Increasingly, I receive requests to manage the filter offset and the focuser’s compensation of position automatically according to the temperature.
Honestly, I consider myself a good astrophotographer and the experience of many years with different setups (expensive and not) has led me to avoid both because they do not bring good results.
Most of the focus systems that we amateurs are able to have doesn’t have the precision to address the two issues. Since the philosophy of Voyager is to obtain quality data and not quantity of data
the approach on the two issues is different. Voyager uses the group by slot. A slot of X poses for filter with focus by slot which means, focus at the beginning of the slot and every X poses if set.
In this way you have the best real focus for the filter in use and for the current sky and position conditions. In the case of Voyager the focus can be on a single star or on fullfield.
The difference is substantial, the LocalField favors the obtaining of a uniform flat field and is useful for refractors or flattened systems. The RoboFire VCurve system working on one
single star in the center field prefers the quality of the focus in terms of the best possible FWHM, leaving the field flat to the goodness of the instrument. Both focus are manageable in Voyager
and it is also possible to indicate that if the LocalField is in use for some filters, the RoboFire VCurve on the single star is used and I think in particular of narrow filters.
Then comes the talk of the download speed of the camera, camera with slow downloads do not suit the LocalField. Surely with the single star and the ROI goes very fast.
The LocalField can also go into ROI, but the benefit of smoothing the field is reduced and the results going in direction of the single star focus in terms of FWHM . The best is to bin the camera and leave the field near full if you want to use LocalField in terms of flat field.
Voyager does not currently handle filters offset directly if you use the ASCOM camera control, but if you use Maxim or TSX camera controls, then you can easily manage the offset of the filters transparently to Voyager, you just have to take care to configure the focuser within the respective programs and set the offset values.
In the future I will also include the filter offset management with camera ASCOM direct in Voyager, is very simple, but I will point out that the solution is not indicated in terms of quality.