TS72 in need of collimation

[Stu]

This might be another job for Mr E Reid. I was just having a quick session with my TS72mm, a scope I've always been been very happy with to date. I was trying it out quickly tonight with my Tak Prism and the two Vixen HR eyepieces, the 3.4 and 2.4mm giving up to x180. The views were generally pretty amazing, no false colour and clean airy disks but the diffraction rings were incomplete and looked offset to me.

I will try again with another diagonal, just incase that is the issue, but if not it is off enough to bother me. I'm not sure whether the focuser could be skewed slightly, always a possibility I guess so I should check that with a laser too. Again, not sure if there is any adjustment on these if needed.

It's a lovely little scope, would be great to have it performing at it's best.

[John]

That does sound potentially like a collimation issue Stu.

Is the TS72 a doublet or a triplet ?

Have you tried the cheshire eyepiece test ?

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p167_TS-Optics-1-25--Cheshire-collimat-ng-eyepiece-for-refractors-and-newtonians---metal-tube.html

Shining a laser collimator down the tube is worth doing - it should help identify if the focuser and objective optical axis align accurately.

[Stu]

21 minutes ago, John said:

That does sound potentially like a collimation issue Stu.

Is the TS72 a doublet or a triplet ?

Have you tried the cheshire eyepiece test ?

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p167_TS-Optics-1-25--Cheshire-collimat-ng-eyepiece-for-refractors-and-newtonians---metal-tube.html

Shining a laser collimator down the tube is worth doing - it should help identify if the focuser and objective optical axis align accurately.

Thanks John. Fortunately it is a doublet so a bit less complex to sort. I've not had this issue on a refractor before, although perhaps the purity and high power of the Vixen's is showing it up? The Tak is spot on fortunately.

I do have a Cheshire and a laser so will have a play around with that.

Thanks