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Contains:  The star Garnet Star (μCep)
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Garnet Star- μ Cep, 


            Mirko M
Garnet Star- μ Cep
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Garnet Star- μ Cep

Technical card

Imaging telescopes or lenses: Skywatcher Esprit 120 ED APO Triplet

Imaging cameras: ZWO ASI 1600MM-Cool Pro

Mounts: iOptron CEM60EC Ioptron

Software: PixInsight 1.8 Ripley PinInsight 1.8.5  ·  Photoshop CC 2017 photoshop CC 2014

Filters: Ha 7 nm  ·  Baader Planetarium Oiii 8.5 nm 2”

Dates:July 4, 2019

Ha 7 nm: 30x300" (gain: 139.00) -20C bin 1x1
Baader Planetarium Oiii 8.5 nm 2”: 20x300" (gain: 139.00) -20C bin 1x1

Integration: 4.2 hours

Darks: ~10

Flats: ~30

Bias: ~30

Avg. Moon age: 1.91 days

Avg. Moon phase: 4.06%

Basic astrometry details job: 2785210

RA center: 21h 42' 36"

DEC center: +58° 28' 22"

Pixel scale: 0.912 arcsec/pixel

Orientation: 272.493 degrees

Field radius: 0.732 degrees

Resolution: 4618x3473

Locations: Frazier Park, Frazier Park, CA, United States

Data source: Traveller


The bright star on the right is known as the Garnet Star or officially known as Mu Cephi, or μ Cep . This star is also a supergiant, and is one of the largest and brightest stars visible not only to the naked eye but in the entire Galaxy. Its distance is not very well known. Parallax measurements and distance estimates in the scientific literature give values between 390 and 1,600 parsec. But even at its great (uncertain) distance, μ Cep is big enough to show a measurable angular diameter, around 0.02" - equivalent to approximately 1,420 times the size of our Sun, or about 15 Times the distance from earth to sun across.

This means that if put in place of the Sun, μ Cep would extend midway between the orbits of Jupiter and Saturn. It could fit over 1 billion suns into its body. Only five known stars (VY Canis Majoris, KW Sagitarii, KY Cygni, V354 Cephei and VV Cephei) are believed to be larger than it. In visible light, μ Cep is 38,000 times brighter than the Sun, with an absolute magnitude of -7.0. Including infrared radiation and interstellar dust extinction gives it a luminosity around 350,000 suns, making μ Cep one of the most luminous stars known. The region surrounding μ Cep is part of the greater IC1396 cloud complex known for the very popular elephant trunk nebula. This image was taken July 4th using narrowband filters Ha and Oiii. 2hr 40min, and 1hr 40min respectively with 5 minute exposures at gain of 139. The camera used (an asi 1600) is known to cause lensing artifacts at these focal lengths (F7) which in this case, I dont mind. I like to think It’s the star flexing its muscles! 💪🏼



Mirko M
License: None (All rights reserved)

Sky plot

Sky plot


Garnet Star- μ Cep, 


            Mirko M