Handbook for the SXVR-H674C Issue 1 March 2012 The SXVR-H674C colour CCD camera Thank you for purchasing a Starlight Xpress CCD camera. We hope that you will be very satisfied with the results. The SXVR-H674C is an advanced, high-resolution one-shot colour, cooled CCD camera, especially designed for astronomical imaging. It uses a third generation version of the very popular Sony ‘EXview’ CCDs that offer very high QE and extremely low thermal noise.
Handbook for the SXVR-H674C Issue 1 March 2012 optional integrated dual serial ports for filter wheel and telescope control. It also includes a CCD temperature monitoring circuit that provides regulated set-point cooling of the chip, adjustable chip alignment and a very compact overall size. The SXVR-H674C uses a Sony ICX674ALG ‘EXview’ progressive scan CCD, with 1940 x 1460 x 4.54uM pixels in a 8.8 x 6.63mm active area.
Handbook for the SXVR-H674C Issue 1 March 2012 normally possible without boosters or extra powered hubs, although you can sometimes get good results at longer distances with very high quality cables. Installing the USB system: First, find a free USB socket on your PC and plug in the USB cable (do not connect the camera at this time). If you do not have a USB2 capable computer, it is normally possible to install a USB 2 card into an expansion slot.
Handbook for the SXVR-H674C Issue 1 March 2012 At the end of this process, the USB interface will be installed as a ‘BlockIOClass device’ and the camera software will be able to access it. You can confirm that the installation is complete by checking the status of the USB devices in the Windows ‘Device Manager’ (see above). Start up the Windows ‘Control Panel’ and select ‘System’.
Handbook for the SXVR-H674C Issue 1 March 2012 Now click on the camera icon at the top of the screen. If the USB connection is OK, a message box will inform you of the ‘Handle’ number for the SXVIO interface and various other version details etc. Click ‘OK’ and the main camera control panel will now be seen.
Handbook for the SXVR-H674C Issue 1 March 2012 As can be seen above, there is a CCD temperature monitoring window at the right hand side of the panel. At switch-on, this will default to full power cooling with an end point of -40C and, needless to say, this is rather extreme. I recommend changing the set point to about -10C for normal use, but you can go much colder if you are imaging during the winter months.
Handbook for the SXVR-H674C Issue 1 March 2012 Or 2) Create a ‘Pin hole’ lens by sticking a sheet of aluminium baking foil over the end of the adaptor and pricking its centre with a small pin. If you use a normal lens, then stop it down to the smallest aperture number possible, (usually F22), as this will minimise focus problems and keep the light level reasonable for daytime testing.
Handbook for the SXVR-H674C Issue 1 March 2012 Point the camera + lens or pinhole towards a well-lit and clearly defined object some distance away. Now enter the ‘File’ menu in the H674C software and click on ‘SX camera interface’. Select an exposure time of 0.1 seconds and press ‘Take Photo’. After the exposure and download have completed (about 4 seconds) an image of some kind will appear on the computer monitor.
Handbook for the SXVR-H674C Issue 1 March 2012 Converting your images to colour: The images from your camera are monochrome at the moment and they need to be converted into true colour before enhancing them. Any processing of the image, other than calibration with dark frames etc., will distort the colour rendering of the result and so the conversion needs to be done before proceeding.
Handbook for the SXVR-H674C Issue 1 March 2012 The synthesis control panel contains several options for correcting colour bias and noise. 1) Daylight Image? – If an unfiltered lens is used, the infra-red content of the light will tend to produce a Green – Blue shift in the balance. A partial correction of this bias is provided by selecting this option, but the best option is to use an infra-red blocking filter when taking daylight shots (see 5 below).
Handbook for the SXVR-H674C Issue 1 March 2012 If the colour is roughly correct, then all is well. However, the colour decoding is reliant on the filter pattern being properly registered with the processing software and this can vary. Colour conversion involves running a software routine which uses the brightness data from each pixel to generate colour values.
Handbook for the SXVR-H674C Issue 1 March 2012 colours until they are equally distant from the beginning of the colour data, but quite close to it. This will both correct the colour balance (apart from any fine tweaks) and increase the colour saturation. In some images, the colour data may be balanced differently in the highlights and shadows. For example, the dark areas may be quite neutral in colour, but the highlights may be bluish in tint.
Handbook for the SXVR-H674C Issue 1 March 2012 ********************************************************************* Astronomical Imaging with the SXVR-H674C 1) Getting the image onto the CCD: It is fairly easy to find the correct focus setting for the camera when using a standard SLR lens, but quite a different matter when the SXVR-H674C is attached to a telescope! The problem is that most telescopes have a large range of focus adjustment and the CCD needs to be quite close to the correct position befor
Handbook for the SXVR-H674C Issue 1 March 2012 it from personal experience. It does not require a yellow filter for aberration correction, unlike some other designs, so it can also be used for tri-colour imaging. If you use a focal reducer, using it at maximum reduction may cause the relatively large chip of the SXVR-H674C to suffer from considerable ‘vignetting’ (dimming towards the corners) and this will be difficult to remove from your images.
Handbook for the SXVR-H674C Issue 1 March 2012 adjustable degree of automatic contrast stretching (for focusing on faint stars). To use this mode, start up the software and select the SXV camera interface (File menu). Set the camera mode to Binned 1x1 and select an exposure time of 1 second. Press ‘Take Picture’ and wait for the image to download. There is a good chance that your selected star will appear somewhere within the image frame and it should be close to a sharp focus.
Handbook for the SXVR-H674C Issue 1 March 2012 view. You can get to see a lot of this, without affecting the image data, if you go to the ‘View’ menu and select ‘Auto Contrast Stretch Image’. The faint image data will then appear in considerable detail and I think that you will be impressed by the result! If you are happy with the image, go to the ‘File’ menu and save it in a convenient directory.
Handbook for the SXVR-H674C Issue 1 March 2012 In the unlikely event that you feel that dark frame really is necessary, please proceed as follows: To take a dark frame, just cover the telescope objective with the lens cap and take another exposure with the same length as that of the light frame. This image will be a picture of the dark signal generated during your exposure and it should be saved with your image for use in processing the picture.
Handbook for the SXVR-H674C Issue 1 March 2012 M42 – 30 seconds exposure at F2 with a C8 Hyperstar 2) Once you have subtracted any dark frame, you can convert the raw image to colour. 3) The resulting image will probably look faint and dull, possibly with a pale yellowish background, due to light pollution so it is now time to process the ‘luminance’ (brightness and contrast) of the image to get the best visual appearance.
Handbook for the SXVR-H674C Issue 1 March 2012 another ‘Normal’ stretch, in which you bring down the ‘White’ slider to just above the main image peak. The best setting for this is rather more difficult to guess and you may need several attempts before the result is ideal. Just use the ‘Undo last filter’ function, if necessary, to correct a mistake. Normal (linear) stretches can give a nice result on many objects, but you may find that bright areas ‘burn-out’ badly with this function.
Handbook for the SXVR-H674C Issue 1 March 2012 directly, or average the images together. Averaging is generally better, as you are less likely to saturate the highlights of the picture. The signal-to-noise ratio will improve at a rate proportional to the square root of the number of summations (summing 4 images will double the signal-to-noise), but different exposures must be used. Summing an image with itself will not improve the S/N ratio.
Handbook for the SXVR-H674C Issue 1 March 2012 The exposure time needed for good planetary images is such that the image histogram has a peak value at around 200 and does not extend much above 220 (Ignore the major peak near zero, due to the dark background). If you use too short an exposure time, the image noise level will be increased, and if too long a time is used you will saturate the highlights and cause white patches on the image.
Handbook for the SXVR-H674C Issue 1 March 2012 In general terms, the larger the image and the worse the seeing, then the wider the radius for best results. My Jupiter shots are usually about one third the height of the CCD frame and I find that the ‘radius 5, power 5’ values are good for most average seeing conditions.
Handbook for the SXVR-H674C Issue 1 March 2012 ‘relay box’ between the guider output and the input to the mount. Please contact your local distributor if a relay box is required. Some mounts (Vixen, for example) use a similar guider input socket, but have re-arranged connections. The autoguider installed on a 70mm refractor guide ‘scope in the author’s garden (the camera shown is the older SXVF version, but the connections are the same).
Handbook for the SXVR-H674C Issue 1 March 2012 The autoguider control panel with a guide star selected 2) Press the ‘Start’ button and a series of 1 second exposure guider images will begin to appear in the picture frame. If the images look too dim, use the ‘Stretch Image’ slider to increase its contrast and brightness until the noise begins to be visible.
Handbook for the SXVR-H674C Issue 1 March 2012 train the system at this time, the default values of 6 pixels per second will serve as a starting point. 9) Now press ‘Go to main camera’ and the guider control panel will be replaced by the camera control panel. Set the required exposure time for the image (say 5 minutes) and press the ‘Autoguide next image’ button. The autoguider window will reappear and, after a few seconds, you should see error values appearing in the text windows at the top.
Handbook for the SXVR-H674C Issue 1 March 2012 The two serial connections are in the form of standard RS232 PC style plugs and provide TX, RX and Ground connections at RS232 levels. Access is via commands sent through the USB connection and, at the time of writing, is limited to any serial controls that are provided by the SXV software. It is expected that many more functions will be added as the software is upgraded.
Handbook for the SXVR-H674C Issue 1 March 2012 will further increase the image brightness and reduce its resolution. However, generally, these are more useful for finding faint objects, than for imaging. Taking and using a flat field: Flat fields are images, which display only the variations of illumination and sensitivity of the CCD and are used to mathematically modify a wanted image in such a way that the errors are removed.
Handbook for the SXVR-H674C Issue 1 March 2012 correction. As we are mainly interested in the bias, any very short exposure dark frame will give a good result. The dark subtracted images should then be averaged together before use. After the above procedures have been executed, the flat field will be ready for use. Load up your image for processing, subtract the dark frame and then select ‘Apply flat field’ in the ‘Merge’ menu.
Handbook for the SXVR-H674C Issue 1 March 2012 The high density parallel port socket provides both control and power for the add-on autoguider, but also includes a pair of serial ports for use with other devices. ********************************************************************* Camera maintenance: Very little maintenance is needed to keep the SXVR-H674C in excellent operating order, however two problems, which are common to all CCD equipment, might show up on occasion. These are dust and condensation.
Handbook for the SXVR-H674C Issue 1 March 2012 OF THE BOARD for correct replacement later. Now remove the lower two spacers from the heat sink plate assembly. 4) The camera heat sink assembly can now be lifted away from the camera front barrel and the CCD will be exposed. Note that a layer of white heat-sink compound is applied to the periphery of the heat sink disc and this should be left undisturbed by subsequent operations.
Handbook for the SXVR-H674C Issue 1 March 2012 ‘Maxim DL’ is another popular choice and you can find out more by visiting http://www.cyanogen.com ‘Nebulosity 3’ also works very well with the H674C. http://www.stark-labs.com/nebulosity.html ********************************************************************* Some details of the camera and CCD characteristics The SXVR-H674C uses a Sony ICX674ALG ‘EXview’ progressive scan CCD, with 1940 x 1460 x 4.54uM pixels in a 8.8 x 6.63mm active area.
Handbook for the SXVR-H674C Issue 1 March 2012 Dear Observer, Thank you for purchasing a Starlight Xpress CCD Imaging System. We are confident that you will gain much satisfaction from this equipment, but please read carefully the accompanying instruction manual to ensure that you achieve the best performance that is capable of providing. As with most sophisticated equipment a certain amount of routine maintenance is necessary to keep the equipment operating at its optimum performance.
