Telescope construction

[cristian abarca]

Hi guys

Just to let you know of my progress regarding my 250 mm scope. I just bought the tube for it and am in the process of making the primary mirror holder. I also just ordered the focuser , the scondary and the sight tube. I will try to post some pictures of my mirror and my tube (it's a monster). I'm still roughly two months away from completion and if I don't have too many set backs with my grinding I should have it finished by early september. Can't wait as my 150mm short tube is just not enough. Just before I go I also ordered a 507mm x 500mm x 35mm Pyrex blank for my next project will post a picture when it arrives.

Regards cristian

[iceman (Mike)]

wow that next mirror sounds like a beauty! Can't wait to see pics of your progress.

[stringscope (Ian)]

Cristian,

Sounds fantastic. Looking forward to pics. BTW what sort of focuser have you ordered.

Cheers,

[cristian abarca]

Hi Ian

I didn,t want to spend too much money so I bought an Asto system phase 1 low profile Crayford type 1.25". I want to save my money and buy a good one when I build the "big one". It only cost me $150. I didn,t buy a rack and pinion as the rubbish that came with my 6 inch scope put me off them.

Regards Cristian

[asimov (John)]

Yep. good idea! r&p suk. I ended up with a low profile helical on my 12.5" but that was as crayfords where just coming on the market & they were way too expensive. Thought of a mount for the 'big one' yet?

[slice of heaven]

I'll have to come to the defence of the poor rack and pinion here.It's not the design that sux ,its the quality of those fitted to a lot of mass produced scopes that gives them a bad reputation.
Though I wouldnt buy a new rack and pinion focuser these days,the cost difference doesnt justify buying one, I have 2 scopes fitted with quality focusers of this design and they perform brilliantly.No slop,smooth and easy to focus.

[ballaratdragons (Ken)]

Your right Slice. The old R&P's were fairly good.

I looked at a scope for my boys last week at a camera shop in Ballarat. It had an R&P and the whole focuser tube jiggled in the housing and when I turned the knob it took almost a 1/4 of a turn to move the focuser tube!!! Cheap garbage!

I'll find my boys a better scope. Does anyone know if the GS 8" Dob R&P focuser is any good?

[asimov (John)]

"Your right Slice. The old R&P's were fairly good."

The appropriate word being 'WERE'

[asimov (John)]

After saying that......I totally agree! I own a poxy little .965" R&P focuser that would eat a crayford for lunch!

[iceman (Mike)]

Does anyone know if the GS 8" Dob R&P focuser is any good

They're the standard GSO ones.. ie: they're ok. They work better after a bit of regreasing (see cahullians other thread about them).

[cristian abarca]

I haven't thought that far ahead but I think it would have to be a good one I read one of your posts about a $300 crayford maybe thats the go

Regards Cristian