10 replies to this topic

[ah.clem]

I have a WO61, 61 flattener, T-ring and a Canon DSLR. I would like to add OAG and was considering the ZWO but the folks at Agena Astro thought the back focus would be too long and they suggested that the thin Orion OAG with their Canon T-ring adapter might be a better choice. Has anyone with this set-up successfully added OAG and if so, how did you do it? Thanks, folks.

[jwestervelt]

My understanding was that Canon DSLRs have a distance from flange to sensor of 44mm, so unless your OAG is 11mm thick, it is going to push the sensor too far back.

[ah.clem]

The thin Orion OAG is 10.5 and has it's own T-Ring setup for the Canon. I guess I'll have to contact Canon and ask if it will work, I've just found Orion support isn't always consistent which is why I was hoping someone here is already doing it. I can't imagine this is impossible to accomplish.

[DeepSky Di]

Why add an OAG to this rig? There's no need for a 61mm OTA. I run an OAG on my RedCat51 and it works well enough, but the only reason I do this is the optical train is bolted together and I move it between OTAs.

[ah.clem]

Due to illness, I need to minimize the number of pieces I need to unassemble/assemble in the field, especially in the dark, if I want to remain in the hobby, which I do. It would be extremely useful for me to get my guide camera off of the OTA in into the image path. I hope this explains why I'm looking for a OTA solution.

[michael8554]

"Thin" OAGs designed to fit directly to a DSLR, such as the Orion and Teleskop-Service 9mm, do work, I have the TS one.

[ah.clem]

Excellent, Michael. Thank you for this information. I will compare the two and get something ordered today and my son can install it for me.

[DeepSky Di]

Due to illness, I need to minimize the number of pieces I need to unassemble/assemble in the field, especially in the dark, if I want to remain in the hobby, which I do. It would be extremely useful for me to get my guide camera off of the OTA in into the image path. I hope this explains why I'm looking for a OTA solution.

Whether it's an OAG or a guide scope, I leave it on the OTA. I wheel one rig out on wheely bars and move the other one in the car. Maybe there's some alternative to tearing down ? Best wishes.

[jwestervelt]

It sounds as if he wishes to do what I do.  I have my imaging unit which has my OAG, filterwheel, and imaging camera assembled and set up so that the backfocus is correct on my refractor and the cameras are aligned to either the RA or DEC axis.  For my reflectors, backfocus isn't a concern, so I just unscrew the OAG from my refractor's M54 thread, screw on a 2" nosepiece, and ram that into one of my reflectors as needed. 

I velcro'd my slim 7port USB3 hub to my filterwheel, and that provides me with a single cable connection back to my laptop.  There is a single USB serial connection going from my imaging unit to the mount's RS232 port.  I can just store the whole thing, USB cables and all, in one of my pelican cases and not have to worry about doing a lot of setup whenever it comes time to go out for an imaging session.

[ah.clem]

Thanks, it's actually an issue with fine motor skills and my ability to unmount and mount items attached with knurled knobs. The thin Orion OAG will fit perfectly in the visual path and maintain the correct back focus. Everything that can be automated is now automated and with a big tablet I can still control things with the ZWO. Two less fittings to deal with. I am thinking that, down the line, a RedCat may be in my future as it is lighter and easier to use than my 61. Maybe I'll add a dedicated camera to replace the DSLR as there is still some fiddling with it's controls. “Never give up - never surrender!” 🙂

[fuadramsey]

For my Z61 I just leave the guidescope and guide camera on. -and sometimes even leave that on if I use my mono camera rig that has an OAG on it.

 

I keep the OTA assembled when traveling too. I just use a hard shelled storage case with foam to keep things safe and from moving around. . -no messing with stuff. I don't need to mess with the guide camera setup at all and never take it off.

 

 

But yeah an OAG is overkill, and almost a guidescope combo too depending on your exposure and mount. One time I forgot to guide on my CGEMII and didn't even really notice anything different in the sub exposures. 

 

If you have issues with knurled knobs, I'd replace them with wing bolts if you have the room. If not get longer wing bolts for extra clearance. Maybe even replace them with allen bolts and use a wrench or large T handle. 

 

z61 with guidescope/camera

 

wing bolt

 

T handle allen

 

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