Locating targets

[D Wright]

The problem I am having is that not having GOTO I can find things manually but when I replace the eyepiece with the camera I cannot get the focus correct. I can focus on a bright star with the camera in live view using a Bahtinov mask but then I can't find anything except bright objects such as M13 and M42. It comes down to guesswork as I can't see many things through the finder scope either. I have had some success but I waste a lot of time taking frames to see if I am on target. Does anyone else have this problem or any ideas on how to accurately find targets.

[spillage]

To be honest even with goto I still have to take some test shots to make sure I am on target and that the target is framed correctly. It might be worth looking at other peoples images and check the star patterns compared to your lights.

Have you tried making a mark on the focuser when the camera is focused. It may allow you to swap back to the eyepiece and then attach the camera back to the scope with it being close enough. I would test it out on a bright star to see if this will work.

 

spill.

 

[D Wright]

My focuser has a scale on it and I have tried using this but I still can't get exact focus. I am thinking of making a removable lockable collar for the focuser tube. Then I could focus the camera and lock the ring then focus out to the EP and when I am centred on a target I could focus back in to to collar and know I am exactly focused. Ithink I have just solved my own problem. Now to put theory into practice.

[spillage]

Sounds like a good solutioin. Best of luck and hope it works

[mikeyj1]

Have a look at this video from Doug German:  HTH

Mike

 

 

[D Wright]

Interesting video but I don't use a laptop. I conrol my camera from a tablet using DSLR controller.

[michael8554]

A parfocal ring on your eyepiece would allow you to swap between the camera and eyepiece without altering focus.

Even then you might find your images slightly out of focus, taking the camera off and on again may not end up in exactly the same position.

Without GoTo you really need large diameter setting circles to get you in the ball park, then platesolve a 30 sec JPG exposure at max ISO using PlateSolve2.

Michael

[alacant]

15 hours ago, D Wright said:

conrol my camera from a tablet using DSLR controller

Hi. JTOL. Does the tablet boot to windows too? If so you could get APT. It has built in plate solving, is really easy to use and will hit your target dead centre every time. HTH.

[D Wright]

Not that I know of. It is an android tablet and DSLR is an app.

[D Wright]

I made a simple aluminium clamp to go round the focuser tube and it works. I tried focusing with the camera with a Bahtinov mask then tightening the clamp. Then I swapped to the eyepiece and focused with that and then swapped back to the camera and rechecked the focus against the clamp and checked with the mask and it was still perfect focus.