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Old 07-03-2018, 01:37 PM
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Tinderboxsky (Steve)
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Thanks for your comments John.

So, two challenges for me, south of Hobart. Orion will be at only 46 degrees elevation just after dark. The second and bigger challenge is to find a large enough suitable scope!

I am attending the SPSP in May, so perhaps there may be an opportunity then.

Cheers

Steve.

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Originally Posted by ausastronomer View Post
Steve,

I have observed H1,H2 on quite a few occasions in one of our 25" Obsessions. I have also observed them on a couple of occasions in Andrew Murrel's 20" Hector and my own 18" Obsession. They are very difficult in any scope under 18".

There's a bit of a trade off here. You need plenty of aperture, the more the better. The rub here is that the bigger the scope the harder they are to cool and keep in thermal equilibrium where you can crank up the power, with sharp stars.

I have found the best time to try them is when Orion is high in the sky just after dark. In the Southern hemisphere this occurs late summer / early autumn. Now is a great time if you have the necessary aperture. You need Orion to have the elevation but you also need to try before the air temperature starts to drop rapidly and take the big scopes out of thermal equilibrium, particularly if you are at any sort of elevation above sea level as the temperature delta is larger from day to night.

Of course the other important factors in addition to the above, are good optics, good eyepieces, good target elevation, good seeing, good transparency, good eyes and a finder chart so you know where to look if you haven't been there before.

Cheers,
John B
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  #22  
Old 07-03-2018, 05:37 PM
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The Mekon (John Briggs)
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Quote:
Originally Posted by ausastronomer View Post
Steve,

I have observed H1,H2 on quite a few occasions in one of our 25" Obsessions. I have also observed them on a couple of occasions in Andrew Murrel's 20" Hector and my own 18" Obsession. They are very difficult in any scope under 18".

Cheers,
John B
Thanks John for the reality check here. I refuse to credit any obs of H1, H2 in 12" scopes. I have looked for these in my 18" in very good conditions (E&F shining like beacons) and failed to see them. Perhaps if I had observed them in a larger scope I may know better what to look for. BUT I am convinced that the magnitude of these stars is no indication as to how well they can be seen due to the nebulosity surrounding them.
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  #23  
Old 16-03-2018, 09:10 PM
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Slawomir (Suavi)
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Well, I know this is not really exciting for seasoned observers, but I was quite thrilled when taking opportunity of clearish skies I finally tested a new to me 3.5mm Delos and could clearly resolve E&F components with my 105mm f/6 refractor. Seeing was okay tonight, but humidity is still quite high in our area.
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