Baffling a newt

[Mokusatsu (Australia)]

Are there any good technical articles showing the formulae I can use to work out how close to the edge of the parallel light beam I can put baffles without impeding off-axis illumination too much?

I just bought a commercial newt with a rather small upper cage. My previous scope was home built solid tube and my backyard is not the darkest place.

I'll make a shroud, I'll flock opposite the eyepiece, but I wonder if a small baffle opposite the eyepiece might also help, casting a shadow over the field behind the secondary. I could easily make one using aluminium from a drink can, cut carefully into an arc to match the inside diameter of the tube, painted flat black then riveted into place.

Thoughts?

[torana68 (Roger)]

thoughts? I don't know its worth it or if there is any difference to be noticed for visual use. Apparently it can play havoc with tube currents.
There is a bit on Cloudy nights, start with tis one then search.
http://www.cloudynights.com/topic/35...ewtonian-8-f4/

[glend (Glen)]

Mak-Newts are heavily baffled, look at any of the Intes Micro or Skywatcher MN190 models.

[torana68 (Roger)]

I was assuming (and commenting on) std. everyday type Newtonian.....

[perrin6 (Alan)]

I think one of mel bartels links might help:-

http://www.bbastrodesigns.com/baffle.html

[astro_nutt]

How about putting the newt in a small mirrored room...that should baffle it...Sorry guys, I couldn't resist that one.

[sharptrack2 (Kevin)]

Here is a link to website for telescope design... might help determine what you are after.

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

[torana68 (Roger)]

it would be good if the OP came back and gave this thread some direction......

[Mokusatsu (Australia)]

I'm back! So I'm the boss of this thread because I started it eh? Need me to keep the plebs in line?

The baffles I am considering making won't be large, I just want them opposite the eyepiece and tall enough to cast a shadow on the area behind the secondary for a light source reasonably close to axis.

I don't mind the diversions. Reading it all with interest.

[Mokusatsu (Australia)]

I ran the measurements for my Skywatcher 12" through the Stellafane calculator and it looks like there is no room for baffles unless I want to cause vignetting. Not even small ones!

Oh well. I'll have to just flock it and be done.

[sl]

Have you tried the empiracle approach? Remove the eyepiece and put your eye at the focal surface and see where there may be a problem. Direct light reaching the eyepiece from around the top end means you need to extend the top end.

Baffles are not usually needed on a Newtonian.

Steve