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Triple Star
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Object : | Beta Cephei or Alfirk |
Coordinates/Direction : | RA: 21h28m, DEC: +70o33' |
Object size : | Double star and variable |
Object magnitude : | 3.16 - 3.27 |
More to know : |
Double Star, Wikipedia: https://en.wikipedia.org/ wiki/ Double star Variable Star, Wikipedia: https://en.wikipedia.org/ wiki/ Variable_star Beta Cephei: https://en.wikipedia.org/ wiki/ Beta_Cephei https://en.wikipedia.org/ wiki/ Beta_Cephei_variable |
Beta Cephei 2024-04-15:(Click on the image to get one in full resolution in a new window) |
Date : | 2024-04-15 |
Time (UT) : | 21:15 to 23:49 |
Mount : | SkyWatcher EQ6 Pro, beltdrive modified (DIY 2019) |
Guide : | QHY5 camera with 200 mm f/3.5 lens |
Lens/telescope : | Pentax 645 300 mm ED f/4 (medium format lens) |
Corrector/Barlow : | - |
Field (FOV) : | 6.8x4.5o (full frame) before crop |
camera : | Canon 6D, QE=0.5, full frame, 20 Mpixel, 14 bit |
camera temperature: | About 6o C above surrounding temperature |
Film/CCD : | Raw, Cr2 |
Filter : | none |
Control system: | Mount, camera, focus, guide (Ekos) controlled by Astroberry (KStars/Ekos Linux) |
Exp. time : | 102x60 seconds, iso1600, dithering mode |
Image process tool : | Siril, Gimp, Irfanview |
Processing : | synthetic bias, flat, photometric color calibration |
Weather : | some clouds, full Moon, temperature +9 C |
Site : | Sweden, Stockholm, Hagsätra.
Bortle 9 Free view Az: 20o to 90o, 165o to 185o, Alt: 20o to 55o |
Comment : |
Not so many objects in the field I have a clear sky to this night.
I concentrated me on a star. The beta Cephei, part of the constellation Cepheus.
The star is bright, magnitude 3, this cause oversaturation of it, that's why it get these strange colors. What's a bit special is that it's a triple star and a variable. The two main stars has the name Beta Cephei Aa and the third Ab. The two main stars has the name Alfirk too. It has a very short variable time, only hours. If I had taken photos of the star I maybe could see or measure this variation. At least at times when the variations is big, 0.3 magnitudes. They are at a distance of 690 ly and could not be separated. The area around the star is relative empty, partly because it looks like that with my heavy light polluted sky. Here is a plate solve of the surroundings: Beta Cephei, by Astrometry.net. Next day I took down the telescope, the season is sadly over now. |
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