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Old 24-11-2013, 02:00 PM
clive milne
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clive milne is offline
Join Date: May 2011
Location: Freo WA
Posts: 1,443
Originally Posted by alpal View Post
Hi Clive,
what do you think about the manufacturers claim from "Hypergraph"
that it has a spot size 8 times smaller than a Ritchey Chretien?
It is my opinion that the claim is most likely factually correct however, if it is implied that the hypergraph is 8 times better than an equivalent rc, 'ipso facto' by virtue of its spot diagrams I would suggest that the claim is specious at best....perhaps even disingenuous.

It would be equivalent to me putting a ridiculously high gear ratio into my honda accord and advertising it as being set up to go twice as fast as an Aston Martin at its rev limit.

Theoretical ray tracing is a valuable tool for the optical industry... but context is required before making assumptions about how relevant that information is to any given real world situation. It is important to view the (potential) performance of a telescope in terms of it being just one component of a larger system designed to perform a specific task... ie) convert the light flux from a distant object into a series of numbers proportional to its intensity and hopefully encoding spatial & wavelength data (colour and resolution) in the most cost effective means possible... ie) for a given investment you would hope to achieve the best signal with the least noise... if that isn't the merit function that is applied, then it probably reduces to an exercise in ego gratification... that is perfectly fine as an end in itself but it is better to be honest with oneself if that is actually the case imho.... the choices you make will be different.

if maximising s/n is your goal then the best bang for your buck is always going to be had from a permanently set up telescope at a dark site using a scripted routine on a robotic mount... A simple well made 14" newtonian on a paramount will likely produce more and better data under a dark sky and good seeing than you will ever hope to achieve with a hypergraph from central Melbourne. .. or even one that you have to drag out to the bush 5 nights a year.


Last edited by clive milne; 24-11-2013 at 02:18 PM.
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