Quote:
Originally Posted by Peter Ward
What's not to like?
Beautiful optics. Excellent guiding.
I'm hard pushed to find any processing artifacts.
None really.
Stars are well resolved and tight (something you can only get with a long FL  ).
More data would smooth out the continuum, but so what.
A benchmark HH for sure |
Thanks very much for the kind words Peter! I also expect improved seeing conditions once more settled weather rolls in here. So even higher resolution should be possible
Quote:
Originally Posted by alpal
Rolf,
Hi Rolf,
I had a look at all your pics & noted this one:
http://www.rolfolsenastrophotography...ss/i-pnZShqQ/A
I can't quite understand how the guitar string collimation system works
& also why it doesn't cause multiple diffraction spikes?
The collimation you have achieved is obviously superb.
An RC or classical Cassegrain would have better spot sizes further off axis
but the KAF8300 is not such a large sensor where it would be apparent.
Still - I have learnt a lot from your thread about building this scope:
http://www.iceinspace.com.au/forum/s...t=98823&page=2
I am thinking of ideas on how to improve my own setup.
Congratulations on the IOTW.
cheers
Allan |
Hi Allan and thanks. There are 8 strings attached to the mirror holder and they are arranged in a cross like traditional spider vanes. You can (faintly) see how they line up in this image from the 10" :
http://www.rolfolsenastrophotography...#!/i-HG6cQrr/O
Each string can be tightened/loosened via its own guitar tuner, so full positioning and orientation is easy to achieve for the secondary mirror. I have found it much easier than traditional spiders where you typically have to adjust with tools and go back to the eyepiece and check. Here I can turn the guitar tuners by hand while looking in the eyepiece to see the effect. It is also really easy to make careful micro adjustments which helps getting everything aligned optimally.
The two strings that make up each 'vane' don't have to overlap each other but just need to be parallel in order to appear as a single spike in the image, if that is what you mean. They of course also need to be parallel with the two strings on the corresponding opposite side, and overall this lineup can be tricky to achieve but once adjusted I don't have to touch it again since collimation is maintained by adjusting the primary, not the secondary.
Hope that helps
