Astrophotography: NGC 6530
Published on Aug 20, 2006 at 12:53 pm.
2 Comments.
Filed under astrophotography.
This is the star cluster NGC 6530.
The star party went well last night. We didn’t have that many people from the public there. But, the park ranger said that there weren’t many people staying in the park. Most of the public schools just started, and thay may have something to do with it. Also, it was HOT. We have had a long string of very hot dry days. This morning, driving back at 2am, it was still 89 degrees out (Fahrenheit, for my friends in the rest of the world other than the US, that is 32 degrees Celsius).
So, when the public got tired of looking at things, then we could try a few things. I got a digital camera so that the students can experiment with taking their own astrophotos that they can keep. That way they get to “own” a piece of the class. In the city, most of the photos will, of course, be moon and planets, and some of the brighter star clusters. The rest is mostly washed out. Anyway, I thought to try a few. This one was the best looking of the bunch. There was some periodic error in the telescope’s mount (for non astrophotographers, that means that it rocked back and forth as it tracked). That meant that most of the photos had stars that looked like little lines instead of dots. I’ll see if I can clean up a couple of those. If I succeed, I might post one of them later.
This particular photo was an attempt at the Lagoon Nebula, M8. The camera was a Nikon D70, and the exposure time was 15 seconds at effective ISO 200. My longer exposures had tracking errors on them. The problem with this was that the nebula didn’t show up!
A nebula is a cloud of gas and dust in space. This particular nebula, M8, is in a region where such clouds are collapsing to form new stars. Some of the first stars to form are generally very large, hot, and bright stars. They shine with a lot of ultraviolet light that then ionizes the gas in the vicinity. When the gas deionizes, it glows. Charles Messier was a comet hunter who lived right at the beginning of the 19th Century. He made a list of things that could appear fuzzy and be mistaken for comets. M8 is the 8th thing on the list, and is what we call the Lagoon Nebula. Associated with the Lagoon Nebula, there is a star cluster called NGC 6530. This name means that it is object number 6530 in J. L. E. Dreyer’s New General Catalog. The star cluster was the only thing that showed up in this photo. The nebula is there, but too dim for this exposure to pick up. The nebula goes from the star cluster up and to the left in this image. The nebula itself has an NGC designation, and that is NGC 6523.
This particular type of star cluster is called an “open cluster” because it has a loose structure, as opposed to a globular cluster, which is a roughly spherical ball of tens or more thousands of stars. Open clusters generally quite young (as far as stars go), and this is one of the youngest ones, perhaps only 10 million years old.
-Astroprof
Andrew on August 20, 2006 at 7:02 pm: 1
Sorry to hear about the problems with the mount.A longer exposure would have definitely helped to show the neb.
Astroprof on August 20, 2006 at 7:49 pm: 2
Yeah, I know. I was using one of the mounts that we use with the astronomy classes. They really aren’t built to take the abuse that they get from the intro astronomy students.