Edge 8" with 0.7 reducer, Baader Clicklock and ASI294 Backfocus

[AndyThilo]

Hi

Just picked up a second hand Edge HD 8". It came with the 0.7 reducer and the 2" baader clicklock. The paperwork with the 0.7 states I need 105mm of backfocus. Unless I'm measuring incorrectly, I need another spacer as shown below. I'll be adding the ZWO OAG but that just replaces the 16.5mm spacer so no problem there. I have a 2" nosepiece on the front with my filter attached.

Anyone with a similar configuration able to post a photo of their setup or advise please? Is my maths wrong? Am I missing something that should have come with the scope?

[Jason_G]

Hey @AndyThilo - curious... did you manage to add the extra 12.5mm in order to get a working focus? If not, what was your alternative?

[knobby]

Not sure what Andy did but an oag will fill that gap nicely.

[AndyThilo]

On 30/06/2020 at 18:08, Jason_G said:

Hey @AndyThilo - curious... did you manage to add the extra 12.5mm in order to get a working focus? If not, what was your alternative?

I got rid of the clicklock and fitted a Celestron OAG. With that, the ZWO filter slider and the stock 11mm spacer, I get almost perfect 105mm backfocus.

[Jason_G]

1 hour ago, AndyThilo said:

I got rid of the clicklock and fitted a Celestron OAG. With that, the ZWO filter slider and the stock 11mm spacer, I get almost perfect 105mm backfocus.

 

Cheers Andy.

What made you go with the Celestron OAG as opposed to the originally mentioned ZWO one - the relatively larger prism area?

[AndyThilo]

Yeah larger prism, better build and rotation both sides. Also bought a 174 mini. Guiding is great and stars so easy to find. 

[lucid]

Hello,

I am looking to do just this with my Edge HD 8 + reducer...

I want to add the Celestron OAG and 2" filter drawer, then the ZWO 2600 MC Pro. I'm not sure which model ZWO camera you have there? Is the sensor always 6 mm behind the front of the camera body. Did you have to purchase any additional spacers?

Thanks.

[newbie alert]

On 05/07/2020 at 09:13, AndyThilo said:

I got rid of the clicklock and fitted a Celestron OAG. With that, the ZWO filter slider and the stock 11mm spacer, I get almost perfect 105mm backfocus.

Nice, have you done a star test yet... Celestron have a habit of throwing out specs that are wrong... Kurt ( astroquest1) seems to think that 105 isn't right, and my 105 mm that I had on my xlt wasn't right... still work in progress as I have it on the money focal length wise @ 1280 mm but spacing is much longer to achieve that, where as if I have the spacing right the focal length is wrong at 1320mm