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Hood yer cat

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#1 PJF

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Posted 11 May 2004 - 06:12 PM

Thought I'd share a cheap and cheerful idea for a lens hood/dew cap I knocked together at the weekend for my new little friend.

Posted Image

Posted Image

Take two suitably sized 'tuppaware' wannabes (cheapo plastic storage tubs) from a discount store, cut the bottoms off, tape 'em together and flock the inside with self-adhesive 'velvet' material. The whole thing is very cheap (less than £5), fairly light, quite sturdy, and won't lead to financial/consumer despondency should you leave it 'in the field'.

The above pics were taken in a field. It was a filthy day - not long after this it rained (or, to be more accurate, I was enveloped in a low cloud). Nevertheless, at high magnifications on some birds sharing the misery, the benefit of this device was clear - much less degraded contrast compared to a view without device. Darker areas showed more detail. More controlled comparisons from my back yard viewing roof eaves confirmed the experience. With hood - detail clear in dark areas; without hood - detail mostly 'washed out'.

The above creation is short of the ideal I read here for such a device, which is, apparently, a length that is double the diameter of the objective lens. I'm not sure if the corrector lens for a Maksutov counts as an 'objective', but if it does then this effort should have an extra 70mm. It'll do for now.

Some notes:
I happened to have some blue paint left over from a long dead car project that was special in the sense that it was suitable for application to flexible, plastic surfaces. Without that, I'd have simply blackened the ends of the translucent white tubs with a permanent marker pen.

In the second pic, the flash shows the flocking nicely. I'm pretty happy that the inside of the OTA is nice and dark, and the reflections on the corrector aren't majorly obvious for a flash bulb going off three feet away. The coatings are doing something.

The scope was quite usable in a light breeze at 150x on the Velbon tripod with Slick trigger head.

It's now over 48 hours since I took the pics. I just checked, and sure enough I'd left the red dot finder switched on. It was still glowing brightly ten minutes ago. I'm impressed (but will certainly pick up some batteries at the next opportunity).

Clear beer to you. :looney:

#2 CollinofAlabama

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Posted 12 May 2004 - 01:41 AM

Peter,

Nice! I like the price tag! I did the slovenly consumer thing, though, and bought the Dew-Shield directly from Orion. They're not super expensive $18 + shipping, but yours wins the Boy Scout award.

Clear skies,

CDS

#3 PJF

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Posted 12 May 2004 - 05:20 PM

Where do I collect the boy scout? :grin: <-Hey, you can get arrested for saying that sort of thing!
My car needs a wash. <- Oh.

The Orion unit certainly seems good value, and has the advantage of being flat for storage purposes. I haven't seen it listed in the UK and wanted something quick.

Another cloudy night here...


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