Dawn Calibration Frames

Scheduler has an option to have ACP acquire dark and bias frames (cal frames) after observing completes and (optionally) after automatic flat frames have been acquired. To do this, Scheduler simply runs an ACP observing plan called SchedulerCalFrames.txt. If this plan exists in the ACP local-user's default plans folder (typically My Documents\ACP Astronomy\Plans), the specified dark and/or bias frames will be acquired. To activate dawn cal frames, enable the option on the scheduler's main window.

Can Be Done in Unsafe Weather

Dawn Cal Frames can be done in unsafe weather. The scheduler will close the dome or roof just prior to starting dawn cal frames (or before, if there is a weather unsafe event).

Closing the dome or roof is normally done by the scheduler itself (through ACP). For "special needs" buildings, like roll off roofs which hang low and can damage the telescope unless special operations are completed, Scheduler depends on a custom script that you need to supply, CloseSpecialRoof.js (or .vbs). We have included a sample SampleCloseSpecialRoof.js that will normally work with roll-offs. Copy it to CloseSpecialRoof.js then review and change it as needed for your specific needs. This script, like other Scheduler special config and script files, should be located in Public Documents\ACP Config\Scheduler (as of ACP Expert 8). This script will be similar to the ACP Weather Safety script. It definitely should not complete until the roof is closed.

Specifying the Calibration Frame Directory

The calibration frames are taken using the ACP image acquisition logic, not the logic normally used by ACP Scheduler. Cal frames are anonymous; they don't belong to any Scheduler Observer. Therefore, they will be saved into the ACP local-user's default images directory in a Calibration subfolder (typically My Documents\ACP Astronomy\Images\yyyymmdd\Calibration). ACP has a feature where calibration image names and folder paths can be customized for the local-user. See ACP Help, Customizing ACP, Customizing File and Folder Names for details.

Note that if you use this facility to customize cal frame naming and location, it will apply to ACP operations on behalf of the local user as well.

Another way to change the directory into which the Scheduler's dawn cal frames are placed is to include a #directory directive in the calibration frame plan. This has the disadvantage that cal frames taken on any night go into the same folder, and will result in name clashes.

Example Calibration Frame Plan

Here is a typical calibration frame plan for ACP. Note that it is a requirement for filters to be listed even though they are not used for cal frames. This is a quirk of ACP's plan language. For more information see ACP Help!

;
; Sample Calibration Frame Plan
;
#chill -25                  ; Take these at -25 temperature

#count 10,10
#binning 1,2
#filter R,R                 ; Unused but required :-(
#interval 600,600
#dark


#interval 0, 0
#bias

This plan will take 10 each 600 second dark frames at -25 and binning 1 then 2, then take 10 each bias frames at binning 1 then 2.

Testing Dawn Cal Frames

Once you have your SchedulerCalFrames.txt plan in place, you can run it via the Scheduler's Utility menu, Test Dawn Cal Frames item. The latter is better as it will test the entire process end-to-end.