Monday, January 26, 2015

20150126 Sun, also testing of Canon 100-400mm f4.5-5.6L (first generation) on H-alpha imaging

Thank God that I can get another Canon 100-400mm f4.5-5.6L finally.

I sold my first one before the release of the second generation, but then my sister bought my a new 70D so I deadly want to get a longer lens to fully utilize its focusing ability, so with some very nice offering, I got one finally.

Given it has the same 77mm thread with my Ranger, so why not try it out on Solar imaging too?  To use the BF10, I have a EOS 1.25" adapter, but to reach focus, I have to insert a 2x barlows before the BF10.  Conventional wisdom gives an estimate with 3x, so the first shot was done at around 300mm effective focal length with the Canon set at 100mm.

The image quality is far from satisfactory.  At first I would guess it's nice to take lower power full disc shot of the sun, but it's no good indeed.

Without much hope but just to complete the test, I set the Canon at 400mm, that means it's working at around 1200mm focal length.  To my big surprise, it's as sharp as my Ranger!  Maybe even better, I don't know.  But it really shines!  Very fine detail could be resolved with great contrast.

Okay, the test is done, so I switched back to my Ranger.  To get a full disc, I've to take two frames and stitch them together.  Transparency is no good today.

Then a close up AR2260 with a 5x Powermate, giving effectively 2400mm focal length.  The first one was obtained by K3CCD, my usual software of choice.

But then since now I've ASI and thus I have SharpCap installed, so why not trying it too with my Lumenera?  K3CCD was a bit troublesome, even I upgrade from Windows 8 to 8.1, it requires me to re-do the registration.  And the author Peter seems not responding after one whole week.  So, I switched for SharpCap.

With the software assisted focusing, the image seems sharper. 

Drop frame is further reduced after removing some more software from my Eee PC.

The sky seems alright until now, maybe I shall try out 2014BL86 tonight after dinner?

Imaging should start at around 8:00pm or else it will be too low.

No comments: