Altair Astro Field Flatener/Reducer

[rockinrome]

Hello all!
I have the Altair Astro ED72-R and have just purchased the 1.0x field flattener for it.
My question is:

Do you know if it requires a (suggested in the blurb) 10mm spacer to connect it to my Canon DSLR to obtain correct back focus?
I have the smaller (1.25in) t-ring that I used to use with the 1.25in eyepiece t-adapter.
The flattener does have the ability to work with 1.25in or 2in adapters too.

I guess I am asking which one of these is best:

1. SCOPE + FLATTENER (2in) + T-MOUNT + CAMERA
2. SCOPE + FLATTNER (2in) + SPACER + T-MOUNT + CAMERA
3. SCOPE + FLATTENER (1.25in) + T-MOUNT + CAMERA
4. SCOPE + FLATTENER (1.25in) + SPACER + T-MOUNT + CAMERA

Any others ...?!?!?!?!

Thank you in advance.

As always .... clear skies .......

 

 

[Anthonyexmouth]

have you tried focusing yet? Id pop out and try to focus on distant hill or tree.

[rockinrome]

Silly I know ...... but .... erm no .........

Was just trying to pre-empt buying kit ....

Good call though, ...... do you think worth using the 2in stuff though as opposed to 1.25in or no difference ...???

Thanks

[Anthonyexmouth]

1.25 might cause vignetting. i think if you've got 2" then use it. 

[rockinrome]

Yeh, seems sensible.
Thanks for your quick replies.

 

[rockinrome]

Just ordered this:
https://www.firstlightoptics.com/adapters/skywatcher-dslr-m48-ring-adapter.html

 

[Waldemar]

That should work with the 2" flattener, which is the best choice. Normally they need about 55-56 mm backfocus, your camera is 44 mm plus the ring (11mm) so your spacing should be close if not right on. Maybe you will need some extra spacing with Baader delrin rings for fine tuning: https://www.firstlightoptics.com/adapters/baader-t2-delrin-spacer-ring-set.html

[rockinrome]

4 hours ago, Waldemar said:

That should work with the 2" flattener, which is the best choice. Normally they need about 55-56 mm backfocus, your camera is 44 mm plus the ring (11mm) so your spacing should be close if not right on. Maybe you will need some extra spacing with Baader delrin rings for fine tuning: https://www.firstlightoptics.com/adapters/baader-t2-delrin-spacer-ring-set.html

Thank you for this information.

 

[Waldemar]

Just realized the link I send you is for 42mm rings sorry about that... 48 mmspacerrings are available too, but maybe not in a set like that.

https://www.astromarket.org/verlengstukken/astoptics-verlengstuk-m48-fine-tuning-kit-0-5mm-0-8mm-1mm/p,57847

[rockinrome]

Thanks ?

[Adam J]

option 1 is correct.

[rockinrome]

14 minutes ago, Adam J said:

option 1 is correct.

Thanks for your reply Adam. Appreciated.