Sun in H alpha 2014 September 26 and October 03

Here are some large images I produced in the process of writing an article on ‘Imaging the Sun in Narrowband’ for the December 2014 issue of Astronomy Now.

The first  is a 3-part mosaic taken with a 100mm f/9 telescope, a vertical slice of Sun. Lack of IR blocking of this image has reduced the H-alpha contrast and put the sunspots back in. I was avoiding using the Lunt blocking filter, which has the defect known as ‘rust’. (Kudos to Lunt that they have offered to replace it free, though it is an old piece of equipment, but I haven’t got the replacement yet.)

The second is a three-part mosaic with the Lunt LS60T, which gets the whole disk in. I hit on a very successful IR blocking method here. This was to use a 2″ Baader 35nm H alpha filter,  that I sometimes use for deep-sky imaging, in the imaging train as a blocker.

Click once or twice to get images full-size. The first won’t fit on most screens.

Sun2014-09-26-DLA Sun2014-10-03-DLA


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