Sunday, November 28, 2010

Broke California

Sometimes, imaging sessions don't work out so well. Unexpected changes in the weather, equipment problems, and even poor planning can bring disaster. Take, for instance, the other night...

I set up in the ObservaRory (my yard) to image Messier 77. I quickly realized, though, that M77 was way too small for my ST80--there's not much to see at that magnification. I wouldn't have wasted my time if I done sufficient research on my target.

Auriga was above the trees, so I decided to try something really ambitious: the Flaming Star Nebula. No good, though. It wasn't nearly dark enough, and even with a 3-minute exposure there wasn't much to see. Again, poor planning on my part.

I've been wanting to image the California Nebula (NGC 1499) for some time. It's a large nebula, from our perspective, but it's also very faint. I figured that if I could get a minimally decent image of the Witch Head Nebula, then I could get the California.

Within a few minutes I was set up and taking 3-minute exposures. It was faint, but I was happy that it showed up at all. Maybe the night wouldn't be a complete loss.

Time was not on my side. For one, the Moon was rising at 10:23 that night, and it was already nearly 9:30 by the time I got everything going. Also, my infant son was asleep and would likely wake sometime between 10:30 and 11:00 to be fed and have his diaper changed. Once everything was set up I went inside to watch a movie with my older son.

I went outside around 11:00 (just as the little one was starting to stir) to check things out, expecting the sequence to be just about done. To my dismay, however, I discovered that the laptop that was controlling the camera had gone into sleep mode due to inactivity. UGGGG!!! (I know that I had disabled the auto sleep mode. How it came to be turned back on again, I have no idea...) The sky was too bright to continue imaging the California Nebula, and I had baby maintenance duties to perform, so I shut everything down.

Upon examining the images later, I discovered that there was an odd blemish--probably something to do with dust and/or dew on the objective lens. I had forgotten to take flats, so I was stuck with it. Add to that the fact that I didn't get nearly as many subs as I wanted...

But, here it is, anyway. Like the real state of California, mine is broke(n), but it's still a pretty nice place:

NGC 1499, the California Nebula. ST80 on Vixen SP. 22x180 at ISO-1600.
The nebula lies approximately 1,500 to 1,800 light years away, and resides in the Orion arm, which is the same spiral arm of the galaxy as the Sun. It is about 100 light years across.

To the south of the nebula is the bright star Xi Persei, also known as Menkib. It is on the right-hand side of this image. Menkib may be providing most of the light that is energizing the nebula

Menkib means "collarbone" in Arabic, and it is part of an old Arabic constellation that includes the nearby Pleiades. Even though Menkib is relatively faint in our skies (apparent magnitude of 3.96), it is actually about 13,500 times brighter than then Sun in the visible spectrum. That makes it the most luminous star that we can see with the naked eye. It appears so dim to us because of its distance and the vast amount of light-absorbing interstellar dust between us.

Menkib is also a "runaway star." It is moving away from us at an unusually high rate of speed (about 20 km/s). Its speed may have been gained from a gravitational encounter with another star, or by the supernova explosion of a previous companion star. Menkib itself is a supernova candidate, and may explode anytime within the next million years.

1 comment:

  1. Very nice! Nice color and great explanation. I'll never look at that star the same way again. Glad you were able to grab what you did notwithstanding the laptop troubles.