ZWO Ultra Thin Spacers

[Aidan]

I have just upgraded my 5 position ZWO filter wheel to an 8 position one.   The 5 positoin one with a couple of the very thin spacers between the camera and the filter wheel had them nicely lined up.  WIth the 8 position, no matter what combination of ultra thin spacers and delrin spacers i try, i am about off either to the left or the right by about 20 degrees.  

Does anyone know where you can buy these ultra thin washer like spacers?   I think they are in the region of .25mm and .50mm ?

Cheers

Aidan

[symmetal]

Are you using the spacers to get the camera rotation angle correct when everything is tightened up. Does your setup not have a built-in rotator somewhere in the imaging train for this purpose. Something like this T2 camera rotator might help or have I misread your post.

Alan

[Aidan]

Its mainly me being a bit OCD i'm afraid.   I can rotate my focuser unit  if required for framing.   

And, the shims would no doubt be useful elsewhere at some point!   I'm suprised that they are not available as a pack of 10 or so from ZWO.   Might just drop them a line and see if they can sell me some!

 

[symmetal]

Teleskop Service sell thin stainless steel rings for fine tuning T2 spacing. They are available in 0.3, 0.5, 1.0 and 1.5mm thickness. They are not cheap but what price do you put on peace of mind. 

Alan

[newbie alert]

Spacing is there to get your distance to your camera sensor correct ..not to align it, I'd rather have a wonky camera than wonky stars

[knobby]

25 minutes ago, newbie alert said:

Spacing is there to get your distance to your camera sensor correct ..not to align it, I'd rather have a wonky camera than wonky stars

I'd rather have good stars and the kit lined up nearly 😂

[Anthonyexmouth]

1 hour ago, knobby said:

I'd rather have good stars and the kit lined up nearly 😂

Can you post a pic of your kit. I'm struggling to picture what you mean by not aligned. 

[hughgilhespie]

Hi Aidan,

With my ZWO 8-pos wheel, I used homemade spacers cut from aluminium cooking foil. This is very thin and I used a stack of 4 or 5 - can't remember exactly. By using a stack I was also able to get pretty much all square. I made the spacers by making up a stack of squares first, then used ordinary scissors to cut out the rings. Tedious and took a couple of tries but it worked eventually.

HTH

Regards, Hugh

[newbie alert]

On 17/05/2019 at 10:11, hughgilhespie said:

Hi Aidan,

With my ZWO 8-pos wheel, I used homemade spacers cut from aluminium cooking foil. This is very thin and I used a stack of 4 or 5 - can't remember exactly. By using a stack I was also able to get pretty much all square. I made the spacers by making up a stack of squares first, then used ordinary scissors to cut out the rings. Tedious and took a couple of tries but it worked eventually.

HTH

Regards, Hugh

Was this all within your spacing to sensor distance? Have you still got a flat field with the stars looking good at edge of the field?

[Waldemar]

On 16/05/2019 at 21:20, newbie alert said:

Spacing is there to get your distance to your camera sensor correct ..not to align it, I'd rather have a wonky camera than wonky stars

If the filterwheel sticks out on one side, the radial balance is off and can cause a guiding problem, it should be in line with the CW bar or have a CW system of it's own. So, no esthetics, but sheer necessity. Getting the spacing right is done between camera and filterwheel.

[hughgilhespie]

1 hour ago, newbie alert said:

Was this all within your spacing to sensor distance? Have you still got a flat field with the stars looking good at edge of the field?

Yes to flat field and stars looking good to the edges - but this was with my Tak 106 so no issues with getting an exact spacing distance.

Petzval rule OK!

Regards, Hugh

[newbie alert]

1 hour ago, Waldemar said:

If the filterwheel sticks out on one side, the radial balance is off and can cause a guiding problem, it should be in line with the CW bar or have a CW system of it's own. So, no esthetics, but sheer necessity. Getting the spacing right is done between camera and filterwheel.

I think the important thing is to get your spacing from the reducer(If using one) and sensor correct, the filter wheel and spacers are incorperated into this measurement getting this wrong affects your stars..unless your using as hugh is above a petzval design of scope

My own camera isn't symetrical 

[Waldemar]

11 hours ago, newbie alert said:

I think the important thing is to get your spacing from the reducer(If using one) and sensor correct, the filter wheel and spacers are incorperated into this measurement getting this wrong affects your stars..unless your using as hugh is above a petzval design of scope

My own camera isn't symetrical 

The distance between fc or ff and the sensor is very critical, the position of the fw with regards to the radial balance is critical as well. Those two things are not interdependant. Very well possible to get the exact fc/ff distance and still get the fw in the right (balanced) position. Totally depends on where you put the spacers, or the rotation ring for that matter.

[newbie alert]

2 hours ago, Waldemar said:

The distance between fc or ff and the sensor is very critical, the position of the fw with regards to the radial balance is critical as well. Those two things are not interdependant. Very well possible to get the exact fc/ff distance and still get the fw in the right (balanced) position. Totally depends on where you put the spacers, or the rotation ring for that matter.

Yes, totally agree with you there..but

He's using spacers to align the filterwheel up..if he had a rotator I'm sure he would of used it 

[Waldemar]

22 hours ago, newbie alert said:

Yes, totally agree with you there..but

He's using spacers to align the filterwheel up..if he had a rotator I'm sure he would of used it 

There are several places available to use the spacers for aligning the fw... before the ff, which is the right place or between the ff and the camera/filterwheel, which of course is the wrong place. I assumed the OP is aware of that. A lot of options are available to rotate the camera without changing the ff distance.

This: http://astrograph.net/Baader-T2-Quick-Change-Ring-/-Rotator-Kit is a great, but expensive solution