Flatteners and spacing - comments please!

[Martin-Devon]

OK - a newbie question coming up here. I have a 102mm Ikharus refractor with supplied 0.8x flattener/reducer, all from Ian King. At the moment my imaging train set up has the flattener, then a ScopeTechnik filter wheel, then the Atik 314. This works well, I get good focus, can takes long subs and still have nice round stars - however it does seem that I have some light gradient/ingress creeping in which makes me suspect that the filter wheel area is not totally light-proof somewhere.

To overcome this, and to get detailed non-binned narrowband subs, I plan to do 3-4 hour single filter runs each night (God blessing with the weather) omitting the filter wheel completely - so the Atik 314 would have the appropriate filter screwed in, then this would go directly into the back of the flattener. So my question is - would this work? The spacing between the flattener & the Atik would be much shorter & I keep seeing comments in various threads that highlight just how important the spacing is apparently to get the proper performance of the flattener & obtain round stars. Do I need to put a spacer in place to substitute for the absence of the filter wheel?

Any views here would be appreciated - thanks, Martin

[martin_h]

In a word - Yes!

[ollypenrice]

Don't do it, it would be a real hassle and your gradients are unlikely to be coming from the FW. If they are then just wrap some dark cloth around it to keep the light out.

Chip distance is important though less critical for a small chip like yours than for a large one. Even so the distance needs to fairly accurate.

You don't want to be shooting new flats each time as you'd have to if you were taking out the camera.

Olly

[shaunster]

Put a black sock around the filter wheel, I was getting some gradients until I used the sock around my wheel.