M68 OAG Off-Axis Guider

Product Description

M68 OAG Off-Axis Guider

Features:

1. Lightweight and Exquisite, 17.5mm thickness

2. Prism size: 8*8mm

3. Connect the main imaging camera and the guide camera simultaneously. No guide scope required!

4. High stability, strong connection to the telescope

5. Can be compatible with ASI6200MM Pro, ASI2600MC Pro and ASI2400 cameras

6. For guiding, only can work with ASI mini camera currently.

7. There’re M2.5*6 screws in the package to help connect the OAG to 2″ EFW.

Mechanical Diagram:

Usage Guider:

5 connection methods of ASI6200 to get 55mm back focus length:

https://astronomy-imaging-camera.com/tutorials/5-connection-methods-to-get-55mm-back-focus-length.html

Note：focusing tolerance ±0.3mm

Our website is continuously updated with the most recent camera drivers as well as software for DSO and planetary imaging. Please make sure the most recent Driver and software have been installed before you start shooting:

It is also recommended to read the Manuals first before shooting.

Do you have question, answer or comment? Post here!

Thomas – December 21, 2020:

Can this OAG be used with a 120 Mini as guider and a 462 as main camera? If so, are all adapters necessary included or is another adapter required? Thank you for your kind response.

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- Support@ZWO – December 22, 2020:
  
  462MC is for planetary photography, no need OAG.
  
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ioan – December 7, 2020:

what size screws are the larger hex screws that are used in the titl adapter?

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- Support@ZWO – December 7, 2020:
  
  M2.5*6mm
  
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Andrew Read – November 26, 2020:

What size of sensor in the guide camera will be illuminated by this OAG?

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- sara.liu – November 26, 2020:
  
  M68 OAG is suitable for full frame camera.
  
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KIRK GRAY – October 28, 2020:

Hi,
Will you ever publish a manual specific to the OAG M68? The manual you have shows a different OAG model with different characteristics.

I saw an answer above from Katharine that said “only one side with M68 female thread, the other side will be connected via screws.” Which side has the M68 female thread (telescope or camera) and which side is bolted? Can you configure the OAG M68 to have the bolted side face the telescope or camera?

Thanks!
Kirk

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- ZWO.Moson – October 29, 2020:
  
  Thanks for your feedback, we will consider to publish a manual.
  The telescope side has the M68 female thread, and the camera side is bolted.
  There is link for your reference: https://astronomy-imaging-camera.com/tutorials/5-connection-methods-to-get-55mm-back-focus-length.html
  
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Shail Srinivas – October 2, 2020:

Is there an adapter that connects via screws to a female M68 or M69 thread so that both sides have female M68 or M68 and M69 threads?

Thanks,

Shail

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- ZWO.Moson – October 9, 2020:
  
  Sorry we don’t have this kind of adapter.
  
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Dale Hollenbaugh – September 11, 2020:

What is the diameter of the hole where the light passes from the prism up into the guide camera? The prism on your regular OAG is also 8mm x 8mm, but the hole is only 5.6mm in diameter, so limits what size sensor to use. It seems the ASI174MM Mini sensor is too large and a bit wasted on such a small aperture. I’m hoping the M68 OAG has larger opening. Thank you.

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- ZWO.Moson – September 11, 2020:
  
  The diameter of the hole in the M68 OAG is the same as the regular OAG.
  
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avik.basak – July 9, 2020:

can you move the prism up or down in the M68 OAG? If so how to do that?

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- Katherine Tsai – July 10, 2020:
  
  Yes, you can loose the retaining screw for prism stalk, it is near the red ring, then you can pull or push the prism stalk.
  
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Toyof – July 1, 2020:

Hi!

Another question please: what is the shorter distance between the center of the M68 thread and the prism? Thanks a lot!

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- Katherine Tsai – July 7, 2020:
  
  Could you send an email to support@zwoptical.com and show us the distance you refer to?shall we confirm the distance you refer to by graph? So we can give you more precise data according to your need? The prism stalk can be adjusted and the distance can be changed.
  
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Toyof – June 28, 2020:

Hello,

It would be very appreciated if you’ll provide a more detailed drawing of your M68 OAG and a manual! This is my question: what is the distance between the M68 female thread and the movable prism holder?

Thanks a lot!

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- Katherine Tsai – July 7, 2020:
  
  Could you send an email to support@zwoptical.com and show us the distance you refer to? Shall we confirm the distance you refer to by graph? So we can give you more precise data according to your need? The prism stalk can be adjusted and the distance can be changed.
  
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Kevin McCarthy – May 31, 2020:

What is the weight of the M68 OAG?

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- Moson – June 1, 2020:
  
  The weight of the M68 OAG is about 100g.
  
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Chris – May 30, 2020:

Just to confirm, will this work with the ASI120mm-Mini as an OAG?

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- Moson – June 1, 2020:
  
  Yes, the ASI120MM Mini can work with M68 OAG.
  
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LukasN – May 12, 2020:

Good day,
what is the thread length M68?
Well thank you,
Lukas

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- Moson – May 14, 2020:
  
  What do you mean of thread length? We can tell you some details of M68 OAG, the thread spacing is 1mm, and the thread depth is 5mm. I hope it can help you.
  
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Todd Bouman – May 6, 2020:

What is the minimum back focus distance for the guide camera? I assume the focuser has 6mm of travel?

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- Moson – May 7, 2020:
  
  The back focus is depend on your telescope which has flattener or reducer. The travel of this focuser is enough to use normally.
  
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sebastien – April 29, 2020:

Hi,

Why this OAG is not compatible with ASI2600 ? the front plate on 2600 has same fixation hole system than 6200.

Thank you,
Sebastien.

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- Moson – April 30, 2020:
  
  Sorry we don’t have a adapter that suit for M68 OAG and ASI2600. But you could connect M68 OAG and ASI2600 with 2″EFW.
  
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Avik Basak – February 26, 2020:

Can I use this ASI120MM-S as a guide camera with this OAG?

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- Katherine Tsai – February 27, 2020:
  
  Yes but you need to pay attention to the back focus.
  
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Kevin McCarthy – February 16, 2020:

Hi. I just received the M68 OAG, which I will be pairing with your ASI6200MC-Pro. Users should note that in the case of this color camera (hence, no filter wheel), the M68 OAG cannot bolt directly to the camera tilt plate, as that won’t allow any guide camera to reach focus. Instead, longer M2.5 fasteners and a disk spacer with four 2.6 mm clearance holes on a 31 mm radius will be required between the M68 OAG and the tilt plate. I measure the prism center to be 7.5 mm from the camera side of the M68 OAG, but this dimension should be called out in your side view drawing. I also measure the lateral mechanical distance from the prism center to the closest a guide camera barrel can get and still allow full focus travel to be 31.0 mm. While the focus ring suggests 10 mm of focus travel, my unit hits a hard stop at +6 mm. This travel range should also be mentioned as a spec. I next took into account the fact that the prism presents an optical thickness of 3.1 + 3.1 = 6.2 mm, which is different from its mechanical light path of 4+4 = 8 mm. As a result, for use with the ASI6200MC Pro, I conclude that the spacer disk thickness to put the focus ring at the center of its range (+3 mm) should be 7.2 mm + the guide camera’s sensor depth. For ASI guide cameras with a sensor depth of 8.5 mm, this means an M68 OAG to ASI6200MC-Pro spacer thickness of 15.7 mm. Please either confirm my calculations, or correct them if I have missed something. Putting this info in an app note similar to the one you already provide for connecting the M68 OAG to filter wheels for use with the ASI6200MM Pro would save other customers from each having to repeat my reasoning, measurements, and calculations.

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- Katherine Tsai – February 18, 2020:
  
  You will need a filter drawer to replace the EFW.
  
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Bill S. – February 10, 2020:

Can the Loadstar x2 Guide Camera fit into the guide cam holder?

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- Katherine Tsai – February 10, 2020:
  
  Yes.
  
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Charles Bonafilia – February 7, 2020:

Will this work with your new 2600?

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- Katherine Tsai – February 7, 2020:
  
  No.
  
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n2068dd – January 5, 2020:

Can I used with ASI-290MM? It looks back focus will not be matched with M42 thread camera. Must I purchase another mini camera?

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- Katherine Tsai – January 8, 2020:
  
  You may need to know the back focus of your telescope/flattener/reducer and calculate the back foccus, since the guide camera and main camera will reach the same back focus.
  
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Marco Maicas – December 20, 2019:

Is it M68 female threaded on both sides?
Thank you,
Marco

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- Katherine Tsai – December 20, 2019:
  
  There is only oneside with M68 female thread, the other side will be connected via screws.
  
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