Barlow Reducer

[rob_r]

Hi again, I recently got a barlow 0.5x reducer for Christmas. I tried this out last week with my camera but could not achieve focus after trying both moving the focus to the min and max positions. I assume I have made a beginner error with the focal length. The camera is slotted into the back of my 127mm Mak with a focal length of 1500mm (f12) via a T-ring adaptor. The lens would reduce that to 750mm but everything is just a huge blur. The barlow lens is screwed into the front of the T-ring. There is also a diagonal in between with no other eyepieces involved between the camera mirror and the scope. Do I need something else to achieve focus, like some kind of extension or another lens to achieve focus without using an eyepiece? I can use the reducer with the eyepieces without any issue. Thanks in advance. 

[Cornelius Varley]

Reducers tend to move the point of focus inwards so you might need to remove any extension between the rear of the telescope and the camera, this would include the diagonal.

[Cornelius Varley]

Also the distance between the reducer and sensor might be crucial.

[rob_r]

Thanks Peter. I will have a go at removing the diagonal and see if that makes any difference. Otherwise, I suspect the distance between the barlow and the sensor could be the issue as you have also suggested.