Moving to OAG

[Bottletopburly]

Thinking of moving over to an OAG for the 200pds , how easy to setup and  is there a particular one to recommend over others , had a look at this one 

https://www.firstlightoptics.com/off-axis-guiders-oag/off-axis-guider.html

or 

https://www.firstlightoptics.com/zwo-accessories/zwo-off-axis-guider-oag-v2.html

 

[Bob Dobber]

I've used the v2 for a couple of years, and did so on the 200PDS when I had one, works well. Prism size can be an issue on things like the Edge HD8 as I found out (spits) but on the 200PDS no issues for me at all, ditto on the other scopes. You may have to fiddle with the prism position to ensure enough stars are visible but I seem to recall mine worked out of the box and it was only when I had my foray into the Edge that I had to tweak. Getting the guide camera focused can be a swine on the default set up, since it is very sensitive and you are basically just moving it in and out of the OAG, so I didn't struggle for long and bought the helical focuser which makes life a lot less fraught (https://www.firstlightoptics.com/zwo-accessories/zwo-125-helical-focuser.html). Adds a chunk of cost but I found it worth it and have never looked back. Focus doesn't need to be pin sharp for guiding but it makes it easier to iterate and find the spot where enough stars are visible for (say) DSS to guide on more than one of them. Obviously you will need to tweak settings in DSS (assuming you use that) because your focal length of your guide scope is now 1000mm but easily done. Think that's it, works well for me! HTH.

 

Edit: depending on what else you have in the imaging train (eg. a filter wheel), the OAG can sometimes limit the position (rotationally) you can have the camera since you've now got a dirty great lump sticking out of the side of the train to interfere with anything else fitted. Again, not been a huge issue for me. Can post a pic of my train if of use? I'm on mono with aforementioned EFW of course.

 

Edit 2: what guide camera are you using? I used the 120MM-Mini for a long time, but then moved to the 290MM-Mini and the increased sensitivity was a real help. The 120 was fine though. You will obviously be seeing far fewer stars in your guiding with OAG since you're no longer on (I presume) a much shorter focal length guide scope.

Edited April 5, 2023 by Bob Dobber
Added waffle.

[Bottletopburly]

@Bob Dobber Thanks I have a 120mni and also a qhy290mm which was playing up though I think this is down to my usb cable not liking usb3 which reminds me I need a 10m cable , I have my zwo533mc hooked up to a zwo Efw so I can switch to my L extreme filer , picture would be good 👍

[Bob Dobber]

Oof, a 10 metre usb cable?? I'm no IT expert but I thought long USB cables was a no no? A mini PC or even a stick PC is plenty as an acquisition machine and then Chrome Remote Desktop to connect into it is going to be much more reliable way of doing it... More expense I know.

[Bottletopburly]

25 minutes ago, Bob Dobber said:

Oof, a 10 metre usb cable?? I'm no IT expert but I thought long USB cables was a no no? A mini PC or even a stick PC is plenty as an acquisition machine and then Chrome Remote Desktop to connect into it is going to be much more reliable way of doing it... More expense I know.

10m will work if I get the right cable , I only need 6m  but cable goes underground to pier and 5m is just a little short I run my lads log gaming pc from the shed remote via Remote Desktop .

[Clive]

50 minutes ago, Bottletopburly said:

10m will work if I get the right cable , I only need 6m  but cable goes underground to pier and 5m is just a little short I run my lads log gaming pc from the shed remote via Remote Desktop .

It will need to be an active (repeater) cable at that length!  The recommended maximum direct cable lengths are 5m for USB2 and just 3m for USB3, anything much longer runs the risk of at least random connection drop-outs.

[Bob Dobber]

@Bottletopburly just realised I was getting my DSS and PHD2s mixed up 🤦 I'm sure you worked it out 😬

[Bottletopburly]

12 hours ago, Bob Dobber said:

@Bottletopburly just realised I was getting my DSS and PHD2s mixed up 🤦 I'm sure you worked it out 😬

Yes i gathered that ,i knew what you meant

[Bottletopburly]

@Bob Dobber can you post an image of your imaging train with OAG , I’ve picked up a zwo OAG and helical focuser for £130 should arrive today 

[Bob Dobber]

28 minutes ago, Bottletopburly said:

@Bob Dobber can you post an image of your imaging train with OAG , I’ve picked up a zwo OAG and helical focuser for £130 should arrive today 

 

I'll try and DM you, although think I've got your email haven't I?

 

Edit: I've emailed you!

Edited April 8, 2023 by Bob Dobber

[Bottletopburly]

7 minutes ago, Bob Dobber said:

 

I'll try and DM you, although think I've got your email haven't I?

 

Edit: I've emailed you!

Cheers rob I will have a look at this later this evening 👍