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Sunday: Bright sunshine from the start though with increasing cloud and SW wind. My first attempt at setting the GPC position was still too far inside focus. I had added a 40mm extender. The image on the monitor was enlarged and soft. I captured some videos for reference. Registax made a poor job of the fuzz so I removed the GPC and extender and captured some more videos with the "naked" PST etalon. See image right.
It was then that I smelt burning. Acrid smoke was filling the observatory! I was about to rush over to ask my wife if she had lit the stove. It was then I noticed smoke pouring from the dewshield of the 6" H-alpha scope! It proved to be a card ring I had fitted as a stop when I was struggling with heavy cloud. The card had warped and bent over into the hot beam reflected back through the objective by the Baader D-ERF! I dunked the card ring in a rainwater collecting bucket and returned to more serious matters. Like capturing more H-a videos.
Now I replaced the 40mm, second extender, with one of 100mm. This brought the GPC to 140mm from the back plate. The back plate is at 300mm inside focus. So 300 - 140 = 160. The desired position for the GPC in front of the PST etalon.
Now I was seeing increased detail in the big proms near the "top" of the sun. I captured more videos.The image scale has increased indicating the GPC is active. See image left. Poorer seeing, with thermal boiling, as the wind picked up. Which is the better image of the two?
12:16 it started raining through the slit!Then carried on with heavy showers in the afternoon! No rain forecast!
Monday: Plans for further Solar H-alpha imaging with and without the GPC are on hold while the cloud clears. Which it did, partially, only to tease me for the next couple of hours.
The image [right] was an experiment with Mono 8 saved as an AVI and processed as usual in Registax and PhotoFiltre7. This is with the GPC in place for f/10. Which is saving me having to use a 2x Barlow.
Interestingly[?] the GPC is giving me two options for capturing prominence videos. I have a red detailed option. Or the usual, overblown gain or exposure to bring out a white prom due to over-exposure of the disk. This Mono capture was using the red version. Another red capture appears on the left. Showing how rapidly proms can change ion a few hours. Both have been recoloured in PhotoFiltre7.
The image right is of a disturbed area near the oncoming limb. Horrible thermal shaking during capture. Pushed hard in processing to bring out the contrast of the light feature against the Sun's normal surface texture.
Monday: Plans for further Solar H-alpha imaging with and without the GPC are on hold while the cloud clears. Which it did, partially, only to tease me for the next couple of hours.
The image [right] was an experiment with Mono 8 saved as an AVI and processed as usual in Registax and PhotoFiltre7. This is with the GPC in place for f/10. Which is saving me having to use a 2x Barlow.
Interestingly[?] the GPC is giving me two options for capturing prominence videos. I have a red detailed option. Or the usual, overblown gain or exposure to bring out a white prom due to over-exposure of the disk. This Mono capture was using the red version. Another red capture appears on the left. Showing how rapidly proms can change ion a few hours. Both have been recoloured in PhotoFiltre7.The image right is of a disturbed area near the oncoming limb. Horrible thermal shaking during capture. Pushed hard in processing to bring out the contrast of the light feature against the Sun's normal surface texture.
Click on any image for an enlargement.
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