Astrophotography and the May sky

The whirlwind is over! I'm embarrassed to see that my last posting was back in March. The last month of this semester has been just crazy with grading, reports, meetings, and all that. But it is finally over (mostly) and now I look forward to the summer. I'm teaching an introductory course during the first summer session though, so the break won't last long.

Over the last several months we have had some exciting things happen in astronomy. The comet PAN-STARRS flew by and I was able to share with you a picture of it on the western horizon. Stash and I went back a week later to observe it again and while I took more images, they did not turn out very well - it turns out that a camera is hard to focus when it's dark outside. I'm still learning. We observed it again in the telescope, but this time it first required using the camera to find it on the sky. Stash painstakingly slewed his telescope around in the vicinity of the comet for what must have been 10 or 15 minutes until it finally popped into view. Much dimmer, but still exciting!

It has now receded off into the darkness of the northern sky, a target for astroimagers with large telescopes and/or CCD cameras. In the meantime, I've continued developing my hobby of astrophotography by taking star trail images. Here is one of some trails over the observatory:

This image was created by turning up the ISO to 1600, turning down the f-stop to 4.5, and taking a series of 15-second exposures. The nearly full moon that night illuminated the observatory setting nicely. These images were then stacked with Photoshop's "Lighten" mode, thus allowing their light to add upon each other. However, as you can see, each trail has a small gap in it where I must have stopped for a reasonable moment to check something. Grr!

So I tried again:

There was no moon that night, so I had to use a flashlight to "paint" in the foreground. This image turned out pretty well, though the foreground buildings might be a bit too bright.
One last try, this time while camping with a few buddies:

This time, I turned down the ISO setting to 800 to reduce some of the electronic noise, increased the f-stop to 8 to increase the field depth a bit, then compensated by increasing the exposure time to 20 seconds. This is a compilation of 85 consecutive images, stacked together. The star trails themselves turned out nice, and the foreground trees are illuminated by the campfire. What is that bright streak through it, you ask? During a couple of these exposures, one of my friends walked in front of the camera (he didn't know I was taking pictures at the time) while wearing a headlamp. I think it adds an interesting artistic element to the picture, so I'm not altogether unhappy with it. I couldn't throw that exposure out because it would have left a gap in the star trails. That's okay though - it looks pretty cool nonetheless. Another such streak appears at the bottom of the image.

We've moved into spring now, and Orion and the winter constellations are basically gone for the year. What is there to look at now, you ask? If you turn to the north-east, Hercules is rising which means the Hercules cluster (Messier 13) is becoming visible. That's a binocular target, so aim for the west side of his broad "chest plate" and about halfway in between the two stars on that side. Look for a fuzzy spot, which represents a globular star cluster comprised of hundreds of thousands of stars, all very old indeed.

Saturn is nice and bright and will be for almost the entire summer:

Jupiter is on its way out for the year, but if you keep an eye on the western horizon you'll begin to see Venus appear nearby. They make a close pass on May 27 just after sunset, but look carefully. It will be quite low on the horizon, so if there are any trees or hills to your west you may not see it at all. Venus will continue to rise higher as the weeks progress.

That's all for now. I will report back at the end of the month with (hopefully) more images and an update on the June sky. Happy viewing!