SKY-WATCHER LightChariot 102AR-AZ, Instruction Manual, Page: 34 / 52

4
Seeing
Seeing .conditions .refers .to .the .stability .of .the .atmosphere .and .directly .affects .the .amount .of .fine .detail .
seen .in .extended .objects. .The .air .in .our .atmosphere .acts .as .a .lens .which .bends .and .distorts .incoming .
light . rays. . The . amount . of . bending . depends . on . air . density. . Varying . temperature . layers . have . different .
densities .and, .therefore, .bend .light .differently. .Light .rays .from .the .same .object .arrive .slightly .displaced .
creating .an .imperfect .or .smeared .image. .These .atmospheric .disturbances .vary .from .time-to-time .and .
place-to-place. .The .size .of .the .air .parcels .compared .to .your .aperture .determines .the .“seeing” .quality. .
Under .good .seeing .conditions, .fine .detail .is .visible .on .the .brighter .planets .like .Jupiter .and .Mars, .and .
stars .are .pinpoint .images. .Under .poor .seeing .conditions, .images .are .blurred .and .stars .appear .as .blobs. .
The .conditions .described .here .apply .to .both .visual .and .photographic .observations.
Seeing conditions directly affect image quality. These drawing represent a point
source (i.e., star) under bad seeing conditions (left) to excellent conditions (right).
Most often, seeing conditions produce images that lie some where between these
two extremes.
Bad Excellent
FIG. 13