averted vision

{{Short description|Technique for viewing faint objects with peripheral vision}}

Averted vision is a technique for viewing faint objects which uses peripheral vision. It involves not looking directly at the object, but looking a little off to the side, while continuing to concentrate on the object. This subject is discussed in the popular astronomy literatureBerman, Bob, “Tormented by open clusters”, Astronomy, March 2019, p. 12. but only a few rigorous studies{{cite journal |last1=Alexander |first1=RG |last2=Mintz |first2=RJ |last3=Custodio |first3=PJ |last4=Macknik |first4=SL |last5=Vaziri |first5=A |last6=Venkatakrishnan |first6=A |last7=Gindina |first7=S |last8=Martinez-Conde |first8=S |title=Gaze mechanisms enabling the detection of faint stars in the night sky. |journal=European Journal of Neuroscience |date=2021 |volume=54 |issue=4 |pages=5357–5367 |doi=10.1111/ejn.15335 |pmc=8389526|pmid=34160864 }}{{citation needed|date=January 2016}} have quantified the effect.

There is some evidence that the technique has been known since ancient times, as it seems to have been reported by Aristotle while observing the star cluster now known as M41.[http://messier.seds.org/more/m041_ari.html M41 possibly recorded by Aristotle] This technique of being able to see very dim lights over a long distance has also been passed down over hundreds of generations of sailors whose duties included standing lookout watches, making one better able to spot dim lights from other ships or shore locations at night. The technique has also been used in military training.{{cite journal |last1=Dyer |first1=JL |last2=Mittelman |first2=MH |title=Evaluation of an unaided night vision instructional program for ground forces. |journal=Military Psychology |date=1998 |volume=10 |issue=3 |pages=159–172 |doi=10.1207/s15327876mp1003_2 }}

The same technique can be employed with or without a telescope (looking to the side with the naked eye or looking towards the edge of the telescope's field of view).{{cite conference |last1=Azevedo |first1=FS |last2=Mann |first2=MJ |title=Embodied Cognition in Observational Amateur Astronomy |conference=International Conference of the Learning Sciences |publisher=International Society of the Learning Sciences |date=2016}} An additional technique called scope rocking may also be used, which is done by simply moving the telescope back and forth slightly to move the object around in the field of view. This technique is based on the fact that the visual system is more sensitive to motion than to static objects.{{cite book |last1=Griffiths |first1=M |title=Planetary Nebulae and How to Observe Them |date=2012 |publisher=Springer Science & Business Media |page=33}}