User's Guide to iStellar
1. Initial Setting
When iStellar is started for the first time, it will present a startup screen asking for selection of your observation location.
As you tap on OK, the location setting screen will be displayed. Tokyo is selected by default. Please pick your location and set it to current (see: 7. Location Setting). Tap on the [Done] button on the top right when you are done.
Location settings can be made anytime after every program start.
2. Star Chart Screen
After completing the first location setting, the star chart screen is displayed immediately at every program start.
The star chart screen is basically composed of a star chart section with superimposed moon age, date, time, time zone, geographical coordinates and field of view, alongside a tab toolbar at the bottom.
Working with the Star Chart
The following operations can be performed on the star chart:
- Tap: toggles the toolbar on and off.
- Slide: scrolls the star chart (changing the view of observation).
- Double-tap: Centers the screen on the location tapped. When a double-tap invokes object information (details further down) a list of celes tial objects in the vicinity is provided (see 9. Object Information).
- Pinch in/Pinch out: Zooms the star chart (field of view) in and out.
- Touch (prolonged): upon touch, a list of objects in the vicinity of the touched point is displayed for browsing (see 9. Object Information).
Tabs & Toolbar
Upon tap on an upper tab, the lower toolbar displays a line of buttons for related sub functions. There are 7 tabs in total.
3. Tabs & Toolbar
Click on an upper Tab button to show corresponding Toolbar and description.
NOTE: Occasionally toolbar buttons happen to react when tapping on tabs. In such an event, please be sure to tap on the upper tab.
Date Tab
Displays a lower toolbar by which year (Y), month (M) and day (D) can be manipulated whilst monitoring the star chart.
Select one of the Y/M/D buttons at the left and change the date using the [+] [-] and [00] buttons at the right.
The [00] button resets month and day to January and Day 1, respectively, and has no effect on the year.
Time Tab
Displays a lower toolbar by which hour (H), minutes (M) and seconds (S) can be manipulated whilst monitoring the star chart.
Select one of the H/M/S buttons at the left and change the time using the [+] [-] and [00] buttons at the right.
The [00] button resets hour, minute and second to 0h, 0m, 0s, respectively.
Animation Tab
Displays a toolbar by which settings for replay of animations as well as date and time can be made in detail.
Reverse Playback
Starts reverse playback at a selected speed. During ongoing animation this button is assigned the stop function.
Playback
Starts forward playback at a selected speed. During ongoing animation this button is assigned the stop function.
Animation Settings
This button is provided for changing animation speed (see 4. Animation Setting).
Current Date and Time
Sets date and time to current.
Detailed Setting of Date and Time
Displays a dedicated screen for the purpose of setting date and time (see 5. Date and Time Setting).
Object Tab
Displays a toolbar by which labels and markings for individual star chart objects can be made visible or invisible. From left to right:
Stars
Tap on this button to toggle star labels on and off.
Solar System Objects
Toggles sun, moon and planet labels on and off.
Constellations
Changes the way constellations are drawn. Subsequent taps on this button cycle the display as follows:
- First tap: all OFF
- Second tap: constellation names ON
- Third tap: constellation names ON and constellation lines ON
- Fourth tap: constellation names ON and constellation lines ON and constellation pictures ON
- Fifth tap: all OFF again
Nebulae and Star Clusters
Changes the way Messier objects are drawn. Subsequent taps on this button cycle the display as follows:
- First tap: all OFF
- Second tap: name labels ON
- Third tap: name labels ON and symbol marks ON
- Fourth tap: all OFF again
Comets
Changes the way Comets are drawn. Subsequent taps on this button cycle the display as follows:
- First tap: All OFF
- Second tap: name labels ON
- Third tap: name labels ON and symbol marks ON
- Fourth tap: all OFF again
Meteor Radiants
Changes the way meteor radiants are drawn. Subsequent taps on this button cycle the display as follows:
- First tap: All OFF
- Second tap: name labels ON
- Third tap: name labels ON and symbol marks ON
- Fourth tap: all OFF again
Detailed Settings
Displays a dedicated screen for the purpose of setting display functions in further detail.
Search & Move Tab
Displays a toolbar by which object searching, object tracking and moving of observation points can be performed.
Object Search
Displays a dedicated screen for searching objects. (see 6. Object Search).
Double-Tap Mode
Changes double-tap operation modes (see 12. Double-Tap Modes).
Object Tracking
Locks (tracks) an object in the center of the screen at any time. Tracking is released upon another tap.
N, E, S, W
Scrolls the center of the star chart to the selected azimuth angle, north, east, south or west.
Projection Tab
Displays a toolbar for changing projection modes. Display of coordinate grids and a field of view circle can be toggled as well.
Projection Mode
Changes the projection mode (horizontal, HRZ or equatorial, EQT) of the star chart (see 11. Projection Mode).
NOTE: Equatorial coordinates mode is supported by all phones, while the sensor mode is only supported by iPhone 3GS devices.
Grid
Toggles the coordinate grid on and off. In horizontal coordinate mode and sensor mode, the grid draws azimuth/altitude lines while in equatorial coordinate mode right ascension and declination lines are shown.
7° Field of View Circle
Draws a 7° (arc degrees) wide circle centered on the screen (a common FOV of binoculars).
Others Tab
Displays a toolbar for the purpose of setting location, time zone, etc.
Location Setting
Displays a dedicated screen for location setting (see 7. Location Setting).
Time Zone Setting
Displays a dedicated screen for time zone setting (see 8. Time Zone Setting).
4. Animation Interval Setting
Real Time
Runs animation in real time, i.e., synchronized with iPhone system time. Date and time cannot be changed during playback.
Adjusted Time & Real Speed
Runs animation in real speed starting from user selected date and time. The star chart carries on changing every second.
xx/sec
Sets animation speed to a multiple of a second in real time.
5 seconds / sec, 5 minutes / sec and 30 minutes / sec
xx/Frame
Sets animation speed to a multiple of iStellar's screen refresh cycle.
1 day / frame and 1 sidereal day / frame
*One sidereal day is about 23 hours and 56 minutes, the time between two culminations (meridian transits) of a fixed star.
5. Date & Time Setting
Upon tap on the Date and Time group button, date and time can be changed using the picker wheel at the bottom.
When finished, tap on the [Done] button at the top right.
6. Object Search
In the search function you can select a named object from a list and have it centered on the screen.
Tap on the Object Search button to open a list of object categories. Then tap on a category for a list of objects therein. Next, upon tapping on a target object, the display will change to the star chart screen and show the selected object in the center.
Grayed object names in the object list are objects currently below horizon. Nevertheless, you can tap on one of them to center it on the star chart screen.
Operation in Sensor Mode
In Sensor Mode, only available in combination with iStellar 2.0 or later and an iPhone 3GS device, the behavior upon tapping on an object is different.
When you tap on an object name, a marker indicating direction is shown on the star chart screen. Hold and move the device towards the indicated direction. As the target object gets closer to the center of the screen the mark is shown with less opaqueness. The marker can be removed upon tapping on the [Object Search] button.
7. Location Setting
Allows selection of a location for which to display a star chart. Under typical conditions your present location is selected, but it is also possible to pick a travel destination, etc.
Setting with GPS
With an iPhone 3G or iPhone 3GS the location can be determined using the internal GPS receiver. GPS measurement starts upon tapping on the [Start Measurement] button. Measurement accuracy is displayed on that button. Touch it once again at arbitrary timing.
Touch on the World Map
If you touch any point on the world map, a red crossbar will move to that point and change the observation location.
Sliding the Crossbar
Touch and slide the vertical and horizontal bars to a desired location. This method allows more accurate setting than touching on the world map.
Input of Coordinates
Direct input of longitude and latitude values is the most accurate means of setting a location.
When finished, tap on the [Done] button at the top right.
8. Time Zone Setting
Allows selection of a time zone and daylight saving time (DST).
A time zone is selected from the picker wheel at the bottom. By setting daylight saving time to ON, an offset of +1H is added to the selected time zone.
9. Object Information
The object information screen is displayed upon a prolonged touch without sliding over the screen. The screen holds a list of object candidates around the vicinity of the touched sky position. Tap on an object to view its data information.
The upper quarter of the screen shows a 24H rise/set diagram, while the remaining space of the screen is reserved for detailed data.
- [Coordinates] Button
- Underneath the object category, right ascension, declination, ecliptic longitude and latitude, galactic longitude and latitude are shown.
- [Rise/Set] Button
- Object rise and set times, azimuth, altitude, Greenwich hour angle and sidereal time are shown.
- [More] Button
- Any further available information specific to an object is shown here.
Tap on [Candidates] button at the top left to return to the object list.
Tap on [Track Object (crosshair mark)] at the top right to track and lock an object in the center of the screen. To release tracking, tap on the [Track Object] button under the Search & Move tab.
10. Object Tracking
Centers a target object on the star chart screen. Object tracking can be selected in the following ways:
- 1. While the star chart is displayed
- Select the Search tab and tap on the [Track (crosshair mark)] button on the toolbar below to track the object in the center of the screen.
- 2. On the Object Information Screen
- When the object information screen is up, tap on the [Track (crosshair mark)] button at the top right to track that object.
The first method is easy to use, however, if two or more objects are located in the center, the object that iStellar assigns highest priority will be tracked. In such an event, please use the second method to precisely track the wanted object.
To release object tracking tap on the [Track (crosshair mark)] button once again.
11. Projection Modes
iStellar 2.0.0 provides three projection modes.
Projection modes are switched on the projection toolbar.
Horizontal Coordinates Mode [HRZ button]
The star chart is projected on horizontal coordinates (azimuth and altitude).
Equatorial Coordinates Mode [EQT button]
The star chart is projected in equatorial coordinates (right ascension and declination).In this mode, the simulated effects of daylight, atmospheric refraction, landscape and translucence below horizon are always disabled.
Sensor Mode
This mode is only available for iStellar 2.0.0 and later in combination with an iPhone 3GS which incorporates an electronic compass (as of October 2009). When horizontal projection mode is selected, the star chart shows the part of the sky centered on the direction to which the phone is pointed.
In sensor mode, the star chart is presented in real time with the following logical restrictions:
- Date, Time and Animation tabs are disabled.
- N, E, S, W buttons under the Search/Move tab cannot be used.
- Star chart scrolling and centering upon tap on the screen are disabled.
NOTE: The star chart will not show correctly when the phone is tilted slantwise. Please move your phone in horizontal or vertical direction without tilting the screen with respect to ground.
12. Double Tap Modes
A double-tap on the star chart screen invokes two different functional modes. These modes can be selected using the double-tap mode switch on the Search/Move toolbar.
- When the button is black:
- Mode for scrolling the screen: a double-tap on the screen will scroll the screen to center the tapped position.
- When the button is blue:
- Mode for object information: a double tap on the screen will show a list of objects located in the vicinity of the coordinates tapped.
