Focuser Upgrade Helo

[nitram100]

Hi guys, i was wondering if someone could give me some advice. I have bought a 2" crayford to upgrade my crappy 1.25" focuser on my orion optics 10". Ive taken the old focuser out and enlarged the diamater of the circle in the tube to compensate for the crayfords larger footprint.

Is there anything i should be aware of when aligning the crayford up for the new holes to be drilled, does the secondary have to be preciscley in the middle, for example, if after i had drilled the focuser in and when looking through it, the secondary wasnt exactly in the middle? could i fix this with a collimation? I think im being paranoid, just thought i would ask you guys first!

Thanks for any help!

Martin

[Kaptain Klevtsov]

I would think that the collimation will have limits past where you can no longer collimate, so you have to keep within the limits. Also, aren't there instructions to go with the upgrade kit?

Maybe a fix with tape and test collimation to be sure wouldn't be a bad idea.

Not being familiar with collimating that 'scope (or really any other for that matter) it seems to me that you will need to keep the focusser in the same axis as the old one or you will need in / out movement of the secondary mirror rather than the usual tilt adjustment.

Good idea to ask I think.

Captain Chaos

[FLO]

I suspect near enough is not good enough.

[geppetto]

I did this mod to a scope once...

To start, I removed the secondary and put a laser collimator in the existing focuser.

Made a mark where the red spot hit the opposite side of the OTA.

Then removed the focuser, enlarged the hole and using the laser in the new 2" focuser,

moved the focuser around to get the red spot on the mark on the OTA.

When aligned, mark the screw holes and away you go.

[nitram100]

Thanks for the info guys! gepetto that sounds like a very good plan, exactly what im going to do when i get in from work!

Thanks!

[nitram100]

Hi guys, using geppettos advice i managed to get it done and looks to be working fine apart from the fact that i run out of focus tube before i have focused an object, so i assume i need a 1.25" extension tube! does anyone know where i could buy one? ive had a look on the net to no avail!

Thanks for any more advice!

Martin

[FLO]

You could try Arthur (Ambermile)

He's a member.

[Jamie]

Or if you have an old barlow kicking about just unscrew the lens and you now

have the extention tube you were after.

[GazOC]

If youre sure which "way" you require more focus you can usually get an extra inch or so either way by collimating the primary mirror either higher up or lower down the tube.

If you do need an 1.25" extension just unscrew the lens from an old barlow and plong the eyepiece in that. Most problems with focussing Newts are due to lack of in-travel not out-travel though.

[Ambermile]

Since most Newt focuser upgrades tend towards the lo-profile genre, I'd go with the "unscrew the lens from a barlow" school. If that does the trick then look for an extension. If not and you need more in-travel rather than out then I think you may have a problem - possibly only solved by spending more money...

Arthur

[russ]

Try Ebay for a cheap barlow, normally the Seben things or similiar pile of poo will do the job nicely. Pick them up from a fiver delivered. Just make sure it has the lens that unscrews.

Even you fancy something purpose made, I bought an Orion USA 1.25" extension from SCS Astro. It cost a bit more than the cheap barlow @ £15.

Can i ask which focuser you used? Only ask as i'm about to embark on the same adventure with my LXD75.

Russ

[nitram100]

Hi guys, some great info there, thanks alot! I will try that nifty little barlow trick tonight and home it is only the out travel which is the problem, which it looks to be that way as Jupiter was literally just about to focus when i ran out of out travel. My scope is pretty fast at f4.8, would this have something to do with the problem?

http://www.scopesnskies.com/prod/antares/telescope-focuser/newtonian/crayford.hml

This is the one i bought here mate, its very smooth and seems well constructed, im looking forward to using it properlly!

[geppetto]

Pleased your getting somewhere with the focuser replacement.

That focuser is the same as the one on my Revelation DOB by the looks of it.

You will be more than pleased with it, a great focuser 8)

[nitram100]

Hi guys, just to let you know, i used that neat little barlow trick using my celestron barlow and luckily it was just a bit more out focus that i needed, i also found an extension tube which will allow me to use the 2" eyepieces aswell.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=7631020290&rd=1&sspagename=STRK%3AMEWA%3AVRI&rd=1

it will be exempt from any customs charges so looks pretty good, is that a decent price?

Thanks!

[GazOC]

Gald you've got it sorted, the tube seems a pair price.

[Kaptain Klevtsov]

Just a question regarding that focuser, as I'll be in the market for one of those soon, when the focuser rotates 360 degrees as it says, do the knobs stay where they were or go around with the camera?

Captain Chaos