• Posted on: 14 February 2019
  • By: tihomiry

HDR stands from High Dynamic Range. In short it is the number of tones that compose the image. The larger it is, the best capability we have to see details in the bright and dark regions of a scene. We mostly use it to prevent burning out bright objects and stars. Best way to do it is to take different exposure shots and stack them with DeepSkyStacker or similar software. Most high-end cameras has a build in function to do that. The disadvantage is that the resulting image is JPEG. This is also a quite power consuming process as using the camera image processor.
Below are single frame of Andromeda Galaxy with HDR OFF and ON. It is shot with Pnetax k-5. ISO 51200 and 30 seconds of exposure, untouched frame. You can easily see the greatest challenge of this object – bright core and faint outline. The core burn out is suppressed with the HDR function on.



For my last trip to the Rodopa mountain I decided to cross the limits and to target an object that is hard to believe that a non-professional equipment could catch.

While cleaning up my PC I found sequences of shots of Virgo galaxy cluster taken during springs of the last 2 years. Those were attempts to shot this object, but I was not satisfied with the result and left them.

I recently bought a pocket spectroscope for laboratory use. You can find it at Ali for 5$. It is with glass prism and well build. So I did some test to use with a telescope but did not

http://www.deepskywatch.com/deep-sky-hunter-atlas.html This is an amazing resource. Detailed atlas of all the sky with NGC and IC objects.

Reading a new product that claims to be 100x time more powerful then conventional telescope, I realise that this is just an astrograph with a digital camera that is doing stacked images and show them trought eyepiece or App.