Robert it is best to guide on a star as close as possible to to the object beeing imaged.
The guiding program will keep the guide star locked as good as possible.
This does depend on a good polar alignment.
But does the star have to be central in the field? I'm asking this because I'm wondering if I can use the imaging scope as the guide scope at the same time, locking onto a star that's in the field but not centrally located but off to one side of the subject matter?
Robert
Thanks Martin,
Does this mean that I can divide the image between the capture program and the guider program? Presumably with 2 computers running the different programs but each receiving the same image? I'm assuming that guiding is a full-time occupation for a laptop. Which guide program would do off-axis guiding?
Robert
Unfortunately technology to do that off a single imaging device isn't available. To do long exposure on faint objects with low signal to noise you need slow read times during which you read and wipe the entire sensor (usually many minute exposures) to keep noise to a minimum. For guiding, you want 1-5 sec exposures. Closest thing currently is SBIG like setup with small guiding chip and separate larger imaging chip.
Ah ha! Thanks for that insight Rob. I guess it means back to the drawing board. I was hoping that it could be done with the one imaging camera. Hmm, mabe a guidescope is the better way to go and use my Phillips web-cam.
Robert
Robert i thought you had a guide camera.
For guiding you need a separate guide camera and scope or a off axis guider and a guide camera.
As Rob said, the imaging camera takes the pictures and the guide camera corrects the mount with small pulses.
Ah ha! Thanks for that insight Rob. I guess it means back to the drawing board. I was hoping that it could be done with the one imaging camera. Hmm, mabe a guidescope is the better way to go and use my Phillips web-cam.
Robert
You can use the web cam to guide with PHD guiding.
That is the easiest way.
Martin, I was trying to do the job with the one camera, (GStar EX2) but obviously, now, that just ain't possible! So what does one need as a guide-scope? Nothing too fancy - I hope!
Robert
Lots of people use finder scopes as guide scopes. 9x50 would be a reasonable size, but you need to ensure you can attach your webcam to it. Bintel (for example) have Orion's mini guide scope and with the right nosepiece your webcam should work.
I have an ST80 guide scope with an Atik 16ic guide camera so can't add more about those setups.
Position of Guiding Star
