Revision: 29.09.2023 (draft)
Author: Rumen G.Bogdanovski
e-mail: rumenastro@gmail.com
Special thanks to Bill Tschumy for reviewing the document
- Introduction
- Main Window
- General Concepts
- Connecting to INDIGO services
- Image capture
- Sequences
- Focusing
- Guiding
- Telescope control
- Plate solving
- Accessing advanced device and agent settings
- Managing service configurations
Ain INDIGO Imager is a free and open source astronomical image acquisition application distributed under INDIGO Astronomy open-source license. Ain is designed to be easy to use and lightweight. It requires a running INDIGO Server.
Ain is supported on Linux and Windows operating systems and is available for download on the INDIGO Astronomy website.
Ain is designed to be simple with very little business logic embedded, all the hard work is done by the INDIGO agents. It is essentially a user interface for the INDIGO agents. Because of that, upon connecting, Ain will automatically load any agents it needs to operate.
The main window is divided in three main areas as seen in the picture below:
Almost all widgets (buttons, drop-down menus, spin boxes etc.) have tool-tips with information on what the widget does. In the case of numeric values they also indicate the range of valid input.
This is the upper left area consisting of several tabs and sub-tabs. The control area is where all configuration is done and all processes are controlled, such as guiding, taking exposures etc. It will be described in detail in the following chapters.
This is the upper right area of the main window. In this area the most recently captured image will be displayed. It is context dependent as follows:
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In the Capture, Focus and Telescope tabs, the last image from the main imaging camera will be displayed. Several overlays can be turned on or off such as image statistics (controlled by Settings -> Show image statistics) and image center mark (Settings -> Show image center).
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In the Guider tab, the most recent image from the guiding camera is displayed and overlays for the selected guide stars and the image’s reference point are shown. This is described in detail in a later chapter.
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In the Solver tab, the image currently being solved is displayed.
When the mouse cursor is over the image, the current pixel value will be displayed in the upper right along with the mouse coordinates and the zoom level. Next to this are several buttons for controlling zooming and stretching.
If the Solver or Telescope tab is active and the current image has been solved, the Right Ascension and Declination of the point under the mouse cursor is shown instead of the pixel coordinates. In this case Right-Clicking on the image will copy the coordinates under the mouse into the Telescope tab. Pushing the Goto button will then slew the telescope to center on these coordinates (use Control + Right-Click to copy the coordinates and slew the telescope as a single action).
The mouse wheel zooms in or zoom out of the image and Left-Click + Drag will pan the image.
When the image area is active several shortcut keys can be used for zooming:
- + zoom in
- - zoom out
- 1 zoom 1:1
- f zoom to fit
Log area is the bottom part of the main window. In this area all messages from the INDIGO framework will be displayed, preceded by a timestamp. There are three types of messages: Information - displayed in white, Error - displayed in red and Warning - displayed in yellow. Ain does not display errors or warnings in dialog boxes, all errors, warnings and messages are displayed in this log. In addition each message can be accompanied by an audible notification. Audible notifications are enabled by Settings -> Play sound notifications.
By default Ain will store the files in a subdirectory of your home directory called "ain_data". Frames obtained on different dates will be saved in different subdirectories with format "YYYY-MM-DD". The output directory changes automatically at noon, to keep the data from the same night in the same directory. The data directory can be changed from File -> Select Data Directory
Ain Imager uses colors to represent the states of the operations. Related widgets will be decorated differently depending on the status. Default color (or green in some cases) means that the operation is idle or finished successfully. Red means operation failed or is canceled by the user. Yellow means the operation is in progress.
For example:
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Aborted exposure, Expose button in red:
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Exposure in progress, Expose button in yellow:
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Exposure completed successfully, Expose button in default color:
Ain will automatically discover all INDIGO services available on the network. And depending on Settings -> Auto connect new services it will connect or not to the newly discovered services.
Services can be managed from File -> Available Services as shown below.
All available services will be listed. Use the checkboxes to connect or disconnect from a service. The connection status of the services will be restored when Ain is restarted, provided the service is still available. In the example above, the service "indigosky" is connected and "vega" and "indigo_test" are not.
The auto discovered services will be listed with the "Bonjour" icon in front of their name ("indigosky" and "vega") and can not be removed from the list. They will disappear when the server shuts down and reappear when it is back online.
Services that are not discoverable (not announced on the network or that are on a different network, in a remote observatory for example) can be manually added by the user. The service should be specified in the form name@host.domain:port or name@ip_address:port in the text field below the service list. If port is not specified the default INDIGO port (7624) is assumed. Also name has only one purpose, to give some meaningful name to the service and has nothing to do with the remote service. It can be any text string. If not specified host will be used as a service name. Such services are displayed with a blue planet icon ("indigo_test") and can be removed manually.
As mentioned above Ain Imager uses agents to operate and the top drop-down menu is for agent selection. In Capture tab, all available Imager Agents from all connected services will be listed. Depending on Settings -> Use host suffix it will show or not show the service name as a suffix (takes effect after reconnect). Ain can use only one imager agent at a time. Multi-agent support will come in the future.
All cameras available to the selected Imager Agent will be listed in the drop-down. The selected camera will be used for image acquisition.
All filter wheels available to the selected Imager Agent will be listed in the drop-down. The user should select the one attached to the selected camera.
All frame resolutions and pixel depths supported by the selected camera will be listed in the drop-down along with the frame types such as "Dark", "Light", "Flat", etc.
Exposure time (in seconds) when the Expose or Preview button is pressed to start capture of one or more images.
The delay (in seconds) between the exposures taken in a batch.
How how many frames should be taken in the batch exposure. Use -1 for an unlimited number of frames. In this case the batch exposure will finish when Abort button is pressed.
All available filters in the selected filter wheel will be listed in the drop-down. The selected filter is the one currently being used.
The name of the object being photographed should be entered here. It is used as a prefix of the saved file name and as an object name in the FITS header. If there is no name specified and Settings -> Save noname images is checked, "noname" string will be used as file name prefix, otherwise the images will not be saved and a warning will be printed in the log.
If the selected camera can report the sensor temperature, the current temperature will be shown. If the camera supports cooling, it can be enabled and disabled here along with setting the target temperature. If cooling, the cooler power will be displayed.
The time (in seconds) used to get a preview frame with the Preview button.
The image file formats supported by the camera driver will be listed here. They can be different for different cameras. The selected format will be used as a storage format for the saved images. Raw data format is a special case. It is supposed to be used by INDIGO internally, this is why batches and sequences will not save images taken as Raw data (as of Ain Imager version 0.99).
The region of interest (ROI) can be configured by specifying X and Y of the top left corner and Width and Height of the sub-frame.
INDIGO can dither between the frames and it is configured in this tab.
All available Guider agents will be listed here. The selected one will be used for guiding and dithering. To disable dithering select "None".
This value, in pixels, specifies the maximum number of pixels the frame should be shifted during dithering. The actual shift is a random value and this specifies the upper limit.
The settle timeout is in seconds. It specifies how much time to wait for the guiding to settle after dithering. If it has not settled before this timeout is up, a warning is issued and the imager agent will proceed with the next exposure.
Specifies how many frames to skip between dithering (0 means to dither after each frame).
In this tab, camera specific parameters can be set: gain, offset and binning.
INDIGO services can work in the so called "clientless" or "headless" mode. This means that the server can operate autonomously. To achieve that the client must connect, configure the service to perform some specific task, start it and disconnect. The server will store the data locally and when the client connects again it can download the acquired data. This mode is configured in this tab.
To enable the server to store the captured frames locally, check Save image copies on the server. If one does not want downloaded images deleted from the server after downloading, check Keep downloaded images on server otherwise images will be deleted once downloaded.
If the server is configured to keep the downloaded images they can still be removed when no longer needed. This is achieved by unchecking Keep downloaded images on server and press Server cleanup. This will remove any images that have already been downloaded. Those not yet downloaded are kept. This is useful when the images should be downloaded to several locations and removed once downloaded everywhere.
Image capture in a sequence is a feature of the Imager Agent and it is executed on the selected imager agent. Currently, sequences work with a single target, and target can not be changed. The user can specify filter, exposure time, delay between exposures, type of exposure etc., in each batch. For example (the screenshot below) we have a sequence with batches that will take 10 x 30s Light exposures in each of the filters: Lum, Red, Green, Blue and Ha. Focusing will be performed for each filter with 1s exposure. At the end it will take 10 Dark and 10 Bias exposures. Exposures will be saved with file name prefix "Rozette". The whole sequence will be repeated 3 times and at the end camera cooling will be stopped and the telescope will be parked. The running batch is indicated by a small arrow next to the batch number in the table.
The sequence capturing will use the Imager Agent selected in Capture tab, which means that the camera and the filter wheel selected there along with their configurations will be used. For focusing the focuser and its configuration will be used from the Focus tab.
Each sequence consists of separate bates that will be executed in a sequence. Each batch is described by several proprieties like: Filter to be used, exposure time, frame type etc. Batches can be added ([+] button), removed ([-] button) and edited. The batch order in a sequence can also be changed. Batches can be saved and loaded from file (.seq) and downloaded from the Imager Agent.
The sequence name should be specified in the text field as shown below, This will be used as a file name prefix and object name in the FITS header. If there is no name entered and Settings -> Save noname images is checked, "noname" string will be used as file name prefix, otherwise the images will not be saved and a warning will be issued in the log.
The user can specify how many times the batches in the sequence should be executed by setting Repeat value (default is 1).
By checking Turn cooler off the cooling of the used camera will be turned off at the end of the sequence.
By checking Park mount the used mount will be parked at the end of the sequence.
To add a new batch to the sequence the user should describe its properties as shown below:
the batch will be added by pushing the [+] button:
In order to remove, move up or down or update a batch the user must select the batch by clicking on it (double clicking will remove the selection):
Once the batch is selected its properties will be loaded in the Batch description. The selected batch can be removed by pushing [-] button or moved up or down the sequence with the up and down arrow buttons. To edit the selected batch, the user must change the properties as needed, in the Batch description and click update button (the most right button in the group).
The already loaded sequence can be downloaded from the selected Imager agent by clicking the download button (left button):
Sequence can be loaded from file by clicking the folder button (the middle one) and choosing the sequence file.
The current sequence can be saved to a file by pushing the disk button (the right one) and providing a file name. The ".seq" extension will be automatically added.
The sequence being edited or loaded will be uploaded to the Imager Agent only when the sequence is started. Before that all the changes will remain in the client only. Because of that, if the user changes the sequence while it is running the changes will not take effect.
NOTE: Loading sequence from file or downloading it from the agent will replace the current sequence and unsaved changes will be lost.
The current sequence can be started with the Run button. This will also upload the current sequence to the Imager Agent as described above.
The running sequence can be paused with the Pause button and resumed later. Please note pausing will not abort the current exposure, the process will pause after the current exposure is complete.
Abort button will stop the current sequence immediately and the shutdown tasks will not be performed. Clicking Run after abort will start from the beginning.
Progress can be monitored using the three progress bars and the operation indicator as shown above. The first progress bar shows the elapsed time of each exposure. The second one shows the completed exposures in the current batch. And the third one shows the completed batches in the current sequence. The operation indicator shows the operation in progress like Focusing, Capturing, Changing filter etc.
Sequence duration shows approximately how long the current sequence will take to complete in HH:MM:SS. Please note that this value is approximate as some operations like image download, filter change and focusing are unpredictable.
Focusing is a feature of the Imager Agent and it works with the selected imager agent.
All focuser devices available to the selected Imager Agent will be listed here. The correct one should be selected.
The current focuser position will be displayed here. Entering a new value and pushing the [>] button will move the focuser to the new position. It can be used to assist the focusing by going roughly to focus or to retract the focuser at the end of the imaging session.
Relative move will help achieve precise focus manually. The value represents how many steps, relative to the current position, the focuser should move when [>>] (focus out) or [<<] (focus in) button is pushed.
The current temperature will be shown if the focuser has a temperature sensor. If Auto compensation is checked, the focus will be automatically corrected with the temperature change if the compensation factor is set in the Misc tab. This value must be determined by the user since it is setup dependent.
Essential focusing statistics along with a graphical representation will be displayed during manual or automatic focusing. The information displayed depends on the on the focus estimator being used. For "Peak/HFD" estimator, half flux diameter (HFD) or full width half maximum (FWHM) will be displayed on the graph (configured with Settings -> Peak/HFD Focuser Graph). For "RMS Contrast", the contrast will be shown.
Exposure time in seconds used during the focusing process.
The focus mode "Manual" or "Auto".
Currently the Imager Agent supports two focus estimators: "Peak/HFD" and "RMS Contrast".
The coordinates of the star that will be used for "Peak/HFD" focusing should be entered here. Right-Click on the image will load the coordinates of the cursor here and will move the selection overlay (a green square).
The radius, in pixels, of the aperture used to estimate FWHM and HFD.
Auto focus configuration is described in INDIGO Imager Agent - Autofocus Tuning Guide
In order to transfer less amount of data through the network sub-frames with size of 10 or 20 radii centered around the selection can be used. This is applicable only for "Peak/HFD" estimator.
This is the temperature compensation factor, in steps per degree Celsius. It specifies how many steps will be applied when Auto compensation is ON with each degree change of the ambient temperature.
This defines what to do if the auto focus procedure fails. If Return to the initial position is checked it will return to the starting position, otherwise it will just stop. This applies to "Peak/HFD" estimator only. With "RMS Contrast" it will always stop.
If the focuser is inverted and retracts on focus out motion the motion should be inverted. This drop-down menu will be active if the selected focuser supports motion inversion.
Ain uses the service Guider Agent for guiding. The top drop-down menu has a list of all available guider agents and the appropriate one should be selected.
All cameras available to the selected Guider Agent will be listed here. The appropriate one should be selected.
All guider devices available to the selected Guider Agent will be listed here. The appropriate one should be selected. They can be part of the mount or the ST4 port of the guiding camera.
- Preview button will start a loop of exposures with the guider camera.
- Calibrate button will start the calibration process during which the guiding parameters will be determined automatically.
- Guide button starts the Guiding
- Stop button will stop each of the above processes.
Exposure time and delay between exposures can be specified in this section. Both are in seconds.
Guider Agent provides several algorithms for drift detection and several options for Guiding in declination. Both can be selected here.
In "Selection" guiding the primary star can be selected by Right-Clicking on the star or by entering the coordinates in Star Selection X/Y fields. The radius of the circle where the star can drift between two consecutive frames is specified in Selection radius field. And for multi-star "Selection" guiding the number of stars to be used can be specified in the Star count field.
Only the first star can be selected manually or automatically. All other stars can only be auto selected. The list of the selected star can be cleared by pushing Clear star selection button. This will force the Guider Agent to make a new selection when any process is started.
If the Declination guiding runs away after meridian flip Reverse Dec speed after meridian flip should be checked. Some mounts track their "side of pier" state and automatically reverse the direction of the declination motor after a meridian flip. Other mounts do not do this. There is no way for INDIGO to know this in advance. This is why INDIGO needs this to be specified.
In "Donuts" guiding the whole frame is used to detect drift but some cameras have unusable border around the frame. This can interfere with the guiding and this area can be excluded by specifying Edge Clipping
Guder Agent configuration is described in INDIGO Guider Agent - PI Controller Tuning and in Guider Agent README
Calibration parameters will be automatically computed during the "calibration" process but they can be fine-tuned manually.
There are two options to reduce network traffic. As the guiding is done on the server Ain Imager does not need full resolution raw frames. It just needs basic images for visualization. This is why the user can choose to download JPEG images which can be more than 10x smaller and image sub-frames.
Frame format, gain and offset of the guiding camera can be specified in this section.
The focal length of the guider scope should be entered in order to enable the drift to be displayed in arc seconds. Otherwise Settings -> Guider Graph -> RA / Dec Drift (arcsec) will have no effect and the statistics and graph views will be in pixels.
Ain uses the service Mount Agent to control mounts. The top drop-down menu has a list of all available mount agents and the appropriate one should be selected.
If the displayed image is solved a Right-Click on it will copy the coordinates under the mouse cursor in the RA / Dec input boxes and pushing Goto button will slew the telescope to these coordinates. Control + Right-Click will copy and slew the telescope in one action.
All mounts available to the selected Guider Agent will be listed here. The appropriate one should be selected.
Displays current target Azimuth and Altitude and uses color coding to give a visual clue of the target suitability to be observed:
- Green - the target is high above the horizon and is good to observe.
- Yellow - the target is low above the horizon.
- Red - the target is very low or below the horizon.
In these fields the target Right ascension and Declination should be entered. They will be used for goto if Goto is button is pushed or to synchronize the mount to these coordinates if Sync is button is pushed.
The mount can be moved by pushing N S W E buttons. The speed is selected from four available presets. The slowest is Guide rate and the fastest is Max rate.
This check box controls the mount tracking. The mount tracking is enabled if it is checked.
Checking this check box will slew the mount to its home position.
Checking this checkbox will slew the mount to its park position.
All available joysticks will be listed here. The mount can be controlled with the selected joystick/gamepad. The button operation of the joystick can be configured in the driver through INDIGO Control Panel.
Typing in the Search field will update the object list as you type with the objects that match the pattern. Once the desired object is selected its coordinates will be loaded in telescope coordinate fields and clicking on Goto will point the telescope to the selected object.
Each object in the list has a tool tip with information about the object like coordinates, magnitude and type.
Custom objects can be added by clicking on the [+] button in the object tab. The following dialog will appear:
The data fields should be filled and the Add object button should be pushed to create the custom object. The current telescope coordinates can be loaded in the Right ascension and Declination fields by pushing the target button.
Pushing the [-] button will remove the selected custom object. Please note that standard library objects can not be removed.
In the solver tab the user should select the image source and exposure time to be used. Three operations can be performed:
- Precise Goto - the selected agent will slew the telescope to the input coordinates and then perform solve and center (available in version 1.2-0 and newer).
- Solve & Center - the selected agent will take an exposure, solve it, and using the solution as a reference will perform a precise goto to the target coordinates.
- Solve & Sync - the selected agent will take an exposure, solve it, and the solution will be sent to the telescope as a reference (sync the telescope with the solution). This will allow precise goto in the vicinity.
In the Source drop-down menu all available geo location sources will be listed. Examples include the GPS device selected in the GPS tab or the selected Mount Agent coordinates, which are set in the Set Location / Time section.
If Keep the mount time synchronized is checked, whenever the time or geo coordinates of the source are changed the mount will also be updated. This is somewhat dangerous as the GPS may lose its signal and the mount will lose alignment.
In the GPS drop-down menu all available GPS devices will be listed. The selected GPS can be used as a time and geographic coordinates source in the Site tab. It also shows the position data from the selected device.
Performing the telescope polar alignment procedure is described in detail in INDIGO Astrometry / ASTAP Agent - Polar Alignment Guide.
Plate solving configuration and usage is described in INDIGO Astrometry Agent - Plate Solving Guide and in Astrometry Agent README
If a local file needs to be solved, Image source should be set to "Upload file". In this case, pushing the Solve button will display a file select dialog for choosing the file to be solved.
If the displayed image is solved a Right-Click on it will copy the coordinates under the mouse cursor in the RA / Dec input boxes and pushing Goto button will slew the telescope to these coordinates. Control + Right-Click will copy and slew the telescope in one action. This can be used to center a certain object in the frame. The telescope coordinates offset regarding to the solved image coordinates will be taken in to account, unless the solved image is an Uploaded file. In this case the solved coordinates will be used as most likely the telescope is pointing to another coordinates and the offset can not be calculated.
If you use the target button (next to the solution status indicator) to load the solved image center in to RA / Dec input fileds, the coordinates will NOT be adjusted to compensate for the telescope coordinates offset.
NOTE: If you want to get the same framing of an object as in a previous session, upload and solve a frame from this session and Right-Click or Control + Right-Click on the image center and center the telescope to these coordinates as described above. Then if the rotation angle is different, rotate the camera until the same rotation angle is reached as the rotation ange of the reference frame.
Ain Imager provides access to a subset of the standard properties of the devices and agents. The whole set of properties can be monitored and modified with the INDIGO Control Panel, free and open source application available for Linux and Windows.
Ain provides a shortcut to it from File -> INDIGO Control Panel.
INDIGO Control Panel is essential for the initial service configuration like loading the necessary drivers and initial device configuration.
Note: This feature is experimental!
Ain Imager can use Configuration Agents running on INDIGO services to manage the configuration of each service. It can save, load, delete and create new configurations for each INDIGO service. The configuration manager dialog can be accessed from File -> Manage service configurations.
Available configuration agents will be listed in the top drop-down menu and available configurations will be listed in the Configuration combo box.
More information about configuration management can be found in INDIGO Configuration Agent README.