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Cracking one arc second.

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On those cracking quiet nights after a storm has cleared and the air has settled, I revisit some tight binaries. I was absolutely chuffed to get Σ1037 in Gemini. Even at x216 there was transient signs of the split. I went up to x400 to get two clean diffraction rings. These stars are quite bright and it was lovely to go back to +200x to observe. This was in the 150 f8 C6r, but I managed just about 1.4" in the 102. 

I've tried hexagonal masks and changing ep from orthoscopic to Plossls and UWA. It's an interesting and challenging area of observation. Anyone any crafty tips in this area ?


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That's very well done, Nick. :thumbsup:

With the 1" seperation, 216x gives 3.5' (1"x216=216"=3,51')on retina, that's about on the lower magnification end of splitting tight doubles when seeing is not very good, using magnifications to give 5' size (300x mag) or bigger is surely the right way:smiley:

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 I bought a 180 Mak last year specifically to beat the 1 arcsec barrier. First outing, I managed to split 14 Ori (0.7 arcsec) to two nearly touching disks, with 52 Ori (1.1 arcsec) easily split.

Some humble tip suggestions (I'm sure you know them better than me) - wait for the right evening when even The Dog doesn't twinkle, make sure the focus is absolutely spot on as even a small error will halve the relative brightness of a faint secondary (I set the focus knob half way between the two points either side of focus where the star is just out of focus), and make sure the line of sight of the scope doesn't pass over a hard surface pouring out heat. I read many years ago that grass was the best surface - it certainly works for me! Use mags well over the theoretical limit for the scope - the Airy disks often appear from the fuzz.

When the warmer Summer evenings are upon us with excellent seeing, I intend to work my way through doubles in the Cambridge list in the 0.7 to 1.0 arcsec range, and maybe image them.


Edited by chiltonstar
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