PHD2 - RA oscillating

[masjstovel]

Ah ok, i see. I was thinking at it the wrong way.
Well i have adaptors that will get me to 55,5mm. (6,5mm camera, 20mm FWH, 16mm OAG, 2mm T2/T2 and 11mm extender) It needs to be more accurate than that? 

[vlaiv]

7 minutes ago, masjstovel said:

Ah ok, i see. I was thinking at it the wrong way.
Well i have adaptors that will get me to 55,5mm. (6,5mm camera, 20mm FWH, 16mm OAG, 2mm T2/T2 and 11mm extender) It needs to be more accurate than that? 

I guess that depends on your CC. Filters also shorten light path by about 0.5mm if I'm not mistaken, so what is in reality 55.5mm will be 56mm due to filters. You might get some residual coma in the far corners, but you better ask someone who actually used coma corrector - how sensitive they are to spacing.

I have not used CC, so can't really give comment on that.

What is 2mm in above list? Can you skip that and use 1mm spacer somewhere? That should get you closer to 55mm when filters are taken into account.

[masjstovel]

The 2mm is T2-male thread - 2mm spacer - T2-male thread

[vlaiv]

10 minutes ago, masjstovel said:

The 2mm is T2-male thread - 2mm spacer - T2-male thread

Ah, ok, I did not get that with my ASI1600 (not pro version, one prior to that). This is the part:

(it looks like it is ZWO filter wheel accessory after all).

Do you need that spacer though?

CC has M48, right? OAG has M48, so that part is sorted.

If you go OAG route - you can get T2 male part for OAG, so we now have male T2 scope side. What is your FWH like? I'm guessing one side male, one female?

That still means we are on scope side male.

ASI1600 is also male, but 11mm extension should connect two male threads, right?

We now have 16mm + 20mm + 11mm + 6.5mm = 53.5mm.

Add 0.5mm for filters and add 1mm T2 spacer somewhere and you are at 55mm. There are 1mm spacers - you can cut one out of thin plastic (3d print even) or purchase set like this:

https://www.teleskop-express.de/shop/product_info.php/info/p7894_TS-Optics-Aluminium-Fine-Tuning-Ring-for-T2-thread---thickness-1-0-mm.html

Just took a look at EFW from ZWO - it has x2 female T2, so one goes on camera directly and then you don't need to use 11mm female / female extension as you'll have male T2 on telescope side and female T2 on FWH side - you just need regular T2 extension to connect them.

[masjstovel]

@vlaiv sorry i didnt notice your reply until now. I've just recieved the EvoGuide and will see how that goes first, then OAG is down the road waiting:)