View Full Version here: : Baffling a newt
Mokusatsu
22-11-2015, 10:45 PM
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
23-11-2015, 06:08 PM
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/358302-baffling-a-newtonian-8-f4/
glend
23-11-2015, 06:20 PM
Mak-Newts are heavily baffled, look at any of the Intes Micro or Skywatcher MN190 models.
torana68
23-11-2015, 06:29 PM
I was assuming (and commenting on) std. everyday type Newtonian..... :)
perrin6
23-11-2015, 10:18 PM
I think one of mel bartels links might help:-
http://www.bbastrodesigns.com/baffle.html
astro_nutt
28-11-2015, 11:33 AM
How about putting the newt in a small mirrored room...that should baffle it...Sorry guys, I couldn't resist that one.
sharptrack2
28-11-2015, 09:51 PM
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
29-11-2015, 06:19 PM
it would be good if the OP came back and gave this thread some direction......
Mokusatsu
01-12-2015, 02:09 PM
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
01-12-2015, 03:20 PM
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.
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
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