William Optics 0.8x Reducer-Flattener 6 spacing

[sloz1664]

 Need to fully understand the spacing requirements of the William Optics 0.8x Reducer-Flattener 6. I am using it inconjuction with a WO Z71ED. The WO site states 68.32mm focal distance to CCD chip. I have adjusted my setup to replicate this and it's a mile out..
I think it should be around 55mm to 57mm dependent on filter corrections. Anyone had the same issues?
 
Steve

[red dwalf]

I have about 55mm spacing as there is 12mm from the front of the camera to the chip, there also a few mm from the back of the reducer lens to the back of the reducer it's self .

[ollypenrice]

Any glass (filters, whether LP or other) affects this distance.

Olly

[msh1]

same scope as yours and my distance is at 68mm and its all good are you using the adapter with it it does need it its 55-57mm from the adapter to ccd makes it 68mm from the glass hope this makes sense 

mark

[sloz1664]

Thanks all.

It looks like my interpretation of the drawing was out of sorts. Old age and first signs of senility kicking in :-)

Steve

[lensman57]

Thanks all.

It looks like my interpretation of the drawing was out of sorts. Old age and first signs of senility kicking in :-)

Steve

Hi Steve,

I wouldn't be so sure as I think mine was stated as 55mm. I noticed that the designation has changed to Flattener 6A in the latest drawing so I wonder if they changed the design without notice again. If I find my original box for the flattener I will check .

A.G

[carastro]

I am sure I read 55mm as being the correct spacing some-where but can't remember where I found it, and that's what i have been using and it seems OK to me.  

Carole 

[lensman57]

I am sure I read 55mm as being the correct spacing some-where but can't remember where I found it, and that's what i have been using and it seems OK to me.  

Carole 

It is still @ 55~57 on the FLO site above the drawing for 68mm. I had the same question about my WO Star71 where the drawing states 65mm or something but WO told Ian King that it was 55 mm and I am still not 100% sure. I wish they'd make their *******mind up.

A.G

[sloz1664]

It is still @ 55~57 on the FLO site above the drawing for 68mm. I had the same question about my WO Star71 where the drawing states 65mm or something but WO told Ian King that it was 55 mm and I am still not 100% sure. I wish they'd make their *******mind up.

A.G

As if Astro imaging is not already a challenging hobby obsession......

Steve

[martin_h]

The longer measurement quoted is from the rear glass element to imaging chip face....So I was told, the 55 mm is from the flange face to chip

[Alien 13]

I agree it should be 55-57mm fron the flange mine is set at 56.2mm and get perfect stars right in the corners with a DSLR.

Alan

[sloz1664]

I reckon I've cracked it..... Not the lens, the problem 

[aPolleti]

I reckon I've cracked it..... Not the lens, the problem 

Hello, I've get the same software to analize my frames, since I'm getting very oval stars in the borders, even with the flattener. How do i fix it?

My GT81 and Canon EOS T3i are pretty new, and I'm certain the polar alignment and guiding are OK.

Thanks,

[sloz1664]

Hello, I've get the same software to analize my frames, since I'm getting very oval stars in the borders, even with the flattener. How do i fix it?

My GT81 and Canon EOS T3i are pretty new, and I'm certain the polar alignment and guiding are OK.

Thanks,

I added Baader delrin spacer rings to eventually bring the image into a flat field and make the stars nice and round. I have now sold the scope so I cannot rember the exact distance that was added, but it would have been a small amount  nothing more than 1 - 2 mm

Steve

[red dwalf]

William Optics give an overall distance of 71.06 mm from rear off the concave lens on the reducer to the chip on the camera,

6.68 mm from the concave lens to the flat flange on the reducer this leaves 64.38 mm left according to William Optics,

i`m using a atik ccd camera which has around 13 mm from front of camera to ccd chip,

so 64.38 mm minus 13 mm leaves me with 51.38 mm extra distance to find.

fairly easy to do as you have a 10 mm canon adapter on the reducer that William Optics provide, then i use a small t2 adapter a delrin spacer a filter wheel to make up the 51.38 mm needed, this should get you about there, i`ve seen on the Atik camera site that the camera front to ccd chip is 13mm + or - 0.5 mm so having another 1 mm delrin spacer might help.

i know William Optics have changed the distances on these flatners a few times and Atik started stating that the distance from front of camera to chip was 12 mm but now they are saying 13 mm.

i now leave the reducer out all together as i found i was under sampling a little on my images. 

[aPolleti]

Thank you guys, now i understand the correct distance from my new SBIG 8300C camera and I've asked to build a custom ring with 46,85mm exactly the distance i need from the flatenner to my new camera sensor, I'll post pictures as soon as i have it. Below the custom ring.