Focal reducer on Meade ACF telescope

[Keith Graham]

Hi,

I am using a Meade 4000 focal reducer (f 6.3) on my Alpy600 connected to a Meade LX200 Classic scope and using an Atik314L for imaging. I am thinking about purchasing a Meade ACF scope, but it appears that this focal reducer may not work properly with the ACF design. Does anyone know if I would have an issue using my current setup on an ACF scope, or would I need to purchase a different FR. My thinking is since the target is near the center of the small Atik chip that the Meade 4000 should work, but I am not certain about this.

Thanks,

Keith

[Jacques Montier]

Hello Keith,

Meade 4000 focal reducers are not very convenient for ACF scopes as they include a field flattener.
I think Meade focal reducer would be correct only if your star is near the optic axis.
I actually work with Alpy600 and Meade ACF 355mm F/D10 so without any focal reducer.
Maybe F/D 6.3 would be a better setup, but I didn't encounter any problem getting spectra with F/D 10 and 28 (or 200) microns slit.
I have a 0.7 Optec focal reducer specially for ACF scopes, but i didn't use it yet.
I think i will have a try some day.

Regards,

[Robin Leadbeater]

Hi Keith,

As you say I don't think off axis aberrations will be a problem because you will be working on axis. On thing I found though is that chromatic aberrations can be pretty bad with this reducer (used with a C11) unless you run it at the correct distance. (I tried increasing the distance to push it to lower fr - not a good idea

Cheers
Robin

[Keith Graham]

Thanks for that info, Robin. It was pretty much what I had suspected but needed a more experienced opinion. I was considering the Meade GPS ACF, but as I gleaned additional info, I do not think the $3000 investment will give me much more than what I currently have with my Classic. And since with the Alpy600 I will be working primarily on the optic axis, I really do not think there will be any improvements with the optics. Then when I read about the FR issue and read your reply to my question, I figured I would simply stay with the Classic as it has been a great work horse for me.

Cheers,

Keith