Averted Vision Technique -How do you use it. Does it work?

[Bill Harrison]

I read something in one of my Astro books called Averted Vision. Im not clear how to use it but apparently you use it to highlight colours and changes of contrast on the object your viewing. Can anybody tell me their experiences using it. Does it work? Will it help me to see detail on the planets?

Thanks in advance for your help.

Bill

[OXO]

Hello Bill,

I would say it's absolutely essential to use Averted Vision whilst observing at the telescope.

It can take a short while to get used to this Technique but once you start to employ it you are guaranteed a 100% improvement in your observing of Deep Sky Objects esp nebula's and globulars also pretty much everything you look at. For planets is esp good i find Saturn and Jupiter need this the most although i cant rule out Mars either.

One way i learnt was to look at the outter edge's of the FOV(Field of view) of the eyepiece and take in the image in the centre of the eyepiece.

Best of luck although it's not hard really Bill.

James :sunny:

[FLO]

For the technically minded:

Averted Vision

Looking at a faint object “out of the corner of the eye”—with peripheral vision—in order to detect it more easily. This method takes advantage of the fact that the most optically-sensitive part of the retina (the layer of cells at the back of the eye) is off-center. Two kinds of light-detecting cells make up the retina: cones and rods. The cones support high light-level, color vision, while the rods are for low-light vision. In the human eye there are about 5 million cones and 100 million rods. The cones occupy a small spot (the fovea) centrally located on the retina, whereas the rods surround the cones and cover a much greater area (the macula). An observer can multiply light sensitivity many times by slightly averting the head so that the projected image from an eyepiece falls onto the retinal region of high light-sensitivity.  http://tinyurl.com/bnofd

In practise Bill, we all have different eyesight.  Whereas one person sees more looking to the upper-right of an object, another might get better results looking lower-left.  Often, an experienced observer will see an object that someone less experienced will miss altogether.  You will also notice brief moments of exceptional clarity as the seeing/atmospheric conditions fluctuate, sometimes from one second to the next. 

Steve

[OXO]

somemore info on Averted Vision. As steve has said Seeing conditions greatly effect what can be seen.

James

[Bill Harrison]

Thanks guys for your replies, I know its not hard to do but on the previous occasions I had been looking at the sky and looking at the planets, I always forgot to try this. I will definately try and use it more regularly. I remember on one occasion last summer, I had a nice view of the ring nebula but I found it difficult to make out the central star. I might have had more success using this technique.

Fortunately I still have young eyes and good eyesight (I'm 22) so I suppose now is the time to make the most of it .

Cheers

Bill

[OXO]

Hi Bill, the central star of M57 can be quite hard even to the more experienced observer as the seeing conditions can reem it impossible amongst a lot of scope's under 12", but i would use Averted vision to try..

When i first started using the tech i would forget to do it as-well but now it comes to mind without thinking about it and will do for you after some time.

Please let us know how you get on Bill.

James

[Rob]

I use peripheral vision a lot when observing, works a treat but it does take practice (lots). You can get false results and you think you can see it, but can't really... just a brain trick.

Rob

[GazOC]

The hard part I found when using averted vision, was resisting the urge to snap your eyes back to the object when you've seen some new piece of detai to to 'confirm' its there! (of course it promptly disappears)l. I still do it now on occasion,

[Astroman]

A great object to practice this technique is Ngc 6826 in Cygnus. It's called the Blinking Planetary. It has a very bright central star that, when viewed directly, overwhelms the nebula, but when viewed with averted vision, the nebula magically appears. Try it!

[GazOC]

A great object to practice this technique is Ngc 6826 in Cygnus. It's called the Blinking Planetary. It has a very bright central star that, when viewed directly, overwhelms the nebula, but when viewed with averted vision, the nebula magically appears. Try it!

I've tried that, it's quite amazing. I think it's recommended in one of O'Meara's books I've got.

[Bill Harrison]

tnx for your tips I will give it a try sometime.

Bill

[AstroTiger]

averted vision is indeed an essential skill. i found out the hard way that this is the ONLY way to observe deep sky objects.

First time i oberved the M42 orion nebula i suprised to notice i could only realy see it with averted vision and it was not in colour either :-)

Those naieve days.

Then i was compensated by being able to observe the structure of the nebular