunlit side of the Moon is overexposed. I also have shots with the sunlit side properly exposed but the shutter speed for those shots was too fast to capture the stars of the Pleiades. I am working on a blend of this shot and the other one. It's a tough edit so wish me luck.
  BTW, the shutter speed for this shot was 2 seconds while the shot with the sunlit side properly exposed had a shutter speed of 1/160th of a second. That's a huge difference, over 9 f/stops apart. Although our eyes can see such a broad dynamic range, most cameras cannot, hence the need to blend multiple images.
• I still want the final image to have the rest of the Moon also dimly illuminated. This is called Earthshine because, well, it is the result of sunshine reflected off the Earth lighting up the part of the Moon that's not lit by the Sun. 
• I want to bring out the stars of the Pleiades better so that they aren't washed out by the Moonlight. However, it will just be a matter of the individual stars being a bit brighter.
  If you have seen images of the Seven Sisters like this one with lots of blue nebulosity surrounding them, it wasn't possible to capture the reflection nebulae that surrounds the stars of the Pleiades with the bright glare of the Moon so close by. 

I'll describe the post-processing I'm doing when I post the final image. 

More to come. 

As always, click on the image to see big.

PS. Here is my EarthSky community photo post of this image.

Chasing A Partial Lunar Eclipse and the Seven Sisters

In the early morning hours of November 19, 2021, a lunar eclipse began. As a partial eclipse, it normally might not have been noteworthy. What brought a lot of media attention about this one is that it lasted just a shade over 6 hours. It's been 1000 years since the last time a lunar eclipse lasted that long. 

The timing for this eclipse is such that the Moon was almost at apogee, the point where it is furthest from the Earth in its orbit, and since a body in orbit moves slower the further it is from the body it orbits, the Moon spent more time in Earth's shadow. It also meant that the Moon was smaller in appearance so this was the opposite of a "Super Moon". 

The other interesting thing about this lunar eclipse is that the Moon is within a few degrees of the collection of stars known as the Pleiades or the Seven Sisters. As both were high in the sky during most of the eclipse, the cold dry air we had in North Texas that night made for great viewing. 

Initially, my plan to capture the eclipse was to shoot with my Nikon D750 using the longest lens I have and the Star Adventurer sky tracker to capture shots of the lunar face throughout the night to create a timelapse video. However, given the close proximity of the Pleiades, I decided to shoot with a shorter lens and include it in the view. 

I won't go into the technical details but given this was really the first time I had used the Star Adventurer for tracking more than a few minutes, I shot a bit wider view than I probably needed to so the Moon is rather small in the frame. The bad news is that the tracker was a little off and so the Moon didn't stay centered in the frame. The good news is that with the wider view, both it and the Seven Sisters were in-frame throughout the 5 hours of the eclipse I captured. 

Here is a frame from about mid-eclipse. I'll post more as I get further through post-processing all the images.