Using Auto-Calibration

MaxIm DL's automatic calibration feature allows scripted systems such as ACP to use its capabilities. MaxIm DL has a sophisticated calibration group facility that allows building a library of calibration images for varying binning, exposure intervals, and temperatures. ACP depends on your having set up MaxIm's cal-group facility. It simply calls MaxIm at the appropriate point in the acquisition process, and expects MaxIm to do the actual calibration.

ACP saves all auto-calibrated images as 32-bit floating point to preserve the dynamic range of the data. This doubles the size of the (nominally) 16-bit raw/uncalibrated image files.

Setting Up the System for Auto-Calibration

Since MaxIm DL's calibration system is used to perform the auto-calibration, you must set up its library of calibration frames ahead of time. You must include calibration frames for all of the image sizes, including binning levels that your astronomers might use, and preferably for several temperatures even though you include bias frames for scaling. In other words, take the time to create a complete calibration frame library in MaxIm. Place the source cal frames (darks, biases, flats) into a separate folder just for this purpose and point MaxIm there. It is suggested that you generate master calibration frames for efficiency. For details see the documentation for MaxIm DL.

How to Access Auto-Calibration

There are several ways you can have ACP perform auto-calibration on your images:

• By enabling the ACP option Auto calibrate final/data images in ACP Preferences, Imaging tab. This causes all images acquired by ACP to be auto-calibrated, whether they are acquired in the observatory via ACP's console or via the web by a remote user. Everyone will get auto-calibration.
• By enabling the Auto-calibrate option in the web request submission form. This will cause all images in that run only to be auto-calibrated.
• By including a #CALIBRATE directive in an observing plan. This affects only the next/upcoming target.
• By specifying the Full Calibrate option in an ACP Expert Scheduler ImageSet.

Preserving Your Original Data

Prior to doing auto-calibration, ACP saves a copy of the original image with "-RAW" appended to the image's file name, and also in a subfolder under the final image's location named RAW. Thus you can access the original uncalibrated image if, for some reason, calibration had undesired effects. Note that this increases your disk space requirements.

If you want to disable this saving of the raw uncalibrated images, you can uncheck (turn off) the option Save original uncalibrated final/data images in ACP Preferences, Imaging tab.