Positioning baffles

[markse68]

Quick question to the knowledgable- when setting baffle position in a refractor tube what’s the best method? If I made a scale drawing of the ota with a cone representing the cone of light from the objective as per its fl, I could position the baffles to quite accurately fit that cone by their diameter and then transfer those distances to positions on the tube. But should they be touching the edge of the light cone or backed off a bit? It would be tricky to get really exact. Or would you fit them by trial and error looking through the ota for each one to eliminate vignetting? That would be very time consuming I think!

[johninderby]

Have a read of this.Very usefull resource. The part on designing the telescope parts has info on baffles.

https://irpoyser.co.uk/how-to-build-a-telescope/

Edited May 6, 2020 by johninderby

[andrew s]

You will vignette the field if you place the baffles like that. You needed to draw two cones to the extreem edges of the field of view not the centre.

Regards Andrew 

PS the book shows the same idea. If you measure an eyepiece field stop to get the field of view use the lowest power,  longest focal length you have.

Edited May 6, 2020 by andrew s

[Peter Drew]

2 minutes ago, andrew s said:

You will vignette the field if you place the baffles like that. You needed to draw two cones to the extreem edges of the field of view not the centre.

Regards Andrew 

+1

[johninderby]

This CN thread has got a lot of info on the subject.

https://www.cloudynights.com/topic/493483-refractor-baffle-setting-out/

[markse68]

Thanks for all the info - I’ll have a read

Mark