Quote:
Originally Posted by Karlzburg
Newts are a walk in the park compared to RC's. Though very fiddly and a cause for another couple of greys.
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Hmmm, sorry I don't agree with that statement, it is generalised and does not account for fast Newtonians.
RC's are relatively simply due to the symmetrical nature of how errors are shown. Correcting the errors is easy to undertake with the right tools. Collimation becomes simple once you understand what is going on with them. Clearly, with an RC, you need to centre the focuser to the secondary (using Howie Glatter laser), then align the secondary and primary (using a Tak scope). Ken Crawford produced a very instructive video on how to use a Tak scope for collimating this type of scope and I suggest many go and take a look at it. I can generally collimate an RC now within 5-10 minutes. Finally, star testing to tweak collimation on the primary.
A fast Newtonian on the other hand are a much harder beast to deal with. I have owned quite a few Newtonians over the years but all of them except the latest ones were f4.5 and up. Yes those are a walk in the park for collimation and less demanding. f4 and below might as well be in the impossible range. The problem lies with weight, the way the secondary is supported and size of the secondary. Getting the secondary in the correct position to produce a flat coma free field is time consuming and frustrating. The faster you go the harder it gets.
Any mechanical errors in both types of scopes makes things difficult to sort collimation and hold collimation. GSO has produced a functional system if you don't use their focuser. All the rest is rigid and put together well. Certainly from the RC10 and upwards. Yes not an Alluna scope but still something that can produce great results.