Anyone ever cut down a refractor

[tom.yates]

I am about to cut down a refractor for binoviewing for use without a diagonal (Dont want to use a barlow either) Anyone done this ? The scope in question is a Meade AR5 5" Acromat F 9.3 Any help views,advise would be great

Thanks

Tom

[Helen]

Andrew just did his ED120 for a PST mod and for better binoviewing. I'd PM him (he might still be on holiday though).

Helen

[tom.yates]

Thanks Helen

[blinky]

He is still on Holiday Tom, I think he has another week.

[Jamie]

Hi Tom

I have cut down a refractor, for my PST mod a couple of years ago.

What are your concerns about doing the cutting?

[tom.yates]

Hi Jamie i need to get it bang on square mate or the colli would be off how did you go about it ????? I dont really want to just get the hacksaw on it I only want to take just enough off the length and know more

[Jamie]

Sorry Tom but i did just use a hacksaw on mine.

I did however spend ages marking the tube all the way round the circumference.

If you do that then you should be able to just cut about 1" deep then rotate the tube and cut another 1" following the line precisely, and so on till you have cut the whole way round. All you need do then is take off the rough with a file....

Just remember to cut the focuser end.

To test if you have done it correctly just stand the tube up on a hard flat strface and test the angle using a set square.....Mine was bang on perfect...... Albert (astro source) will testify to that.....

[Earl]

Sawing straight lines....

My Dads a carpenter and can cut straight so easily its annoying..

Me.. forget it!

[michaelmorris]

The best way would be to cut it on a lathe.

[Merlin66]

You can make a very accurate guide by wrapping some wide card strip around the tube and sticking the ends.

Mark 6 or so points around the tube at the required cut distance and line up the edge of the card. Cut along the edge of the card with a fine tooth hacksaw blade and smooth off with a fine file.

Also watch the internal baffles in the OTA; sometimes the focuser tube will interfer with them and the focuser tube itself may need to be cut.....

[Peter Drew]

I've done several Tom, if you call over to the Astronomy Centre I'll do it for you while you wait.

[tom.yates]

Thanks everyone for the advice, Peter i will take you up on your offer

Tom

[Jamie]

Now that's what i call taking your time making your mind up......

Nice one Tom...

[tom.yates]

Well young Jamie i took the saw by the scruff of the neck n cut the tube down

To be quite honest though it was a piece of cake just got some card wrapped it round the tube making sure the edge was flush and started cutting whilst rotating the tube

See you at Kielder

[tom.yates]

Thanks fot the offer Peter

I must come over one night to the centre to meet you in person

Tom.

[Jamie]

Well young Jamie i took the saw by the scruff of the neck n cut the tube down

To be quite honest though it was a piece of cake just got some card wrapped it round the tube making sure the edge was flush and started cutting whilst rotating the tube

See you at Kielder

Now yer talking.....

See ya then matey...

[Merlin66]

No problems with the internal baffles?

[tom.yates]

No mate i thought it may cause a problem myself but it works fine the reason for cutting it down is so i could binoview through it and i must say i am very happy with the outcome the star test shows collimation is spot on perfect concentric rings at high powers ( I cut 4" off the tube)

[Merlin66]

Sounds like a good outcome. Well done.

[tom.yates]

Yep very happy with it

[Peter Drew]

Well done Tom, told you it was relatively straightforward once you've plucked up the courage!. Still pleased to meet you over here one night.

[tom.yates]

Will defo come over one night soon Peter