The user interface for the PiFinder is split into various screens that you can switch between to perform different tasks. The A key is used to cycle between the three main screens:
- Chart
- Catalog
- Locate
By holding down the Enter key and pressing the A function key you can get to the less commonly used screens:
- Console
- Status
- Camera Preview
Some actions in one screen will move you to another, for instance selecting an object from the Catalog will switch automatically to the Locate screen.
The remaining function keys serve different purposes depending on which screen you are on at the time you press them, but there are some key-combinations that act across any of the individual screens:
- Long press A: For screens with options, such a the Catalog screeen, holding down the A function key will bring up the options for that screen. See Options below.
- ENT + UP/DN: This combination will adjust the screen brightness up and down at any time.
Many screens have options which change the way they behave or perform other less commonly used actions. Pressing and holding the A button will bring up the options for whichever screen you are currently using. To exit the option screen press A to return to the previous screen.
The options screen will show one option or action item per line with the name or description of the item to the left and the current value to the right. The bright numbers along the left edge indicate the key on the keypad to press to access that item.
Once an item is selected the item will be highlighted and the available values or types of actions will be listed along the right hand side. The bright numbers along the right hand side will let you select the value(s) for this item.
Some types of options can only have a single value, like Magnitude above. Others, such as Obj Types will allow you to select multiple values. If an option only has a single value, selecting it will return you to the main options page. For options that can have multiple values, you'll need to use the ENT key to confirm your selections and return to the main option page.
The Options screen can also contain less commonly used actions which will take place when a value is selected.
The Options screen shown above (for the Status screen) has general PiFinder options along with a couple actions. Selecting an action item, such as 1, will always have one additional step to confirm the action, or allow you exit.
To exit the option screen press A to return to the previous screen.
The chart screen will display a star chart centered around the current RA / Dec coordinates the PiFinder has determined. By default it shows stars down to magnitude 7 and has a 10 degree field of view. As you move your telescope the chart will be updated several times a second using either a plate solve for a captured image or an approximation based on the last plate solve and the Inertial Measurement Unit (IMU).
There is a Telrad style reticle that can be used to help orient the chart. The outer ring is four degrees in diameter, the inner two degrees and the middle 1/2 degree.
If you have a target selected, an arrow around the outer rim of the reticle will point in the direction that target is located.
If the target is within the current chart, the arrow will disappear and a small X will mark the spot of the target.
While viewing the chart you can adjust it's appearance and FOV in several ways:
- B Function key: Toggle reticle state. There are several brightness levels including off.
- C Function key: Toggle constellation line brightness.
- D Function key: Toggle observing list marker brightness. This will show markers for DSO objects in your observing list.
- UP/DN : Increase or decrees the field of view (zoom). This ranges from 5 degrees to 60 degrees.
- Holding the A function key will bring up settings for the chart including the above reticle/constellation brightness
The catalog screen allows the searching and selection of astronomical objects to locate. It has multiple catalogs available (Messier, NGC, IC) and displays some basic information about each object. You can set filter criteria (Altitude, Magnitude, Object Type) to limit the objects surfaced via the search.
The B function keys toggles between a description of the object, if available, and information about how often you've observed that object.
The C function keys will cycle through the various catalogs available. The upper-left will show the count of filtered objects over the total number of objects in each catalog.
Use the number keys to enter the id of the object you are looking for. As you type, any matching object will be displayed. Typing in 74 to look for Messier 74 will bring up Messier 7 and 74 in turn as you enter numbers.
If the number you have entered matches an object in the catalog, information about the object will be displayed below including:
- Object Type
- Constellation
- Magnitude
- Size
- Other names
- IC/NGC coded observing notes
Pressing the B key will cycle through various pages of information about the selected object. This includes object descriptions in NGC shorthand, information about when you have observed this object, and potentially images of the object.
Use the D key to clear the number field out and start fresh. If you find an object you are interested in, pressing the ENT key will add it to your target list and switch to the Locate screen.
Holding the A key for two seconds will bring up the settings for the catalog. You can filter by apparent altitude, magnitude and object type. The Options page also has an action to push the currently filtered catalog to the Observing list. Pressing A will bring you back to the catalog and update the count of objects that match your filter.
- The UP/DN keys will scroll through the currently filtered objects.
If you have downloaded the set of catalog images you can view what the selected object looks like via images from sky surveys. Pressing the B key will cycle through various pages of information about each object including images from the Palomar Observatory Sky Survey and potentially updated images from the Sloan Digital Sky Survey.
As an example, here are the images available for M57
These images are oriented as they would be through the eyepiece in a newtonian reflector pointing at a specific area of the sky from your current location. You can use the UP and DN keys to switch between various eyepiece field of views. If you have your telescope and eyepiece collection information entered into the PiFinder these will be used to determine the FOV's to cycle through. The defaults are 1, 0.5, 0.25, 0.12 degrees.
The bottom left of the screen shows the source of the current image and the left side shows the current FOV / Eyepiece information.
The Locate screen uses the last solve and currently selected target to provide a visual indication of which direction to move your telescope in order to center the target. It also provides a summary of the current target and information about the overall target list.
Values are expressed in degrees with the top line being rotation in Azimuth and the bottom line in Altitude.
- UP/DN will cycle through the active list. The numbers in the upper-right corner of the screen represent the index of the current object / total number of objects in the list and the list name is displayed directly below.
- ENT will switch back to the catalog screen to access full information about the current target
- B will toggle between the History and Observing lists
- Holding the A key will open the Options page where you can load and save observing lists to disk
The currently target is also displayed on the Chart screen as a small tick mark.
The screens listed below are more rarely used and do not show up when rotating through the regular UI screens using the A key. To access these screens, rotate through them using the ENT-A combination.
The Log screen can be accessed at any time by long holding the ENT key. It allows you to record your observation of the currently selected target in a database as part of a session. Each session starts when you power-up, or reset, the PiFinder and every observation logged during the session will be grouped together for later review.
Summary information about the current target is displayed along with the distance from the current telescope position. This distance allows you to make sure you are observing/logging the correct object in a crowded field, like Virgo.
You can add some details about your observation by holding down the A key to add notes.
- Transp. : The transparency of the sky. This is often noted along with Seeing below
- Seeing: The stillness of the atmosphere.
- Eyepiece: You can note which of your eyepieces you are using.
- Obsabillit: Observability - How easy is it to spot and recognize this object
- Appeal: Overall rating of this object.. would you refer a friend?
Pressing the A key from the Observing Notes options will bring you back to the Log screen.
- B key - Logs the current target to the database and saves a 512x512 snapshot image with current exposure settings.
- C key - Logs the current target to the database and takes a high-resolution photo. Takes longer, but you get a nice image of a 10 degree patch of sky that should have contained your target.
- D key - Abort and return to the previous screen
The preview screen displays most recently taken exposure from the camera. You can adjust the processing of this image (just for display purposes), adjust exposure and zoom in to focus.
- B key - Adjust reticle brightness or turn it off completely
- C key - Turn background subtraction on/off
- D key - Adjust gamma correction intensity
In the options menu (long-press A) you can adjust these same display parameters and also enter Focus Help mode. In this mode the camera image is enlarged to help achieve good focus on a star. Since this only shows the center of frame, get a star lined up in the reticle before activating Focus Help.
You can adjust overall exposure using the UP/DN keys (check the Console for specific setting). If you'd like to save this exposure as the default for future sessions, use the ENT key.
The status screen displays:
- LST SLV: Seconds since last position solution, plus last position solution source (CAM or IMU)
- RA/DEC: Last solved Right Ascension and Declination
- AZ/ALT: Last solved position in Azimuth / Altitude. This can only be displayed if a GPS lock is achieved to provide location and time information.
- GPS: GPS Status (Locked/--)
- IMU: Inertial Measurement Unit status. Moving/Static + Confidence level (0-3)
- IMU PS: Current IMU position (Azimuth / Altitude) before conversion to astronomical AZ/ALT position.
- LCL TM: Local time (requires GPS fix)
- UTC TM: UTC Time (requires GPS fix)
- CPU TMP: Temperature of the Raspberry PI CPU
- WiFi: Current WiFi mode, either AP for access point, or Cli for client
- IP: Current IP address for connecting to via software such as SSH or SkySafari
The Options page for the status screen gives access to general PiFinder options and actions. Press and hold the A key to access the option page.
- Set the Power Save timeout
- Change WiFi Mode between client and access point
- Switch between left/right side orientation
- Restart the PiFinder software
- Shutdown the PiFinder
- Update the PiFinder software
Logged information from the various parts of the PiFinder system is displayed here.
- UP/DN key - Scroll the log display