Handbook for the SXV-M8C Issue 1 Jan 2005 Starlight Xpress Ltd SXV-M8C 4 Megapixel USB2 One-Shot Colour CCD camera User manual Thank you for purchasing a Starlight Xpress CCD camera. We hope that you will be very satisfied with the results. The SXV-M8C is an advanced, very high-resolution cooled CCD camera, especially designed for ‘One-Shot’ colour astronomical imaging. Its special features include a built-in, fully programmable, USB 2 super-fast computer interface (USB 1.
Handbook for the SXV-M8C Issue 1 Jan 2005 dark current, well below that of any comparable CCD currently available. The ICX406AQ incorporates a ‘Bayer Matrix’ of Red, Green and Blue filters, deposited directly onto the CCD pixels and a downloaded image may be quickly converted into a full-colour picture by application of the software provided. The full-frame download time is approximately 14 seconds and binned 4x4 downloads take only 3 seconds, so finding and centring are very quick and easy in this mode.
Handbook for the SXV-M8C Issue 1 Jan 2005 expansion slot. Almost all machines manufactured after 1996 provide a pair of USB 1.1 sockets on the rear panel and either of these may be used if USB 1.1 is satisfactory. Please note that it may be necessary to enable your USB system in the computer BIOS (the SETUP menu which can usually be accessed at start-up). Many BIOS systems have the ability to disable ‘Plug and Play’ devices, such as the USB ports, so please make sure that these are enabled.
Handbook for the SXV-M8C Issue 1 Jan 2005 At the end of this process, the USB interface will be installed as an ‘SXVIOClass 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’. Now click on the tab labelled ‘Device Manager’ and all of the system devices will be displayed in a list (see above).
Handbook for the SXV-M8C Issue 1 Jan 2005 Connect up the power supply and switch it on. You can start the ‘SXV_M8C’ software by double clicking on the icon and you should see the main menu and image panel appear. 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. The main program window will now be seen.
Handbook for the SXV-M8C Issue 1 Jan 2005 Or 2) Create a ‘Pin hole’ lens by sticking a sheet of aluminium baking foil over the end of the 1.25” 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. The pin hole needs no such adjustments and will work immediately, although somewhat fuzzily.
Handbook for the SXV-M8C Issue 1 Jan 2005 After the exposure and download have completed (about 14 seconds) an image of some kind will appear on the computer monitor. It will probably be poorly focused and incorrectly exposed, but any sort of image is better than none! In the case of the pinhole, all that you can experiment with is the exposure time, but a camera lens can be adjusted for good focus and so you might want to try this to judge the high image quality that it is possible to achieve.
Handbook for the SXV-M8C Issue 1 Jan 2005 1) Ensure that the power indicator lamp is on and that the cables are properly home in their sockets. 2) If the screen is completely white, the camera may be greatly overexposed. Try a shorter exposure time, or stop down your lens. See if covering the lens causes the image to darken. 3) If the USB did not initialise properly, the camera start-up screen will tell you that the connection is defective. Try switching off the power supply and unplugging the USB cable.
Handbook for the SXV-M8C Issue 1 Jan 2005 This includes various options for correcting the colour synthesis for variations in the lighting conditions, filters etc. Briefly, these items perform the following functions: 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.
Handbook for the SXV-M8C Issue 1 Jan 2005 8) High Pass filters: - Automatically sharpen the luminance data to emphasise fine details. Most useful for sharpening planetary images but will also increase the noise content. For your first test images, I suggest that you turn on the Anti-Alias option and possibly the ‘Daylight Image’ option. Now press the ‘Create Image’ button. After a couple of seconds, your raw mono image will be replaced by a full colour version.
Handbook for the SXV-M8C Issue 1 Jan 2005 The colour balance controls seem complex, but are really quite easy to use. The most useful controls are the ‘Start’ and ‘Saturation Factor’ settings. Saturation factor will simply vary the colour intensity, without any alteration of the colour balance, but the ‘Start’ settings for each colour will alter the colour rendering of the dimmer parts of the image.
Handbook for the SXV-M8C Issue 1 Jan 2005 software. However, there will come a point when you say, “That’s the best that I can get” and you will want to experiment with the effects of image processing. In the case of daylight images, the processing options are many, but there are few that will improve the picture in a useful way. The most useful of these are the ‘Normal Contrast Stretch’ and the ‘High Pass Low Power’ filter.
Handbook for the SXV-M8C Issue 1 Jan 2005 When the par-focal eyepiece is fitted into the telescope drawtube, you can adjust the focus until the view is sharply defined and the object of interest is close to the field centre. On removing the eyepiece and fitting the CCD camera, the CCD will be very close to the focal plane of the telescope and should record the stars etc.
Handbook for the SXV-M8C Issue 1 Jan 2005 In this case, the camera and eyepiece are made par-focal with each other by locking up the mirror, focusing the camera on an easy object, such as a moderately bright star and then flipping the mirror down to view the same star with the eyepiece. Once the eyepiece has been locked into the correct position, you can use it to focus on the image by lowering the flip mirror and operating the telescope focus wheel until the image is sharp.
Handbook for the SXV-M8C Issue 1 Jan 2005 imaging. If you use a focal reducer, do not try to use it at maximum reduction, as the large chip of the SXV-M8C will suffer from considerable ‘vignetting’ (dimming towards the corners) and this will be difficult to remove from your images. To achieve this, use only a short extension tube between the focal reducer lens and the camera. The longer the extension tube used, the greater the focal reduction will be.
Handbook for the SXV-M8C Issue 1 Jan 2005 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 SXV-M8C Issue 1 Jan 2005 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 as a FIT file in a convenient directory. Most competitive brands of CCD camera require a ‘dark frame’ to be subtracted from your images to achieve the best results.
Handbook for the SXV-M8C Issue 1 Jan 2005 1) Make sure the ‘Auto Contrast Stretch’ is switched off and load your image into the SXV_M8C program. Select ‘Merge’ and then ‘Subtract Dark Frame’. Pick the appropriate dark frame and the software will then remove the dark signal from your image, leaving it somewhat darker and slightly smoother than before.
Handbook for the SXV-M8C Issue 1 Jan 2005 imagers will use a combination of ‘Normal’ and ‘Non-linear’ contrast stretches. The best settings are different for different objects, but performing a non-linear or power law stretch, followed by normalising the background to black with a normal stretch, is the usual procedure.
Handbook for the SXV-M8C Issue 1 Jan 2005 (summing 4 images will double the signal-to-noise), but different exposures must be used. Summing an image with itself will not change the S/N ratio! Although I have concentrated on the use of a telescope for deep-sky imaging, do not forget that you have the option of using an ordinary camera lens for impressive widefield shots! A good quality 135 or 200mm F3.
Handbook for the SXV-M8C Issue 1 Jan 2005 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 SXV-M8C Issue 1 Jan 2005 there are rarely any stars to use when imaging the planets, but Jupiter’s satellites can be useful reference points. Otherwise, you will have to find a well-defined feature on the planet, or estimate where the centre of the disk is located. Some more sophisticated software can automatically align planetary images and you may find these programs to be very useful.
Handbook for the SXV-M8C Issue 1 Jan 2005 The autoguider installed on a 70mm refractor guide ‘scope in the author’s garden 23
Handbook for the SXV-M8C Issue 1 Jan 2005 To use the autoguider, please proceed as follows: 1) Having started the SXV-M8C software, open the autoguider control panel by clicking on the autoguider menu button. 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.
Handbook for the SXV-M8C Issue 1 Jan 2005 calculations. The training will also determine the angle at which the guide camera is oriented with respect to the RA and Dec axes. If you do not wish to 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.
Handbook for the SXV-M8C Issue 1 Jan 2005 box and cables are available as an accessory and may be chained in series with the autoguider cable, when the guider is in use, or may be used on its own. 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.
Handbook for the SXV-M8C Issue 1 Jan 2005 its resolution. However, generally, these are more useful for finding faint objects, than for imaging, as the colour information is lost in all these modes. 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 SXV-M8C Issue 1 Jan 2005 ‘bias offset’ of the camera in each image and this can produce an error in the final 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.
Handbook for the SXV-M8C Issue 1 Jan 2005 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 SXV-M8C 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 SXV-M8C Issue 1 Jan 2005 4) The entire camera electronic assembly can now be lifted away from the camera front barrel and the CCD will be readily accessible. Note that a layer of white heatsink compound is applied to the periphery of the heat sink disc and this should be left undisturbed by subsequent operations. 5) You can now closely examine the CCD faceplate under the spotlight using the watchmaker's glass when any dust motes will show clearly.
Handbook for the SXV-M8C Issue 1 Jan 2005 Some details of the camera and CCD characteristics CCD type: Sony ICX406AQ SuperHAD interline imager with RGBG Bayer colour filter matrix. CCD size: Active area 7.225 x 5.375mm CCD pixels: 2312 x 1720 pixel array. Each pixel is 3.125 x 3.125uM Well depth: Full res. mode approx.10,000e. Mean visual QE: Approx. 25% effective, 60% for pixels at peak response Useful spectral response: 360nM – 1100nM Readout noise: Approx. 5e RMS typical, 10e max.
Handbook for the SXV-M8C For further info. or advice, please call: Mr Michael Hattey, Starlight Xpress Ltd., Briar House, Foxley Green Farm, Ascot Road, Holyport, Berkshire, England. SL6 3LA Tel: 01628 777126 Fax: 01628 580411 e-mail: Michael.hattey@starlight-xpress.co.uk Web site: http://www.starlight-xpress.co.
