Some Time Under The Stars

I find that time spent under the stars, even when the skies are not very good, as they are not around Starlight Observatory any more, is time for me to recuperate, especially since the diagnosis. Last night I was able to take the Canon DSLR out for an hour to try something different for me: nightscape imagery. Basically, this amounts to pointing the camera at the sky, and taking as long of an exposure as you think you can get away with and not have star trails; ie, the stars remain round looking, not as streaks. I had been wanting to take a time lapse image of the sky to show the grandkids how the sky moves, so last night, I did. Basically, the time lapse is just multiple nightscape images.

The start time was about 9PM EDT, with obvious clouds. The sun set almost an hour before I started, but you can see the sky still getting darker as we come to the end of astronomical twilight. You can also see a change in color, as the light dome from the college town to my south (we are looking south, towards the town) emerges and grows prominent. This was fun, and I might try it from other locations, should I be able to travel again. It wasn't hard to do. The area of the sky is around Canis Major (the big dog) and Orion, to the right (west). Best seen full screen.

The second thing I wanted to try was ultra short imaging, by which I mean lots of short exposures to see how that might stack up against fewer longer exposures. Below is a stack of 50, 5 second exposures, same area of the sky, with only dark subtraction applied for calibration frames. Each of the frames in the video are 20 seconds each, while each frame used for the image below is only seconds each. I think I can see more stars in the stacked 5 second image than the 20 second image. I could also work on the 5 second image a little to decrease the effect of the light dome. Over all, though, I'm pretty impressed.

50, 5 second images stacked. Sorry about the large file size.

Is This A Discovery?

Or Why It's Probably A Good Idea To Take A Closer Look At Your Images Sooner Rather Than Later

Well, much has transpired since the last entry; we've traveled to middle Georgia to work at a children's home for 3 weeks, and I've managed to come down with an autoimmune disease for starters. That will severely limit my activities for a while. On the up side, however, I've looked at one of my images taken in February and found something interesting; or is it?

M108, mine on left, compared to Palomar DSS on right showing "star" in circle

This is the area around M108 taken the night of February 5^th. Hopefully, you noticed there are two images. Mine is the one on the left, the other is one taken by the Palomar 48 inch Schmidt telescope (which is 6 times bigger than my scope and collects 36 times more light). Notice also the circle I've drawn on both. On my image, there appears to be a “star” which is absent in the Palomar image. So, what did I find? Anything? Some possibilities are 1) a nova (or supernova), possibly, 2) an asteroid passing through the neighborhood, 3)a cosmic ray hitting the camera, or 4) ???? It is quite dim, on the order of 18^th magnitude or so. On close examination, the “star” is one pixel wide, and 2 high. That implies, somewhat, that it probably is not a cosmic ray strike. But what else? If I had found this sooner, I could have re imaged the area quickly. If it were an asteroid, it would have moved. But, M108 is nowhere near the asteroid belt, so probably not that. If it were a nova, it would still be there, most likely, since they seem to stick around for about 3 months or so. Cosmic ray hit; not likely to get exactly the same pixel two nights in a row. We will never know what this is, unless another astronomer just happened to have imaged the same area, seen the same thing and reported it and it has been tracked down.

Lesson learned.

A Break From The Herschels

On the evening of February 5, I wasn't able to see any Herschel objects I would like to image. And, it would appear, there may be quite a few I won't be able to image because they will be too low in the sky and blocked by trees. We'll see. However, I wanted to continue imaging the Messier catalog, so I found, and imaged 5 more objects.

M36

This is Messier 36 (M36) in the consellation of Auriga. This is also the only image made in color that night, which is part of the reason why I'm putting it here. Looking closely, you can see that the stars are blue. Blue stars are hotter than average and usually younger. The stars in M36 are estimated to be about 25 million years old. Compare that to the age of our sun, which is in the range of 4.6 billion years old. The cluster is about 4000 light years from us. It is estimated that these stars may share many similarities with a close by cluster that is easy to spot, the Pleiades.

Decisions, Decisions, Decisions

But this one was an easy one to make.

Reader(s) of the last episode will remember (or just scroll back to the last entry) that I had just imaged 52 Herschel objects. Since that time, I've also imaged 8 Messier objects in roughly the same area of the sky. The decision was to not post all the images, since they are what I'm calling survey images (meaning I'm looking for particularly interesting objects, so I'm surveying what's out there to come back to to make longer exposures and in color). Fifty-two images would take up a lot of internet bandwidth, so I think I will post only the more interesting ones. This might be another to come back to at a later date (probably next year).

M46 and NGC2438

This is M46, an open cluster in the constellation of Puppis (the stern or poop deck of a ship, or so I'm told). The interesting part of this is the planetary nebula that is found in it. The nebula is known as NGC2438, which just happens to be on the Herschel list I'm imaging. So, in this case, I get a two-fer; an M and a NGC object in the same image. M46 is about 5500 light years distant. NGC2438 is the gaseous shroud cast off by a dying star (which is pretty much what all planetary nebulae are) and lies about 3000 light years away.

LOTS More Herschels, But Not All At Once

I've had a few nights that were clear enough for imaging and with out a moon to interfere. Over the course of two nights, I managed to image 51 Herschel objects and one Messier object. As it turns out, a lot of the Herschel objects are open clusters. Fortunately, my scope has a pretty good (much better than most, I imagine) GOTO, and has found all of the 52 objects quickly, allowing me to image that many in such a short period of time. At least, I think I have 52 objects. How will I know? Well, that's a fair question. So I thought I would give an example using one method I use to verify what I have imaged.

NGC129 in Cassiopeia

This is my image of NGC 129 in Casssiopeia. At least, that's what I think.

MegaStar version of NGC 129. Yellow rectangle is what the camera shows.

This is a screen shot of my star mapping program called MegaStar. It provides a fairly accurate representation of the stars, planets, and deep sky objects like open clusters, galaxies, and nebulae. This shot shows the stars to about magnitude 16, which is very, very dim stars. My image shows stars to an even dimmer level, but this is sufficient to check where I'm pointed. Actually, it's fairly confusing to go this “deep” (meaning showing so many dim stars).

NGC129 fewer stars to show patterns better.

NOTE: PLEASE DON'T SCROLL BELOW THE FOLLOWING PARAGRAPH UNTIL AFTER YOU HAVE READ IT.

This is the same image as above, but I changed the lower limit of star brightness to magnitude 12.4. There are now fewer stars to compare to my image, and those stars are brighter. Just for fun, can you make the comparison between the my image and the above image to see that they are showing the same stars? Take a minute and try. I'll give you a hint; it's just pattern matching. (Try looking around the number "129".)

NO PEEKING!!! :)

Both images, showing matching areas. Can you see the matches?

OK, now a side by side comparison, but with six different areas shown where the pattern of stars match in both the Megastar image and my image of the sky. I usually don't try for only one matching pattern, but several, at least two. That way, I'm pretty sure I have correctly identified my target object.

NGC7789, also in Cassiopeia. Cluster is basically in the center of image.

For something a little different, and while I continue processing and verifying other images, I decided to take a color image of one of the objects, NGC 7789, also in Cassiopeia. Two things to note about the image : 1) the color image is much nicer on the eyes than the black and white images that I'm using for identification and hopefully you can see that there are blue, yellow, and red stars in the cluster (which is in the center of the image) and 2) since 7789 is in Cassiopeia and the Milky Way runs through Cassiopeia, there are a lot of other stars than just the cluster, making it more difficult to tell which stars are part of the cluster. This identification has been verified as well.

Herschel in the Ram and Whale

On January 6, 2018, about a week ago, I got the first clear night in a looooong while. I used the time to continue imaging objects on the Herschel 400 list. As I, hopefully, mentioned before, this is a survey of the objects to determine if I want to come back to any of them for further imaging. I don't think I will be coming back to many of these, but maybe one or two (of the 13 this time). One, NGC772, is in Aries, the Ram. The rest are in Cetus. This list is all of the Herschel objects in their respective constellations. And that's what I'm trying to do; image all the objects in a constellation to see if I want to return for further imaging. So, without further ado, here are the images, almost all galaxies, and almost all just L band for 1 minute, Bin x3 at -10degrees C, 3 images stacked to make the final image, 8” LX200GPS operating at F6.3, camera QSI683...if you wanted to know. :)

NGC772. This is the one in Aries.

NGC720

NGC157

NGC246. This is one I might come back to.

NGC584 (in the center), plus at least 2 other galaxies.

NGC596

NGC615

NGC908

NGC936

NGC1022

NGC1052 in center.

NGC1055, another possibility to re-imaging.

NGC779

Hubble, ISS, Geminids.

(Obviously, the post that I thought was going to be the last one for the year wasn't.)

This entry may be one of my shortest. Last night, December 13, 2017 was the Geminid meteor shower. I usually don't go out for meteor showers, but I decided to have a look last night, and I'm glad I did. The reason I usually don't go out for meteor showers is I usually don't see any. But last night was different. I was out for about an hour and saw at least 11 bright meteors. I saw a 12^th , but I think that was space junk burning up rather than a Geminid. It was cold, but worth the effort this time. UPDATE: Tonight, the 14^th, the grandkids and I watched the Hubble Space Telescope and the International Space Station go over. Following that, we saw a few stray Geminids fall as well. A first for the grandkids, seeing the satellites and the meteors. That was a fun 35 minutes spent under the stars.