Focus questions

[dawson]

1. Do you all know how much you'll need to adjust your focus if you add say a Barlow to your setup whilst looking at an object, say Jupiter, or do you still use trial and error?

 

2. My DSLR has the infinity setting for focus, but the telescope doesn't. How close will the focus be if I were to focus the scope on a very distant terrestrial object (say a block of flats on the horizon) and then switched to a celestial object?

 

Thanks

 

James

 

[Astrocookie]

I find if the moon is about, that makes a good object for focus.

I must admit I recently purchased DSLR focus and I find that very helpful for focus.

Like you I'm not sure how much the focal lengths change between barlows.

I do know there's not enough travel on my SW130 unless I use a Barlow and I have to use a star diagonal if I use a 5x Barlow on my ED!!!

Cheers

Paul