User manual SBIG AO-7

[. . . ] AO-7 Adaptive Optics Accessory Operating Manual Revised November 2003 Santa Barbara Instrument Group 147A Castilian Drive Santa Barbara, California 93117 Phone: (805) 571-7244 Fax: (805) 571-1147 E-Mail: sbig@sbig. com Home Page: www. sbig. com Introduction SBIG's adaptive optics package is designed to enable users of SBIG Dual CCD cameras1 (like the ST-7) to achieve the ultimate in resolution when imaging deep sky objects. The package consists of two components: a high speed tip-tilt mirror capable of correcting the telescope pointing at rates up to 50 times a second, and a software package that implements the LucyRichardson deconvolution technique for image sharpening. Both items were developed by SBIG in concert with Benoit Schillings and Brad Wallis, two advanced amateurs well known in the film and CCD imaging field. This package can produce a 2X improvement in resolution over normal self guided images, where corrections are applied only to the telescope drive. [. . . ] The X axis is the same as the long direction of the CCD. The CCDOPS software includes an Exercise command under the AO menu. This option allows one to drive the mirror to its limits in a rectangular pattern, or each axis individually. You can select the axis or combination, and the update rate between moves. This option is excellent for checking out the AO device after unpacking. Make sure it is connected to the camera, and the combination powered up. (only connect and disconnect the AO module to camera when both are unpowered!). Try an update time of 100 milliseconds initially, and look at a distant light reflected in the AO module mirror. Next increase the update rate to 20 milliseconds. The light should blur into a rectangular pattern of light, with no more than 20% overshoot at each corner. It will probably not be square, and may be slightly parallelogram shaped, with the axes not at exactly 90 degrees. This is satisfactory, since the resultant error of the move is small. Connecting the module to the Camera There are three ways to attach the AO module to the camera, depending on your configuration. In all three you start by removing the T-Thread D-Block adapter from the front of the camera using a Philips head screwdriver as shown in Figure 1A below: · · Method 1: Without a CFW-8, directly connecting the AO-7 to the Camera. Method 2: With a CFW-8, directly connecting the CFW-8 to the Camera and then using the Male-to-Male T-Thread coupler to connect the AO-7 to the CFW-8. · Method 3: With a CFW-8 and SBIG's new CFW/AO Adapter Plate, direct connecting the CFW-8 to the Camera then using the Adapter Plate to connect the AO-7 to the CFW-8. Method 1 ­ Direct Connect AO-7 to Camera without a CFW-8 Using the supplied four 4-40 x 3/8 Pan-Head Cap-Screws attach the AO-7's Diagonal Piece to the camera as shown in Figure 1B below: A Removing the T-Thread D-Block from the Camera Attaching the AO-7 Diagonal Piece to the Camera AO-7 Diagonal Piece B T-Thread D-Block Adapter 4-40 x 3/8 Camera Camera Figure 1 Method 2 ­ Direct Connect CFW-8 to Camera, T-Thread AO-7 to CFW-8 After unscrewing the CFW-8 front cover and removing the Filter Carousel, attach the CFW-8 body to the camera using four 4-40 x 3/16 Socket-Head Cap Screws as shown in Figure 2A below. Reassemble the CFW-8, making sure you install the Filter Carousel with the index pins pointing up (away from the camera). Then attach the T-Thread D-Block from the camera to the AO-7 Diagonal Piece with four 4-40 x 5/8 Flat Head Screws and four 4-40 Nut. Make sure when attaching the assembly to the telescope that the threads are properly aligned. A good way to ensure this alignment is to rotate the attachment backwards until the threads fall into place, which can be easily felt. The adapter sold with the AO-7 will attach to most commercial Schmidt-Cassegrain telescopes. If can be removed by loosening the set screw that bears against the threads and unscrewing the adapter. The exposed threads in the AO-7 unit are M42 x 0. 75 mm pitch and will mate with commercial T-Thread adapters. [. . . ] If no box is marked the software will process the whole image. When both isolated stars and the selected region have been chosen, click the GO icon button in the toolbar. Select the number of iterations from the dialog box that pops up, and the deconvolution process will begin. The number of iterations that is optimal can best be determined by processing a small portion of the image initially before doing the whole image. [. . . ]