Home > Uncategorized > Testing out the Takahashi FSQ 0.73 focal reducer on the Virgo Cluster

Testing out the Takahashi FSQ 0.73 focal reducer on the Virgo Cluster

I recently purchased the 0.73 focal reducer “QE”for my Tak 106ED. It promises to turn it from a speedy f/5 to a ridiculous f/3.7 while still filling a full frame sensor. In fact, with the full frame sensor of the STL-11000M, we’re looking at a field of view of 5.3 x 3.5 degrees.

Of course any new purchase like this causes days of clouds and rain, but that’s been the case for about six months anyway. It gave me time to order the insanely priced adapter required to mate it with the STL camera. Once I had a clear night, I seized it, even though it was a full moon. Because of this, the image you’ll see below is far from optimal. Consider it a test image more than a aesthetic image (though the effect is still pretty cool). I fought a valiant battle with gradients in PixInsight, but for the most part they got the best of me.

Wide Field of the Virgo Cluster of Galaxies

Wide Field of the Virgo Cluster of Galaxies

Even after cropping a little, that’s a WIIIIDE field. Looking in detail at the extreme corners, the left side showed a little distortion, but that could potentially be due to some non-orthogonality in the connections.

Extreme corners of the image

Extreme corners of the image

Overall, the image is very sharp, and it’s a pleasure to capture a field that would normally require a mosaic. I look forward to the beginning of narrowband season to really give this new system a try.

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  1. Dodi
    August 22, 2014 at 7:11 pm

    Ah, with my Q and reducer, it is the top right corner creating havoc. You were able to solve the issue? I must say, I haven’t put a lot of effort into it myself. I did notice the Tak adapters could provide a bit more spacing (I get better results with a rubber between the CA35 and EOS adapter). And the tilt of the reducer is all but easy to tune.

    • August 22, 2014 at 10:25 pm

      At f/3.7, the zone of critical focus is incredibly narrow, so even the tiniest bit of sag, tilt, or misalignment shows! And you’re right: it’s far from easy to identify the source of the tilt.

  2. lawrence
    February 3, 2016 at 3:28 pm

    Very helpful post, thank you.

    I have an FSQ106 + 11000, and was wondering about the tak 0.73x FR – it quotes the image circle as 44mm, but the 11000 sensor is larger than that across its diagonal, although your images seem to show it is a perfectly usable combination.

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