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Old 23-06-2015, 05:06 PM
clive milne
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clive milne is offline
Join Date: May 2011
Location: Freo WA
Posts: 1,443
btw) Thanks for posting the article Brett, it was on the whole very informative and interesting.

I believe the guy in the video could have saved a stack of cash if he had actually applied the scientific method to his assumptions with respect to optics as well.

fwiw) The paper he derives much of his narrative (on optics) can be found here:
It is my understanding that he either misquotes or does not understand the conclusions of the people writing the paper.
He infers that the limitation of the (Kitt Peak) 24/36 Schmidt telescope is light scatter implicitly due to it's central obstruction and use of reflective surfaces. The paper actually makes no such assertions, and in fact does not support this conclusion, empirically. The limitations were found to be due to internal reflections off of the surfaces of the refractive elements, ie) filters, Schmidt plate and Dewar window. What is also not stated directly, but there if you read the fine print, is that the read noise level for single exposures is equivalent to 27.6 mag arcsec−2. So the instrumentation (electronic) noise is 10x what he is trying to measure. Interesting that later he derives an expression of the S/N value advantage of his Dragonfly lens system to be a factor of 10x better than the Kitt peak 24/36 Schmidt.....
See page 4 for notes on atmospheric internal scattering.
See page 12 for the statement relating to CCD read noise.
His other reference point by which he determines that 'these new cannon lenses are the best imaging instrument ever devised for faint, extended obects' is by way of comparison to a lens that has 17 elements (without Gallium Arsenide coatings).. does anyone else see a problem here?

Furthermore, if you forward the video to 1:03:45 you will hear him acknowledge that the lens system used in fact has more than one element that does not have the Gallium Arsenide coatings (plus the filters and Dewar window) Therefore, it follows that; it is possible to use an optical prescription that includes refractive elements without these coatings and reach the depth of exposure that this lens system achieves.
ie) He has just proven his base premise to be incorrect by definition.

So much for the scientific method....

And.... I have to point out,
he waxes lyrical about a new class of low mass galaxy which implicitly is beyond the reach of all other instruments.... then uses images taken through a reflective telescope (Keck) for confirmation... in the form of a measure of its recessional velocity derived from its spectrum no less...


Last edited by clive milne; 23-06-2015 at 05:23 PM.
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