Wierd looking thingie

[Kaptain Klevtsov]

Looking through old images I came across something odd. I was trying to zap the ring and got Sheliak which should look like this:-

But on one frame it looked like this:-

Anybody any idea what it is?

Captain Chaos

[Astroman]

Most likely a cosmic ray hit.

[Kaptain Klevtsov]

Thanks AM, I had guessed at one of those but never seen one on a photo before. It more or less had to be a local phenomenon, happening at my end, as the size of the thing would be huge at the other end, and something that big can't come and go again within such a short space of time.

So do I win a prize?

Captain Chaos

[Astroman]

So do I win a prize?

I thought I won the prize for guessing. :scratch: Oh well. If you take enough photos, especially at high magnification, you're sure to get a hit every so often. I'm fairly amazed at the resolution of the Airy disk and first refraction ring around the star. Nice shot. Did you notice the seeing being exceptional?

[Kaptain Klevtsov]

Hairy what?

Nothing unusual, but I'm not qualified to comment. Seeing is something that I can understand with a webcam or EP as the target wobbles about, couldn't score it though. With the DSLR I'm just point, shoot and hope.

BTW amazed in a good way, or that my 'scope is so badly set up?

Sorry for the dumb answers, I'm learning here.

Captain Chaos

[Astroman]

Airy disk. Not 'airy disk. (I got an old off-color joke like that, but not for mixed company.)

At any rate, we see stars as sharp points of light. When we view them through a telescope, we introduce an interference pattern due to the interaction of the wave behavior of light and the physical structure of the aperture of the scope. When seeing is perfect, (yeah, right, "when", ok "If"), there is still an interaction between the incoming light and the edge of the mirror or lens. This shows up as what's called the Airy disk in the center and another bright refraction ring around the outside, separated by a dark ring. You've managed to capture this in your image. I just wanted to know if you noticed any extraordinary steadiness of the view through the scope before you took the picture. So, I was amazed in a good way.

[Kaptain Klevtsov]

Cool, so el-cheapo Fracs are OK in some respects then. This is the 120mm Synta Achro. and I should have been using more aperture. Nice to know it has its uses and maybe that's why it does so well on lunar images.

Thanks for the info there AM, I can actually see two rings so it looks similar to what the books say it should (having now looked it up).

Captain Chaos