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Old 25-05-2012, 01:43 PM
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mental4astro (Alexander)

mental4astro is offline
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,869
Blinking for planetaries

Hi all,

I had a marvelous experience a month ago to do with "blinking".

Blinking is a technique where you look for an object by switching between a neat image through the EP and then switch to a view with a filter, and back and forth, and so one. This technique is useful for finding very tiny DSO's that on their own are drowned out by the surrounding stars or background skyglow. Planetary nebulae respond very well to Blinking using an OIII filter.

Our mate erick showed me his DIY Blinking paddle. It is a $1 plastic paint spatula with a hole drilled in it and an OIII filter threaded into it. The spatula is also painted matt black. Such a marvelously simple and effective tool! Blinking is such an easy task as you hold the paddle in one hand and flick the filter between your eye and the eyepiece as needed.

I'm hoping to make a little paddle for myself now after a clumsy but successful blinking session to find one of the three planetary nebulae that lie within the boundaries of the giant open cluster M7 three nights ago. Clumsy as I had to hold the OIII filter between my fat fingers making the blinking process rather trying. Still, I managed to track down on of them.

Eric, thanks for showing me the paddle! Great and effective tool that is sooooo simple to make, . As soon as I make mine I'll post a picture of it, unless eric beats me to it.

By the way, Blinking was the method used to discover Pluto back in 1930. Then, the blinking process was done by switching between two photos taken a few days apart of the same patch of sky time and time again to spot a tiny 'dot' that had moved between each of the exposures.
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