Plate solve failures [solved: pointing]

[Robert Brewington]

I am still having problems getting plate solves to work. I am using a modded Canon Xsi/450D on a Celestron Edge C11; I think the pixel scale should be 0.379 (0.76 when binned 2) with a focal length around 3000 mm.

I did get an image link in SkyX that indicates the 0.76 scale (using a bin 2 image).

I tried the cool SkySolve utility. It worked once, and yielded the 0.76 and a focal length of 2850 mm.

I put these values back into ACP, but still no luck getting anything to solve. Also, Maxim doesn't solve successfully either.

I am using exposures of 30, 45, and 60 seconds, thinking that maybe there is too much noise or something? Doesn't seem to matter. I generally get a lot of stars (400-900) and a lot of catalog stars (300-400). I use sigma=8, min brightness 18. I don't know that there are really that many stars in the image - hence my concern about noise.

The images are at iso1600, Raw Monochrome.

Interestingly, I used the AAG utility to run the TPoint models in theSkyX. This apparently uses PinPoint to determine the actual position of the points? It never failed to solve, somehow. It worked great with 20 second exposures, never with 15 or less.

The mount seems to be pointing fairly accurately; thus, even though my field of view is somewhat small (I forget, something like 24x18 arcminutes) the stars seem to be on the chip appropriately. Thus, the FITs starting position should be reasonably close, I would think.

I have attached 3 images I tried in case that helps.