Last updated: 23 December 2004
Subject: Some Technical Tips: "Radioactive" focusing aid Sent: Wednesday, December 22, 2004 02:10:27 From: Mr. Tom (MrTomsMail@gmx.net) here is a picture for your Some Technical Tips area: "Radioactive" focusing aid This cardboard made focusing device for my Celestron 9 has 3 triangle shaped holes, pointing towards the SC middle axis. So all in all it looks a bit like a radioactivity sign. It has 3 advantages: - 3 wholes means more light than 1 or 2 holes - 3 objects are easier to overlay than 2 (and their dancing looks funny ...) - in focus you can even fine-focus because of the 6 spikes around a star, due to the triangle-shaped holes
Try it yourself ! Cheers, Tom
Mike here: For more on the usefulness of the Hartmann Mask see the article '"Hartmann Mask" Focusing Aid'.
Return to the top of this page.
Go back to the Astrophotography Page.
Go back to my ETX Home Page.