Telescope Reviews: Yellow fringe around full moon

Seeing yellow around the edge of the moon when the image is centered is pretty common. Here's a list of some excellent binoculars that describes the chromatic aberration in each, note in the on-axis image, if ca is present, these premium binoculars show yellow. Only one of these binoculars had no on-axis false color.

below the moon observations are some Jupiter observations. Note the false color around Jupiter was blue.

these posts were from a few years ago.

chromatic aberration

waxing moon 1 day past half full

Nikon 10x70
moon centered in view, see a thin yellow band along the edge, no color on the terminator. I could sometimes see no color on-axis.
moon 70% off axis right, see yellow band, double the intensity from on-axis. Still pretty thin.
70% left, less intense, purple,
images 70% off-axis were pretty good. But 10x is not enough power to see much detail or any of the tiny craters.
images good to about 60% off axis.

Nikon Astrolux 18x70
moon centered, yellow band along edge is twice or more as prominent in the 18x70 compared to the 10x70.
at 70% out to the R, color is a thick yellow band on the outside edge much thicker than the 10x70.
70% L, the color is a bright blue, broad color band.
sometimes see no color on-axis. image very good. many smaller objects visible.
image good to about 60% off axis.

Fujinon FMT-SX 16x70
moon center and at L and R, the false color is identical to the Nikon 18x70.
The scale is noticably smaller. There is less detail in the tiny craters.
images good to 70% off axis

William Optic 22x70 ED
no color on-axis. 95% out to R, a slight yellow/green could be seen just on the outer 1/3 of the edge. Very thin color band. With moon at extreme L, slight purple color along edge, again only along maye 1/3 of edge. I thought this binocular was fairly remarkable for its near total lack of color both on and off axis. The detail and size made tiny dots easy. Saw many more craters than at 18x or 16x.
images good to about 80% off-axis.

Oberwerk Ultra 15x70
on and off axis color was just about the same as the 16x70, which in turn was about the same as the 18x70.
scale getting too small to see great detail in the many tiny craters. Many not seen at all.
images good to about 70% off-axis.

The Nikon 10x70 with thin color bands was the 2nd best performer with regard to false color, a long step behind the WO22x70. The 18x70 and 16x70 were about equal and considerably worse than the 10x70. In the 10x, 16x and 18x, occasionally the on-axis image would be without color, but most of the time there was yellow in the image. Off-axis there was a thick color band in the 15x, 16x and 18x.

I did not notice any particular color cast from any one to the other. Nor did I see any difference in brightness in the mid 15-16-18 powers.

JUPITER
Fujinon 10x50-- no belts seen,
Nikon 10x70--no belts seen,
Obie Ultra 15x70-- bright flair, false color blue halo, barely see NEB
Fujinon 16x70-- no flair, false color blue halo, NEB easy
Nikon 18x70-- no flair, false color blue halo, NEB easy, color shading on the planet disk suspected
WO 22x70-- no flair, no false color, NEB easy, SPB noticable

edz

Edited by EdZ (07/07/12 07:56 AM)