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Revolution Imager Solar Observing with ETX-90RA and PST

Posted: 12 June 2016

Friday, 10 June 2016, was mostly overcast, with three brief thundershowers in the afternoon (0.3" rain). I received good news on Friday: the replacement 12" LX600 telescope will be shipped soon. Saturday, 11 June, was mostly cloudy. Sunday, 12 June, dawned clear.

Equipment Used:
1.25" 26mm eyepiece
1.25" 12.5mm eyepiece

Revolution Imager

0950-1100 MST: set up the ETX-90RA and PST (Coronado Personal Solar Telescope) on the house patio for some solar observing. I wanted to check out the Revolution Imager for solar observing in white light (using the Coronado White Light Solar Filter with the ETX) as well as H-Alpha (with the PST). Here are the telescopes and Imager:


I first viewed the Sun through the ETX at 48X and then using the Wide-Field Adapter (WFA). Sunspots AR2553 and AR2554/2552 were nicely visible. With the PST at 32X some good details were visible on the solar disk but only a few small prominences were visible.

I then mounted the Revolution Imager on the ETX using the Wide-Field Adapter. Since I had no sunshade for the monitor it was very difficult to see the image from the camera. This made focusing and determining the appropriate camera settings challenging. I was able to finally get the image in focus and adjusted:


Unfortunately, since I was photographing the screen, reflections were a problem. But as you can see, using the WFA I was not able to view the entire solar disk with the Imager. I added the Imager's 0.5X focal reducer while still using the WFA but the image would not reach a focus.

I then mounted the Imager with the 0.5X focal reducer on the top eyepiece holder. The entire disk was not imaged in the camera field-of-view:


I was never able to see any of the small sunspots on the monitor while using the lower magnifications. Whether that was due to the difficult viewing conditions without a sunshield or whether the Sun was overexposed, I don't know.

I removed the focal reducer and this time I was able to get sunspot AR2553 (below center):


Next, I mounted the Revolution Imager on the PST with and without the focal reducer. As with my past PST imaging attempts when using a DSLR, I was never able to achieve a good focus (due to limited focus travel). This image (without the focal reducer) shows what I was able to get:


Certainly not good enough to image the prominences.

But this exercise did allow me to get some initial settings for the Revolution Imager for the Sun. I have updated the Revolution_Imager_settings.xlsx file.

I then took this handheld iPhone 6s Plus afocal photo of the Sun as seen at 32X in the PST:


Three prominences are visible about 3 o'clock on the Sun's limb with AR2553 just to their left.

This handheld iPhone afocal 48X photo was taken through the ETX, with AR2553 at the right and AR2554/2552 at the left:


I plan to do more solar work with the Revolution Imager after I receive the replacement 12" LX600 telescope.

If you haven't seen it already, check out the The New World Atlas of Artificial Sky Brightness. Also see this article: 80% of World Population Lives Under Skyglow, New Study Finds.

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