smersh
04-04-2011, 12:00 PM
I'm having a frustrating time setting up my Canon 40D, LX90 with a Meade Series 4000 Focal Reducer / Field Flattener and Meade Zero Image-Shift Micro-focuser.
The problem is that I have serious coma and I am unable to collimate;
After collimating using a defocused star in the center of the field, it appears uncollimated (i.e. The donut and whole are not concentric any more) as soon as it is moved out of center of field.
I have 3,6 and 20mm spacers also.
I understand that this is all to do with the spacing of the FR/FF to the secondary, and FR/FF to the camera focal plane.
Can someone please tell me the correct configuration for these items.
e.g. Should the FR/FF be between the Focuser and Scope or the other way around?
Are the spacers actually required if the Focuser is used?
thanks for any help
Michael
The problem is that I have serious coma and I am unable to collimate;
After collimating using a defocused star in the center of the field, it appears uncollimated (i.e. The donut and whole are not concentric any more) as soon as it is moved out of center of field.
I have 3,6 and 20mm spacers also.
I understand that this is all to do with the spacing of the FR/FF to the secondary, and FR/FF to the camera focal plane.
Can someone please tell me the correct configuration for these items.
e.g. Should the FR/FF be between the Focuser and Scope or the other way around?
Are the spacers actually required if the Focuser is used?
thanks for any help
Michael