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Instrument Browser

Instrument Browser is one of the equipment browsers available in Deep-Sky Planner. To learn about equipment browsers in general, please see Equipment/Log Browsers.

Browsing Pane

Instruments shows a list of all instrument names in the database and their (Enabled) or (Disabled) status. Select an entry to edit, delete or view its properties. Double-clicking an item opens it in the property pane for editing.

Property Pane

Enabled allows you to choose whether the item is used actively or not.

Instrument Name allows you to specify a unique name for your instrument. This name appears in other lists in Deep-Sky Planner so the name should be descriptive. The name can contain up to 30 characters.

Instrument Type allows you to specify whether your instrument is a telescope or binoculars. In this context, a camera lens is considered to be a telescope. This value is required.

Units of Measure allows you to specify whether aperture is entered in Metric (millimeters) or English (inches) units. For your convenience aperture is displayed in both units. This value is required.

Notes allows you to record any comments about your device. This value is not required.

For Telescope Type Instruments:

Aperture allows you to specify the aperture of the instrument using the selected unit of measure. This value is used to compute the working magnification, true field and exit pupil for visual observations made with a telescope, or field of view and image scale for photographic observations made with a telescope or lens. This value is required.

Focal Ratio allows you to specify the focal ratio of the instrument. This value is used to compute the working magnification, true field and exit pupil for visual observations or field of view and image scale for photographic observations. This value is required.

Transmission allows you to enter the total light transmission of the instrument's optical system. You can use Transmission Calc to calculate this value for popular instrument types.

Obstruction allows you to enter the amount of light obstructed from the primary optical element in the instrument's optical system. You can use Obstruction Calc to calculate this value for popular instrument types.

Cleanliness allows you to enter the relative cleanliness of the instrument's optical system. This value is used by the visibility model for stars. Note that this is not the same as Transmission above. You should find that changing the cleanliness level by one step changes the magnitude of visible stars by 0.1 magnitude or less, so this is not a significant input to the visibility model for stars.

Cleanliness levels are:

▪Clean: Optics had just been cleaned the optics and there is no visible dirt or residue.

▪Normal: Optics have very little noticable dirt or residue.

▪Dirty: Noticable dirt or residue - the optics probably need to be cleaned.

Information calculated and displayed for telescopes includes:

▪Focal Length in millimeters and inches

▪Dawes Limit in arcseconds

▪Theoretical faintest visible stellar magnitude

▪Theoretical useful magnification range

▪Theoretical useful eyepiece focal length range

For Binocular Type Instruments:

Aperture allows you to specify the aperture of the binoculars using the selected unit of measure. This value is used to compute the exit pupil for visual observations made with the binoculars. This value is required.

Usually, a value such as 8x50 is printed on the body of binoculars. Using this example, the aperture is 50 millimeters and the magnification is 8x.

True Field allows you to specify the true field of view of binoculars in degrees. This value is often printed on the body of binoculars, along with the magnification and aperture of the lenses. Sometimes rather than field of view in degrees, manufactures may give the width of an image (in feet or meters) at a given distance (in yards or meters.) You can use Binocular Calc to compute the true field of view from these two values.

Magnification allows you to enter the fixed magnification of binoculars. This value is required.

Transmission allows you to enter the total light transmission of the instrument's optical system. You can use Transmission to calculate this value for popular instrument types.

Instrument information calculated and displayed for binoculars includes:

▪Exit pupil

▪Dawes Limit

▪Theoretical faintest visible stellar magnitude