Sun

The natural celestial objects nearest to earth are of course those found in our Solar System. Closest to earth is the moon, which gives stunning views, even at the lowest modest magnification. The Sun (see figure 22) is the closest star to earth. Light only takes 8 minutes to arrive here. Using the Lunt LS80THA nice images can be made of the granulation on its surface and of the solar flares (protuberances) around the edge. Using the SkyWatcher Esprit 150ED and a Baader white-light foil-filter images in the full visible spectrum can be taken, reveiling sunspots as if they were projected.
All images on this page have been taken with a monochrome camera and are artificially coloured.


16 June 2021

Solarspot AR2833 as imaged on 16 June 2021 with the C11 @ f/20.
Figure 1: Solarspot AR2833 as imaged on 16 June 2021 with the C11 @ f/20.
On 16 June 2021 I imaged AR2833 using the Celestron C11 XLT EdgeHD. This region was also visible two weeks earlier and at the time known as AR2824.
Imaging done with the ZWO ASI174 and TeleVue 2x PowerMate, processing in AS!3 and PSP, animation in EZGif.com.
The full resolution animation can be found here


AR2833 as imaged on 16 June 2021 using SkyWatcher Esprit 150ED.
Figure 2: AR2833 as imaged on 16 June 2021 using SkyWatcher Esprit 150ED.
That same day I also used the SkyWatcher Esprit 150ED to image AR2833, which produced a very similar image as on 20 May when the spot was still named AR2824.


10 June 2021

The partial solar eclipse as seen from InFINNity Deck on 10 June 2021.
Figure 3: The partial solar eclipse as seen from InFINNity Deck on 10 June 2021.
On 10 July 2021 a partial solar eclipse was visible from InFINNity Deck. That day all four telescopes were used to observe the Sun. The GTT60 was used to project the solar disk onto paper, the Celestron C11 XLT EdgeHD for visual observations using a Baader ND5.0 foil and a polarizing filter in between the star diagonal and 41mm TeleVue Panoptic eyepiece.
Adjacent image was the result of a series of images taken with the SkyWatcher Esprit 150ED through a Baader ND5.0 foil filter, using the ZWO ASI1600MM Pro Cool camera. In total 37 recordings were made of 20 seconds (145 frames per recording). These were processed in PSP and downsized to 1338x1290 pixels in order to create the animation from it.
On the surface several sunspots can be seen. Positioning your mouse next to one of them allows to see the rotation of the sun during this 3 hours time-lapse. The first frame was shot at 08:07UTC, the second at 09:01UTC. All following frames were taken from that moment on at an average 5 minutes interval.
Along the limb of the Moon clearly some mountainous terrain can be observed.
The full resolution version can be found here.


The partial solar eclipse in H-alpha (inverted processing) as seen on 10 June 2021.
Figure 4: The partial solar eclipse in H-alpha (inverted processing) as seen on 10 June 2021.
The fourth scope used to catch the partial solar eclipse of 10 June 2021 was the Lunt LS80THA, which recorded the Sun in H-alpha mode. Again 37 recordings were made to create adjacent image, but now of 30 seconds in length (2200 frames per recording). These were processed in IMPPG and PSP and are shown here at their original scale.
On the surface several sunspots can be seen. Positioning your mouse next to one of them allows to see the rotation of the sun during this 3 hours time-lapse. The first frame was shot at 08:24UTC, the second at 09:00UTC. All following frames were taken from that moment on at an average 5 minutes interval.
Two additional recordings were made around the time of first and second contact. From these the first contact was found to be at 09:18:11UTC (theoretically, according to Stellarium for our location, this would have been 09:17:55UTC) with an uncertainty due to undulation of 1 second. The second contact was found to be at around 11:31:45UTC (theoretically 11:31:26UTC) with an uncertainty of 3 seconds.
The full resolution version can be found here.


The partial solar eclipse in H-alpha (normal processing) as seen on 10 June 2021.
Figure 5: The partial solar eclipse in H-alpha (normal processing) as seen on 10 June 2021.
That same dataset can also be processed in a non-inverted fashion to produce adjacent image.
The full resolution version can be found here.


The partial solar eclipse as projected using the GTT60.
Figure 6: The partial solar eclipse as projected using the GTT60.
Using the GTT60 I projected the Sun to see the partial eclipse and accompanying sunspots.


2 June 2021

The Sun in H-alpha on 2 June 2021, showing sunspots AR2827.
Figure 7: The Sun in H-alpha on 2 June 2021, showing sunspots AR2827.
Today AR2827 is still active and a few nice prominences are visible along the limb. Image taken with the Lunt LS80THA and ZWO ASI174MM at 09:51UTC.
Post-processing in PSP, the full image can be found here.


1 June 2021

Sunspot AR2827 imaged on 1 June 2021 using the C11 EdgeHD and Baader ND5.0 foil.
Figure 8: Sunspot AR2827 imaged on 1 June 2021 using the C11 EdgeHD and Baader ND5.0 foil.
On 1 June 2021 I gave sunspot AR2827 another try, again using the Celestron C11 XLT EdgeHD with Baader ND5.0 filter foil and the green filter from the filter wheel. The rest of the optical train consisted of a TeleVue 4x PowerMate and ZWO ASI174MM. A gain of 300 was used, resulting in exposure time of 2.4ms. In 30 seconds 1136 frames were captured, which were processed in AS3! using a stack length of 50 and some 2750 APs (AP-size was set to 48 and rendered full-frame).
Post-processing in PSP, the full image can be found here.


The full disc image of the Sun taken on 1 June 2021.
Figure 9: The full disc image of the Sun taken on 1 June 2021.
To give an idea of scale, sunspot AR2827 from above C11-image is shown here in a full-disc image taken with the SkyWatcher Esprit 150ED. For imaging a ZWO ASi1600MM Pro Cool was used, as well in combination with a ND5.0 foil and luminance filter.
The full image can be found here.


31 May 2021

Sunspot AR2827 imaged on 21 May 2021 using the C11 EdgeHD and Baader ND5.0 foil.
Figure 10: Sunspot AR2827 imaged on 21 May 2021 using the C11 EdgeHD and Baader ND5.0 foil.
Last week I got myself a decent sheet of Baader ND5.0 solar filter foil (49x50cm). I had read on various fora that the ND5.0 foil was not suitable for solar imaging as it reduced exposure times too much, but then the main purpose for the filter was for visual observing. Of course I could not resist using it for imaging as well, just to see how far I could get with my first attempt.
So this morning I gave it a try at 7:30am UTC with the Sun just peeking over the tree-tops into the observatory and showing sunspot AR2827. The imaging scope is my Celestron C11 XLT EdgeHD. I used a green filter (have no continuum filter yet), a TeleVue 4x PowerMate and ZWO ASI174MM.
Setting the camera to a gain of 300 resulted in 3.2ms exposures and a 66FPS frame-rate. Seeing was the greatest issue, but out of 10 SER-movies of 30s and 2000 frames each, 10 frames of one of them were good enough to stack. The Earth was added to scale.
The full resolution image can be found here.


20 May 2021

Sunspot AR2824 as imaged on 20 May 2021 09:03UTC with the SkyWatcher Esprit 150ED.
Figure 11: Sunspot AR2824 as imaged on 20 May 2021 09:03UTC with the SkyWatcher Esprit 150ED.
On 20 May 2021 sunspot AR2824 showed up very nice. I had been seeing it during the previous two days using the GTT60 and the SkyWatcher Esprit 150ED, but today I decided to image it with the Lunt LS80THA as well. Adjacent image was taken on 09:03UTC with the Esprit 150ED. The image is the result of 30s capturing with FireCapture, which resulted in 237 frames, 25% of which were stacked with AS3!. Post-processing done with IMPPG and PSP.


Sunspot AR2824 as imaged on 20 May 2021 09:17UTC with the Lunt LS80THA.
Figure 12: Sunspot AR2824 as imaged on 20 May 2021 09:17UTC with the Lunt LS80THA.
A few minutes later, on 09:17UTC, the adjacent H-alpha image was taken with the Lunt LS80THA. Again 30s exposures, now resulting in 1853 frames, 25% of which were stacked.


Close-up of sunspot AR2824 as imaged on 20 May 2021 10:01UTC with the Lunt LS80THA.
Figure 13: Close-up of sunspot AR2824 as imaged on 20 May 2021 10:01UTC with the Lunt LS80THA.
Finally a close-up was taken at 10:01UTC with the Lunt LS80THA, but now with a TeleVue 4x PowerMate in between the scope and ZWO ASI174MM camera. Once again 30s exposure, resulting in 1001 frames, 15% of which were stacked. Postprocessing with IMPPG and PSP.


10 May 2021

The sun as imaged on 10 May 2021 around 12:11 UTC.
Figure 14: The sun as imaged on 10 May 2021 around 12:11 UTC.
On 10 May 2021 two active regions could be seen: AR2822 and AR2823. In addition several prominences could be seen. Adjacent image was taken with the Lunt LS80THA in combination met the ZWO ASI174MM.


The sun as imaged on 10 May 2021 around 12:11 UTC in white-light.
Figure 15: The sun as imaged on 10 May 2021 around 12:11 UTC in white-light.
That same day I also imaged the Sun using the SkyWatcher Esprit 150ED and ZWO ASI1600MM Pro Cool.


Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.
Figure 16: Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.


Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.
Figure 17: Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.


Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.
Figure 18: Detail of the sun as imaged on 10 May 2021 around 12:11 UTC in H-alpha.


16 - 27 April 2021

A 12 day long animation as imaged in April 2021, showing the rotation of the Sun with sunspots.
Figure 19: A 12 day long animation as imaged in April 2021, showing the rotation of the Sun with sunspots.
Between 16 and 27 April 2021 I managed to daily image the Sun in white-light using the SkyWatcher Esprit 150ED. From these 12 frames the adjacent animation was created.
The same animation at 900px x 900px resolution can be found here.


27 April 2021

The Sun on 27 April 2021 at 08:28UTC.
Figure 20: The Sun on 27 April 2021 at 08:28UTC.
On 27 April 2021 I took adjacent image of the Sun in H-alpha using the Lunt LS80THA and ZWO ASI174MM monochrome camera.


26 April 2021

The Sun on 26 April 2021 at 09:13UTC.
Figure 21: The Sun on 26 April 2021 at 09:13UTC.
On 26 April 2021 I took adjacent image of the Sun in H-alpha using the Lunt LS80THA and ZWO ASI174MM monochrome camera.


5 March 2021

Half an hour animation of a protuberance on 5 March 2021.
Figure 22: Half an hour animation of a protuberance on 5 March 2021.
On 5 March 2021 a nice protuberance could be seen at the limb of the sun. Using the Lunt LS80THA with the TeleVue 4x PowerMate and ZWO ASI174MM nine SER-videos of 30 seconds were captured. Processing was done in AS3!, IMPPG and PSP. Finally the resulting images were combined using EZGIF-maker.
The image shown here as figure 22 is a cropped and resized version of the original, which can be found here.


11 April 2021

The Sun showing a nice large protuberance on 11 April 2021.
Figure 23: The Sun showing a nice large protuberance on 11 April 2021.
On 11 April 2021 the Sun was quite active, showing a large prominence at the western limb. Image was taken with the Lunt LS80THA solar-telescope and ZWO ASI174MM camera.


A close-up of the large protuberance of 11 April 2021.
Figure 24: A close-up of the large protuberance of 11 April 2021.
A close-up of the large protuberance of 11 April 2021.


26 February 2021

The sun as imaged on 26 February 2021 around 11:34 UTC.
Figure 25: The sun as imaged on 26 February 2021 around 11:34 UTC.
On 26 February some nice activity could be seen on the sun. Solar spot AR2804, an active region AR2805 and a large protuberance were visible at the same time.


Solar spot AR2804 as imaged on 26 February 2021 around 11:34 UTC.
Figure 26: Solar spot AR2804 as imaged on 26 February 2021 around 11:34 UTC.


The largest protuberance of 26 February 2021.
Figure 27: The largest protuberance of 26 February 2021.


9 November 2020 with sunspot AR2781

The sun as imaged on 9 November 2020 with sunspot AR2781.
Figure 28: The sun as imaged on 9 November 2020 with sunspot AR2781.
Slowly but surely the Sun it showing more activity. On 9 November 2020 sunspot AR2781 was well visible and imaged using the Lunt LS80THA. Adjacent image is taken with the ZWO ASI174MM camera directly mounted on the blocking filter (so without Barlow). Processing was done using an inverted histogram.


Detail of sunspot AR2781 as imaged on 9 November 2020.
Figure 29: Detail of sunspot AR2781 as imaged on 9 November 2020.
Using a TeleVue 4x PowerMate behind the blocking filter of the Lunt LS80THA, sunspot AR2781 was imaged in some more detail.


Sunspot AR2781 as imaged on 9 November 2020 with the SkyWatcher Esprit 150ED.
Figure 30: Sunspot AR2781 as imaged on 9 November 2020 with the SkyWatcher Esprit 150ED.
Using the SkyWatcher Esprit 150ED and a white-light filter, sunspot AR2781 was imaged in full spectrum.


31 July 2020

The sun a simaged on 31 August 2020 around 09:21 UTC.
Figure 31: The sun a simaged on 31 August 2020 around 09:21 UTC.
On 30 and 31 July 2020 a nice long protuberance was visible at the sun. Imaging was done on 31 June with the Lunt LS80THA in combination with a TeleVue 4x PowerMate and ZWO ASI174MM. During 60 seconds 7k frames were captured 10% of which were stacked using AutoStakkert. Post-processing done in PSP.


The full Sun captured on 31 July 2020.
Figure 32: The full Sun captured on 31 July 2020.
That same day I also captured the Sun in full. During 2 minutes 4809 frames were captured, 30 percent of which was stacked using AutoStakkert!. Stretching was done using the inverted method in IMPPG, post-processing in PSP using the method described in my second article on solar processing.


19 June 2020

The Sun as imaged on 19 June 2020.
Figure 33: The Sun as imaged on 19 June 2020.
In June 2020 I learned a new technique of solar imaging processing. Using ImPPG it is possible to invert the histogram, a method I explain in more detail here. Using this method allows to show more surface detail and protuberances.
The image was taken with the Lunt LS80THA and ZWO ASI174MM monochrome camera.


25 May 2020

The Sun as imaged on 25 May 2020.
Figure 34: The Sun as imaged on 25 May 2020.
On 25 May 2020 a nice prominence was visible, captured again with the Lunt LS80THA with a 4x Barlow and ZWO ASI174MM.


20 September 2019

A solar flare imaged on 20 September 2019.
Figure 35: A solar flare imaged on 20 September 2019.
On 20 September 2019, with the assistance of two high school students, we imaged the sun around 08:45am UTC. Imaging was done using the Lunt LS80THA in combination with a 4x PowerMate and ZWO ASI174MM, focusing was done manual. In 2 minutes time 2584 frames were captured, 30 percent of which were stacked. Some processing in AutoStakkert, IMPPG, and Paint Shop Pro resulted in this rather pleasing image. The Earth has been added to the image at the same scale.


29 July 2019

A solar flare as seen on 29 July 2019.
Figure 36: A solar flare as seen on 29 July 2019.
Recently I received a M42 to 2" adapter for the blocking filter of my Lunt. This adapter allows to include a barlow in the optical path. On 29 July 2019 I tested it for the first time using a TeleVue 4x PowterMate and ZWO ASI174MM. A movie of 10,000 frames was shot in 40 seconds, processed in AutoStakkert using sharpening and finally enhanced, colourised and sharpened in PSP. In the lower left corner the Earth is shown at scale.


9 May 2019

The sun as imaged on 9 May 2019. It seems sun spot season started again.
Figure 37: The sun as imaged on 9 May 2019. It seems sun spot season started again.
Ever since InFINNity Deck became operational the sun was quite boring, only occasionally showing some activity. That changed a few weeks ago and now it starts to be interesting again as can be seen in this image. The large sun spot at the right is number 2741.


19 March 2019

A better picture of the sun, taken on 19 March 2019, with a turbo-prop plane flying past.
Figure 38: A better picture of the sun, taken on 19 March 2019, with a turbo-prop plane flying past.
In March 2019 I experimented with the Lunt to improved the quality of the images taken through the Lunt. From another Dutch amateur astronomer I learned to improve my processing. Although the Sun is still quite dull, having something in the foreground makes the image much more attractive. Just above the cockpit a small sunspot can be seen, while above the left wing a protuberance can be spotted.


My first attempt from InFINNity Deck on 9 June 2018

The sun imaged on 9 June 2018 using the Lunt. At nine o'clock a small protuberance can be seen.
Figure 39: The sun imaged on 9 June 2018 using the Lunt. At nine o'clock a small protuberance can be seen.
Currently (2018) the sun's activity is at its lowest point, resulting in a rather dull view with only minor protuberances and an occasional sun spot.
figure 39 was my first attempt to image the sun and was a rather mediocre attempt. As can be seen in the following images my skills gradually improved.


Solar images before 2018

Until the construction of InFINNity Deck I had no astronomical telescopes of my own. Before that time I used geodetic instruments like the 1969 Wild T2E or 1937 Wild T3 (astronomic) to look at celestial objects. In addition I borrowed a Celestron C5 telescope in 2015 from the Alkmaarse Weer- en Sterrenkundige Vereniging Metius.


Partial solar eclipse 20 March 2015

The partial solar eclipse of 20 March 2015 as imaged through a C5.
Figure 40: The partial solar eclipse of 20 March 2015 as imaged through a C5.
On 20 March 2015 a partial solar eclipse could be seen from the Netherlands, although "seen" has to be taken with a grain of salt as most of the day the Netherlands was covered with thick cloud. I was lucky to have some moments where the cloud cover became thinner and the Sun could be spotted with the naked eye. Adjacent image is one of six taken that day. Imaging was done afocal using a standard hand-held compact camera behind the Celestron C5 using the clouds as the only filter.


The partial solar eclipse of 20 March 2015 as imaged directly around 09:30UTC.
Figure 41: The partial solar eclipse of 20 March 2015 as imaged directly around 09:30UTC.
Using that same camera I took this image, clearly showing the lousy sky-conditions of that day.
The eclipse started at around 08:30UTC, maximum occurred at around 09:37UTC with a coverage of about 82%, while it ended at around 10:48UTC.


Venus-transit on 8 June 2004

The Venus-transit of 8 June 2004.
Figure 42: The Venus-transit of 8 June 2004.
On 8 June 2004 the first of two Venus-transits of the 21st century took place. At the time I had no telescope, but used a 1969 Wild T2E to project the Sun on a piece of blank paper while sitting indoors. In adjacent image the transit as imaged around 7am UTC is shown. Being an instrument with an erect view, and therefore projecting an inverted image, south is shown upwards.
Slightly off-centred the deliberately defocused horizontal and vertical cross-hairs can still be faintly seen.


The theodolite set-up used to image the 2004 transit of Venus.
Figure 43: The theodolite set-up used to image the 2004 transit of Venus.
Adjacent image shows how I captured the 2004 transit of Venus using the 1969 Wild T2E. A page of a local newspaper served well as a shade around the theodolite's telescope. An A4-size sheet of blank paper was used to catch the Sun's image.
Eight years later, on 6 June 2012, the second Venus-transit of the 21st century occurred, but was hardly visible in the Netherlands, partially because of its early time of day (22:04UTC on 5 June until 4:55UTC on 6 June) and partially due to heavy cloudcover.


If you have any questions and/or remarks please let me know.


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