disappointed with the WO 0.8x III

[troypiggo (Troy)]

Bought this flattener hoping to eliminate some of the eggy stars in the corners of images with my SW ED80 Pro and 30D DSLR. As you can see from the attached image, there doesn't seem to be much improvement. It's just a single sub for the purposes of this post only.

The way I used it was:

ED80 -> WO 0.8x III -> EOS adapter -> 30D

It's been suggested that sometimes the distance between sensor and flattener is critical and may need specific spacers to see the benefit. Can anyone confirm what this distance would be and how/where to get the correct spacers?

Or is it perhaps that 0.8x is not enough and I need a 0.6x or something?

Any other ideas?

[Peter Ward]

Originally Posted by troypiggo

Any other ideas?

I hear Astro-Physics are pretty good

[[1ponders] (Paul)]

Try did you read the article on ED80s and focal reducers before purchasing the III? The WO II is a much better option than the WOIII.

http://www.iceinspace.com.au/93-458-0-0-1-0.html

[troypiggo (Troy)]

Thanks Peter and Paul. Where's Mary? Sorry, couldn't resist.

Peter - gimme a year or 2

Paul - You know I read your article there and some other threads. I must be a goose for assuming the III would be better than the II

[iceman (Mike)]

Even with the WO 0.8x II, I find it can be very difficult to get round stars in the corners.

Sometimes it appears to be a case of pushing the reducer in or pulling it out. There's a bit of in/out play in the thing itself.

I would get different results from night to night and never found what the exact right position was.

Very frustrating.

[rogerg (Roger)]

I've had only mediocre success with the III on my Megrez 90 APO. I read all the articles and threads about them prior to purchasing and decided to go with it, probably should have got the II. My reading suggests it's the spacing that needs changing, but I haven't worked on that at all. I haven't really used it enough to quantify the improvement it makes, if any.

Roger.

[DeanoNZL (Adrian)]

Hi All,
I have the Flat II & III, the II is much better towards the edges.
But, you must focus 1/2 way out from the centre to the edge.
Interesting that the suggested distance supplied by W/O from their website has changed from 46.448mm to 56mm, for the same reducer...
Maybe a spacer would be worth a try?
Any thoughts?

[Hagar (Doug)]

I was always under the impression the distance from the face of the reducer to the CCD was 56mm. Info gleamed from WO themselves but that of course was the PFlatII. Appears spacing is quite critical to correcting the image well.

[Tilt (Michael)]

Originally Posted by iceman

I would get different results from night to night and never found what the exact right position was.

Yep, Ive found the same thing with my WO 0.8x II. Maybe it could be the distance between the sensor and the reducer? Agreed, frustrating.

Michael

[citivolus (Ric)]

I'm currently comparing the III, Borg, and IV flatteners, but waiting for a clear night to do it. To be honest, I've never heard anybody say "wow, the WO Flattner III is amazing".

[Alchemy (Clive)]

interesting to see, anything that has the potential to move during imaging is a bit of a concern, i bought a WO II then never used it as i got me the big 68mm flattener for the 132 which indeed has a 46 or so mm focus (sort of means its no good for dslr) havent tried the .8 II on this yet and possibly never will as its currently got perfect edge to edge focus.

note the 68 is only made for the huge WO focuser

[TrevorW]

Have the Flat 2 and found it better, also did some research prior to buying and it was recommended over the 3

Cheers

[AlexN]

I had both the P.Flat-II and P.Flat-III when I had the Megrez 90 and the Megrez 102.. I found the III to work brilliantly on the M90, but not so well on the M102, where as the II was fantastic on both.. I'd love to still have one of them, as they might be useful in putting a bit more sky onto the ST10 chip with the RC..

[troypiggo (Troy)]

Following up my own threads here, seems I posted about flatteners a few times on the ED80. Bought and tested the WO FF IV here. Very happy with the stars.

[MuntiNZ (Daz)]

Hey mate
every thing I read about these always said the type III was crap on the 80 and you should only be using the II which is sposed to be best.

[troypiggo (Troy)]

I haven't tried the II, but the IV is working great for me.