Prime Focus Problem

I know there is a thread already about this, but none of the fixes work in my case. Ok, I have the T-Ring, Orion Combined Camera Adapter 1.25 and the part that screws on to the adapter and then slides into the Focuser. Well out of trial and error, I took off the adapter. So now its just the T-ring and the piece that goes into the focuser. The problem is that it still wont focus, I can tell that I just need to be a few cm or mm closer and I will have a perfect focus.

I was able to get a picture of M42 but that was with the barlow lens.

Here is a pic of the setup.

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I think this is a common problem with Newts. Check scopestuff.com for a low profile adapter. That'll probably give you the infocus distance that you need.

Jeff nailed it, low profile is what is required. It's very common to be just a hair away from focus, very frustrating. I would take an accurate measurement of the adapter rise outside the focuser and ask the person you contact to give you the measurement of their adapter to be sure it's lower. You've got plenty of back focus so be sure you get a low enough profile to get past focus on the in travel and that the adapter won't hit your secondary mirror when inserted.

I was looking through my dads astrophotography gear and I think I found what I need to get the focus. It seems to give a lower profile, also the silver ring comes off don't know if that make it even closer.

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I still haven't got my scope collimated spot on, but one thing I did find is that, given the range of adjustment of the collimating screws, the primary mirror can be angled for correct collimation with the mirror at any distance from the open end of the scope. i.e. the collimating screws can be adjusted all the way in, in the middle, or all the way out and the angle of the primary mirror can still be correct. The effect of this in my case was to make it impossible to focus a normal eyepiece, because the focus tube had to be wound all the way out and it still wouldn't quite focus. However, I also noticed that I COULD get prime focus with my DSLR.

It turned out that I had the primary mirror too close to the open end of the scope. Unwinding all the collimating screws equally moved the primary back and allowed me to focus the eyepiece correctly. Unfortunately, this meant that I LOST prime focus with the DSLR! If I can get the primary somewhere in-between, I should be able get both the DSLR and normal eyepieces to focus.

It occurs to me that this might also be the cause of you not being able to get prime focus?

I hope this makes sense.

Rgds,

/\/\

That certainly looks like it should do it. Good luck and post some shots.

It did work, tried it on M45 last night.

devildog2222 wrote in post #11103119
It did work, tried it on M45 last night.

So can we see the results please

Click on the link to view my post of M45. Its not the best picture. I didn't have a lot of time so I just did some quick testing.

https://photography-on-the.net/forum/showthre​ad.php?t=945488