User Tools

Site Tools


CCDciel is free software released under the terms of the
GNU banner GNU General Public License


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, a more sophisticated scheduler is planned for version 2.0,

The top grid show the current list of targets.

You can Load an existing file with a list of target, create a New one, Edit the current list, Copy to a new list or Delete a list.

Use the Start and Stop button to start or interrupt a sequence.

When the sequence start it first check if the autoguider and camera cooling are available and try to start them if not. If the telescope is parked it will be unparked.

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

  • If is not checked a message prompt you on the screen what you want to do.
  • 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.
When the sequence is running the current target and step is highlighted.

Sequence editor

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

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 corresponding button to add the target you want.

You can edit a value directly in the table or change the values for a whole column by a click in the column title.

Image an object

You can type the object name and coordinates in the corresponding box or click the Planetarium button 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 button to not change the telescope position.

Note that the target coordinates are apparent and could differ from the planetarium if the planetarium displays the position in equinox J2000 coordinates.

Select the exposure plan to apply to this target using the dropdown box, or type a new plan name to create a new empty plan. After a plan is selected you can change it's properties on the lower part of this screen. Use the Plan Save as.. button to make a copy of an existing plan.

The plan are saved in separated files and can be shared by many target list. This way you not have to edit the detail of the plan every time, so be sure to save the plan with a new name if the change you do is only for this target.

If you are imaging a fast moving asteroid or comet you can check Update RA+Dec 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… box to refine the telescope position with an astromery solved control exposure. In this case you are ensured the selected object is framed exactly as required.

You can check Stay in place for autofocusif you are sure that 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 also 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.
Select rise or set in the dropdown to 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.
To not use this function click the Any time button.

You can also select to skip a target that not meet the begin/end condition 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.

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.

More option are in the right pane. 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 in the list.
Select the number of flat to take for each filter, the binning 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.
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.

Termination options

You can configure the action to take after the sequence is finished. The color dot are a reminder of what options are currently active, click the button to open the setting screen.
This actions are not taken when you voluntarily stop a sequence with the Stop button and the Unattended checkbox is not checked.

Select the actions you want from the list, for more action you can use a script.
In case of error an additional script can be configured for more actions.

Import observing list from Skychart

You can import an observing list from Cartes du Ciel / Skychart.

Click the corresponding button to select the observing list you have saved from Skychart. All the objects from the list are imported with their coordinates.
The other option like the plan to use, the astrometry or the autofocus options are copied from the current target. If you import to an empty sequence, be sure to configure the default target so this is copied to the data you import, then remove this target after the import is completed.

Manage the target list

You can add a new target, script, flat or delete one with the four buttons at the bottom of the list.
You can 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.

Restarting a sequence

When running a long sequence you may find it not finish during the night and you need to restart it a next night 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, maybe the clouds invited themselves in the middle of the night or some cable decided to unplug itself.

For this version CCDciel do not include an automatic restart capability to continue the sequence where it was stopped. This must be added for a future version.

For now the recommended way to handle such case is the following:

  • Copy the sequence with a temporary name such as “M13-restart”
  • Open this copy for editing
  • Delete any target that where completed successfully
  • Eventually modify the number of repetition
  • If a target was partially done :
    • Edit the plan to remove any step that are completed
    • Change the number of exposure for a step partially done
    • Eventually modify the number of repetition
    • Use “Save plan as” to copy the plan with a temporary name such “LRGB-4H-restart”
  • Save and run this modified sequence

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 and number of exposure, as in the Capture tool.

The Gain, Autofocus and Dither option are set in the right pane.
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.

Manage the steps

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

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

The plan is saved when you click the Save or Save as.. button.

If you no more need this plan you can delete it with the Delete plan button

en/documentation/sequence.txt · Last modified: 2018/11/22 10:22 by pch