Optics and the eye piece mode

The sky map can be turned into eye piece mode to display what you see in the ocular, camera, binocular or finder scope. In the eye piece mode, the images provided by starmapShare.com are exactly aligned with the stars. Before using it, you must define your optics configuration, meaning the optical elements used for the observation. First touch the Optics icon in the main menu, and touch the + icon in the top menu bar. This lets you enter the optics elements settings.

The elements that can be added are:

Telescopes are defined with a name, a focal length (mm) and an aperture (mm).
Eyepieces are defined by a focal length (mm) and a field of view in degrees.
Barlow lenses are defined by their magnification factor.
Focal reducers are defined by their focal divider.
Finder scopes are defined with a name, a magnification factor, a field of view (degrees) and an aperture (mm).
Cameras are defined with a name, and the size of the CCD in millimetres. For cameras, the magnification factor is computed as for an equivalent 55° ocular, providing the same real field of view.

When the Show info option is activated, the present optics configuration will be displayed in the top left corner of the map.
For adding a new optical element, touch the element name in this menu, then press the + icon in the top menu bar to reach the element editor. Enter the numerical and text values for this element and press save. The elements can be edited again by touching the blue arrow. Delete an element by swiping your finger over it, as in all other iPhone applications.

Note: when you only observe with binoculars, their provided optical parameters are often not those used for telescope but those of scope finders (magnifying power and field). Just define any kind of telescope (use the default values proposed by Starmap) and add a finder with your binoculars parameters.

When all elements have been entered in your optical settings go back to the Optics menu. At least one telescope must be defined. Touch the Telescope icon and select it. Touch Optics icon and select an ocular, a finder or a camera. If your present configuration has a focal changer, like a Barlow lense or a focal reducer, select it under Focal. If you wish a single or double reticle to be displayed, in alt-azimuthal or equatorial mode, use the Reticle section. Go back to the map, it is now in eye piece mode.

In practice you will switch very often between the normal and the eye piece mode. Using the optics menu each time and selecting one or no ocular can be tedious. A simple gesture lets you switch easily between both modes. Turn the device face down and face up again in one go. This gesture will become very natural and will enhace you observation experience with Starmap.

The image of your device can be flipped, horizontally or vertically, depending on the telescope kind or if you use a diagonal mirror. The eye piece map image can be inverted, by swiping your finger over the screen, in one or the other direction. The state of the inversion is displayed by vertical and horizontal arrows shown in the top left corner of the map (just under the camera icon, in the previous image). The flipping state differs between camera, oculars and finders. Setting the flipping state for one optics will not alter those of the other elements.

Changing the element on the map happens with pinching and zooming, as you would do for changing the map field of view in normal mode. There is no need to go back to the Optics menu and select another ocular.

A Telrad target can always be displayed on the map from the main menu. A Telrad is a non-magnifying finder used by many astronomers. When activated, the 4° Telrad circles is displayed in the centre of the screen and grows when zooming, reflecting the present field of view. Using the Telrad on the map helps a lot in pointing toward faint objects, thank to the portability of the device.

The Telrad horizontal and vertical graduations are oriented towards declinations and right ascensions axis.

Note that the Telrad can also be used by the object finder as target image. This behaviour can be activated in the Navigation settings.