I tried an experiment using the new Pentax O-GPS1 accessory. The lens is simply my 55-300mm at 300mm. The exposure time was 1 minute and 10 seconds. As you can see, the GPS does a good job at keeping the stars round. The subject is the nebula in Orion. This is my first experiment using this combination. Some cropping was done in Photoshop. It would be nice to have a 1000mm f/4 lens to get a bigger image. Comments welcomed.

[bossa]

Great stuff! I am about to buy one of these GPS units in a few weeks. It's hard to believe that it can make the sensor track the sky but from some of the shots I've seen it will be much fun.

[VE2CJW]

Here is a stack of three long exposure pictures stacked in Photoshop. The first two were combined with an opacity of 50% and the third was added with 33%. No boosting of color was done. The fact of stacking the pictures brings more natural color to the result. I plan on doing a stack of around 50 pictures but won't be using Photoshop since it's not really made for that. A freeware called Registax does a fine job with lots of pictures and even .avi files. I forgot to mention that these pictures were taken in an urban area so the sky was very light polluted. Using the Pentax viewfinder, it's very hard even to see the stars. The liveview function doesn't help at all in this case. I'll try going to a place where the sky is darker but that''s at least 40 miles from where I live. I have to play with the levels to get a dark sky without modifying the stars. Comments welcomed.