Help with ASL224 focus

[Neil H]

Hi sorry this may be a long story, I have the 224mc I want to use it on my bresser AR127L and sharpcap, I had no luck at night so I tried it day time to see if I can find were I am going wrong , the only target I can see is a chimney on a house over the back ( I don't know if it's too close) I watched a video by Carl Smith on the 224 and sharpcap  he used a small Newtonian scope with one extension put in an eyepiece and focused the telescope then changed to the camera he said all the cameras he has used to focus you need to turn in on the focuser and he got focus 

I can't find focus I do with the eyepiece but not the camera I tried with extension and without extension, and diagonal with extension diagonal and no extension , camera direct in extension, eyepiece will focus what ever the set up but not camera 

The best I got was a light patch of fog moving in image which I think was a tree in the wind 

Any ideas please ??? , just to add I did a long time back got an image of Jupiter with this camera and my VX8L Newtonian but was not good as I am still trying to work sharpcap out

[kirkster501]

Have you got enough gain and exposure such that even had you achieved focus you'd actually be able to see something on the screen?  Conversely, have you got too high an exposure so that it washes everything out?

It is quite normal to require an extension to make up for the removal of the diagonal and the back focus distance that it made up. 

Regarding focus itself a chimney/eaves of a house/trees etc 50-100 metres away to practise in the daytime will be very close to precise focus at night so you are correct trying this method first. I do this all the time to save precious clear sky time.

[kirkster501]

..... I have a text document where I record all my starting point focus points, imaging train components, and starting gain/exposure for every combination of scope, camera, ADC, Barlow etc so that I can assemble, dial in and go.  I keep this up to date. 

[PeterCPC]

I use an extension when I use the 224 with my ED80 so I think that you will need an extension. Still need to rack the focuser well out. Good points made above about exposure/gain.

[Neil H]

I will have another go tomorrow I will try a power pylon it's better distance 

When I tried to day I got histogram at 15% peak but image looked out of focus and a mess 

So is it best to have camera direct in focuser and not use the diagonal

[kirkster501]

Never use the diagonal when doing AP at prime focus.  Always use an extender.  With my TEC 140 I have the focuser racked out almost fully AND I have a 2" extender.

Almost 100% certainly, your problem is due to you not reaching the correct back focus.

[Neil H]

Thank you so much I will give it a go tomorrow I have a few extension 2 came with the scope and others I have brought

[Neil H]

Focus at last I think you guys were spot on about object to close 

Set up the 2 extensions that came with scope plus a 35mm x2 inch with 2inch to 1.25 eyepiece holder it's nearly doubled the length of the scope lol 

Thank you every one that helped just need clear night