Thin Spacers

[Emuhead]

Hi guys,

Where do you get your thin spacers?

Im pretty sure ill need M48 size.. and im after 2 specific sizes.
2.56mm & 7.9mm

Open to suggestions, Ive not used them before.

The variable spacer that i do have cant be used as its already too large at about 24mm and up.

Thanks,

[The_bluester]

Bintel has a set of M48 extension tubes with a 5mm in it and I know Sidereal Trading brought in some thin stainless ones when I bought a few. You would have to stack a couple of the spacer washer ones to make up the 2.5 (Not sure you would get 2.56 exactly) and a threaded 5mm tube and spacer washers to get to 7.9mm. Other than that you would have to get something made I reckon.

[glend]

Not sure about M48s but you can buy packs of very thin nylon spacers, as thin as 0.25mm, 0.5mm. 1mm, etc. I bought mine from Teleskop-Express. They are made by Baader. They simply slip on over you adaptor threads, to tune exactly the length of spacing you require. Link here.

https://www.teleskop-express.de/shop/product_info.php/info/p3619_Baader-T2-adjustment-spacer-rings---for-the-right-distance-control---15pc.html

BTW, most Correctors have a working range, and do not necessarily need precision like 2,56mm, they could work well 50% either side of that probably.

[The_bluester]

The only problem I have found with the Baader ones is that they are designed as a close fit over the threads, you have to push them on and down in to position, that is OK in itself but they can be a royal pain to remove. I cant recall if they do M48 ones though.

I mention the spacer washers Sidereal Trading has as I know that they have some M48 ones and they are already here in Aus, which is sadly a factor at the moment. The stainless washers are an expensive option (I more or less sent about $50 worth with a scope I just sold to help the new owner get it up and running) but it looks like the M48 extension tubes are on backorder at the moment but it is worth checking with them if they have just had some come in. Bintel may or may not have them on the shelf at the moment but as far as I know they don't carry the M48 spacer washers. Sidereal Trading bought some extras when I bought a set through them last year.

[Xeteth]

I'd give anything for some sort of product that you can do variable spacing and adjust for tilt also. I know it's unlikely since there might be a lot of moving parts, plus it would have to hold sometimes quite a hefty imaging system but damn it would make adjusting backfocus a much nicer procedure.

[The_bluester]

The problem I have seen with pretty well any variable spacing adjuster is that the tilt changes all on it's own any time you so much as look at them, OK on something slow with a big critical focus zone but harder and harder to deal with as the optics get faster..

Tilt adjustment wise these look like a good idea, using a cone shape, tapered radial screws and heavy springs to adjust tilt without push/pull screws, which are a PITA to adjust and also often blocked access wise.


https://www.gerdneumann.net/english/astrofotografie-parts-astrophotography/ctu-camera-tilting-unit.html

[Joshua Bunn]

I can make you there if needed.





I'm currently making a variable spacer for a customer here on IIS so he can easily dial in his corrector spacing. You can contact me if you'd like to discuss having one made :)