Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Edge 11 + celestron OAG, adapters and camera?

  • Please log in to reply
2 replies to this topic

#1 markm75c

markm75c

    Viking 1

  • *****
  • topic starter
  • Posts: 526
  • Joined: 17 Sep 2009
  • Loc: Pittsburgh, PA

Posted 11 September 2019 - 03:44 PM

I've decided to jump into the world of guide cameras, in the case of the edge 11, off axis guide cameras, though i will do hyperstar, so i dont think there is any value there, but for f7 or f10 i would use the oag (or do you leave it attached during hyperstar to see phd2 data)?

From what i've researched, it appears the best bet is the celestron OAG + 174mm mini camera (though the 174 price is a bit steep at 499).
(At least i think it was the 174mm mini).

I'm trying to confirm the camera and any accessories that i might need (i read that maybe the 290mm mini for around $300 would work as well, but maybe the 174mm mini is really needed in my bortle5 light polluted skies, i think more guide stars would be visible with the larger 174 sensor).

 

I was thinking of maybe getting the oag off the classifieds, but i think it was mentioned there is something about newer ones that is better, but i'm unsure how to spot a newer from older?

I noticed some are using this adapter: (large sct adapter)
https://www.celestro...off-axis-guider

Since i'm still a newbie to this area, is this meant for a larger sensor guide camera or for situations where you have a larger sensor main camera?
Right now i have the asi294mc pro, but will likely get the asi1600mm in the future as well.

Are there any elements that i need to get to make this all connect properly?

Thanks in advance for any clarifications on this one.

 

 

edit: i guess a guide scope due to the wider field when doing hyperstar is still useful, so perhaps the oag 174mm mini camera in this case i could use for that with an st80 or similar guide scope for hyperstar  (here for f7, maybe the 1.4lb 60mm zwo guide scope or maybe this slightly heavier 1.9lb svbony version), if not the 174mm mini maybe the 290mm mini with this setup (if dual setups/not changing cameras or possibly just the 120mm mini)


Edited by markm75c, 11 September 2019 - 04:52 PM.


#2 Endymion

Endymion

    Explorer 1

  • -----
  • Posts: 69
  • Joined: 16 Jan 2016

Posted 16 September 2019 - 01:25 PM

* I don't do hyperstar so can't comment there

* I used the cheaper ASI120MM for guide camera  C11EDGE + Celestron OAG.  I seem to get enough stars for the most part.  More is better though so if you have the cash, future proof yourself with the better camera.

* Yes the large SCT adapter is used to avoid clipping the light cone so you can use larger sensors (in my case a full frame DSLR).

* You will need an adjustment at the output of the OAG to get the back focus distance right for the C11 Edge (146.05mm).  The distance is very important for optimal results.  You'll have to look at the supplied extensions and see if they will get you the right distance to the sensor or whether you have to buy different length extensions.  

  Here are some old calculations I did for my cameras that may help with your calculations:

 

   OTABackToOAGFlange.jpg

 

  OAGFlangeToFlange.jpg

 

  So this means from C11 FR back focus start point (furthest back point of the focal reducer or OTA) to back flange of OAG is 58 mm

   Given 26.5 mm for ASI1600 and Filter Wheel this means need the
   following extension:

     146.05-58-26.5=61.55

   Need 61.55 mm of extension

 

    42+106+12.5-10=150.5

 

   For the DSLR with 55mm back focus need:

   146.05-58-55=33.05. mm extension tube

    8+5+20 would work

    For the ASI224MC with 12.5 mm back focus need:

     146.05-58-12.5 = 75.55 mm

 

 * You will also need to adjust the OAG guide scope distance correctly as well.   That distance depends on how deep you set the OAG prism into the light cone.  The focuser on the guide path has about 9mm of travel.  You will need the appropriate extension for the prism setting and the guide camera optical path length.  I think you can download the OAG manual from the Celestron website and see what it recommends for distances.

 

John

 

 

 

 



#3 ckhorne

ckhorne

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 23 Sep 2016
  • Loc: Roswell, GA

Posted 16 September 2019 - 02:50 PM

I've decided to jump into the world of guide cameras, in the case of the edge 11, off axis guide cameras, though i will do hyperstar, so i dont think there is any value there, but for f7 or f10 i would use the oag (or do you leave it attached during hyperstar to see phd2 data)?

 

You unfortunately can't leave the hyperstar on when using f/7 or f/10, and the OAG can't be used while in hyperstar. The hyperstar takes the place of the secondary mirror, so it's an either-or setup.

 

From what i've researched, it appears the best bet is the celestron OAG + 174mm mini camera (though the 174 price is a bit steep at 499).
(At least i think it was the 174mm mini).


I use the Celestron OAG and I've been very happy with how sturdy it is and flexible for different configurations. I use the 290mm for my guide camera and never have a problem finding a star. Would a 174mm be better (larger FoV)? Sure... just costs more.
 

I noticed some are using this adapter: (large sct adapter)
https://www.celestro...off-axis-guider


The Celestron OAG gives a lot of options. The large sct adapter is the best case to remove all vingetting, but isn't the only option - I use a 2" nosepiece adapter with my Baader clicklock (see my post here). IIRC, even with the standard OAG adapters, you won't get vingetting with the 294MC or 1600MM/MC.
 

Are there any elements that i need to get to make this all connect properly?

It depends on if you want to add a filter wheel or other equipment. Backspacing is important (146.05 mm for the C11 from the flange of the rear nut), and so you'll need to play with the OAG and camera to get the correct spacers. I'd highly recommend a set of digital calipers ($20 on amazon).
 

edit: i guess a guide scope due to the wider field when doing hyperstar is still useful, so perhaps the oag 174mm mini camera in this case i could use for that with an st80 or similar guide scope for hyperstar  (here for f7, maybe the 1.4lb 60mm zwo guide scope or maybe this slightly heavier 1.9lb svbony version), if not the 174mm mini maybe the 290mm mini with this setup (if dual setups/not changing cameras or possibly just the 120mm mini)


Correct. You can use anything, but you don't need much. I have good luck with a very lightweight Orion 30mm Ultra Mini guidescope with my 290mm. It's just far less cumbersome than an ST80 attached.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics