Hi,lsintampa wrote: ↑Mon Jan 27, 2020 3:41 amOzEclipse wrote: ↑Mon Jan 27, 2020 3:16 am
If you can find the reference, post it. It sounds wrong.
If the mount is polar aligned, anything driven while on the mount is also polar aligned. Perhaps the comment you read referred toGOTO alignment? I mount camera with 135, 200, 300mm telephoto lenses straight onto my Takahashi EM200, the mount is a clone of the Skywatcher EQ6. The principle is the same for a CG4. I do the polar alignment using APPS, Artificial Projected Pole Star alignment, then put a star dead centre of the field of the tele lens using full magnification live view and do a one star alignment in Sky Safari. From that point I have bothGOTO and precise polar alignment.
Joe
https://www.cloudynights.com/topic/5030 ... -eq-mount/
This thread - see response 9
There are many forms of 'alignment' in astronomy and
That post #9 is referring to the misalignment of the auto-guider and the camera. This only applies of you are using some sort of auto-guiding. From what you have written, you want to add dual axis motors to your CG4 primarily to drive the polar axis then put a camera on the scope and do exposures tracked / driven by the motor but without an auto-guider system applying corrections.
Response 19 refers to
If that is the case, then as stated in my earlier post, "if the mount is polar aligned, anything driven while on the mount is also polar aligned."
Without guiding, you are relying on the precision of the drive system. Most drives have an oscillating error called periodic error. This is something like what your mount performance will look like.
Lucky imaging - you take a series of exposures, one after the other. Throw away the images where the error changes rapidly. The ticks and crosses indicate this. You do this by inspecting the images in the computer afterwards and throwing away those that show trailing, you don't need to produce an error graph.
cheers
Joe