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Sequence Tool

This tool is to control a sequence of exposure on one or more objects.
The current implementation support only sequential processing of the targets, with options for repeating or skipping some target.

The top grid show the current list of targets. You can enlarge the right pane with the mouse to see all the column.

You can Load an existing file with a list of target, create a New one or Edit the current list.
Using the Manage button you can Copy, Delete or Edit any sequence present on the computer.

Use the Start and Stop button to start or interrupt a sequence.
The Pause button allow to pause the sequence after the current exposure is completed.

The Status button show the detail of the current completion status of the sequence.

The Reset button remove all the completion status about the images already done, allowing to restart a sequence from the beginning.

The button you cannot use at any moment are show in light gray and disabled.

The Run unattended check box control how the program react in case of error.

  • If not checked a message prompt you on the screen what you want to do. After a delay without response the operation is canceled.
  • If it is checked the operation is canceled. Also the termination actions are always taken anyway the sequence is stopped.

The bottom grid show you the plan for the current target. A plan name ending with a “*” indicate it is modified from the base template.
When the sequence is running the current target and step are highlighted.

You can edit a sequence while it is running but there is some limitation to ensure consistency and be sure you get the required number of exposure with the new parameters:

  • The option “Record restart information” must be checked.
  • No autofocus or slewing operation are now active.
  • Current camera exposure continue normally during the editing but a new exposure is not started until the editor is closed.
  • Change to future target is applied without limitation.
  • Change to already complete target is used only for an eventual future repetition.
  • The following action are taken if the running target is modified:
    • If changing only the repeat count or the autofocus option the sequence will continue.
    • If changing the object name, the coordinates or the rotator angle, the sequence is stopped and restarted with the new parameters.
  • The following action are taken if the running step is modified:
    • If changing only the total number of exposure, the dithering or autofocus frequency, the sequence will continue.
    • If changing the description, exposure time, frame type, binning, filter, gain or offset, the current step is interrupted and the sequence is restarted with the new parameters.

Sequence editor

After you click New or Edit, the target editor let you modify the list of target and the plan steps.

At the top of the screen is the global sequence option, when it start and end, how restart is managed, what action to take when it start and end.

Then is a list of target with the name, exposure template, coordinates, time constraint, slewing and autofocus options.

At the bottom is the list of exposure steps for the selected target. This give all the capture parameters for each exposure series. This can be selected from a template or be specific for only this target.

You can adjust the size of the target and exposure steps list depending on your needs.
For a monochrome camera with a filter wheel you typically want 3 or 4 steps for each filter. But with a color camera a single step is generally used, in this case you can reduce the step list to get more space for more targets.


Target list

Add a target

A target can be an object you want to take the images, a script to run in the sequence, or a series of twilight flats. Click the button Insert rows and select the desired option to add the target you want.
When already editing the target list you can add more rows using keyboard shortcut. Use Ctrl+a to add an empty row, or Ctrl+o to add an object from the internal database.
You can edit a value directly in the table or change the values for a whole column by a click in the column title.
Click the Options button to access more parameters for the target.

When you add a New object, or click the Search menu, the program will search for the object coordinates in the internal database. You can use wildcard to list all the matching objects. For example if you enter NGC you will get a list of all NGC objects in the database. But if you enter NGC100 you will get the coordinates of NGC100 because this object exists. To get all object starting with NGC100 in the list, you have to enter NGC100*.
If the object is not found in the database, you can enter the coordinates directly or click the Planetarium menu to select the object in the connected planetarium application.
The coordinates can also be selected by plate solving the current image.
Or click the No move menu to clear the coordinates and not change the telescope position.
Note that the target coordinates are always J2000 and could differ from those show by the mount or the planetarium if they use local apparent coordinates.

Select the template exposure plan to apply to this target using the dropdown box, or type a new plan name to create a new empty plan. If you not want to use a template you can even let it blank. After a plan is selected you can change it's properties on the lower part of this screen.
The template are saved in separated files and can be used by many target list. When the exposure properties for the current sequence differ from the saved template this is indicated by a “*” at the end of the template name.

If you are imaging a fast moving asteroid or comet you can check the Update RA+Dec from planetarium column to ask the planetarium for the object coordinates just before the telescope is slewed to the target.
Be sure the planetarium is connected before to run the sequence.
Check the name of the object is compatible with the search function of the planetarium. No problem if you set the coordinate and name from the planetarium.
The planetarium must be set to follow the system time, otherwise the asteroid position is not updated.

Check Use astrometry to refine the position column to refine the telescope position with an astromery solved control exposure. This ensure the selected object is framed exactly as required.

You can check the Stay in place for autofocus column if you are sure the center of the image field contain suitable stars for auto-focus. It is recommended to use the Dynamic focus method in this case.
If unchecked, the telescope is first moved to a focus star of the magnitude defined in the auto-focus preference, and returned to the target after the operation.
The default value for this option is set in the auto-focus preference.

Type the desired value in the PA column to move the rotator at the specified angle.
You can also use the current image orientation after plate solving.
Be sure the rotator is calibrated before to start the sequence if you use celestial PA.


Set the begin and end time

You can set a time range for this target to be imaged, it will wait for Begin time to start. If End time is reach during the exposure plan it is stopped and the next target is selected.
The default is rise or set if the object coordinates are set. This automatically use the rise or set time of the object above the limits you define in the Observatory configuration, for the date of the observation. Similarly you can select a time from meridian crossing for the begin or end time. The default is no time constraint if the coordinates are not set.
To reset to the default values, click the Any time menu.

You can also select to not wait a target that not meet the begin/end condition. In this case it process the other targets instead of waiting. This can be useful if you have a list of target you repeat over the night using the option Repeat the whole sequence and take the object when they are visible, or at a given time from the meridian.

You can also select to skip a target if it is not fully dark night because of the twilight or because of the Moon. This way you can skip the faint target when the Moon is up and take them at the next repetition after the Moon is set.

You can also define when the whole sequence start and stop.
Check the box Start at“ or Stop at” and enter the time you want.
Check dusk or dawn to adjust the time for the astronomical twilight for the date of the observation.


Repeat a target

You can set this target to repeat it's whole plan for a number of time at a given interval between two consecutive start. Set the number of repetition in the target list.
To temporarily skip a target but keep it in the list you can set it's Repeat count to zero.

More option are available in the repeat panel that appear when the count is greater that one. The interval is measured between two consecutive start of the sequence, this is not the delay to wait. If the interval is smaller than the total plan duration the next repetition start immediately.
You can also start a preview loop while waiting for the next repetition, this is useful to keep the Sun or Moon centered if you do an eclipse sequence.


Add a script

To add a script you just have to select the one you want from the list, or create a new script here.


Add an automatic twilight flat

To add an automated flat click the Sky flat button.
Note: to take a dome/panel flat set a standard No move target and use a plan with an image type = Flat.

Set if you want the flat series to be taken at dusk or at dawn, this change the position on top or bottom in the list.
Select the number of flat to take for each filter, the binning, gain, offset, F-Stop and finally check the filters to use.
The automatic exposure time must be configured in the flat preferences.
To better manage the changing sky luminosity the filter are selected from the darker to the lighter at dusk, from the lighter to the darker at dawn. This require you configure the filter exposure factor.
When you add a sky flat to the plan this disable the “Start at dusk” and “Stop at dawn” global options. Do not re-enable them otherwise the sequence will not run during the twilight and the flat are bypassed.
For the same reason you must be careful the sky flat remain in first or last position in the list. The only acceptable steps before or after them are script to manage the equipment because they will run in full daylight. The flat and this scripts are run only one time if the Repeat the whole sequence option is set.


Repeat the whole sequence

You can also repeat the whole list a number of time by checking the box at the top of the list. The Infinity button set a value of 999999.
There is no option for the interval here, the repetition is immediate. But you can add scripts in the sequence to delay the execution in a more flexible way.


Restarting a sequence

When running a long sequence you may find it not finish totally and you need to restart it to complete the missing frames. There can be a number of reason for that, maybe you just put too many frames to be taken in a single night, or you need to stop the sequence to fix something with the equipment.

To allow a sequence to be restarted at the point it was interrupted you need to activate the Record restart information option. It is active by default for a new sequence but not for the one created by a previous version before this function exists to keep the compatibility.

Normally you want this option to be active. A typical case to disable it is if you run a survey, for example for asteroid or variable stars, and want to always restart the same full sequence every night.

The option Clear restart information on repeat define how Repeat the whole list manage the completion of individual targets.

  • If checked (default option), the targets already completed on the previous pass are re-done completely from the start. If the target plan define 5 images of M13 and the number of whole list repetition is 10 you end with 50 images of M13.
  • If unchecked, the target completion is not reset when the whole list is repeated. This meant that targets already completed are not done again. In the previous example you only get 5 images of M13. A typical use is a “Messier marathon”, you want 1 image of every Messier object taken when the elevation is high enough. For that you repeat the full Messier list of targets all the night and not redo the objects previously taken, only the new that are now high enough.

You can force a sequence to restart from the beginning by using the Reset button in the Sequence tool.


Start options

You can configure the action to take when the sequence actually start, after the start time is reach.

It is possible to start cooling the camera using the configured automatic cooling temperature. This way you can disable cooling at the camera connection so it is at ambient temperature when waiting for the start of the sequence.

You can also unpark the mount only at this point. When the dome park slaving is configured this allow to let the dome closed until the time the sequence start.


Termination options

You can configure the action to take after the sequence is finished normally.

Select the actions you want from the list, for more actions you can use a script.
In case of error an additional script can be configured for more actions. A selection box to select the script is show when the action is checked.

This actions are not taken when you voluntarily stop a sequence with the Stop button and the Unattended checkbox is not checked.

Beware that Do nothing let the mount tracking after the sequence is terminated.


Import a mosaic from the planetarium

You can import a mosaic definition from the HNSKY or Cartes du Ciel/Skychart planetarium. Be sure you connect to the planetarium before you start.

  • Take a preview image, plate solve and send the image frame to the planetarium. This ensure the planetarium know your exact CCD frame size and orientation.
  • Use the instruction from the planetarium software HNSKY or Skychart to create the mosaic.

  • Give a name to the mosaic frame, this will be the target name prefix in the sequence.
  • In the CCDciel sequence editor, click the “Insert rows” button, select the menu “From planetarium”.
  • For HNSKY select from the right click menu “Export via server / All frames”.
  • For Skychart click the button “Send via server”. You can also save the mosaic to a file, then use the menu “Import mosaic”.
  • Close the planetarium import tool and adjust any option you want to take the images.

You can also use this import tool to input as many object you want from the planetarium, as long this tool is open any click in the planetarium insert a new row in the sequence.

Import observing list from Skychart

You can import an observing list from Cartes du Ciel / Skychart or other software that produce file in the same format.

Click the Insert rows button and select the corresponding menu to open the observing list you have saved from Skychart. All the objects from the list are imported with their coordinates.
The other options like the plan to use, the astrometry or the autofocus options are copied from the current target. If you import to an empty sequence you can set the template globally afterward by a click in the ”+“ column header.


Manage the target list

You can add a new target, script, flat or delete one with the buttons at the top of the list.
A value can be change for a whole column by a click on the ”+“ in the column header.
The list can be sorted by name, RA or DEC by a click in the “v” column header.
You can also change the target order with a mouse drag/drop on the first column of the list.

The target list is saved when you click the Save or Save as.. button at the bottom right of the window.


Plan steps list

Use the plan list to specify the exposure steps to take of a target.

Add a step

Give a description of the step that can be used to make a subfolder.

Set the type of frame, exposure time, binning, filter, number of exposure, gain, F-Stop, autofocus and dither as in the Capture tool.

Check corresponding box if you want to run an auto-focus at the start of this step.
For long steps you can also repeat the auto-focus after a given number of images or when the temperature change, as configured in the focus options.

The Gain and Offset column are only visible if supported by the camera and the option to manage the gain from the program is checked.


Manage the steps

You can add a new step or remove one with the two button at the top of the list.

You can change the steps order with a mouse drag/drop on the first column of the list.

The template is saved when you click the Save template button and select an option from the menu.

Save and apply to targets save the template file and update all the targets using the same template with the new exposure parameters.

Save template save the template file, the other targets are not modified.

Save template as… save the template file with a new name.

If you no more need this template you can delete it with the Delete template button. This not modify the exposure parameters for the current target or any other targets.


en/documentation/sequence.txt · Last modified: 2021/03/14 15:59 by pch