Ocal Collimator with Edge HD8

[Bargy]

Hi,

I'm new to the Edge HD8 and have been struggling with collimation, focus and polar alignment. I think a lot of the issue is that I didn't have the reducer, so been trying to do everything at the native focal length (2032mm). Anyway, I have managed to get hold of a .7 reducer and I'm going through all steps logically.

Question I have first is - should I do the collimation with or without the imaging train? And also, which circles should I align the collimator to?

Here is an image of the Ocal camera with no focal train apart from the .7 reducer which is attached.

Here are the reference points I chose

This next one is after collimation - note that the crosshair on the camera seems central, but the mirror still seems a little off? Not sure if I should go by the mirror or by the camera crosshair.

 

 

Main questions then:

1) have I chosen the correct reference points (circles)
2) Should I fine tune to the cross hair or the primary mirror
3) Should I be collimating with just the reducer or the whole image train which would be: Scope-Reducer-OAG-ZWO 21mm Filter draw-ASI2600MC

 

Many Thanks in advance.

 

Bargy

[Bargy]

Just to add to this - here is an image once I put the imaging train back on and attach the ocal again

 

[myk68]

Hi Bargy

I need to say Snap. I have recently got myself the Edge HD8 as well.

After a few imaging tries, damn these clouds and rain. I thought my stars were very flary to one side as it focused and tried to collimate on a star, but the next session I got didn't seem to have made a difference.

So I got the Ocal 3 as you have, however, I have used a different strategy for the ring placements so it will be interesting to see the consensus on where these should be put.

In my image, a bad screenshot from my phone, I didn't think the mirrors looked round compared to the rings, I also didn't know what the bright circle around the red ring was as it didn't go right around. you don't seem to have that in your images.

I also have the green ring central but then the baffle?? is off-center to that.

 

One thing I would say about yours when you add the image train back on is that it looks like you have sag in the train, so something is not straight or tight. see if you can move it while the Ocal is on for how much it moves. 

Maybe someone else will have some ideas.  hope you don't mind me jumping on your thread

Mike

 

[M40]

Hello myk68, I have a similar telescope in the skymax180, so these are my thoughts only so hopefully others will jump in to correct me. One difference between the two telescopes is the secondary mirror in your telescope can be adjusted whereas the secondary in the skymax is fixed, so first step on yours has to be to ensure the secondary is centered and it looks like yours is out slightly. When you have centered it then look to center the primary. And similar to the skymax its the end of the primary baffle that you are looking to center.

Hope that can provide some help, here is a link to a thread neilh started on the collimation of the skymax....