Views of the Universe

Remarkable images of.....Nothing!

And one exception. I think I'll start with the exception. And in it's own way, it's remarkable, too.

Saturn

Obviously, this is Saturn. The black “space” in the rings is called the Cassini Division, usually a test of seeing and telescopes, focus, etc. When this image was taken, Saturn was just starting to go over the metal roof of the observatory, which means that the seeing was going to be terrible. You've looked over the hood of a car on a hot summer day and seen the optical distortion there, what I called, as a kid, “heat waves”. The heat rising from the hood of the car causes a change in air density, which changes the refractive index of the air, which causes the visible distortion. Same thing happening here. As mentioned before, I image the moon and planets with a video camera, which produces .avi files. The video file of Saturn looks terrible. One frame from the .avi file looks like this:

Fuzzy Saturn

I had a lot of trouble just trying to focus the scope. Wasn't sure it was focused! Anyway, I recorded the file. Next day, I ran it through a program (app to you youngsters) called AutoStakkert, which is a program that examines the .avi file frame by frame, picks out the image, and then tries to stack the good frames on top of each other to make a clear image. In this case, I am amazed. This image is remarkable simply because of how clear it is, considering what it started with.

The remaining images are remarkable because of what is not there. This explanation is mostly for the imagers out there (assuming any are reading this, which is a big assumption!). These images were taken with the same scope, just optically “rearranged” to image at F6.3 (normal is F10). (For you non-imagers out there, what that means is that the focal length of the scope is normally 10x the aperture. My scope is an 8 inch scope; that is, the mirror is 8 inches in diameter. That is it's aperture. That makes the focus 10x 8 or 80 inches from the mirror. My scope is a type of reflector known as a Schmidt-Cassegrain Telescope or SCT. The SCT optical design “folds” the optical path back onto it's self so that light comes in the front and goes out the back. Most people think of a refractor when they think of light coming in the front and going out the back. If I'm running the scope at f6.3, the focus is 6.3x8 or 50.4 inches from the mirror. Visually, this makes no real difference. For imaging, it's a pretty big difference. For reasons I won't go into now, it's more desirable.) The test was for focus, and to be sure the field imaged was flat, meaning all of the image was in focus. With the moon up, I had little choice but to image star fields, so I chose several globular clusters. Also, since this was only a test, I chose to not cool the camera. This combination would cause 2 really bad problems: 1) light gradients from the moon and a (very) nearby street light, and 2) lots of thermal noise in the image. And, guess what? I got both! The thermal noise shows up as lots of gray or white dots (pixels, actually) in the image, and the light gradient looks like fog or a cloud over parts of the image, but not necessarily all of it. Notice also how the gray sky “hides” the dimmer stars. This is why astronomers look for and go to “dark sky” sites, where arrificial light won't cause this type of problem. The moon still will, though. Last but not least, these are 1 minute, guided images and only one image was taken. Usually, I would take at least 15 images, probably 3 minutes each.

M4 pretty much as it came from the camera

I processed the image in Nebulosity 4 like I always do. Not like I always do, however, I tried using an old dark frame to create a Bad Pixel Map (BPM) and also tried a new-to-Nebulosity 4 feature called Synthetic Flat Fielder. (The reason for creating a BPM was that I don't have a 1 minute dark at 28 degrees C available.)

Much to my pleasant surprise, the thermal noise is practically all gone, as is most of the light gradient. As alluded to before, these aren't really astounding images in and of themselves. But, considering the conditions under which they were taken, I, as does at least one other imager who has seen one of them, think they are remarkable; not for what's there, but for what's not there. Images identified by their Messier number.

IMAGES OF M4, 9, 19, 62, 80