Views of the Saturn

 Continuing from yesterday's post, today's post is views of Saturn. I can't say that I see much change over the last month.

From October 7, 2020.

From October 21, 2020.

From November 9, 2020.

Images from Nov 11

Views of the Sun

 Over the past several weeks, I imaged several objects when I could. Sometimes it was the sun, or a planet, or star cluster. What I have today is several images of the sun and I'm pretty sure you will know what the prime object in the image is supposed to be; ie sunspot, etc. 

 

Prom, October 6, 2020.

"Full" sun, November 04, 2020 Sunspot upper left filament at its right, Proms at 4 and 5 O'clock.

Closeup of above sunspot/filament, prom at 11:30.

A Numbers Game

 (Aren't most things?) Anyway, in the previous images of NGC6823, I was wondering just how dim the nebula is. Of course, this would have to be referenced to my location, since local light pollution would affect how dim the nebula appears. Another way of thinking about this is, light pollution makes the black portions of the sky lighter, thus decreasing the contrast between it and the nebula. Lack of contrast would have the effect of making the nebula look dim. (Find a polar bear in a snow storm type of thing.) Since this is a LRGB composite, and the nebula is red, I decided to use the red channel for the determination. So, what did I get? I looked for the darkest portion of the image and found that it had a mean reading of 599 ADU. (ADU means analog-to-digital unit. In my case, since I have a 16 bit camera, 1 ADU represents 1 of 65536 levels of brightness. 0 or zero equals black, 65535 equals white.) The mean reading in the brightest part of the nebula is 749. That's pretty close. In other words, the nebula is only 150 ADU brighter than the blackest part of the sky (in this image). That's not very bright. It turns out that the nebula is only 0.23% brighter than the darkest part of the sky.

More Of The Same

 In this case I'm referring to NGC6823. A cold front has moved through Georgia, leaving somewhat clearer skies. I wanted to use N.I.N.A to try positioning the scope to the same coordinates as the previous image of NGC3823. However, the updated version was, shall we say, uncooperative. I ended up using Stellarium to move the scope to the region, then plate solved the image I took to be sure I was where I thought I was, and it came back as being very close. I decided to go with that and see how close it actually was when I added two nights worth of data together to see if there was a substantial improvement. (I'll let you decide what you think.) The previous blog entry was 7 minutes (one minute at a time) in each of the four filters, L,R,G, and B. Below is that same data, plus an additional 10 minutes in each of the four filters; so 17 minutes in each filter for a total of 68 minutes total exposure. Post processing was different for each image, but I don't think that was a major factor in the outcome.

 

NGC6823, two nights worth of data. MUCH larger nebulosity showing.

Working Through Frustrations

 It seems so long between imaging sessions at the scope that I forget how to image. Part of getting old, I guess. Plus, astronomical (or as I do it, astrocomical) imaging is a complex activity at the best of times. At any rate, I have imaged several objects since the last entry to the blog. And I can't say I'm impressed with the results, with one exception. That one will be obvious, I think. High clouds, high humidity, and light pollution all seem to conspire against astronomers trying to bring the beauty of the night sky to a computer near you. (Will it every change? Sigh.) Here is seen some of the latest trials and tribulations.

NGC 6401, the "fuzzy spot" to upper right of center.

Above is the globular cluster NGC6401. This is actually a color picture, it just doesn't seem so. If it shows up in the blog image, there is also a large “X” looking feature in about the center of the image. That is dust in front of the stars, blocking out the starlight. It's known as Barnard 82. The Barnard Catalog is a list of “dark nebulae” (basically areas of the sky where no light is coming through from the light source located behind it, whether that source is stars or a emission/reflection nebula) and was compiled and published in 1919 by Edward E. Barnard. A lot of the catalog can be found along the plane of the Milky Way, as in this case.

NGC 6823 et al.

Above is and image of several things, one of which I haven't been able to identify yet. NGC6823 is the open cluster in the center of the picture. As far as I can tell, it's the brightest stars in the picture. I suspect several of the dimmer stars are included, but I have no idea which ones. NGC6820 is a small reflection nebula nearby. Reflection nebula are usually bluish in color. I can't say that I see anything like that in this image. The redish area is an emission nebula, which I think will be Sh 2-86. The “Sh” designation refers to an entry in the Sharpless catalog of emission nebula. The color image is composed of about 7 one minute exposures in each filter (LRGB), and I'm really not pleased with the result. However, the black and white image is the same image devoid of color. It would be (almost) the equivalent of 28 one minute exposures. I think it shows more detail. The take home message from this is that I suspect I will go back to this object and try to get more data by taking about 21 more images in each color and restacking them. Hopefully, this will make the color image at least as good as the b/w image. We'll see. If you look at the bottom edge, about ¼ the way towards the center you can see something that looks like a small comet. I haven't been able to identify this as yet. It could be part of the emission nebula that is “thicker” in that area, or it could be a comet or one of several other things. Currently, I'm betting on it being part of the nebula.

Caldwell 19

Finally, the above image is that of Caldwell 19. This one actually turned out pretty good, I thought. This one is also in the plane of the Milky Way, but much further North, closer to the star Deneb in The Swan.

 

Jupiter and Saturn

On the night of September 7,2020, we still had the persistent high cloudiness, but otherwise had almost decent skies. It appears this will be the last time for at least a week, but I took advantage of the opportunity to photograph Jupiter and Saturn. Although, in full resolution I can easily see the image degradation, they are otherwise not too bad. Actually, probably fairly decent for the conditions. Picture of Jupiter also has the moon Europa at the far left, almost at the edge.

Europa and unnamed star to far left of image

 

Three Day Prom

(as vs. a 3 dog night? Sorry.)

We have had unusually clear(ish) skies for the past 3 days. A cold front moved through and lowered temperatures and humidity to more bearable levels, but alas, that's about to change. So today, I got out before the clouds started to return and took one image of the sun. And, it was a blank sun. However, just because something is not immediately visible doesn't mean it's not there (as hopefully we will see later this week). At any rate, what I decided to show this entry was a prominence over the past 3 days. All images were taken at approximately the same time of day, but the second day entry was taken with a longer exposure because it was looking like the prominence was becoming sufficiently dim that the longer exposure was needed. However, today's (the 3^rd entry) was taken with no expectation of seeing the prominence. However, with an extreme “stretch” the remnants are visible. Well, you've waited long enough, so here the images are from day 1 (September 6, 2020) until today (September 8, 2020). 

 

Day 1

 

 

Day 2

 

 

Day 3. Image part of a full sun image.