Table of Contents Quick-Start and Tutorial Imaging Basics Registax User's Guide Troubleshooting Quick Start Make sure your NexImage comes with all of the following: 1.25" Barrel USB Cable Installation CD Rom 1. Plug camera into the USB port of your computer. 2. Double click the Amcap icon to start the program. on your computer's desktop 3. Make sure "Preview" is selected from the Options menu. If "Preview" is not already selected (checked), click on it once. 4. Select an easy target like the moon to begin with. Center and focus your telescope on the specific feature you wish to image. 5. Remove the barrel cap from the 1.25" barrel of the imager. Remove the eyepiece from the telescope and slide the barrel of the imager into the eyepiece barrel of your telescope. You should see bright light displayed in the imaging window of Amcap. 6. Use your telescopes focuser to focus down the image until the moon is visible and sharp. 1 7. From the Options menu select the Video Capture Filter. Adjust the Brightness and Gain settings to make sure the image is not over or under exposed. In order to control the gain setting, deselect (uncheck) the Auto box under the Exposure group of controls. Once the desired image is focused and centered in the imaging window you are ready to capture a video image. Before taking the image you must first set the frame rate, time limit and resolution for the video. 8. From the Options menu select the Video Capture Pin. · Set the output size to 640x480 resolution. · Set the compression to I420 9. From the Capture menu, choose Set Frame Rate. · Check the Use Frame Rate box · Set the frame rate to the desired frames per second. For example 30 f/sec. 2 10. From the Capture menu, choose Set Time Limit. This determines how long of a video image will be recorded. · Check the Use Time Limit box · Set the time limit to the desired amount of time. For example 20 seconds. Now you are ready to capture the image. 11. From the Capture menu select Start Capture · Select OK to begin image capture. The bottom of the imaging window will display the amount time of video recorded and the number of frames captured. 12. Once recording stops select Set Capture File from the File menu. Select a location on your hard drive and name the file that you have taken including the .avi extension at the end, for example, moon.avi. Now that your video stream has been captured the individual frames can be inspected, aligned and stacked using the included RegiStax software. Before you begin processing your image, take a moment to read and use the tutorial provided in the next section. 3 RegiStax Tutorial Your NexImage CD ROM comes with a sample .AVI file which you can use to learn and experiment with the features of the included RegiStax software. This tutorial will guide you through the steps you need to align, stack and process video frames into a single high quality image. 1. Start RegiStax by clicking the icon on your desktop. Press the Select Input button to select the directory where the NexImage CD is located. 2. Select the file called Lunar Tutorial.avi from the Celestron folder and press Open. 2 3 3. Next, indicate what type of image is being processed. Is it a color image of a planet or a black and white image. Since the image being processed is of the moon, color is not important. Uncheck the color checkbox otherwise leave this checkbox checked. 4 4. Now its time to choose which frame from the video file we want to use as a reference. All the other images will be compared and aligned using the reference-image. To find a good candidate use the slider on the lower part of the screen. Just select the slider and step through the images to find an image that looks high in contrast and sharpness. Alternatively, you can check the Show frame list box in the lower left corner and scroll through each frame individually. 4 5 5. Once the alignment frame has been selected, you need to set the size of the alignment box. Ideally this box will contain either the whole object you have imaged or a bright, high contrast feature. You can set this box to a square of 32, 64, 128 or 256 pixels in size. Select a size and move your cursor over the image. For this example choose 128 and move the square around one of the major craters and press the LEFT mouse button. RegiStax will now take you to the alignment page. 5 Alignment Page Here you are presented with many different controls that are discussed in detail in the User's Guide. For this tutorial we will only discuss the most important features. On this screen you should see two smaller windows that are on top of the RegiStax Aligning window. One of them is the FFT-spectrum and the other is called Registration properties. They are displayed using the two checkboxes under the Options box. Both of these panels are useful when aligning images. 6. FFT-spectrum. This filter is used to estimate the alignment shift between the reference frame and the rest of the frames in the sequence. Your initial image should show a multi-colored square with a red circular area in the middle. The red area in the middle represents where the program estimates the best alignment. The FFT-spectrum is used to calculate the similarity between images and estimates the best shift when aligning the images. Increase the value of the Alignment filter to 12 and press the Recalc FFT button. Notice that the red-area becomes smaller and the blue line in the Registration properties graph changes position. Ideally only a small group of pixels in the image should become red. This part of the image is used to register (align) the images more accurately. 6 The next step is to weed out the blurred frames from your video sequence. The Quality Filter Band shows the distribution of large and small details on each frame. Images that show a high number of small features are a good indication that the image is sharp. 6 7. Set the "start" quality filter to 10. This will position the two green lines so that one is to the left of the blue line and one is to the right of the blue line. Setting the band "width" filter to 9 defines the area under the Registration Properties graph that is calculated as a proportion of the total area below the graph. Ideally one of the vertical green lines should lie on the lower part of the red curve while the other is positioned where the red-curve nearly touches the bottom. 7 8 8. Press Align & Stack and Registax will automatically start the alignment process. During this stage the program determines how much the object is misaligned compared to the reference for every frame in the AVI file. Next is the optimization process where only frames with good image quality are optimized further. This is a more precise way of aligning the images. Once all the frames are aligned and stacked you will automatically go to the Processing Page. 7 Processing Page The power of RegiStax sits in the usage of Wavelets. This is a special filtering technique that is very good for enhancing details in images. Each wavelet layer carries part of the image within it. The lower numbered wavelets control the fine detail stored in the image whereas the larger numbered wavelets control the coarse detail. Each layer can be adjusted individually to reveal the desired amount of detail for your image. The processing page is where it all happens! 9. Before processing your image it is a good idea to save the aligned and stacked image as a Registax file before processing. This will allow you maintain your pre-processed image without having to go through the Stack and Align process over again. 9 10 10. On the right side of this screen are the six wavelet sliders that are numbered from 1 to 6. Start by moving slider #1 to a value of 50 and watch the image change when you release the slider. Move slider 1 back to its origin (or press Reset) and now move slider 2 to a value of 50, notice that this slider also changes the picture but in a much different way. As you will see the sliders with a larger numbers display more "averaged" images with less fine detail. Whereas the lower numbered sliders bring out more fine detail (and sometime unwanted "noise"). Now play with some of the layer-sliders to enhance your image to a desired effect. Press Reset to return to the normal settings. 8 11. On the lower bottom there are two additional sliders called Contrast and Brightness, these can be used to prevent the image from becoming too bright. Notice that when you enhance the image with the layer-sliders the image contrast increases. You can control this by reducing the overall contrast with the contrast slider. 11 Once you are happy with the appearance of your image you can save it as a BMP, JPEG, TIFF or FITS file. Or you can "tweak" the image further on the Final processing page. 9 Imaging Basics Congratulation on your purchase of the Celestron NexImage solar system imaging camera. Parts list Your NexImage comes with the following: · NexImage Camera with 1.25" adapter and USB cable attached · CD-ROM including: AmCap video capture software Registax image processing software NexImage drivers Complete operating instruction in PDF format Recommended Minimum System Requirements PC running Windows 98SE or better 333Mhz Pentium II or better 128 MB of RAM 40 MB of hard drive space Screen resolution of 1024x768 or higher How it works NexImage utilizes a light sensitive CCD imaging chip to capture streaming video of any solar system object. This video can easily be viewed as hundreds of individual images (frames) that can be digitally stacked to significantly reduce the electric "noise" inherent in video chips and bring out the unseen fine detail (signal) hidden with in your image. The NexImage camera takes advantage of the fact that the signal to noise ratio of your stacked composite image is proportional to the square root of the number of frames combined. This means that stacking as few as 16 frames will reduce the grainy noise of the composite image by 4 times. While stacking as many 1600 frames will improve the image by 40 times! However, stacking the individual frames is only half the power of the NexImage imager. With the included software package, each individual frame is analyzed for quality to filter out those frames most affected (blurred) by poor atmospheric "seeing". This form of after-the-fact adaptive optics, leaves only the sharpest, clearest frames to be stacked and aligned into a high quality image. Finally, powerful processing features automatically break the image up into individual unsharp mask layers that can be used to bring out tremendous detail and reveal final images that will rival those taken with astronomical CCD cameras costing thousands of dollars 10 The Basics Focusing As with all astrophotography, sharp focus is essential for high quality results. Although there are many techniques and devices for focusing your telescope, the human eye still remains one of the best detectors in subtle changes in detail. One advantage that video imaging has over imaging with more sophisticated (and expensive) CCD cameras is the speed in which it can display its image. Focusing NexImage is more similar to focusing a eyepiece than a CCD camera. Unlike with long exposure cameras you don't have to wait many seconds to see the effect of a focus change. Focusing Tips To achieve best focus, concentrate on a high contrast feature of the object you are imaging. Focusing on small features such as a moon's shadow on Jupiter or Cassini's division in the ring of Saturn will guarantee best focus across the entire image. Once the frames of your video are stacked, the overall brightness of the composite (stacked) image is usually brighter than its individual component frames. For this reason it is best keep the brightness of the video image seen on the screen dimmer than you would normally desire. It is important that no part of the image is over exposed to assure the maximum amount of detail in the final composite image. Collimation No matter what type of telescope you image with, poor collimation (alignment of the optics) will ruin your chances for a good image. Before you begin imaging, always check the collimation of your instrument and make adjustments if necessary. Refer to your telescopes owner's manual for instruction in collimating the optics. Finding Objects At first it can be difficult to locate individual planets due to their relative brightness. To make it easier to initially find your object in the imaging window, increase the brightness and gain controls under the Video Capture Filters menu. This will allow you to better see the object as it passes through the imaging window. Once the object is located and centered, you can adjust the setting until the object is at the desired brightness and contrast. 11 How long to take Streaming Video On first thought you may think that the more frames you record the better. However there are some limitation to ...