Sunrises and sunsets are popular photo motifs. Never look directly at the sun! If you want to observe the sun with a telescope, you need special filters before you can look through the telescope. White light solar filters filter out the infrared and ultraviolet and reduce the remaining light to a fraction, so that the sun may be viewed without danger. Then you can see the dark spots of the sun. For prominences, an Hα filter is needed, which only lets through a very narrow part of the spectrum. Only in this line are the faint prominences visible. The bright photosphere below is cut out.
Fig. 1:Glowing Treetops: Sun setting behind trees making the treetops appear to glow. Shot through a 1m refracting telescope without filter. — Minolta X-300, Kodak Ektar 125, September 1991Fig. 2: Sunset through a f=1000mm f/11 refracting telescope in prime focus. The round shaped thingie on the right is the radar dome from Zurich airport. July 1992, Kodak Ektar 100-2Fig. 3:Sunset with dead Tree: Sun is setting behind a foggy forest with a dead tree. This picture was taking during Starparty 1995 on the Gurnigel — Minolta SRT-101, 4.5/300mm telephoto lensFig. 4: Sunset in december 1999.Fig. 5:Sunset: Sun setting behind two trees on a hill. Shot from a meadow at Hirzel village on 19th October 2001. Well, this is a combination of two images (one bright with the trees but without Sun and one dark just with the solar disk and the silhouette of the tree). The film was almost filled and I did not have another one in the bag (shame). The bright image was shot accidentally while pointing the camera and the one with just the sun was too dark because I measured the brightness of the sky too early (shame again). I combined those two images using Photoshop and negative multiplication of the two layers and graduation curve corretion of the bright image. The Sun will set at this point every year from about 18-20th October and 20-22th February. I hope the next time the weather will be as good and I will have enough films. 8/500mm RF tele, Fujichrome Velvia.Fig. 6:Flying into the sun: A little airplane which started from Zurich airport flew across the sun's disk while I was taking this picture. It's a bit small. Next time I'll get closer to the airport and try it again. — Nikon D200, ISO 100, William Optics Zenithstar 105 ED Triplet APO f/7, Scheidegg at Wald/ZH, 10 June 2006Fig. 7:Sunset refraction: The sun is setting behind a very low horizon. Refraction and air turbulences cause deformations of the sun's disk. — Nikon D200, ISO 100, William Optics Zenithstar 105 ED Triplet APO f/7, Scheidegg at Wald/ZH, 10 June 2006Fig. 8: Sunset with cloud belts. I wanted to take picture of the thin sickle of the setting moon but the weather gods were against me. — Nikon D200, William Optics Zenithstar 1 05 ED Triplet APO f/7, 2x Teleconverter, 1/160s, ISO 100, Wernetshausen, Bachtel, 24 June 2006, 21:14Fig. 9:Airplane crossing sun: An airplane crossing the sun. This is no photomontage. It took several hours at the telescope and a sunburn to make this picture. Unfortunately I lost the original slide. — Minolta X-300, Vixen Refractor, d=90mm, f=1000mmFig. 10:Sun Spots: The surface of the sun shot through a telescope with white light filter reveals many pretty dark spots. More spots on the sun surface mean more activity. Nikon D3; Δt=1/4000 s; ISO 200; 10 August 2012 11:36:59Fig. 11:Sun on 20 June 2022 in Hα, stacked: Second try with new ZWO ASI 290MM on a Lunt Hα 60 telescope. Stacking of 47 single 16 bit frames with 4.5 ms exposure using Autostakkert!3. HDR toning with Photoshop 2022 and orange colour filter.Fig. 12:Sun on 21 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope. Stacking using Autostakkert!3. Postprocessing with Photoshop.Fig. 13:Sun on 21 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope with 2.5x Barlow lens. Stacking using Autostakkert!3. Postprocessing with Photoshop.Fig. 14:Sun on 21 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope with 2.5x Barlow lens. Stacking using Autostakkert!3. Postprocessing with Photoshop.Fig. 15:Sun on 21 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope with 2.5x Barlow lens. Stacking using Autostakkert!3. Postprocessing with Photoshop.Fig. 16:Sun on 23 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope. Stacking of sharpest 50 out of 500 frames using Autostakkert!3. Postprocessing with Photoshop. 23 June 2022 12:12:49Fig. 17:Sun on 23 June 2022 in Hα: ZWO ASI 290MM + 2.5x TeleVue Powermate on a Lunt Hα 60 telescope. Stacking of sharpest 50 out of 500 frames using Autostakkert!3. Postprocessing with Photoshop. 23 June 2022 12:18:56Fig. 18:Sun on 23 June 2022 in Hα: ZWO ASI 290MM on a Lunt Hα 60 telescope. Stacking of sharpest 50 out of 500 frames using Autostakkert!3. Postprocessing with Photoshop. Stitch of two images. 24 June 2022 10:14:00Fig. 19: Sun in Hα on 29 June 2022, 3/3: That's how I like it best. A single 16 bit image with shadows and highlights nonlinearly enhanced to reveal both the bright solar surface and the much fainter prominences along the edge. It's not scientifically correct, but looks more natural. ZWO ASI 290MM, Lunt Hα 60.Fig. 20:Sun on 3 July 2022 in Hα: ZWO ASI 290MM, Lunt LS60T, 2.5x TeleVue Barlow.Fig. 21:Sun on 3 July 2022 in Hα: ZWO ASI 290MM, Lunt LS60TFig. 22:Solar Prominences on 3 July 2022 in Hα: Size of Earth as comparison. ZWO ASI 290MM, Lunt LS60T, 2.5x TeleVue Barlow.Fig. 23:Sun on 5 July 2022 in Hα: ZWO ASI 290MM, Lunt LS60T 5 July 2022 12:15:00Fig. 24:Solar prominence on 5. Juli 2022 in Hα: ZWO ASI 290MM, Lunt LS60T, 2.5x BarlowFig. 25:Sun on 8 July 2022 in Hα: ZWO ASI 290MM, Lunt LS60TFig. 26:Sun on 11 July 2022 in Hα: Panorama of three images to get the full Sun, because the size of the camera chip and the sweet spot of the Hα filter are not big enough to cover the entire disk. Actually they're much more images: 3 x video sequences of 500 frames, taking the sharpest 20% and 1 video sequence for the flat frame to compensate the brightness changes of the Hα filter, the whole telescope and dust. ZWO ASI 290MM, Lunt LS60TsFig. 27: web20220712-asi290mm-makingof.jpgFig. 28:Sun on 12 July 2022 in Hα: Panorama of three images to get the full Sun, because the size of the camera chip and the sweet spot of the Hα filter are not big enough to cover the entire disk. Actually they're much more images: 3 x video sequences of 500 frames, taking the sharpest 20% and 1 video sequence for the flat frame to compensate the brightness changes of the Hα filter, the whole telescope and dust. ZWO ASI 290MM, Lunt LS60TsFig. 29:Sun on 15 July 2022 in Hα: Sun on July 15, 2022 in Hα. ZWO ASI 290MM, Lunt LS60TFig. 30:Solar prominence on 17 July 2022 in Hα: Size of Sun and Earth to scale ... and felt also the distance. ZWO ASI 290MM, Lunt LS60TFig. 31: Sun on 17 July 2022 in Hα. ZWO ASI 290MM, Lunt LS60TFig. 32: Sun on 25 August 2022 in Hα. ZWO ASI 290MM, Lunt LS60TFig. 33: Sun on 26 August 2022 in Hα. ZWO ASI 290MM, Lunt LS60TFig. 34:Sun on 26 August 2022: Giant prominence and bright flare compared to the size of the Earth. Lunt LS260T, 2.5x barlow, ASI 290MM. Postprocessing with Autostakkert and Photoshop.Fig. 35: web20220826_asi290mm_layers.jpgFig. 36:Sun Hα, 5.10.2022: Lunt LS60T, ASI 290MM. Postprocessing with Autostakkert and Photoshop. Panorama from 3 video sequences. Best 10% of 1000 frames with 16 bit depth.Fig. 37: web20221006_asi290mm_pano.jpgFig. 38: web20221022_asi178mm_pano.jpgFig. 39:Sun Hα, 24.2.2023: Lunt LS60T, ASI 178MM. Post processing with Autostakkert and Photoshop. Panorama from two shots of upper and lower half. Shadows and highlights enhanced to boost up prominences and photosphere.Fig. 40:Sun Hα, 27.4.2023: Lunt LS60T, ASI 178MM. Post processing with Autostakkert and Photoshop. Best 10% of 3000 shots in 16 bit. Shadows and highlights enhanced to boost up prominences and photosphere.Fig. 41:Sun Hα, 4.5.2023: Lunt LS60T, ASI 178MM. Post-processing with Autostakkert and Photoshop. Panorama from two images of the upper and lower half of the sun. Shadows and highlights have been enhanced to emphasise both the faint prominences and the bright sphere.Fig. 42:Sun Hα, 22.5.2023: Lunt LS60T, ASI 178MM. Post-processing with Autostakkert and Photoshop. Panorama from two images of the upper and lower half of the Sun. Video with 1000 x 16bit video frames, best 10%, flat-frame with semitransparent foil in front of the lens. Shadows and highlights have been enhanced to emphasise both the faint prominences and the bright sphere.Fig. 43:Sun Hα, 26.5.2023: Lunt LS60T, ASI 178MM. Post-processing with Autostakkert and Photoshop. Panorama from two images of the upper and lower half of the Sun. Video with 1000 x 16bit video frames, best 10%, flat-frame with semitransparent foil in front of the lens. Shadows and highlights have been enhanced to emphasise both the faint prominences and the bright sphere. See also timelapse video.Fig. 44:Huge solar flare on 5/27/2023: 970 16-bit frames (actually 1000, but there were some clouds) with a 20-second interval (about 5.5 hours). Lunt LS60T + ASI 178MM. Post processing with Lightroom to improve shadows and contrast and PiPP to align the images and LRTimelapse to create the video. Next time I should shoot with short video clips 20s apart and pre-process each clip to preserve the sharpness and detail created by the atmospheric blur. That's a lot of work, even for an M2 MacBook Pro. See timelapse video.
