Clicking “Defaults” will reset the histogram: The same effect can be achieved by typing a lower value, say “30” in the “Right” box. This will “stretch” the histogram (or compress it depending on your point of view), and it will dramatically brighten the image in real-time. You can set the portion of the histogram which is displayed by moving your mouse on the edge of the graph, and then clicking and dragging the little line from the righthand edge towards the left. Where there’s a peak, you have a lot of pixels with high intensity. You may not see anything on the graph if the image is very dark, so try it in daytime or shine a light into the lens just to see the graph move, and to get a feel for the interface. Height shows the relative number of pixels with this value. Intensity runs along the horizontal axis from left to right, right being the most intense. The graph represents intensity levels of the camera pixels against their volume. Colour cameras display separate peaks on the graph for each colour, mono cameras just show a grey graph. Histogram stretch. Open the histogram menu on the left. A graph appears, which will “react” in real time as the camera picks up light. Go on – dial it up to full to see what happens! Gain. Increase the gain in the gain menu to amplify the signal. Sometimes it helps to increase the gain and change the histogram settings: Eventually you’ll have small star points. Now you know what direction to turn the focuser knob.Īs your focus gets better and the blobs condense to points, you can decrease the exposure time. You can start off with 3-5 secs exposure to find the blobs against the background sky, and then try turning the focuser knob one way or the other so that the blobs decrease in size. An out-of focus star will appear as a large “blobby” thing which can be rather faint. Start off with a relatively long exposure duration. Here are some tips to get a better star-image to work with. The problem is that stars can become quite faint at less than a second exposure, making it more difficult to see what’s going on. To focus manually, you need a reasonably fast frame rate so you can see the effect of turning the focuser knob on the screen. This is about manual focusing using those opposable thumbs and is aimed at the beginner.
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