Quote:
Originally Posted by peter_4059
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Quote:
Originally Posted by Atmos
Just got back from Bunnings, it’s black but it’s not quite black enough :/ Or, I should say, it’s black but a little too shiny.
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First,
I am NOT promoting any material here, nor putting down any other. How I am presenting this post is with my DIY hat on
The two above posts need to have some context put into them, otherwise it will be giving confusing and even misleading information about the materials in question by the way each item has been presented.
Colin's test is not an accurate way of how the flocking material is used (I have PM'ed Colin about this). There is a bright torch used to create that photo, which is firstly not how an astro situation would present itself, and hence not how the velvet itself would be acting as a flocking/light attenuating tool. In an astro application, this material may well provide excellent light baffling properties.
The photo that Peter's link goes to, similarly is a little out of context. There is obviously a significant difference between the two velvet products, but again this photo does not present an astro situation. The only appropriate comparison is one where each material is put into a scope and both are then subjected to the same imaging and visual scrutiny/comparison.
By all this I mean if one product is available and the other ("better") product is not, in an astro application there may not necessarily be that much if any difference.
What concerns me most about any flocking material is just how stable it is over time, and then if I would want to put any of these products inside a scope of mine,
. My experience is limited to one scope and I do not know what the product was that had shed fibres. So with the experience I do have I have limited the use of flocking materials ONLY to the inside of dewshields.
There are other ways of controlling stray light that does not involve flocking materials. Sand lining the tube and then painting it over with a suitable black paint works very well. This process is much more labour intensive. But with a sealed OTA, such as an SCT or Mak or refractor, Black 3.0 could be used to enhance things even more. One scope Brand that I know of does this internal sand layer and the result is quite striking.
I've also experimented with my own dewshield making, where I used both sand and extra baffle rings on the inside of a rigid dewsheild (see pic below). If you do look at using extra baffle rings, these MUST be carefully made, circular and smooth or it will introduce unwanted diffraction patterns from those uneven areas. The dewshield pictured below I made for an 8" Newt, and it actually works to improve contrast with the Moon.
Alex.