Diadem - Alpha Comae Berenices

[chiltonstar]

A rare clear night, with excellent seeing but relatively poor transparency (haze/mist) gave me the opportunity to have another try at this close double with my 180 Mak. I've tried before with smaller scopes, without much success - maybe a hint of being a double with my 127 Mak.

At x270 (10mm Baader Ortho), the star was clearly a figure of eight shaped double. At x540 (5mm WO Plossl) the shape was clear and very close to this simulation with Aberrator 3:-

 

Interestingly, the parameters given in CDSA appeared correct (at least compared with what I could see) in the sense that the PA was 12 degrees, with the fainter star nearly to the N of the main star. The value given in Stelle Doppie is 192 degrees, ie with the secondary to the S of the main star. The separation given in CDSA (0.6 arcsec) appears closer to what I could see than the SD value of 0.5 arcsec, although it is a fast-moving pair. Worth noting that it is an Eclipsing Binary!

M53 nearby was spectacular, although NGC 5053 was barely a stellar point because of the mist.

Anyone else had a view of Diadem??

Chris

[jetstream]

On 15/04/2018 at 03:41, chiltonstar said:

A rare clear night, with excellent seeing but relatively poor transparency (haze/mist) gave me the opportunity to have another try at this close double with my 180 Mak. I've tried before with smaller scopes, without much success - maybe a hint of being a double with my 127 Mak.

At x270 (10mm Baader Ortho), the star was clearly a figure of eight shaped double. At x540 (5mm WO Plossl) the shape was clear and very close to this simulation with Aberrator 3:-

 

Interestingly, the parameters given in CDSA appeared correct (at least compared with what I could see) in the sense that the PA was 12 degrees, with the fainter star nearly to the N of the main star. The value given in Stelle Doppie is 192 degrees, ie with the secondary to the S of the main star. The separation given in CDSA (0.6 arcsec) appears closer to what I could see than the SD value of 0.5 arcsec, although it is a fast-moving pair. Worth noting that it is an Eclipsing Binary!

M53 nearby was spectacular, although NGC 5053 was barely a stellar point because of the mist.

Anyone else had a view of Diadem??

Chris

Hi Chris I might try this one, I'm looking for a few tough but do able doubles for the TSA120. Any suggestions is appreciated, Gerry

[chiltonstar]

15 hours ago, jetstream said:

Hi Chris I might try this one, I'm looking for a few tough but do able doubles for the TSA120. Any suggestions is appreciated, Gerry

With a 120mm clear aperture, I suppose anything around the Dawe's Limit of 1 arsec would be fun. This table comes from Sky and Telescope, and has some nice doubles with decreasing separation......Good Luck!

Chris

14 Double Stars in Order of Decreasing Separation
Star		R.A.	Dec.	Mag 1	Mag 2	Sep.	P.A.	Comments	Scope
ι Cnc		08h 47m	+28° 46'	4.2	6.6	31"	308°	Spring Albireo!	Any
γ Leo		10h 20m	+19° 51'	2.2	3.5	4.5"	127°	Stunning, colorful!	60 mm
90 Leo		11h 35m	+16° 48'	6.0	7.3	3.3"	209°	3rd comp. 63″ SW	60 mm
38 Lyn		09h 19m	+36° 48'	3.9	6.1	2.5"	224°	Wide mag. spread	80 mm
γ Vir		12h 42m	–01° 27'	3.5	3.5	2.5"	2°	Easier than 38 Lyn	60 mm1
Σ1333		09h 18m	+35° 22'	6.5	6.7	1.8"	50°	---------------	80 mm
OΣ215		10h 16m	+17° 44'	7.2	7.5	1.6"	177°	Slowly widening	150 mm
57 Cnc		08h 54m	+30° 35'	6.1	6.4	1.4"	~316°	Orange, very nice	100 mm
Σ1338		09h 21m	+38° 11'	7.2	7.5	1.1"	~315°	Slowly widening	150 mm
OΣ186		08h 03m	+26° 16'	7.5	8.2	0.8"	73°	---------------	150-200 mm
Σ1555		11h 36m	+27° 47'	6.4	6.8	0.8"	148°	---------------	150-200 mm
ω Leo		09h 28m	+09° 03'	5.7	7.3	0.7"	103°	Tough one!	200 mm
Σ1517		11h 14m	+20° 08'	7.5	8.0	0.6"	115°	---------------	200-250 mm
φUMa		09h 52m	+54° 04'	5.3	5.4	0.45"	~300°	Equal mags. Ideal!	250-320 mm
Data are from the Washington Double Star Catalog and Sky Catalog 2000.0, Volume 2. Right ascension and declination are for equinox 2000.0

[jetstream]

8 hours ago, chiltonstar said:

Good Luck!

Thanks Chris!

I'm having fun with doubles now that I the AZEQ6 can find some...