Astrophotos Taken Through A Discovery 6 Inch Newtonian
As an example of what can be accomplished with a small telescope, this page
presents images captured with a Discovery 6 inch Newtonian (f/5) telescope
using a Modified
QuickCam Express Webcam. The QuickCam was disassembled, and the circuit
board mounted on the end of a plastic bottle bottom that happened to fit
tightly on my T-adaptor. Images are taken at either prime focus, or through a
3x to 4x barlow.
Some of the images list a 5 inch f/6 instrument. For those, I used my
6 inch f/5 stopped down to 5 inches, and my Edmund Barlow. By focusing without the stop, then
taking photos with the stop, I found that I decreased critical focus
problems by increasing the depth of field.
All of the moon photos except the Appenine image are composites made
by averaging from 2 to 6 of the best images for the region.
Click On Any Image For A Larger View
The Equipment: Discovery 6" f/5 Newtonian on equatorial mount.
Clavius Image, Feb 2, 2009, Modified QuickCam Express Webcam,
6" f/5 Newtonian, 3x Barlow. Stack of 15 images.
Composite of 3 frames taken with 6 inch f/5 Newtonian (masked to 5 inches)
and Quickcam Express webcam. Shots were all taken at prime focus, each photo is
a stack of about a half-dozen frames.
Moon Image, Alpine Valley Region, Modified QuickCam
Express Webcam, 5" f/6 Newtonian, 3x Barlow. Averaging but
a few images brings out the subtle variations in surface color.
Moon Image, Eratothenes crater, Modified
QuickCam Express Webcam, 5" f/6 Newtonian, 3x Barlow. I always thought
I could glimpse about 3 mountains in the crater. These images, excellent
for the 6 inch f/5 I think, show the mountains clearly.
I took these photos with my 6 inch Newtonian. I found that stopping down
the instrument to 5 inches after focusing helps insure the images are in
sharp focus. One could certainly do as well with greater convenience using
a telescope like that at left. It's more compact, has about the same
aperture, and has a clock drive.
Most of these images were obtained with my modified webcam, and a few of the
more recent ones with a Celestron NexImage camera, shown at right. If you have
a laptop, that form of photography is reasonably convenient. Early on I only
had a desk top computer (used for the planetary and Lunar Appenine photos), and
dragging out the equipment was quite a chore.
I now use an HP laptop running Puppy Linux to take my
pictures. It has a webcam software package that lets me take movies (avi
files), from which I select the best frames. The Celestron NexImage comes with
a software package that runs in Windows. Once image files are created, I use a
Yorick script I wrote
that aligns and averages the images to produce the type of images shown
here. You could also use Registax, which is included in the Celestron NexImage package.
Many people have had good results with digital cameras. The advantage to
using them is that they are self contained -- no computer required. I've
constructed a mount so I can start using my Fuji digital camera. The Mercury
transit images at The 2"
Lens were taken with my Fuji digital in this manner.