Pictures of the motion of the stars around the north or south poles look terrific. But if you point your camera to any other part of the sky with an exposure long enough that the stars move then they just look like lines and IMHO are pretty much worthless.
HiYou don't want any filters. Keep the camera on a tripod and use a remote to trigger the shutter. Shutter speed above 15 seconds will start showing the movement of the stars, so if you want them point-like keep it under 10-15 sec. The noise reduction will take a dark frame shot with the same shutter speed, and it works very well. If you want things like Milky Way you'll probably need to stack several images of about 30 sec each. Milky Way also have regions that are rich in features, and regions that are boring. Read up on what to photograph, when and in what direction. Light pollution is the biggest problem. Fortunately right now at least the moon is gone.
Wide angle is more interesting because it can include both land features and a large part of the sky. Remember, the constellations are very big, We only see about 6 zodiac ones on any given night.
Here's Orion over a cabin in Yosemite: ISO 800, 15 sec, f/3.5, 14mm. The blue light in the sky and the light on the outside wall is from the full moon.
Milky Way over Isla Spiritu Santo: ISO 1600, 30sec, f/3.5, 14mm.
Vlad
Thank you for your compliment! The image with the house is not stacked, it's a single exposure. This was just an illustration that a single 10-15 sec exposure with ISO 800 will produce a nice result even with the kit lens, and if you use a faster lens it will be even better.
That's all the article says about it. No explanation why. It's a bit terse, I agree.
I just got this shot, processed with the tip from Iskender and Sean Nelson. Orion belt with the dagger. There's even some glow from the Orion nebula. Taken in the middle of San Francisco! Amazing! Now I want the tracking mount and the 300mm lens
Look at the drive bolt again. The article tells you to bend it in a circular shape, with a radius equal to the distance between it and the hinges. That pretty much eliminates the problem (linear motion) with the single arm design.
That's all the article says about it. No explanation why. It's a bit terse, I agree.
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Florin Andrei
http://florin.myip.org/
Thanks Vlad
it seems that the curve would effect the angular speed of the platform. The curved bolt would provide a constant angular speed, whereas a straight bolt would give angular speed that's different near the end and start point from that near the middle of the arc. In comparison with the straight bolt, in case of the curved bolt the nut travels a longer distance between exactly same end points in the same amount of time. Is it not so?
What about AFing on a very far away object during daytime, then switching to MF and turning the camera off with the Lens Reset option OFF? Then it should keep the focus to infinity.
Genius? That's definitely too much, thanks!
You're very welcome, glad you found it useful.
