Connecting ASI1600 pro to 2.5" Stellarvue flattener/reducer

je2000

Here is the order from camera to flattener. I can't mate the camera+EFW+spacers to the reducer/flattener. The Stellarvue flattener calls for M42 X.75 42mm extensions be used.

Camera->EFW8->some male to male 1mm spacer with a knurled grip wheel that extends out past the filter wheel-> what looks like a 10mm spacer, not labeled->16.5mm spacer

This gives me 54mm. The 16.5mm spacer won't thread to the flattener, it's too big. The pieces I have before me don't match up with documentation and there is no manual for the EFW8 except for software. As far as I can tell the knurled grip spacer is 1mm and most likely the M42-M48 adapter although it doesn't look like it exactly in the camera manual. I've seen several pictures and explanations in other forums but I can't seem to make this work.

I have the Stellarvue SFFR102-25 reducer/flattener

http://www.stellarvue.com/reducer-flattener-for-svr102t-with-2-5-focuser-sffr102-25/

It may appear I need one of these.

http://www.stellarvue.com/42-mm-extensions/

Also I am not sure to add or subtract 1mm for Astrodon filters

rdbeck

I have the SFF6-25 flattener which requires 55mm to the image sensor from the back of the flattener. I assume you are in the same situation. I purchased a Baader 20-29 mm varilock adapter. With the EFW at 20mm and the image sensor at 6.5 mm, I needed 28.5mm to obtain the 55mm spacing. Depending on which of the thin spacers I end up with between the camera and the EFW, I will need to reduce the 28.5 by up to ~0.5mm.

On my flattener, the last thread is an M42 which is what the adapters which came with my camera are. So your comment about not fitting doesn't make sense to me.

One plus on the Varilock is there is a ring which can be released (several allen set screws) to allow the camera assembly to rotate to your preferred orientation. I rotated mine to EFW motor down.

je2000

RDBeck wrote:
I have the SFF6-25 flattener which requires 55mm to the image sensor from the back of the flattener. I assume you are in the same situation. I purchased a Baader 20-29 mm varilock adapter. With the EFW at 20mm and the image sensor at 6.5 mm, I needed 28.5mm to obtain the 55mm spacing. Depending on which of the thin spacers I end up with between the camera and the EFW, I will need to reduce the 28.5 by up to ~0.5mm.

On my flattener, the last thread is an M42 which is what the adapters which came with my camera are. So your comment about not fitting doesn't make sense to me.

One plus on the Varilock is there is a ring which can be released (several allen set screws) to allow the camera assembly to rotate to your preferred orientation. I rotated mine to EFW motor down.

Interesting little bit of tech. $79...ouch.

The 16.5mm ZWO spacer does not fit the Stellarvue reducer. Interestingly, the ZWO 20mm spacer does fit, but this brings back focus beyond 55mm.

either way looks like a I need a new spacer.

astrobug

The 16,5 spacer is an adaptot from T2 to M48. The 21 spacer is T2 to T2.

About the right distance. Take account of the thickness of your filters.

55mm minus 1/3 of the filter thickness.

Maybe your flattener has enough tollerance.

je2000

Astrobug wrote:
The 16,5 spacer is an adaptot from T2 to M48. The 21 spacer is T2 to T2.

About the right distance. Take account of the thickness of your filters.

55mm minus 1/3 of the filter thickness.

Maybe your flattener has enough tollerance.

1mm for astrodon 1.25" mounted.

The bottom line is that the 16.5mm spacer doesn't fit the flattener but the 20mm does. Why on earth would they include two different sized spacers?

6.5 for camera

20 for EFW8

1 for male to male adapter which doesn't match the picture in the manual.

10 for the spacer that was removed from the front of the camera

16.5 ZWO spacer that threads to the previous train but not to the SV reducer

Brings me to 54mm minus 1/3 of astrodon filters which is 1mm.

Is this correct? Even then this is 53mm.

The front of the reducer comes off but it appears to be some kind of its own spacer and the threads it comes from are the same and of no help in mating the 16.5mm ZWO spacer.

This is kind of ridiculous. If someone can figure out how to make this work without spending $79 then I'll buy you a beer. Maybe I have the order of these components wrong. I've tried every combination I can think of. Having it fit but wrong spacing, or right spacing and no fit is frustrating to say the least.

I know I am not the only one with this setup. All I want is 27.5 spacing from (M42 X.75) threads to the front of the filter wheel.

astrobug

My coma corrector (GSO) & flattener are both M48. They should better use M48 on the filterwheel & camera.

The distance can change from scope to scope. On my newton it is 55 and on my apo it is 106.

I agree with you, more standards would help us all.

Many of use have wrong spacers laying around :(

je2000

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