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13.56 [CET] AR3131 First acceptable image. Quite detailed but the cloud is obviously taking the edge off.
14.12 AR3135 Multiple spot group east of AR3131.
14.21 The multiple spots in AR3133 seems to have dissolved.
15.00 [CET] Conditions are getting worse. With more cloud and softer images. I am having to use more an more gain to brighten the image because of the cloud. I usually keep Gain under 100 but I am using over 200.
15.30 61F Giving up for today.
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11.20 [CET] First image of AR3131 a new large spot. Captured through cloud. Strangely coarse image texture. Probably due to the cloud.
11.19 AR3133 Multiple small spot group. Just east of AR3131.
11.40 Fully overcast with several layers. More sunshine forecast for later. I'll do something more useful until it clears again.
13.44 Back again. It cleared to full sunshine and then clouded over again as I started to capture. AR3131 There is a central feature inside the umbra but I have lost it in processing.
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14.59 [CET] First image. Using suggested settings for ImPPG instead of my usual arrangements.
14.59 My usual ImPPG settings.
15.33 Retuned and refocused. 1200x1200
15.47 Prom on SW limb.
16.10
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I am try to capture a series of images at 5mm steps of the primary focuser. This moves the etalon further out relative to the objective. I have to refocus with the secondary focuser and then re-tune the etalon each time. The idea is to pin down the best spacing and tune.
I have also been advised to use the Stretch button in ImPPG. Instead of messing about with moving cursors in the curves box. Also to use 1.65 in the L-R settings with 150 iterations. This is all new to me. I have always used the default 1.3 and 50 iterations in ImPPG: [See image.]
If only a could get enough time to tune and focus properly. Then I could see if the Stretch button and L-R settings are beneficial. It's solid cloud! I am using huge quantities of Gain just to be able to see the image on the monitor! I am using only 500 frame captures. Because I don't have time for 1000 frames before the clouds roll over the image.
The seeing conditions are dreadful. With the image boiling furiously. I have lost track of which was the best focus setting.
16.38.[CET] Too late now. The trees have swallowed the sun!
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09.30[CET] Clear and bright but the eastern sky is plastered in persistent vapour trails! The seeing is ridiculously soft, shaking violently and the wind blowing into the dome.
13.30 Lunch is over but not a single worthwhile image so far.
The 2x Focal Reducer arrived but it proved unable to focus the telescope + 60MT etalon system once fitted. The T-S focal reducer has a focal length of about 10cm or 4". I have fitted the reducer as close as physically possible to the front of the Lunt etalon's collimation lens.
It won't work. The correction is far too strong.
I have now been advised to forget the focal reducer and just move the MT etalon in and out until I find the best tuning point. In conjunction with the pressure tuning knob on the etalon and the secondary focuser for the camera.
Unfortunately the sky is heavily clouded this afternoon. With rain promised for later. So I can't experiment with etalon distance and tuning until it clears. It is blowing a gale into the dome as well!
A bit of sun and it proved to be beneficial to use the previous distance. 264mm inside focus
480-264mm = 216mm to the MT etalon housing's shoulder. When the actually sun shines I am using most even brightness as my reference for best tuning.
I have now been advised that it is the 60MT etalon module which needs to be moved nearer the objective.
None of this makes any sense. The etalon is neutral in power. So it does not affect the focal length of the 15cm/ 6" f/10 objective. Adding the focal reducer to the bare etalon instantly produces a 4" /10cm focal length. Because that is the native focal length of the reducer. If the beam was converging at f/10. Then the combined focal length becomes something even shorter than 10cm or 4"! The only place that the focal reducer will work is if it is just inside focus. Which is not the point at all. The idea is to feed the etalon with an f/7 converging light cone.
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10.19 Very odd! The image is superimposed on sand! Using 1448x1216 to cover AR3112 & 3116 spot group. Unfortunately this slows the video capture to only 58fps.The next capture was similarly covered in sand! 😟 Weird!
10.30 Lots more cloud has arrived from the SW.
10.48 Retuned the etalon for even darkening and sharpness. Improving. The large frame size risk finding the limits of the Lunt's sweet spot. This is a result of using a larger aperture [150mm] than the Lunt 60mm system was designed for. Smaller frames and higher powers [magnification] will tend to stay within the sweet spot.
The sky, in the south east is veiled by thin, high cloud. With vapour trials being created by umpteen, crossing planes!
10.58 Using 912x912 for 88fps and much faster processing. Note the smaller field of view.
I am struggling to capture detail within the umbra after processing. The entire image is washed out if I try to keep the umbra.
The quality graph in AS!3 is showing better seeing conditions [contrast] so I have increased the stacking to 100/1000.
11.09 912x912 Deliberately left light in ImPPG. Used PhotoFiltre to darken and improve contrast.
11.16 800x800 100fps Even smaller field of view. Higher power but softer detail. The sky is clearer of thick cloud but thin, high cloud persists.
Heavily cropped due to very light, top right corner.
11.38 1448 x 1216 Pushing the limits of the etalon sweet spot at top right.
11.48 1280x1024 78fps Reduced stack to 60 as image quality is dropping on the AS!3 graph.
1280x1024 allows AR3112/6 to be nicely framed and detailed.
12.11 1280x1024 Best so far? The sun is higher an in the gap between the house and the trees.
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10.13 CET 1000x1000
10.21 1448x1216
11.47 1448x1216 Slightly better detail.
11.47 A composite of three overlapping images above and below AR3112. Resized to 1000.
12.12 Transparency is improving. Thermal shaking is worse. I have retuned the Lunt etalon for more even brightness across the frame.
12.18 More cloud! Better transparency.
12.35 Time for a break. Too much cloud.
I tried again after lunch but the seeing was softer. Probably caused by the house roof. It rained hard just after 3.00!
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15.52 First capture. AR3112 1448 x 1216
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10.13 [CET] AR3112? Captured some videos between clouds in boiling seeing conditions. Set SharpCap to 1448x1216 to capture the huge spot group in one frame. Also useful to confirm the Lunt 60MT etalon's sweet spot over such a wide field of view.
10.44 A composite of several frames [912x912] stitched together in Ms ICE.
The composite image cropped:
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Sunday 2nd 50-53F. Became sunny. Seeing conditions poorly transparent and thermally shaky. Weather arriving from the WNW.
First capture 9.55.
10.56 AR3110 This large and very complex spot group remains active as it heads for the western limb.
According to SpaceWeather.com the group on the lower left have been assigned their own AR number AR3113. [AR: Active Region]
11.06 AR3112 Another complex spot group. Leaving the eastern limb to cross the sun. Showing a lots of flaring from first visibility coming around the limb. Difficult to capture well.
I have been advised to try a focal reducer. To try and tame the variable brightness and tune across the frame.
The LUNT 60mm MT etalon is designed for an F7 converging beam. I am using an F10. So a positive lens, placed just in front of the etalon, should better match its optical needs for best performance. Duly ordered.
12.00 Cloud crossing the sun. Increasing in volume and speed.
15.34 AR3112 [CET] Momentarily better seeing. I had just hung a white sack out of the bottom of the slit to block solar heating of the area below the optical path. Flaring in the east of the group.
16.22 Still here. Still hoping for better seeing conditions. Back to AR3110 to check the seeing. Still poor. No longer able to focus sharply. I focus back and forth until it seems least smudgy. Note the lack of bristles and fine texture.
16.45 The sun is approaching the trees in the west.
16.52 Last image for today. There are two light bridges across the largest spot. One very fine and the other much broader.
16.55 The sun has gone behind the trees.
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