| |
Overview
top
Position Criteria
-
Select criteria values from the droplists in the upper left portion of the
deltaStar screen, then click the "Search" button.
-
Right Ascension criteria specify a North/South "slice" of the sky to search.
-
Delclination criteria specify an East/West "belt" of the sky to search.
-
TIP: The default values 00 and North respectively
search a 15 degree "slice" of sky beginning at the celestial equator and
reaching a point at the celestial north pole (very near Polaris, the North
Star).
Separation and Magnitude Criteria
-
Separation and Magnitude criteria set limits on visual distance between stars
and brightness of the primary, or brighter, star.
-
When a "Minumum Sep Arc Secs" value is selected, only stars with that amount
of visual separation, in arc seconds, or more will be displayed.
(See Glossary).
-
When a "Minumum Primary Magnitude" value is selected, only systems having a
primary star of that magnitude or brighter will be displayed.
(See Glossary).
-
TIP: When neither "Minumum Sep Arc Secs" value nor
"Minumum Primary Magnitude" value is selected, all double stars in the designated
area of the sky are displayed.
Refining Search Results
top
Right Ascension
A Right Ascension Hour is selected with values ranging from 00 to 23,
then 10s of Minutes and 1s of (single) Minutes may be selected within the
chosen Hour. These values narrow the "slice" of sky to search progressively.
Declination
Declination is first selected as North or South of the celestial equator.
Next 10s of Degrees and 1s of (single) Degrees may be selected to further
narrow the "belt" of the sky to search.
TIP: The Right Ascension "slice" and Declination "belt"
intersect specifying a larger or smaller area of the sky to search. This can be
very useful in identifying and verifying observations.
Minimum Separation Arc Secs
Minimum Separation values limit how close the stars can be visually. This can
also be helpful depending on available equipment for observing (eyes, binoculars, small
telescope, large telescope).
TIP: Exaggerated differences in magnitude can further
limit the ability to see very closely separated stars.
Minimum Primary Magnitude
Minumum Primary Magnitude values limit how dim the brightest star may be.
This is also helpful in allowing for available observing equipment
(eyes, binoculars, small telescope, large telescope).
TIP: Separation and Magnitude values are very useful in
planning observations. They may also aid in further refining searches for
identifying and verifying observations.
|