Reducer/Flatter choice for SW100ED

[Ellery]

I just received my Skywatcher 100ED and was looking forward to suit it a little better for astrophotography. I found reviews and comparisons of most popular focal reducers but not many recommendations about their pairing with this particular scope. So far the candidates list looks like this (in no particular order) :

Skywatcher .85x Reducer/Flattener : http://www.skywatcher.com/product.php?cat=28&id=179

Astrophysics CCDT67 0.67x Reducer : http://www.astro-physics.com/index.htm?products/accessories/photo_acc/photo_acc

William Optics .8x Reducer /Flattener Mk IV http://www.williamoptics.com/accessories/flattener4_features.php

William Optics .8x Reducer/Flattener Mk II http://www.williamoptics.com/accessories/reducer_features.php

Meade/Celestron 6.3 FR

The SW .85x an WO 0.8x Mk IV I'm sure are suited for this scope and should perform in line with their prices. The Mk II version of the WO 0.8x I'm uncertain about, I was looking at its specs and they described it as "optmized for 66mm refractors while also suited for 80 and 90" however in the bottom the Megrez 110 APO is also listed, which gives me some hope.

The CCDT67 is commonly used on RCs type scopes but seems compatible with refractors too as long as the focal ratio is  f/9 to f/18. I've read about people who have fit it to their SW80ED but there weren't comments on the performance.

The Meade/Celestron I have read mixed reviews and seem to require a bit of tinkering to fit.

Any thoughts will be appreciated

P.S. I have also been wondering what parameters to look for to see if they're compatible with my setup. I only have my DSLR with a T-nose adapter and UHC filter as image train, that means I just have to buy extensions to bring the camera chip at the distance indicated in the reducer specs, and eventually another adapter to fit the reducer to the 2" focuser (as in the Meade/Celestron reducers), right ?

[Dr_Ju_ju]

Hi Ellery,

I went for a Baader MPCC Mk-III, which replaces the 'open' T nose piece. I've not tried it on my SW 100, but on my newts it performs well... 

[RikM]

This is the one you need for the SkyWatcher ED100 http://www.firstlightoptics.com/reducersflatteners/skywatcher-85x-reducerflattener-for-ed100.html

The first one listed in your original post.

[Ellery]

Thanks Julian and Rik

I was wondering about the Baader MPCC Mk-II. If I understand well field curvature and coma are two different effects, even though they may be visually similar. What would the outcome be of a CC mounted on a refractor ?

I know I'll probably gravitate towards skywatcher's own reducer but was curious to know the factors you should be looking at in reducers. There doesn't seem to be a lot of information on the subject. For example when they say 'optimized for refractors of focal lengths xxx-yyy' what change does it mean in the lens design of the reducer ? What would happen if you mounted it on a scope with greater focal length ? I know that's a lot of questions, bear with me

[ollypenrice]

There is simply no way of knowing for sure which reducer will work with which scope unless a) it's dedicated to that scope by the manufacturer or, b ) it's been tried and tested by someone else.

You could be confident that the dedicated SW one would work but it would be great to drop the F ratio still further with the AP. Provided someone can confirm from experience that the pairing works then that 0.67 would be a superb choice.

If you decide to ask around do be sure to note the chip sizes that have been tried with the pairing. Very small chips are not an exacting test. A very common enemy of the focal reducer is the internal reflection on or around bright stars.

Olly

[Ellery]

Thanks for the tips Olly, indeed a .67 would be great on this scope! I have noticed it's only a focal reducer though, I guess a flattener becomes a must then with all the extra detail "squeezed" in the image field curvature should become pretty bad ?

On a side note I found some nice pics made with the WO .8x MkII and an 80ed, it's quite a different scope but it's something ^^

[Dr_Ju_ju]

Just to add further, I've just bought the SW .85 to go with my ED80, but one gotcha is that you need an additional Synta M48 to EOS\Nikon camera adaptor, which is another cost\delay...

Edited January 26, 2016 by Dr_Ju_ju

[ndabunka]

Wondering if the SW flattener for the ED80 and/or ED120 are the same product simply with different parts numbers as the SW flattener for the ED100?

[Adam J]

58 minutes ago, ndabunka said:

Wondering if the SW flattener for the ED80 and/or ED120 are the same product simply with different parts numbers as the SW flattener for the ED100?

Optically the same no doubt but not sure if they dont have a different spacer incorporated.

Wow just realised that this is a real zombi thread...

Edited September 25, 2020 by Adam J

[ndabunka]

3 hours ago, Adam J said:

Optically the same no doubt but not sure if they dont have a different spacer incorporated.

Wow just realised that this is a real zombi thread...

Thanks.  I can find used ones for the 80ED or the 120ED but not the 100ED.  If it's as simple as an additional spacer, then perhaps one or the other of the used ones could work.  I'll reach out to Skywatcher on Monday to see if they are able to provide clarity.  It's almost halloween so it is a good time for a zombie thread.  LOL

[Adam J]

9 hours ago, ndabunka said:

Thanks.  I can find used ones for the 80ED or the 120ED but not the 100ED.  If it's as simple as an additional spacer, then perhaps one or the other of the used ones could work.  I'll reach out to Skywatcher on Monday to see if they are able to provide clarity.  It's almost halloween so it is a good time for a zombie thread.  LOL

I doubt that they would want to admit it if they are the same unit to be honest.