Should my locking screws extend beyond the tube?

[Bart]

Hello everyone,

I noticed when i took the OTA from the Dob base to work on the base (Az circles) and stood it on some foam matting, that when I removed it, 3 marks remained on the foam corresponding to the locking screw heads for the primary. Is this ok? or do I have them too far out? For some reason I imagined the OTA would sit of the edge of the tube all round.

Thanks

Bart

[brantuk]

Hmmmm..... The locking screws are keeping the mirror in place - I wouldn't want the entire weight of the scope bearing down on them for fear of cracking the mirror. Good job you had some foam in there. How far they stick out will depend on how far back the mirror is after collimation. Hope that helps

[Bart]

Thanks Brantuk,

Thats exactly what I was thinking! Now, the tube usually sits in the rocker mount/box and only comes out occaisionally.

BTW, I posted aweek ago approx regarding the Wixey, and you suggested Az circles. I work in an engineering company and so got a 360 degree marked circle printed (sshhh) on the plotter, taped acetate onto and below, got it onto the base with some adjusted system (4 small screws), cut out a 1.5 in hole in the base and Bang, there she is! Only got a few mins of clear, full moon sky since complete, but randomly picked some bright DSOs and WOW, found them really quick, almost dead on in the 32mm. Oh, how my back is thanking me! Makes me think some of the hunting fun is gone, though, that feeling of finally saying 'Gotcha!'.

Bart

[brantuk]

That's great news Bart - didn't I tell you it works with surprising accuracy! It's smashing to know you had a success from my recomendation

[Bart]

Yep, can't wait for the next clear night/morning when I can nick my wife's smartphone with Skyeye (which I was kind enough to download for her!) that I can use at the scope, rather than running in and out of the garage to look at the laptop

[John]

I've put 3 rubber stops on the bottom of my newtonian tube so that the scope can sit on those when it's stood on end without putting any pressure on the collimation or locking nuts. They are held in place with strong double sided tape.

[Bart]

I've put 3 rubber stops on the bottom of my newtonian tube so that the scope can sit on those when it's stood on end without putting any pressure on the collimation or locking nuts. They are held in place with strong double sided tape.

Thanks John, might do this