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1. Alcyone (Eta Tauri, η Tau, 25 Tau) in the Pleiades open cluster, spectral type B7IIIe+A0V+A0V+F2V.
This star is a multiple system, but my goal of observation was the H-alpha profile of the main component:
Horizontal axis scaled to radial velocity:
2. Pleione (28 Tau, BU Tau) also in M45, spectral type B8Vne, variable star, the brightness changes in range: 4.83 - 5.38 V.
This is the faintest star, which I observed with using APO 107/700 & Low Spec spectrograph 1800 l/mm.
It was difficult, but obervation was positive (high gain, exposure time 4 min):
3. Tianguan (Zeta Tauri, ζ Tau), spectral type B1IVe+G8III: (mark ":" according to the VSX database means uncertainty).
This is an eclipsing binary with variability type E/GS+GCAS, period is 133 d. The brightness changes in range: 2.80 - 3.17 V.
4. Cih, Tsih (γ Cas), spectral type B0.5IVpe, variable star with a magnitude range of 1.6 to 3 V:
5. Alnitak (Zeta Orionis, ζ Ori), spectral type O9.5Ibe+B0III. Variable star with a magnitude range of 1.74 to 1.77 V.
Spectral lines have characteristic P Cygni profile, below H-alpha:
Adding my latest image to the comp. This is the Swan (or Omega) nebula imaged during multiple nights between 28 July - 8 August 2019 with my Canon 40D DSLR through my 8" SCT at F10, 2032mm focal length. Imaged in narrowband through Baader SII, HAlpha and OIII filters and combined as SHO (Hubble Palette) colour.
Total exposure time was 27 hours.
HAlpha Subs are 10 & 15 minutes long, OIII subs are 15 & 20 minutes and SII subs are all 30 minutes so I had to spend at least 2 whole nights per filter, except in the case of SII which was 3 nights. The amount of time it took to gather the subs wasn't crucial since I have a permanent setup and resuming exposures night to night took about 10 minutes, and I wanted as many subs as possible to keep the noise level to a minimum, and to be honest I could just keep on adding subs for as many nights as M17 was in the sky on moonless nights but I find that more than 40 subs per channel on brighter objects seems to have diminishing returns.
Gathering more and more subs is made it easy when we're in a drought and there are hardly any clouds in the sky, mostly dry and cloud-free nights lately, which allowed me to have 100% successfully exposed subs.
All subs are ISO1600 and the active cooling definitely helps with the noise levels, most noticeable with SII when comparing to my SII 1800 second subs captured in the past.
Sharing with you my finished image of the Swan nebula imaged through SII, HII and OIII narrowband filter using my modded and cooled Canon 40D. Imagd trough my C8" SCT at 2032mm focal length.
Total exposure was 27 hours across multiple nights.