Colors of Yesterday
Panoramic Astrophotography
F. Chevenet


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Cassiopeia/Cepheus, from NGC7635 to NGC7380
5x4 panes mosaic, each pane is 2 hours exposure in Halpha 3nm, with 5 minutes sub-exposures (24x300s). Total exposure is 40 hours. Equipment: William Optics FLT98 refractor + William Optics ARF WO IV flattener/reducer 0.8x (focal length of 496 mm, F/D 5) + RoboFocus. Camera: QSI 583 wsg -20C bin1x1 (CCD pixel size of 5.4m) + Starlight Lodestar (autoguiding) + Astrodon 3nm filters. Mount: Vixen SXD + Nex-SXD. Process: MaximDL, CCDInspector, PixInsight. Location: Aniane, France. PixInsight Image Plate Solver script version 3.5.1: Resolution: 2.18 arcsec/pix Rotation: -4.38 deg Focal: 510 mm Pixel size: 5.40 m Field of view: 6 31' 40.6" x 5 59' 24.8" Image center: RA: 23 00 26 Dec: +60 27 42 Image download(JPEG format): Annotated 25% (~5Mo) scale 25% (~5Mo) scale 50% (~20Mo) full (~80Mo)



IC 1396, Elephant's Trunk nebula
IC 1396, Elephant's Trunk nebula in Cepheus, Distance: ~ 3000 ly From: Aniane Date: 29/30 et 30/31 Jully 2011 Exposure Filters 3nm: Ha: 11*600s N2: 9*600s O3: 13*600s S2: 11*600S Total: 7h10 Dark: 25x(-20°C, 600s), Bias: 25x, FlatFields: 15x for each frame Features Focal: 618mm(nominal*0.8)=494mm, F/D: 5 Sampling: 2.25''/pixel (206*5.4/494) File: 2364x2364 pixels Field of view: 1.48°x1.48° (57.3*2364*0.0054/494) FWHM: 4 to 5''(CCDI) Equipment Refractor: William Optics FLT98 + Televue TRF-2008 flattener/reducer 0.8x + RoboFocus Camera: QSI 583 wsg -20°C bin1x1 (5.4x5.4m) + Starlight Lodestar + Astrodon 3nm Mount: Vixen SXD + Nex-SXD Process MaximDL, CCDInspector, PixInsight Color palette: Red = 0.78xNII+SII Green = 0.15xNII+OIII Blue = OIII Luminance = H-a Publication in Astronomie Magazine, Sep. 2011

The Elephant's Trunk nebula is a concentration of interstellar gas and dust in the star cluster IC 1396, an ionized gas region located in the constellation Cepheus about 2,400 light years away from Earth. The entire IC 1396 region is ionized by a massive star (HD 206267, center of the image) , except for dense globules that can protect themselves from the star's harsh ultraviolet rays. The Elephant's Trunk nebula, IC 1396A, is thought to be a site of star formation, containing several very young (less than 100,000 yr) stars that were discovered in infrared images. Two stars are present in a small, circular cavity in the head of the globule (Source: Wikipedia)



Monoceros Mosaic, 3x3 frames
Localization: Monoceros. From: Aniane, Feb. 2012 Exposure: Halpha 3nm, 3x3 frames (each frame : 2h, 12x600s sub-exposures) Dark: 25x(-20°C, 600s), Bias: 25x, FlatFields: 15x Features: Focal: 432mm(nominal*0.8)=345mm F/D: 4.8 Sampling: 3.22''/pixel (206*5.4/345) Field of view: 8.5°x5.8° (57.3*9580*0.0054/345) FWHM: 4 to 5''(CCDI) Equipment: Refractor: William Optics Megrez72mm refractor+ Televue TRF-2008 flattener/reducer 0.8x + RoboFocus Camera: QSI 583 wsg -20°C bin1x1 (5.4x5.4m) + Starlight Lodestar + Astrodon 3nm Mount: Vixen SXD + Nex-SXD Process: MaximDL, CCDInspector, PixInsight



NGC 7635, Bubble nebula, 1x4 frames
The image is a 1x4 panes mosaic, between Cassiopeia and Cepheus. Each pane is 3 hours exposure in Ha, with 15-minute sub-exposures (12x15min). Total exposure is 12 hours. Sampling is 2.25 arc seconds per pixel (refractor with a focal length of 496 mm (F/D 5) and a CCD pixel size of 5.4m). FWHM vary from 3 to 7 pixels (6.75 to 13.5 arc seconds). Equipment: William Optics FLT98 refractor + William Optics ARF WO IV flattener/reducer 0.8x + RoboFocus. Camera: QSI 583 wsg -20°C bin1x1 + Starlight Lodestar (autoguiding) + Astrodon 3nm filters. Mount: Vixen SXD + Nex-SXD. Process: MaximDL, CCDInspector, PixInsight. Location: Aniane, France (2011).

NGC 7635, also called the Bubble Nebula, Sharpless 162, or Caldwell 11, is a H II region emission nebula in the constellation Cassiopeia. It lies close to the direction of the open cluster Messier 52. The "bubble" is created by the stellar wind from a massive hot, 8.7 magnitude young central star, the 15 5 M° SAO 20575 (BD+60 2522). The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel. The star SAO 20575 or BD+602522 is thought to have a mass of 10-40 Solar masses, Distance: 7100 to 11000 ly (source: Wikipedia).



IC 1805, Heart Nebula, 1x2 frames
Exposure Filters 3nm: Ha: 12*600s, 2h per frame, Total 4h Dark: 25x(-20°C, 600s), Bias: 25x, FlatFields: 15x for each frame Features Focal: 618mm(nominal*0.8)=494mm, F/D: 5 Sampling: 2.25''/pixel (206*5.4/494) File: 4039x3045px pixels Field of view: 2.51°x1.90° (57.3*4039*0.0054/494) FWHM: 4 to 7''(CCDI) Equipment Refractor William Optics FLT98 + William Optics ARF WO IV flattener/reducer 0.8x + RoboFocus QSI 583 wsg -20C bin1x1 (5.4x5.4m) + Starlight Lodestar + Astrodon 3nm Mount: Vixen SXD + Nex-SXD Process MaximDL, CCDInspector, PixInsight Publication Ciel & Espace Nov. 2011, Nov. 2011

The Heart Nebula, IC 1805, Sh2-190, lies some 7500 light years away from Earth and is located in the Perseus Arm of the Galaxy in the constellation Cassiopeia. This is an emission nebula showing glowing gas and darker dust lanes. The nebula is formed by plasma of ionized hydrogen and free electrons. The very brightest part of this nebula (the knot at the right) is separately classified as NGC 896, because it was the first part of this nebula to be discovered. The nebula's intense red output and its configuration are driven by the radiation emanating from a small group of stars near the nebula's center. This open cluster of stars known as Melotte 15 contains a few bright stars nearly 50 times the mass of our Sun, and many more dim stars that are only a fraction of our Sun's mass. The cluster used to contain a microquasar that was expelled millions of years ago. (source: Wikipedia).