Focusing guide scope

[Kryptic]

Seeking wisdom as to how to go about focusing one of these please

https://www.rothervalleyoptics.co.uk/rvo-32mm-f4-mini-guide-scope.html

[gilesco]

2 minutes ago, Kryptic said:

Seeking wisdom as to how to go about focusing one of these please

https://www.rothervalleyoptics.co.uk/rvo-32mm-f4-mini-guide-scope.html

With a lot of pain!

It's a helical focus on a normal 0.75 thread, so:

1. You rotate (and rotate, and rotate some more) the black bit at the end until you reach focus.
2. Once you achieve focus you can rotate the red bit to fix focus in place.

You don't need absolute perfect focus for guiding, so hopefully once you've achieved rough focus, you won't be trying to change it all that much.

The black bit is on a normal M48 thread by the looks of things, so it can take a lot of rotation to get it in place, I would recommend setting it up during the day and first achieving focus on a landmark that is very far away (1-2km or more). Then point at stars at night and try and find a sweet spot from that point.

 

[Kryptic]

5 minutes ago, gilesco said:

I would recommend setting it up during the day and first achieving focus on a landmark that is very far away (1-2km or more). Then point at stars at night and try and find a sweet spot from that point.

 

Super - thank you

[Chefgage]

18 minutes ago, Kryptic said:

Seeking wisdom as to how to go about focusing one of these please

https://www.rothervalleyoptics.co.uk/rvo-32mm-f4-mini-guide-scope.html

Watch this video. At the 5.12 mark he explains how to measure the focuser barrel to gain focus. I was having problems focusing mine with a zwo120mm mini guide camera attached. Followed his measurements and it was then perfectly focused.

https://youtu.be/2oiTVGA2zIs

[m.tweedy]

I have the exact same one and Yep. It goes out a loooooong way before you reach focus. However it is quite easy as the camera does not rotate as unlike most systems its the front that you unscrew.

Edited November 2, 2020 by m.tweedy
additional info

[Kryptic]

5 hours ago, Chefgage said:

Watch this video. At the 5.12 mark he explains how to measure the focuser barrel to gain focus. I was having problems focusing mine with a zwo120mm mini guide camera attached. Followed his measurements and it was then perfectly focused.

https://youtu.be/2oiTVGA2zIs

Perfect - same camera.

Thank you