Well, I am normally offering advice in this section but I am a complete novice at astrophotography with a digital camera so I need some guidance.
I have an 18" Obsession which has argo navis and servocat (alt az tracking), which I wish to use for taking short exposure astrophotographs of moon planets and brighter DSO's, with my Canon 400D digital camera. I have all the accessories I need to attach the camera to the telescope and the camera to my Pentax XW eyepieces. I am aware that because of the alt/az tracking of the mount, I am limited to short exposure images because of field rotation.
My main question revolves around getting the camera to do its thing.
If I want to take say 50 x 3 sec exposures at a given ISO setting, how do I tell the camera to do this. I am used to the camera taking 1 exposure every time I press the shutter. Do I need to connect the camera to my laptop and do I need some special software on my laptop? I have Photoshop CS2 for processing and the proprietary Canon software, but that's about all. Do I need some other software to get the image focused properly ?
For 3 sec exposures all you need to do is program you ISO into the camera which you can find out how to do in the manual, set your exposure time, you can do up to 30 sec using the camera timer and you shouldn't get too much field rotation is you are only using a short FL lens and then get a bulb release cable. And that's it. If you want to automate then yes you need a computer.
With the bulb cable all you need to do is set your exposure time, set the camera to multiple exposure and click and lock the bulb switch down. It will keep taking exposures at your required exposure length until your turn off the switch. Easy as.
BTW, you can open and process canon RAW images in photoshop if you have the RAW plugin. I'll have a look to see if I can find it. It woul be easier to download the free DeepSkyStacker to preprocess your RAW images before taking the final one into photoshop.
Like anything new, astro photography can appear a hard apprenticeship until you become familiar with the procedures and steps for setting up the ‘scope and camera, adjusting the various controls, acquiring the target, framing, focusing, exposing, etc.
My recommendation would be to start off with prime focus work first, on bright targets such as the Moon and Jupiter, as they are relatively easy to locate and frame, as well as being bright enough to focus on.
This will get you used to how the system behaves and what operations are required to set up, find, frame and focus. There is nothing like a few successful images of the Moon, or even a small Jupiter to give you a sense of accomplishment and to inspire you to continue.
After you feel comfortable with the prime focus stuff, you can move onto afocal photography (camera attached to your eyepiece) which I suspect will be frustrating to start with, as the FOV is much smaller making it difficult to find objects, and the object is dimmer making it more challenging to frame and focus the target.
My sentiments as well, start with prime focus, and something bright like Omega Cent, that will get you hooked.
As for hardware, I am sure someone will help you.
I use the 20D and use a standard USB cable to connect the camera to PC. This gives exposures up to 30 seconds and software I would suggest is either Images Plus, or MaxDSLR, both can control the exposures.
If you want to go longer than the 30 seconds, you need to tap into the Remote socket, in my case I got a cheapo remote and it had a mini plug socket on the side, Robby built me a lead that fitted the mini plug and then finished with a serial plug. Serial plug then has to fit into a serial to USB connector, but that is because I only have one serial port on the computer and this is used by the goto part of the mount.
Confused? Sing out if you are, this forum is full of clever dickies, and all are here to help.
Gary
Photoshop CS2 processes the Canon raw images without the need for a plug in so I am fine there. I will get the stacker. I also have the cable shutter release attachment which I had from my Canon film camera, that also works on the 400D, so I am fine there also.
I am in the process of building an attachment that will enable me to securely mount the camera onto the focuser board of the telescope, thus allowing me to do short exposure piggy back images. I have a 17mm Tokina AF prime lens, a Sigma 24-70mm EX DG Macro lens and a Canon 75 to 300mm lens. I will also be buying a 70mm to 100mm prime in the very near future, for macro and portrait photography.
That should keep me going for a while.
CS-John B
Last edited by ausastronomer; 29-06-2007 at 02:58 PM.
For prime focus work, I use an adapter that mates the DSLR with the 2” focuser tube where the eyepiece normally fits.
Basically you remove the camera lens from the DSLR and mate the T2 end of the adapter with the bayonet mount of the camera, then slide the 2” end into the focus tube, tighten the thumbscrew and voila, your 18” F4.5 ‘scope is now a super telephoto lens just over 2000mm in focal length!
Here are a couple of photo’s with my old 35mm film camera, showing how the SLR is connected to the focus tube on the Vixen 4" refractor.
![[1ponders]'s Avatar](../vbiis/customavatars/avatar45_9.gif){kind=avatar}
Welcome to the dark side John. 
