Catching up.....M13

Always a favorite object, the great Hercules cluster, M13. This is probably the longest exposure I've made, about 40 minutes each channel. I was taken the morning of April 3, 2020, just before closing the observatory. That night, I let the scope run all night, with somewhat variable results. Unfortunately, this one looks to me to have a green color cast, which is indicative of light pollution. Not surprised by that. But, other than that, it seems to be one of the better images of it I have to date. I would usually take this image much later in the year; taking it in the early morning is the reason I got it now.

M13

Extra

Also on the night of April 2-3, 2020 I imaged the galaxy pair M65 and M66. I questioned whether I would be able imaged it through the high cloudiness, and it did present a problem. As with clouds, 3 of the channels did not have as much problem and 1 did; the blue channel. While all this happened as I was sleeping, more or less, there is some evidence I can show below that leads me to that conclusion.

Same image in different channels, process identicaly.

The image above is a composite of part of the green channel and the same part of the blue channel. As you can see, the sky background is much lighter in the blue channel than the green. I think that's a cloud passing over. Looking more closely, the edges of the galaxy are softened, which also occurs when viewing through a cloud. When I use one of my 2 normal processing routines, the overall “blueness” becomes vividly apparent.

Image process "normally"

After giving it some thought, I decided to try Nebulosity's “match histogram” function on the ready to “LRGB combine” frames. (Usually, I calibrate the images, stack each channel, align all channel, and end up with 4 images to use for the LRGB Synthesis function. So, in this case, 40 separate images become 4 images, then synthesized to one color image.) My goal was to decrease the blue in a more uniform way than I otherwise could. This is the result.

Histogram corrected color channels. This one is a little closer to correct, maybe.

All in all, I think it turned a lemon into lemonade. I think I worked fairly well.

Some Solar System Activity

Which is more than I can generally say for us, considering the COVID-19 shelter-in-place order we are now under. I have tried to image more, but the clouds remain stubbornly close by, or in the way. What I have this time is 2 images of the sun and one of a close pairing of Venus and the Pleiades. Sun first.

Filament and barely visible plauge (very light area) above left of center

In this image, which is a black and white image falsely colored yellow, there is a filament, which is a prominence seen face on, near the top, about the 11 o'clock position. It is the dark-ish line that's not very big, or dark, for that matter. BUT, and that's a big but, it's there. That's pretty much the 1^st thing I've seen this year on the surface of the sun.

Prominence on right.

This image, shows a small prominence on the right side on the sun, as oriented. Believe it or not, the yellow is the same as in the previous image. However, I had to considerably lighten this image to be able to see the prominence, so the true yellow color shines through.

Venus "in" the Pleiades. Taurus and Aldebaran to upper left.

And finally, last night, April 3, 2020, there was a close pairing of Venus and the Pleiades. This is a single photo with a small amount of “correcting”, basically to make the sky a little darker. This was shot with a Canon Xsi DSLR, which is a fairly old camera at this point, especially for an “astronomy camera.” It's a 5 sec exposure using the 18mm-50mm “kit” lens. Viewed like this, it's not too bad. However, I have an extremely hard time focusing the lens; extremely small movements of the lens changes focus. Add to that the extremely small image of Venus (by far the biggest and brightest object seen) on the camera screen, even at 10x, and focus is not seen until the image is out of the camera and on the computer screen. Or, in this case, “out of focus”, is not found until the image is viewed on a computer screen where I have the ability to really zoom in on it. A good solution would be to have a different lens, but I can't justify that at this time. Maybe later; much later. By the way, if you zoom in really closely, you can see that the stars are out of focus and that Venus has a slight halo around it from the high clouds in front of it. Thicker clouds are just off to the right of Venus in this picture; I darkened the photo enough to hide them; well, almost, it is just barely visible. Also, in the upper left corner is the constellation of Taurus. The uppermost orange looking star is Aldebaran. The “V” shape is the asterism called “The Hyades”, which is an open cluster of stars. A longer, guided, exposure would show many more stars in this open cluster.

Sun...Through the Clouds

The weatherman (person, I know, I know) promised “clear” weather for today. Of course, by the time I could take care of other responsibilities, partly cloudy was more appropriate. But, that's the story of the last several months. Moving on. I decided to look at the sun, since we are supposed to be coming out of solar minimum. There were no sunspots to be seen, but there was a prominence to be found. The unfortunate part of imaging celestial objects, even the sun, is that clouds can soften the focus at best, blur at worst. I took several images at different focal lengths. I also changed the size of the image that is downloaded from the camera. About all that does is increase the frame rate. However, that can sometimes help clear up the image by decreasing the movement between frames. At any rate, I hope you enjoy the images. Note that I painted the disk of the sun black, but not the sky portion, to make it easier to see the detail in the prominences.

F10

F30

NOT the Moon

I've just spent a pleasant afternoon processing images taken last night of the comet C/2019 Y4 ATLAS. This was fun and educational. The sky was definitely not perfect for photographing the comet, since the comet was behind quite a lot of high cloudiness. My original thought was to get an LRGB (color) image, then see if I could get a time lapse showing it's movement across the sky. Well, it almost worked out that way. As I was imaging the different colors, the movement of the comet was faster than I thought it would be. From start to finish of the LRGB run, there was enough movement that the comet head could not align in the three colors. The result was a mostly color correct image, with the red channel showing thru separately at one point, just behind the head. It's clearly visible.

Comet C/2019 Y4. Yes, it really is green. (It isn't easy being green.... or so I hear.)

The second task was achieved by taking all of the channels separately and processing them into the “movie”, which is actually an MP4 file. If it's uploadable, I'll put it up here. If not, well, sorry. It's really pretty cool. It moved about 150,000 miles closer to the sun during the almost 1.5 hours of the imaging session.

Dorsum Burnet and the Head of the Cobra

Both of which are located in the image below. This is the continuing saga of processing the images taken the evening of March 7^th.

The general area is of the western edge of the moon, in Oceanus Procellarum, the Sea of Storms. Again, this is slightly “higher” up the terminator, but also slightly east, or right. The circled area contains the Dorsum Burnet. A “dorsum” is a lunar wrinkle ridge (dorsum is just the Latin name for ridge). A wrinkle ridge is a low, sinuous ridge on the moon. They are tectonic features formed when lava cooled and contracted. They are found in the mare and some crater floors. They often follow features, especially circular one, under the mare. The naming of the dorsa is apparently a somewhat hodge-podge affair. But this particular one seems to be fairly well identifiable. There are also many other dorsa visible, but not named, on the moon. This one was named for the 17^th century English naturalist Thomas Burnet.

The white arrow points to the “Head of the Cobra”, which is the southern end of Vallis Schroteri. Schroter's Valley is considered the longest sinuous rille or valley. I suppose the sinuous descriptor means that others can be longer if they are not sinuous. The “Head” is a crater. At the point of the arrow is a small rille on the floor of this valley which is the location of several transient lunar phenomena. From Wikipedia, a transient lunar phenomena is a short-lived light, color, or change in appearance of the surface of the moon. The assumption is that the TLP is outgassing or possibly impact cratering, although, if this seems to be a common location, I would guess outgassing. The very light crater the arrow is over is Aristarchus.

More on the Moon Take 2 … and more to come, probably

Continuing image processing from the 7^th, the following image is from further “up” the terminator.

Reiner Gamma and Kepler

I've marked 2 areas that I think are interesting. First, the crater Kepler, pointed to with the arrow. It's about 31 miles in diameter. I find the rays, ejecta actually, to be the interesting aspect. The ones to the left are quite long, reaching almost to the 2^nd area of interest, Reiner Gamma, the circled area. I wonder if the sparsity of ejecta on the right side of the crater means that the object that hit the moon there was traveling from right to left, more or less. I also wonder what caused the “jaggedness” of the rays. I would think they would be straighter. Is it just an illusion caused by the terrain?

Renier Gamma is something that has puzzled astronomers for 50 years or so, apparently. First identified as a crater by Francesco Maria Grimaldi and named Galilaeus by Giovanni Riccioli. IF, and that's another big if, I'm reading Virtual Moon Atlas correctly, the name Reiner Gamma was not adopted until 1935. However, what it is remains a mystery. It's called a lunar swirl, which I think is meant to be more of a descriptive name than anything else. It has the interesting characteristic of having a very strong localized magnetic field, as shown in this overlay map from the Quickmap reference below. The red area is around Reiner Gamma, the red indicating the strong magnetic field.

Magnetic field around Reiner Gamma

One of the theories of why it looks like it does, meaning lighter in”color”, is that the magnet field has not allowed the weathering of the solar wind that has occurred around it, darkening the surrounding area. All in all, this has been one of the more interesting rabbits I've chased in a long time. The moon is still an interesting place to study.

More on the Moon

Continuing image processing from the 7^th, the following image is from further “up” the terminator.

Rima Sirsalis

This is an annotated image from near the crater Sirsalis. However, the large dark-ish area on the right side is Mare Humorum (Sea of Moisture), with the crater Cassendi in about the 11 o'clock position on the rim of the Mare. But the star of the image is what is both circled and pointed to, Rimae Sirsalis. Rimae Sirsalis is, both apparently and in several references, the longest rille on the moon, about 460 km or about 265 miles. So, what's up with rima and rilles? “Rima” is the Latin term for rille. A rille is a fissure or long, narrow channel on the moon. Another interesting point I found while looking this up (while in “social isolation” for the COVID-19 virus pandemic); sources give different lengths for the rille (Virtual Moon gives it at 182 miles, WiKipedia is the source for 426 km). It would seem there is a problem that really shouldn't be a problem. My own estimation is around 217 miles, but I'm looking at it from an angle and at relatively low resolution. I suppose my guess is no better than the other 2, and perhaps no worse!