QHY8 - WO FF Type IV

[multiweb]

Just got my WO Field Flatener type IV. I want to use it on an Orion ED80. I was wondering if anybody has used one and what the ideal spacing should be from the camera face to the FF T thread? Thanks.

[mldee]

Not getting a lot of responses, eh?

I can't help, but as a proud new possessor of a WO 80ED II triplet apo, a WO Field flattener is high on my list of toy purchases soon.

Looking forward to some reports from you on how it flies with the QHY8.

[multiweb]

:lol: Yeah... bit quiet. I'm starting to wonder if I've asked a stupid question. :P It's says adjustable back focus from 66 to 86mm so the back lens travel is 20mm. The lens surface is approx 9.7mm off the face of the T-thread. I assume there must be an optimal spacing between this T-thread and the camera sensor. That's what I'm trying to figure out. I can't seem to find much on Google either. :shrug:

[OzRob]

WO might be able to answer the question if you don't get one here.

wo@williamoptics.com (wo@williamoptics.com)

[multiweb]

Thanks Rob. I'll try that. :thumbsup:

[multiweb]

Here's an update on the WO FF Type IV.
Scope Orion ED80, Camera QHY8 with Baader 7nm Ha filter.
Spacing of 56mm. Image scale of 2.68asp.

[mldee]

As the uneducated but interested bystander, do you consider that a good result or not? (I don't even know what it's supposed to be, but suspect it should show an even coverage, not 33%).

It looks like you borrowed the blue carpet thingy from Avatar :)

[multiweb]

:lol: Blue carpet is alright, that's the blue salad bowl you have to watch for. :) More details here (http://www.ccdware.com/products/ccdinspector/). The result is not bad let's put it this way.

[monoxide]

looks good, ive been looking at these reducers for a while.
ill have to keep track of how it goes

cheers

[multiweb]

I think it works alright Tj. There's 20mm of travel approx and a rotating ring for orientation of your FOV. It's a big piece of glass and a bit bulky so you wouldn't put it on anything smaller than an ED80. The good thing is by the time I reach focus the focuser barrel is drawn out only 10mm so the focuser doesn't sag as it's mostly in. As a result I haven't had any flex (on 5min exp). I spaced the QHY8 with the same spacers I had for my MPCC as it's ~55mm. I was recommended 56mm.

I've attached a shot of a corner to show the difference. Previously the lack of focus was due to the field curvature of the ED80. The stars are more in focus across the whole field now. This the corner edge of the QHY8 sensor not a crop.

[gbeal]

If you can make head or tail of the results spewed out by CCD Inspector then good on ya mate.
Personally, the simple "Before & After" says it all to me.
Gary

[multiweb]

You're right Gary. If at the end of the day it works it's all that matters.

CCDIS is a good little program though. I bought it when I was playing with my newt collimation, then with the poor C11 I dismantled. It's a great tool to use and it does help tweaking things until you close in to the sweet spot. Takes a lot of guessing out of the equation. I also use it as a plugin in CCD Stack for star patterns registration on busy starfields. And finally use it all the time to select the best sub to register to or normalise to when I do my data rejection.

[CoolhandJo]

MArc,

according to this threads its 56mm
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/3297121/Main/2987816

But I think it depends on the set up (according to this site http://www.firstlightoptics.com/proddetail.php?prod=William_Optics_ AFR-IV )

[troypiggo]

Looks like a great result! You're happy, I hope?

[multiweb]

Ooo yeah! :cool: