Imaging the Sun Last updated: 4 August 2011

Thursday, 4 August, started out partly cloudy, but by mid-morning, the sky was mostly clear. I opened the observatory at 1030 MST, 102°F. I first viewed the sun in Hydrogen-Alpha with the PST. Several nice prominences and filaments were easily visible in the 12.5mm eyepiece (32X). The sunspots looked super in H-Alpha as well. I then quickly viewed the sun in white light through the 8" LX200-ACF with the 26mm eyepiece (77X). One nice sunspot group was near the middle; the sunspots seen the other day had moved off towards the limb. Seeing was not too good but I decided to try imaging anyway.

I added the focal reducer to the 8" telescope and began imaging with the iPhone 4. This full-disk image was taken afocally with 26mm eyepiece + focal reducer using the MX-1 afocal adapter. Saturation was removed during post-processing (for all these images).

This cropped image showing the line of sunspots was taken afocally with a 26mm eyepiece:

This cropped image was taken from one frame of an iPhone video recording afocally with 9mm eyepiece:

The above image shows some lines from the penumbra (the outer grey area) going into the umbra (the dark central area). You can see one line in the larger sunspot on the left and five in the smaller sunspot on the right.

I finished imaging with the 8" and before I set up for imaging on the PST, I did some solar viewing with the 8". Using a 9.7mm eyepiece (206X), a lot of detail was visible in the right most sunspot group (the last image above). During moments of good seeing, I could easily see the lines going into the umbra. They were also visible with a 15mm (133X) eyepiece. I had never seen such details before, although I have seen photographs showing them in other sunspots. I was surprised when my images captured them (albeit, not well).

I set up for PST imaging with the iPhone. I managed one image, way overexposed, before thin clouds became a problem. I'll try again another day.

Closed the observatory at 1140 MST, 100°F.

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