Anyone using a Tak 100mm fluorite doublet for imaging?

[gregbradley]

There seems to be several models of 100mm fluorite doublets from Tak. I don't know what the differences are or why there are so many variants but I am curious about their performance.

The original FS series were good visual instruments but for imaging they lacked.

Are these newer Tak doublets the same or have they improved the colour correction to be similar to an FPL53 triplet?

Greg.

[Atmos]

I’ve seen someone on CN using a FC100DL F/9 with a Tak reducer flattener and it surprised me with the level of colour correction and star sharpness 22mm off-axis BUT even reduced it was still about F/7 so quite slow.

I believe the difference between the DC and DF is the focuser and dew shield but Lewis or Matt will know better than I.

[gregbradley]

F7 is a bit on the slow side these days.

Do you have a link though?

I imagine Tak has advanced their fluorite doublets over the FS series. Just how much I don't know. It seems they are more geared towards being a visual scope with F9 native. That also helps with the colour correction.

Greg.