- Double Stars (CVn) -

And (32) Cep (13) CVn (4) Her (13) Mon (1) Sex (2)
Aql (9) Cet (1) Cyg (19) Hya (4) Oph (1) Tau (11)
Ari (8) CMa (1) Del (2) Leo (19) Ori (8) Tri (4)
Aur (27) Cnc (10) Dra (8) Lib (1) Peg (16) UMa (24)
Boo (12) Com (8) Equ (5) LMi (6) Per (18) UMi (1)
Cam (10) CrB (4) Eri (1) Lyn (18) Psc (7) Vir (6)
Cas (17) Crv (1) Gem (19) Lyr (8) Ser (2)

25 CVn (**)
Name: 25 CVn
Type: **
Constellation: CVn
Coordinates: 13h37m27.70s / +36°17'41.40"

Components:
m1 m2 ρ θ Year
STF1768 AB 5m0 7m0 1.7" 99° 2018
STF1768 AC 5m0 11m6 214.3" 321° 2015
KZA73 AD 5m0 13m0 335.6" 92° 2015
KZA73 AE 5m0 12m7 369.5" 139° 2015
KZA73 AF 5m0 9m4 437.3" 118° 2015

../images/binary-star-orbits/STF1768-AB-orbit.jpg

Robert Zebahl
60mm f/18.7, 160x
AB: 2020-03-16: 102/1122mm ED refractor stopped down to 60mm. The diffraction ring of the primary component is virtually invisible. The companion appears only in few moments as an extremely faint, elongated brightening in the diffraction ring. Very difficult. Telescope should be in very good optical condition!
70mm f/16, 160x
AB: 2020-03-16: 102/1122mm ED refractor stopped down to 70mm. Companion only visible as a subtle, elongated, not permanently visible brightening. The diffraction ring of the primary component is only visible occasionally. Difficult. Telescope should be in good optical condition!
80mm f/14, 160x
AB: 2020-03-16: 102/1122mm ED refractor stopped down to 80mm. Companion permanently visible as elongated brightening in the diffraction ring. But the diffraction ring itself appears rather faint. Moderately difficult.
90mm f/12.5, 160x
AB: 2020-03-16: 102/1122mm ED refractor stopped down to 90mm. Companion quite clearly recognizable as elongated brightening in diffraction ring. Relatively simple.
102mm f/11, 160x
AB: 2020-03-16: The faint companion is immediately recognizable as a distinct, slightly elongated brightening in the diffraction ring. Easy.
152mm f/5.9, 150x, Bortle 6-, SQM-L 19.1
AB: 2020-03-19: At 150x the clearly fainter companion is visible as a roundish brightening. Due to the chromatic aberration of the achromat (152mm f/5.9) the companion is almost outshined. At 180x the companion is then well, at 225x and 300x very well visible as a tiny separated star.

STF 1692 (**)
Name: STF1692, 12 CVn, alpha CVn, Cor Caroli
Type: **
Constellation: CVn
Coordinates: 12h56m01.67s / +38°19'06.20"

Components:
m1 m2 ρ θ Year
AB 2m9 5m5 19.5" 230° 2018
Robert Zebahl
70mm f/5.7, 22x
Beautiful view. Clearly unequal with nice angular distance. Primary component appeared in pale yellow, secondary component silvery-white.
4.5" f/8, 28x, Bortle 6, NELM 5m3, SQM-L 19.7
Well split with big difference in brightness.

STF 1755 (**)
Name: STF1755
Type: **
Constellation: CVn
Coordinates: 13h32m21.99s / +36°49'05.60"

Components:
m1 m2 ρ θ Year
7m3 8m1 4.1" 133° 2018
Robert Zebahl
70mm f/5.7, 67x, Bortle 6-, NELM 5m0, SQM-L 19.1
At 31x just separable, extremely tight. At 44x clearly separated, but still close, relatively dim pair with moderate difference in brightness. At 67x and 100x well separable. The primary component appeared slightly orange.

STFA 24 (**)
Name: STFA24
Type: **
Constellation: CVn
Coordinates: 13h10m03.27s / +38°29'55.90"

Components:
m1 m2 ρ θ Year
AB 6m0 6m3 275.6" 296° 2012
This double star contains of the components 15 and 17 CVn.
Robert Zebahl
B 8x40, Bortle 7, NELM 5m0, SQM-L 19.2
Both components similar in brightness with large distance.