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Full Version: Focal Reducer not "sticky"
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Either I don't understand something or there is a problem with the persistence of choosing a focal reducer.

I have a 12" TPO RC and I have it's primary focus parameters defined as the stock values:

 dia: 304
focal ratio: 8
focal length: 2432

Then I have an Astrophysics 27TVPH which takes it to f6.4 or an effective focal length of 1946mm, so I have that focal reducer defined with a magnification of 0.8x.

Now the problem comes in that all the dialogs in ST default to "Primary Focus" each and every time I open them. For instance in "edit imaging project" no matter how many times I select my focal reducer, it always shows "primary focus" as selected the next time, and the composition and tiles is then wrong as a result. 

I think this get's propagated to other parts of ST as well.

I guess I could fix it by redefining the primary focus of my rig to be f6.4 and delete the FR entry, but I don't think that's how it's supposed to work?

I had the "built in focal reducer" checked and unchecked, but it didn't seem to help, but re:reading the instructions just now I see I am supposed to change the definition of the scope AND check that box so I will try that, but then how to define if I remove the FR (for deep sky) and add a barlow (planetary)? Define a whole different imaging system?

Thanks
This does sound like a bug. You are correct that it should remember your selection. Focal reducers were not tested widely because I didn't have any testers who used them. I created several systems in testing but I could have easily missed something.

Only use the built-in option if the focal reducer is never changed. In this case you would select the check box (which adds another piece of glass to the optical system) and enter the effective focal length, as modified by the reducer, into the OTA.

If you change the reducer, then it should be selectable and the selections should normally stick. I will look into it.
OK Thanks!

For now I will use the built in option.