February 27, 2009

Luna & Venus (2-27-2009)

The Moon and Venus were very close in the sky tonight. It was a great photo opportunity. If you click on the images, you can see Venus as a crescent like the moon. That is because its orbit around the sun is inside of the earth's. All of these were taken with the Canon XTi and a Nikon 300mm f/4 lens. The last image is six separate images stacked in Registax 5 (which worked on Venus but not so well on the Moon). It was taken at around 6 pm. The others were taken between 6 and 7.

February 24, 2009

Comet Lulin Passing Saturn---the Movie!

The sub-frames taken for the image below are put together in a movie accessible here! What you will see in the movie are two, 9-minute periods with about a 20-minute break in between them (during which 20-minute break the comet shifts position noticeably). This is time lapse: the whole movie is only 1 minute long---40 minutes crammed into 1 minute.

Pay careful attention please to the position of the comet relative to the background stars. The movement is easiest to see against those stars' positions.

The first 9-minute set of sub-frames was taken at 800 ISO and is 20 frames of 20 seconds each with 3-second intervals in between. The second is the same only taken at 1600 ISO.


Saturn & Lulin (02-23-2009)

This was Saturn (the bright one on the left, with at least one moon) and Comet Lulin around 11:50 pm on the night of February 23rd. The comet was moving so fast that I can see its position change in each of my 20-second exposures. Flipping through them looks like a movie! So this is just 5 x 20" with the XTi and WO 0.8 ff II through the AT66ED, processed in Nebulosity and PSE7.

Here is a focus on just the comet. This is 20x20" of the same set of subs stacked on the comet itself.

February 22, 2009

Mars, Jupiter, Mercury, Luna (2-22-2009)

This was the view this morning to the east, from a tall hill in The Woodlands, TX:

February 19, 2009

Lulin (02-19-2009)

This is Comet Lulin on the morning of February 19, at about 7:00 a.m. U.T., or 1 a.m. Central Standard Time. This image was taken through the AT66ED and the WO 0.8x reducer ff II with the XTi, and is 32 x 17" processed in Nebulosity and PSE7, unguided.

Lulin passed not just through a field of stars, but also through a field of galaxies. In this next image, the galaxies are labeled (some of the galaxies are pretty faint; you may have to adjust your monitor to see them) (I have also labeled two of the brighter stars near the center of the image):
The galaxies are a long way off, of course. Comet Lulin is speeding through our solar system. the stars in the image are relatively nearby in our galaxy. NGC4697, the brightest of these other galaxies, is probably 35 million and may be 50 million light years away. NGC 4697 has attracted attention because its X-ray output is high; see images in X-ray here. NGC 4602 and its neighbor NGC 4604 are probably around 41 million light years out. One study I read suggested that NGC 4691 is nearly 72 million light years away. PGC42868 is way out there, but no one knows how far.

Of course, Lulin itself does not look like a streak of light, but it is moving so fast that an exposure of any length requires that one either stop the stars or stop the comet. The images above stop the stars. Here is one that stops the comet and lets the stars move. Each of these images represents the passage of about ten minutes. In other folks' exposures, Lulin has a tail. In fact, it has one pointing toward the sun and one pointing away. My skies were too light-polluted to record either tail, however, and this is more or less just the comet's nucleus.

February 5, 2009

Lulin & Zubenelgenubi (02-05-09)

This morning Comet Lulin was just south of the star with the coolest name: Zubenelgenubi. That is the name of the two stars at the top of this image. Zubenelgenubi is actually a double star, as you can see. In fact, sharp-eyed people see the two stars without optical aid. The two are probably gravitationally bound. The dimmer of the two is actually also itself a double star, though these two are too close to split visually.
Comet Lulin was discovered at Lulin Observatory in Taiwan last July. It is an odd comet because it is moving along roughly the same plane that the planets move around the sun, but Comet Lulin is moving backwards! It is expected to appear near Saturn later this month (only apparently near the planet) on its way out of the inner solar system.
This image is about 9 x 30' with the Canon XTi and a Nikon 300mm f/4 lens. Processing was done in Nebulosity and PSE7.

February 3, 2009

Comet Lulin (02-03-2009)

I found Comet Lulin this morning from the backyard with the 100mm f/6. The comet was floating in Libra. At 17x, it was bright and obvious, a big fuzzball. I thought it oblong but noticed no tail(s).