Newtonian baffles

[Nathan_Pembs]

Was wondering if anyone has ever put baffles into their Newtonian to improve contrast?

Worth while do you think, or too much hassle?

[JamesF]

Surely if you added baffles you'd be reducing the effective aperture?

James

[Kropster]

You can put baffles in a refractor, but not a Newtonian... you need the full mirror sized aperture end to end.

[Moonshane]

That's what flocking does. A small baffle round the end of the drawtube is known to help a bit but as above don't lose aperture

never bothered myself although I have flocked some scopes

[Moonshane]

If you have an oversize tube baffle can reduce scattered light and break up tube currents

[JamesF]

If you have an oversize tube baffle can reduce scattered light and break up tube currents

I can see that might work, but I can't quite put to bed the feeling that an oversize tube will also let in more light to be scattered in the first place.

James

[Nathan_Pembs]

I've searched around online a little bit and apparently some people do add baffles, involves a few equations to work out the spacing so that the light cone isn't impeded?

[Moonshane]

Anything is possible with enough time and money/effort. I am not sure the benefits are worth the effort unless you run a system dedicated to planetary specialism.

[Nathan_Pembs]

More curious really, after looking at the baffled RC's on AltairAstro.....just got me thinking

[Ruud]

Here is an article on how to baffle a Newtonian: link

It's a lot of work.

[JamesF]

I've searched around online a little bit and apparently some people do add baffles, involves a few equations to work out the spacing so that the light cone isn't impeded?

I don't think it's the light "cone" as such that you need to worry about, because that only happens after the light hits the primary.  It's the "light cylinder" travelling down the tube before it gets to the primary that I'd be more concerned about.  I'd have thought any baffles need an aperture that comes pretty close to matching the size of the primary.

James

[Joseki]

Well, the Skywatcher Quattro newt does use baffles, http://stargazerslounge.com/topic/106566-skywatcher-quattro-f4-imaging-newtonian-telescopes/?p=1054631 and I've come across others.  I always assumed that commercial scopes had tubes not much bigger than the mirror for commercial reasons rather than optimum thermal design but since that's how they've been made I guess you're probably stuck 'just' flocking it - which may well do just as good a job.  Baffling the tube might increase contrast however as it's a fairly well known tweak to mask off the edge of the mirror though I can't remember the reasoning behind that (I think it's because that part of the mirror is more likely to have defects).  The software "Newt" is specifically designed to calculate size and positioning of baffles and other details for reflectors btw

http://stellafane.org/tm/newt-web/newt-web.html

[John]

I've read of a single baffle being installed just above the primary mirror in newtonians. This can be used in conjunction with a fan to more quickly disperse the boundary layer of air that sits across the primary mirror.

Maksutov-newtonians are often baffled down the tube:

[Joseki]

That Newt software is pretty easy to use - I had a go once.  I put my numbers in and pressed go.  The internal baffle sizes were about the same size and the primary near the primary and a bit bigger towards the front.

[JamesF]

I think as Shane suggested, the reflectors/cats with baffles have somewhat oversize tubes so the baffles don't reduce the aperture.  The 10" Altair Astro RC looks like the internal diameter could easily be 40mm more than the mirror diameter.

Flocking would seem like a world less pain

James

[Nathan_Pembs]

I've fl

[Nathan_Pembs]

Urgh touch screen phone! Lol

I've flocked the tube, didn't seem to make much difference...maybe need to replace the stock eyepieces