Settings when using reducer


#1

Are there any setting in equipment profiles that need to be set when using a focal reducer?


#2

You need to change the pixel scale, since you are changing the focal length of the system.


#3

Thanks naavis, would this effect the plate solving in any way? I see it effect the size of the selection window in the “Framing &Mosaic wizard”.


#4

I think SGP is passing any pixel scale information to the plate solver, so yes.


#5

you also need to put in the new scope focal length in equipment profile manager ==> telescope tab. With a focal reducer of say 0.8X you’d enter the native scope focal length X 0,8. So a native FL of say 1000mm becomes 800mm when using the reducer.


#6

When I set up my ED127 with focal reducer, I used the 952 focal length, with 3.8 CCD pixel and used the formula to set my arc-sec/pixel at .82 I did not account for the focal reducer however, and everything seems to work fine.
Now I am about to set up my SV70T which has a 420mm focal length. But with the reducer, it goes to 2.33 arc-secs/pixel. Now I am wondering, which one do I actually use when setting the equipment profile?
In fact Plate Solve works fine on the 127 profile (maybe a tad long as it goes through 6 attempts with 60 pixels of error). So how much does it really change when adjusting for reducer/flattners?


#7

Your pixel scale needs to be as close as possible. Just make two equipment
profiles, one at the native focal length and one at the reduced focal
length.


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