66 mm Apo query

[michaelmorris]

I presently have two refractors. An Orion 80ED (identical to the Skywatcher 80ED Pro) and a Revelation Astro 66mm ED. Up until now I've used the 80ED with 0.8 reducer/flattener as my main imaging scope and 66 mm ED has had dual usage as an Ha solar scope (with Coronado Etalon and blocking filter) and as a guide scope for the 80ED.

I want to explore using the 66mm as an imaging scope. However, I have a problem.  The internal diameter of the focus barrel on the 66mm is less than 2" so I can only attach anything to the scope via either the built-in SCT thread on the end of the focus barrel or via a SCT/1.25"adaptor.  This leaves a problem in that If I am to use the 66mm with a DSLR I'd want to fit a field flattener or reducer/flattener.  These all seem to have 2" barrels.

As I see it,  I have a number of options.

• Sell the Revelation and replace it with something very similar in size, but which has a 2" focusser. - if so, what?
• Replace the focuser on the 66mm - with what?
• Find someone who makes a reasonably priced field flattener that has an SCT fit
• Do without a field Flattener

Which one?     

I've set myself a budget of no more than £250 (and preferably less) for the whole upgrade, includng the focal reducer.

Suggestions on a postcard to ......

[Scooot]

My baby tak has a 1.25" focusser but the flattener, (that's in the post) screws onto the main body, so doesn't require a 2' focusser. Don't know if there are other similar configurations.

[RobertI]

I have the WO Zenithstar 66 with the SCT thread on the drawtube which I imagine identical to yours. I also have the WO 0.8 reducer which has a 2" barrel but also has a thread on the end. Using an adaptor (from Ian King) I can connect the reducer to the drawtube, a DLSR on the other end and it comes to focus fine.

So I believe all you need is the adaptor for a few quid.

I can post some pics if that would help.

Rob

[michaelmorris]

I have the WO Zenithstar 66 with the SCT thread on the drawtube which I imagine identical to yours. I also have the WO 0.8 reducer which has a 2" barrel but also has a thread on the end. Using an adaptor (from Ian King) I can connect the reducer to the drawtube, a DLSR on the other end and it comes to focus fine.

So I believe all you need is the adaptor for a few quid.

I can post some pics if that would help.

Rob

A picture would be really helpful, thanks.

[RobertI]

Re-reading your post I am not entirely sure which reducer/flattener you have, so this may not help, but below is a diagram of how I attach my WO 0.8 Reducer/Flattener to the scope (I can do a photo later tonight if you want).

The adapter is described here and I got mine from Ian King (although it's not on his website). Let me know if you need a photo.

Hope that helps.

Rob

[michaelmorris]

Thanks Robert.  I don't have a flattener at present.  WO seem to make loads of different 0.8 flatteners. Which model flattener do you use?

[RobertI]

It's the William Optics Flattener 6 - as you say they do a number of variants but I believe you want the the one for the Zenithstar 71. Again FLO or Ian King will advise on the right one. They aren't cheap and seem to have gone up in price since I bought mine.  But they do work.

[Sp@ce_d]

Before I found the matching reducer/flatener for my WO66 I used a baader quick lock (sct) on the end of the tube. Worked fine with a gt81 flatener but that gives you a 2" to attach anything.

Sent from my iPhone using Tapatalk

[michaelmorris]

It's the William Optics Flattener 6 - as you say they do a number of variants but I believe you want the the one for the Zenithstar 71. ... ... seem to have gone up in price since I bought mine.  But they do work.

CRumbs, yes.  At £149 it looks like I may end up having to wait until Astrofest!

[michaelmorris]

I've heard back from Williams Optics and they say the best focal reducer for their now defunct zenithstar 66 is their type ll 0.8 focal reducer (also defunct). As the zenithstar 66 appears to be pretty much identical to my Revelation 66, I guess it's an old type ll FR I need to find.

[RobertI]

Thanks for the update, interesting, I guess that's quite an old one. Just for your interest below is a pic I took with the ZS66 + 08 reducer and unguided (my first ever! I didn't do AP for long, so please don't judge the pic) and you can judge for yourself whether it's a good match, just in case a flattener 6 comes up for sale used.

Rob

[michaelmorris]

Thanks Rob

That does look pretty sharp.

[michaelmorris]

Finally found a Type Il reducer. Now waiting for the postman. :-)

[RobertI]

Well done - perseverance pays off. Was that the result of a wanted ad?

[Sp@ce_d]

The postman is on his way