WebCam Astrophotography
by Tim Hornbeck
This is the process I have used successfully to image Mars.
I have a Philips Vesta 680 webcam with a
special 1.25" adapter made from Delrin. This adapter replaces the
original focuser that ships with the camera. I insert the webcam with
adapter into the telescope eyepiece and attach the camera to my laptop via
a USB port. This method is called prime focus and esentially
makes the telescope a huge telephoto lens. I use a special software
package call QFocus that interfaces the camera to the laptop. There
is a live preview window that allows me to line up the object into the field
of view of the telescope. Once the object is centered I have two methods
to capture images; individual images (BMP) or movie (AVI). Individual
images are automatically captured, named sequentially and stored into a
directory on the computer hard drive. A movie file is captured
into one large file and also stored within a directory on the laptop hard
drive. The movie file sizes can be as large as 500MB, while individual
images files can be roughly 200KB each.
Once I have captured a good sampling of
images or video, use a software package called K3CCDTOOLS, that aligns
and stacks each image or frame. This allows you to gain more surface
detail than just an individual image. There is an automatic algorithm
for planets that speeds up the process. First you input your source
files or movie file and select the area that containts the image to be stacked.
The software takes each image or frame of the movie file and orders them
in a list that is sorted from best to worst. You have the option of
choosing the best "N" images or a percentage of the best images. After
this option, you finalize the alignment and stacking and your completed
image is displayed and ready to be saved. To further enhance surface
details, you can utilize a photo package like Photoshop or Paintshop Pro.
The Mars photos on the BRAS home page are
a combination of both individual images (BMP) and movies (AVI) taken
with a Meade 395 - 90mm F/11 equitorial refractor with and Ultima 2x
barlow lens.
Here are some useful links for Webcam Astrophotograph:
Various WebCams
General WebCam AstroPhotography Site
Modified Long Exposure WebCams
Delrin 1.25" Adapter
General WebCam AstroPhotography Site
K3CCDTools