July 1, 2017 on 12:04 pm | In Sun | Comments Off

I did see a ghost ring developing in my full disk Ha images over the last 1/2 year.  I contacted Meade support and asked them if they could indicate what the problem was.  The reply was that they did not see the ring and they thought the image was pretty good.  Well Tim Geib was so good and offered to stop by on a clear day with his Solar Max 60mm etalon and his blocking filter.  I made two reference images using the same gain and gamma but varying the exposure time so both images would cover the same histogram max. The one with my blocking filter needed an exposure time of 2.142 ms. and the one with his filter did the same job with 0.87 ms., a 2 1/2 times faster.  I then processed both images the same way in AS2. this was followed with a simple wavelet adjustment in Registax6 so the image taken with Tim’s filter showed some good contrast (Fig 2-A, first image). Now I went back to the image taken with the old filter.  Fig. 1-A (second image) shows the raw image as it came from AS2. Fig 1-B (third image) uses the same wavelet settings as Fig 2-A and shows no contrast.  I had to push various filters in Registax and  PS a lot to come up with the image Fig 1-C (fourth image) which represents approx. what I had been doing for the last 6 months or so. Needless to say the life time of the blocking filter is very much restricted.  So I ordered a new filter which arrived earlier this week and will have the old repaired after the Great American Eclipse.

Entries and comments feeds. Valid XHTML and CSS. ^Top^ Powered by WordPress with jd-nebula-3c theme design by John Doe.