Astral Imaging at Dogwood Ridge Observatory

Latitude: 3748'51.0" N"
Scottsville, Virginia 24590


(click on thumbnails to go to that image's page)






Pix Insights
A New User's Quick Start Experience
Applying Histogram Transformation

Using the "Histogram Transformation" process is where you finally stretch the image to bring out the dynamic range of the image. At this point you'll open the save image that's already been cropped and Dynamic Background Extraction has been been performed if needed.

As seen above, I've already clicked on the "Spinning Top" icon, third from the bottom left which turns the real time preview and the check mark icon which turns on the track view. It also shows the data range in the graphs. Using the middle slider, mid-point adjustment, left towards the data as seen above. You want it close but not too close for the first adjustment. Click the square icon to apply and then the reset icon, far bottom right, to reset the graphs and sliders. Make the next adjustment moving the black point, far left slider, close to the left side of the data. You see that as you move the sliders you'll see the adjustment in the real preview window. Move the black point slider and watch the Shadows box. If you get too close you'll start to see the number increase as well as the percentage. This represents the pixels being clipped. This should be very low or avoided if possible. This adjustment should also include the mid-point as well. The second mid-point adjustment will usually go into the lower curve of the data. Adjust until the preview looks right and save the resulting image. For me that would be NGC2359-11_avg_c_DBE_HST See Harry's video for more.


  Last Modified :01/23/09 12:40 AM