Eyepiece projection halation?

This is probably a stupid question, but I haven't been able to figure it out on my own, so any enlightenment you folks could offer would be welcome.

I set up to try some eclipse photography the other night, and my intent was to use eyepiece projection through the T-mount camera adapter so I could readily change magnification while preserving my scope for visual observation. The lunar image, when observed visually, looked nice and sharp. Sadly, my early-evening test shots weren't:

When you had the mirror in the original position was your focuser racked all the way in or all the way out when close to focus? It sounds like a classic case of a factory Newtonian focuser unable to bring a DSLR to focus. I pose my question because I've never had the same issue while using eyepiece projection because I've never used the method with my Newtonian. The hardware you're using to attach the camera to the eyepiece places the camera even further up from the focal plane so that compounds the problem.

Your second image is right on and obviously changing the focal length via moving the primary solved the problem which essentially is what you would be doing if you were to switch out your focuser to achieve the same optical adjustment. The trick is to determine if you need a higher or lower profile focuser than your current one and if it's worth the investment to switch it out or just shoot prime focus which leads to this question. Are you able to reach focus shooting without the eyepiece, using your T-mount/DSLR?

Thanks for the comments, Nighthound. The the focuser isn't being racked all the way out before achieving focus, although it is approaching the max. I'm using Live View for final focus, adjusting back and forth until fine details are clear. If you look closely, the very center of the problem image is acceptably sharp, but gets progressively softer closer to the edges of the frame. Back in the summer I thought I had coma issues because of it and spent an inordinate amount of time trying to get perfect collimation. The issue doesn't seem to manifest consistently. I took some good (well, relatively speaking) images of Jupiter and its sats a year ago using eyepiece projection and didn't have the halation issue.

I cannot bring anything into focus with the mirror in the visual observation position without using an eyepiece, either with the T-mount extender or without. I suppose I'll have to plan on devoting a night just for troubleshooting, photographing in various configurations to try an narrow down the problem. Thanks for your input--it's given me some additional factors to consider.

The optical qualities that make an eyepiece better for visual use, make it less useful for use as a positive projection lens and you do get a lot of field curvature. That's usually not a problem with a planet in the middle of the field, but does show on the moon. If you add more distance between the eyepiece and camera (I use a set of macro extension tubes) you can get down into that sharper part in the middle, although it isn't very rigid.

Steve, that's an interesting observation. I've got a couple of old MA eyepieces from the early 80s when I started observing, but I've been using Plossls since I got back into astronomy a few years back. Specifically, 15-25mm Plossls, which fill up the T-mount extension thoroughly leaving little space between the optic and the camera. In fact, the 25mm is the widest eyepiece I can fit in there. My 32mm and 40mm Plossls won't fit in the T-mount extension, and now that I compare them, my 25mm MA is almost a half-inch shorter than my 25mm Plossl. I've been thinking the halation might be a result of too much magnification and going wider as a result. IF the effect is a physical/proximity issue, that would make things a lot easier.

Thanks for the suggestion. As soon as these infernal clouds go away, I'll give your theory a shot.