|
focusing a SCT with a f/6.3 reducer
I recently bought a celestron f/6.3 reducer.
The instruction for focusing (for imaging) is to get a sharp focus at the centre of the image then turn the focusing knob 1/24th turn anti clockwise.
I guess this is to give a uniform focus? However, it mean the focus is out at the centre (?) where the main DSO will be. The centre spike of the bahtinov mask moves a fair way from the centre.
I thought the idea of a reducer/corrector was to get a uniform, in focus, image across the entire field.
Is there a better method - or does this sound okay?
Regards,
Tony.
|