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Tx for this John,
I do need to critically collimate the scope once I've stabilized the primary
against tilt displacements as the OTA moves around the sky. Using the star
test it is pretty good - as was the seeing this evening. The in-focus images
of Vega gave a seeing of 6-7 on the Pickering scale and there was no problem
with high cloud.
I found the intrafocal images this evening similar to those seen on a recent
night afflicted by a thin veil of high cloud - I am now sure that either the
primary is over-corrected or that there is a bit of turned edge. The latter
possibility I will exclude via a 1/2" edge mask. Is this a reasonable width
to mask off on a 10"?
Notwithstanding the problem, ther scope 'snap focuses' fairly well and
generates more detailed images than my 6" F8 TMB lens can do, with lower
scatter. There were no signs of any spikes BTW apart from those attributable
to the 4 vane spider.
Tony
> -----Original Message-----
> From: John Sherman [ <mailto:atm@johnspics.com> mailto:atm@johnspics.com]
> Sent: 05 May 2006 02:31
> To: atm@atmlist.net
> Subject: Re: [ATM] Star Test Interpretation
>
>
> Hi Tony,
>
> >Some room for improvement there, I suppose.
>
> After all that, did you also try the Cheshire to align the primary?
>
> >noted that the intrafocal star image was very soft and 'wooly',
>
> Sounds like a bit of overcorrection in the primary, were there spikes
> also?
>
> John
>
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