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TAL200K Owner - Focuser woes or am i being picky

astrodingbat

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astrodingbat

astrodingbat

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Have a TAL200K (Golden Oldie) i think someone on here might know it No22 2002.

Bought a while back to compliment my shortie refractor.. only just got the mount and everything sorted.

Used it couple of weeks ago and after many attempts at findind my first alignment star got up and going...

Finally found jupiter and it was rubbish (but was glad to see that it was rubbish in everyone elses scope). It was a bit weird not having flares on stars,,,,

I had re done the tal focuser but it is not the best.. and am thinking of trying to adapt a low profile crayford, heard a lot about in focus problems BUT using my eyepieces I was right on the limit of out focus, in fact had to raise my eyepieces a bit on the higher mags. Looked at light path lengths and a low profile crayford seems ok. but making an adapter plate will be interesting anyone have any thoughts??

Most crayfords come with a removable curved foot.. I need to make a flat version. Anyone know the accurate measurement of the mounting hole in the base plate??

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astrodingbat

astrodingbat

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Yep I saw those - House of optics - i think! But was priced at about 100euro. I'm originally from the black country - that much money for a bit of ally - makes me sweat and sssttuuttterrr!

Not sure if this scope will be what i am looking for - but want to give it every chance. Do like TAL stuff - It won't blow over in a breeze..

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AndyH

AndyH

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Hi !

Yeah the original Tal R&P on this scope had been used n abused sometime in the distant past. I did a quick fix on it to get working a wee bit better, but it was still rather rough.

I took some pics of the crawmach VLP focuser and cunning low profile baseplate(If I remember correctly, thought up by former owner of this scope, Eliot) that came with the scope. Worked very well with this 200K. Might be of interest.

See pages 8 & 9 on here..... http://www.flickr.co...6911@N08/page8/

Bear in mind, when looking at potential replacement focusers, that the Tal focuser is only 44mm long, plus the 5mm of the baseplate, so that's really low profile.

Andy.

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astrodingbat

astrodingbat

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Thanks for that Andy,

As i mentioned in one of my posts the ep's i use are hyperions (I like looking through shop windows) and the other night to achieve focus I was racked right out and even had to lift the eyepiece at one point looking at Jupiter. Taking this light path into account a 50mm deep crayford should be ok shouldn't it?? (will still be using the TAL diagonal - no imaging - me and cameras are incompatible.) My back adapter may not be as fancy as that to start with - not too fussed about acess to the collimating screws as I can always put the old base back on if i ever get brave enough to twiddle the screws...

Is this a plan or pie in the sky??? (mind you wouldn't see the pie for the clouds)

Plus the burning question....... Am I right to give this scope a chance???

Rich

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AndyH

AndyH

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Am I right to give this scope a chance???

Absolutely !!

Another thing to bare in mind with a crayford......... make sure the focuser drawtube isn't too long. Remember the opening in the back of the 200K has an internal diameter of 40mm, so there's nowhere to go for the focuser tube, whe it's fully racked in.

I realise you mentioned that you have plans for a backplate, but there is another one available from 'berlebach' for 49 euros ..... http://www.berlebach.de/?bereich=details&id=380&sprache=english

Cheers,

Andy.

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astrodingbat

astrodingbat

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Thanks Andy

have had a look and emailed them to see what low profile focuser will fit and what they recommend. Would save a lot of hassle for 40 quid or so. Had thought about the draw tube and taken that into account with the calcs etc (hopefully). Nowt that a hacksaw wouldn't fix! only jokin

Rich

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AndyH

AndyH

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Absolutely !!

Another thing to bare in mind with a crayford......... make sure the focuser drawtube isn't too long. Remember the opening in the back of the 200K has an internal diameter of 40mm, so there's nowhere to go for the focuser tube, whe it's fully racked in.

I realise you mentioned that you have plans for a backplate, but there is another one available from 'berlebach' for 49 euros ..... http://www.berlebach...sprache=english

Cheers,

Andy.

Got the sizes screwed up. Should've been, 'internal diameter of 44mm, with a 38mm field stop(58mm deep in the baffle tube)'.

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