General If your computer processor were completely devoted to camera-control, image download would be uninterrupted. But in many cases, the computer running the camera is also running other programs and equipment, such as image-processing, telescope-control, etc. When other processes are running in the background during the download of an AP7 or AP8 image, bright lines may appear in the images, such as the bias frame shown at right. The end result of the interruptions may be bright or dark lines in the image, depending on the software settings. For instance, if you are automatically subtracting dark frames from the images, the dark frame may contain bright lines, whereas the image frame did not. Thus, the result would be dark lines in the final image. When both the dark and the image frame contain the bright lines, the subtraction will produce a combination of both bright and dark lines. Because the bright lines in each image are not repeatable and therefore will not subtract out, the only real solution is to lockout interruptions during download.

To prevent interruption of the processor during image download, MaxIm DL CCD and CCDSoft have a "priority" setting, otherwise known as a "download lock." Follow the instructions below to set the download lock.

MaxIm DL CCD

MaxIm has a priority setting located in the "Setup" tab of the CCD control window. Click on the "CCD" button beside the "Apogee" camera type box.

Next, click the scroll arrow by the "Priority Level" setting and choose "High." Click "OK."

Click the "Restart" button under the "Setup" tab of the CCD control window to make the priority change take effect.

CCDSoft

In CCDSoft, the download lock is set in the Windows registry. Click the "Start" menu on your taskbar, then choose "Run..." Type the word "regedit" into the "Open:" text box and click "OK."

As in Windows Explorer, click the "+" signs next to the folders to navigate down to the HKEY_CURRENT_USER\Software\Software Bisque\CCDSoft\APOGEE section of the registry.

Next, right-click (right mouse button) on the white space (background) of the right pane to add a new "DWORD Value."

Replace the default "New Value #1" by typing "DownloadLock" into the text box. Press "Enter" to accept this value

Press "Enter" again and change its "Value data" to "1" (download lock on) rather than "0" (you can also right-click on the "DownloadLock" dword and choose "Modify").

Set the "Value data" back to zero if you do not want to lock out other processes during download. Close the registry editor by clicking the "Registry" menu and selecting "Exit."

No rebooting is needed. Close out of CCDSoft before editing the registry. Launch CCDSoft afterward and the change will take effect.