Sun in Ha with large filaments 18th feb 2013

In 2013 there is a lot of solar activity can be expected. Very clearly an enormous Quiet Region Filament (QRF) can be seen. Both images were taken with a Lunt 60mm pressure tuned, single stack telescope using a DMK31 camera. The bottom image required an additional Meade/Robtics 3x apochromatic Barlow, but is unfortunately not in focus.


  1. The images were aligned and stacked by means of Registax, using the best  20% of 1000 frames.
  2. By means of Astrasoft image processing software, a Lucy Richardson / Moffat deconvolution filter was applied.
Following processing steps are applied with thanks to Andre van der Hoeven:
  1. In photoshop: applied gamma correction: Levels -> blue gamma 0.3, red 2.5 Levels –> blue gamma 0.5, red 2.0
  2. Finally high pass filtering applied: Created two copies of the original layer: layer 1: highpass filter r=7 pixels, mode= overlay, luminosity 30%; layer 2: higpass filter r= 40 pixels, mode= soft light, luminosity = 30%.

Sun in Ha

This picture of the Sun in the light of ionised Hydrogen. Passing through H-alpha light (656,28 nm) only exposes granulation and several protuberanses. Due to the extreme narrow bandwidth (0,7 nm or less)  which is required to observe the smallest details, an Etalon filter is used in combination with a blocking filter.




This is basically an interference filter composed of two parrallel glass plates. In order to get rid of , consisting of two  in combination with a conventional absorbtion filter which gets rid of UV, IR and wavelengths not equal to 656 nm. The latter are only visible at a wavelength of (almost) exactly 656,28 nm a