Focus issues

[Andywilliams]

On 10/01/2022 at 03:24, teoria_del_big_bang said:

There should be 2 mm in the adapter I think on the scope side of the FV so this is still aiming for the 56 mm shown on ZWO website but either way 55 or 56 mm should give proeet good images that can be focussed.

Steve

Hi guys !

Success !!

Thankyou so much for your advice .... I love this forum because the advice is so freely given and is of top quality !

So, I didn’t have my spacing right, my measurements were out of whack.....I should have realised this a while ago.

Im still not sure how back focus relates to the scope focus but I can now reach focus half way along the draw tube 🤷‍♂️🤔

I used the moon as my focus aid 👍

I gave it a quick go last night. I’ve also had some issues with guiding but have ironed out some gremlins there as well.

The upshot is that for the first time ever I was able to do a 300 second sub !....before the high cloud swept in.

You will notice that the focus is a little soft but it’s very much in the ball park and will improve as soon as I attach my eaf.

This is the 300 seconds on the Rosette through the Ha filter.

Again , thanks so much 🙏🙏🙏😃😃😃

 

 

[teoria_del_big_bang]

Brilliant, thanks for letting us know, it's so good when something goes right isn't it 🙂 
Personally I am not so experienced so can't help with many aspects but if I can I am so happy to do so because that's what others on here did for me, and still do 🙂 , and thats how it should be and one of the main aims of a forum like this.

Steve

Edited January 11, 2022 by teoria_del_big_bang

[Andywilliams]

28 minutes ago, teoria_del_big_bang said:

Brilliant, thanks for letting us know, it's so good when something goes right isn't it 🙂 
Personally I am not so experienced so can't help with many aspects but if I can I am so happy to do so because that's what others on here did for me, and still do 🙂 , and thats how it should be and one of the main aims of a forum like this.

Steve

Totally agree....

I didn't get much sleep  last night before a work day....but I dont care....I'm so happy ! 

You are right....its a wonderful feeling when the gremlins start to go away and things start going right ! 

Again, thanks for your help 👍👍😃😃

Edited January 11, 2022 by Andywilliams

[The Lazy Astronomer]

3 hours ago, Andywilliams said:

Im still not sure how back focus relates to the scope focus

Back focus just relates to the distance required between the corrective optics (coma corrector, flattener, etc.) and the imaging sensor in order for those corrective optics to be performing optimally. If that spacing is slightly out, it shouldn't affect focus particularly, but star shapes will be off away from the centre of the frame. But, as you discovered, if it's significantly out, it may present focusing issues. 

Glad you got it sorted though 👍