Comments on: Astrophotography with the Canon 40D http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html (there are many more like it, but this one is mine) Sun, 07 Sep 2008 15:32:30 +0000 http://wordpress.org/?v=2.5.1 By: Jack http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11644 Jack Sat, 19 Jan 2008 18:41:45 +0000 http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11644 A camera (35mm film or DSLR) can be coupled to a telescope in several ways. First though; what type of telescope are you using: Refractor, Reflector, or Schmidt Cassegrain? For any telescope you can use a Piggyback mount. This is probably the best way to start learning how to take astrophotos. The camera is simply mounted to the top of the telescope using a bracket. This "camera mount" has a 1/4 x 20 threaded bolt that screws into the bottom of the camera. You can then use any lens on the camera for wide field photography and the telescope is the tracking platform. With most astrophotography you will need a “T-ring” to couple the camera to the various pieces of equipment. The T-ring has internal threads and is attached to the camera in lieu of a lens. This configuration allows for the attachment of several pieces of astrophotography equipment. These T-rings can be purchased through any telescope dealer and are made for specific cameras. If, for example, you are using a Canon 40D, you will need a T-ring built for a Canon EOS. For a Schmidt Cassegrain there are several ways to couple the camera to the telescope: 1. Prime Focus Camera Adapter – screws directly into the T-ring. This entire assembly (camera, T-ring, Adapter) then attaches to the back of the telescope in place of the eyepiece. Simply speaking, you are using the telescope as a big lens for the camera. 2. Tele-Extender – is used for high power "eyepiece projection" photography. The Tele-Extender fits over an eyepiece and couples to the camera via a T-ring. This entire assembly attaches to the telescope. The camera takes the place of your eye, so to speak, and looks through the eyepiece. These Tele-Extenders are available for all types of telescopes. 3. Off-Axis Guider – is similar to the Prime Focus Camera Adapter, but has an eyepiece attachment set at 90 degrees to the line of sight. The Off-Axis Guider screws into the T-ring allowing for attachment to the telescope. An Illuminated Reticle Eyepiece (a special eyepiece that has illuminated crosshairs) is set into the Off-Axis Guider. The guider has a small prism that picks off a portion of the field of view and projects it up through the Illuminated Reticle. By finding a star within this small field of view the observer can then use the telescope mounts directional controls to keep the star centered in the Illuminated Reticle during a long exposure. This is a complicated setup which requires good Polar Alignment and a great deal of patience and practice. The Prime Focus and Tele-Extender applications can also be used with a Reflector as well as a Schmidt Cassegrain. A camera (35mm film or DSLR) can be coupled to a telescope in several ways. First though; what type of telescope are you using: Refractor, Reflector, or Schmidt Cassegrain?
For any telescope you can use a Piggyback mount. This is probably the best way to start learning how to take astrophotos. The camera is simply mounted to the top of the telescope using a bracket. This “camera mount” has a 1/4 x 20 threaded bolt that screws into the bottom of the camera. You can then use any lens on the camera for wide field photography and the telescope is the tracking platform.
With most astrophotography you will need a “T-ring” to couple the camera to the various pieces of equipment. The T-ring has internal threads and is attached to the camera in lieu of a lens. This configuration allows for the attachment of several pieces of astrophotography equipment. These T-rings can be purchased through any telescope dealer and are made for specific cameras. If, for example, you are using a Canon 40D, you will need a T-ring built for a Canon EOS.
For a Schmidt Cassegrain there are several ways to couple the camera to the telescope:
1. Prime Focus Camera Adapter – screws directly into the T-ring. This entire assembly (camera, T-ring, Adapter) then attaches to the back of the telescope in place of the eyepiece. Simply speaking, you are using the telescope as a big lens for the camera.
2. Tele-Extender – is used for high power “eyepiece projection” photography. The Tele-Extender fits over an eyepiece and couples to the camera via a T-ring. This entire assembly attaches to the telescope. The camera takes the place of your eye, so to speak, and looks through the eyepiece. These Tele-Extenders are available for all types of telescopes.
3. Off-Axis Guider – is similar to the Prime Focus Camera Adapter, but has an eyepiece attachment set at 90 degrees to the line of sight. The Off-Axis Guider screws into the T-ring allowing for attachment to the telescope. An Illuminated Reticle Eyepiece (a special eyepiece that has illuminated crosshairs) is set into the Off-Axis Guider. The guider has a small prism that picks off a portion of the field of view and projects it up through the Illuminated Reticle. By finding a star within this small field of view the observer can then use the telescope mounts directional controls to keep the star centered in the Illuminated Reticle during a long exposure. This is a complicated setup which requires good Polar Alignment
and a great deal of patience and practice.

The Prime Focus and Tele-Extender applications can also be used with a Reflector as well as a Schmidt Cassegrain.

]]> By: MikeTannenbaum http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11586 MikeTannenbaum Thu, 17 Jan 2008 22:44:26 +0000 http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11586 How do you couple your camera to the telescope?? How do you couple your camera to the telescope??

]]> By: Jack http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11432 Jack Thu, 10 Jan 2008 19:24:41 +0000 http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-11432 I found that connecting the 40D to a laptop computer, via the supplied USB Cable, then running the 40D Utility (software supplied with the camera) gives you access to all camera functions and modes. The Live View can be displayed on the computer screen for a easy to see, and focus, picture. The Live View magnification works with this program which lends itself to accurate focusing of the telescope. Further, all photos are downloaded to the computer providing more image storage than what is available on any Compact Flash Drive. Since the camera's shutter release can also be triggered through the computer program the camer remains untouched and steady throughout the photo process. I found that connecting the 40D to a laptop computer, via the supplied USB Cable, then running the 40D Utility (software supplied with the camera) gives you access to all camera functions and modes.
The Live View can be displayed on the computer screen for a easy to see, and focus, picture. The Live View magnification works with this program which lends itself to accurate focusing of the telescope. Further, all photos are downloaded to the computer providing more image storage than what is available on any Compact Flash Drive.
Since the camera’s shutter release can also be triggered through the computer program the camer remains untouched and steady throughout the photo process.

]]> By: sugar daddy http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-10637 sugar daddy Fri, 30 Nov 2007 02:42:55 +0000 http://www.donniepinkston.net/2007-11-07/astrophotography-with-the-canon-40d.html#comment-10637 do you have any of the pics you took with your 40d to share with us? i just got my own 40d and interested in astronomy ;) do you have any of the pics you took with your 40d to share with us? i just got my own 40d and interested in astronomy ;)

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