Zenithstar 73 Collimation and WO quality Control

Is there a way to collimate that telescope at home? Or at least check it is right?

I had pinched optics so I did remove the dewshield and loosen the screws like it was suggested on Cloudynight.

But I also realized that the frint lense mlenle that screw i the telescope is far from tight. Actually EVERYTHING is kinda loose on that scope.

WO quality control do not impress me so far. the first day I got it, i found a GrubScrew inside my focuser mecanism, now that.

Karl

If the cell is collimatable yes, you can if you have an artificial star or means to make one.

As Andrea already said, you can check it with an artificial star.

I own(ed) two WO ZenithStars. One ZS61II which I gave to my Dad and just recently purchased a ZS81. Both of them had their collimation dead on and by own experience low temperatures (only -5C until now) aren't a problem yet.

I could tell you a personal story about a scope from a high-end manufacturer that came with pinched optics (at 2 deg C already) and coma.

Björn

andrea tasselli:
If the cell is collimatable yes, you can if you have an artificial star or means to make one.

*What could I use to produce one ?

You can either buy one (this would give you a well defined star size in the range of about 25um) or use a flash light with aluminum foil in front, where you carefully pinched a hole into it with a very fine needle (this typically leads to a 100um to 200um hole if done with care). A web search should give you a bunch of instructions with pictures.
The distance of the artificial should be at least 20 times the focal length of the scope (rule of thumb); depends on the size of the hole you achieve.

Björn

A torch (light source) , tinfoil and a very sharp needle. Just slightly pierce the tinfoil then wrap it arund the business end of the torch. Put it 20 times the scope focal length away and you're in business. Or buy one.

my ZS73 collimation was perfect but also had the pinched optics the 1/8 turn of those screws solved that. For the rest everything on mine was tight and has worked as expected.

https://telescopescanada.ca/products/hubble-optics-5-star-artificial-stars

So this should do the trick. I will order one

Thank for the help

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