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Post by davy on May 2, 2017 19:37:13 GMT
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Post by ChrisV on May 3, 2017 5:14:21 GMT
I can feel another spinal tap quote coming ...
But honestly I've been wondering about internal reflections with my newt. I'm sure I'm getting them from nearby lights as the patterns of light in my pics occur only when I point to parts of the sky which are above neighbouring lights. And there's quite a few of these.
When i look down the newt tube it does have a bit of shine even though it's matt (and it's near new). Would a really good matt repaint like this help ? Or a dew shield ?
I've already blocked off possible light entering from the back behind the primary mirror and around the focuser.
Any suggestions ?
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Post by Dragon Man on May 3, 2017 12:15:32 GMT
Chris, the Matt Black paint used inside telescopes is simply 'Matt Black'. To make commercial Matt Black paint, the mixture is any black paint (Enamel, Acrylic, etc) and Talcum Powder. Mix well. That's where the problem is for us that want a super non-reflective black paint. Talcum, even though flatt itself, is a light to white colour which actually lightens the black when making it Matt. And the Microscopic particles of Talc actually still reflect a bit of light. But they use it because it kills the Gloss effect of paint. Blackboard paint has more Talc added than normal Matt Black which makes it Matt dark grey. The paint that Davy has linked to above would be fantastic for us, but you would have to let the vapours and smell of the Cherry flavoured additive totally evaporate for several days or those vapours could coat your optics. At the end of last year they have created a blacker black than what was the blackest black in the world. They even shine a laser on it and get no reflection at all. None! But it will be a super-expensive product if they commercialise it. www.surreynanosystems.com/vantablack-s-vis
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Post by johnno on May 3, 2017 19:27:24 GMT
Inside my scope it looks like a very dark grey, when I made my home brew solar finder I bought a cheap matt black aerosol can off flea bay and that was darker than whats in my scope, god knows what the manufactures use when they build scopes
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Post by ChrisV on May 3, 2017 23:31:52 GMT
Don't know if I fancy pulling apart the newt and painting right now. Maybe I'll get a dew shield - its been really dewy lately. Dew all around the secondary and running down the inside of the ota.
What about flocking material ? I've seen that you can flock just some crucial spots - inside the ota opposite the focuser + inside the focuser tube ?
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Post by johnno on May 4, 2017 0:01:39 GMT
Chris have you seen this video from Dion, Astronomy Shed
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Post by ChrisV on May 4, 2017 4:00:01 GMT
No. Thanks Johno. I've see some of his others and they are great. Will watch tonight
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