I split Sirius A and Sirius B

james and james mceachern

I split Sirius A and Sirius B

Unread post by james and james mceachern » Mon Feb 12, 2007 8:46 pm

:D Tonight at 8:00pm I finally separated Sirius A and Sirius B. I was using my trusty old 10" Antares Dobsonian (thanks Mark) with my 5.7mm W70 EP. I got it with no filters by just barely moving Sirius A out of my FOV. I could see it clearly, which was a huge surprise since I've had no previous luck. To make sure it wasn't just reflected light I moved Sirius A to the other side of my field of view. But I found that it was for real. I've at least spent about 1/2 hour every observing night trying to split these two, and finally my determination payed off. I was also surprised because the sky was a little hazy, maybe that helped? I also could see it with a LP filter, but not as good as with no filter. All and all, when it comes down to spliting this double, I think that a good collimation, and a steady cold night are all one needs. You have to take any chance you get, no matter how cold it is. Who will be the next to split Sirius A and Sirius B? 8)

Clear Skies,

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Unread post by NGC7000 » Sat Feb 17, 2007 10:41 pm

Congratulations, J!!! Do you think it can be done with a good 4" refractor? :D

james and james mceachern

Unread post by james and james mceachern » Sun Feb 18, 2007 12:49 pm

Like I said, with good skies and good optics it looks like it can be done by anyone willing to face the wrath of nature. At the time I got it I wasn't thinking about how hard it would be for smaller sized telescopes to get it. But I don't think it will be much of a problem. For some reason, I got it when it was just slightly hazey, so I am going to test out that theory again some time. If hazey skies is all we need then we're in luck because we live in New England :lol: . The next time I view it I will see if I can get it with my 6" Newt. and then my 80mm Baytronix refractor. My 80mm doesn't have that good optics so, if I don't get it I won't be too surprised.
Keep on trying.


Unread post by twmiller123 » Mon Feb 19, 2007 2:22 am

Congratulations James! I always love the way it feels when I have been trying to see something for a while and finally it happens. Your persistance paid off. :wink:

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Unread post by Dan Chieppa » Wed Feb 21, 2007 1:40 am

Congrats on seeing the Pup. I've been meaning to try it with my ETX125 but end up doing other things when I'm set up. The last night out the clouds shut me down after just one hour of observing. It's on my list for the next clear night with no wind. I have a fairly good view to the south and Sirius is well-placed for me by 9PM.
Clear skies,
james and james mceachern

Unread post by james and james mceachern » Wed Feb 21, 2007 4:10 pm

it took constantly adjusting the scope to keep "a" & "b" seperated but the method of "keep sirious A just out of view using the scope tube to shield it, then look for B at about 5 o'clock" this is what we did and they are so close together that the space between them gives the illusion of being flat sided, figure as the glow of "A" is over powering the light being observed from "B" so it causes a distortion and makes it looked like a flat sided star, we observed it at about 4 o'clock to sirious "a" not at 5 o'clock as the article mentioned and there were light rays from "a" going above and below sirious"b". we used 10" dob w/ w70 15 mm ep, tried to view better with filters but best results were from the ep alone, once found we tried other ep's(9,12,19) but 15mm ep gave us the best view, clear skies j&j
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The "Pup"

Unread post by Mark G » Sat Feb 24, 2007 10:07 am

James & Jim,

Sweet on finding the "pup". 8) Good optics, occluding the primary star and steady skies are what is needed to split that pair. Usually hazy skies means the air above is steady, and yes not good for contrast on extended faint objects like DSO's but it is considered good seeing conditions for planetary observers.

Wind will clear out the haze (moisture) usually, unless you live in New England, then the wind brings in the haze that seems to condense into clouds just after sunset. :evil: Seem that way these last few years huh? :lol:

Some times a higher power EP will place the close companion star of a double star system in a diffraction ring of the primary star making it more difficult to see, but not impossible for a trained double star observer. So trying different EP's is key.

I do love the way you push your Antares 10" Dob. These scopes do have some good optics. Matt & I had my Antares 8" f/5 holding 500x on a rare night of excellent seeing on the day past full Moon, and Uranus last fall, with no image breakdown. On Uranus we noted a BB sized orb with definite pole lightening on the hemisphere with that massive hurricane. Checking online later that night confirmed our sighting as that storm was presenting itself towards earth. And surfing the thin terminator on the Moon was a real joy at 500x. There was only the occasional boil to note not the opposite. That is past the theoretical maximum useful power of 50x/inch of aperture of an 8" mirror. I'd bet it could of gone higher too as I had my 4 mm UO ABBE Ortho in my ClearVue 2" 2x Barlow. I had no means to get a higher power! :o

Finally, FWIW I recently had an Antares 6" f8 primary mirror tested for surface accuracy. Averaging the results rated at 1/16th wave. So you've proved that an Antares 10" f/5 can be a very versatile telescope with good optics, at a good price. Don't tell anyone! :lol: Then everyone will want one! :wink:
Clear skies,


iOptron CEM25P w/ Tri-pier
LXD750 w/ CDS #1697
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Antares 8" f/5 Newt
Antares 4" f/15 "Vixen Spec" long focus refractor
Orion 4" f/7 ED refractor
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and so much more
james and james mceachern

Unread post by james and james mceachern » Wed Feb 28, 2007 10:36 pm

Got it again, this time with my 4" scope. Go to "A Wierd and Amazing night" to see whole story.

james and james mceachern

Unread post by james and james mceachern » Wed Feb 28, 2007 11:46 pm


The Antares scopes have excellent magnification, I've had my 10" up to 525X once. Comes in handy when kick'n the crap outta them double stars 8) :wink:

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Unread post by RobCos » Thu Mar 01, 2007 11:09 pm

james and james mceachern wrote:Got it again, this time with my 4" scope. Go to "A Wierd and Amazing night" to see whole story.

James, what magnification are you using in both scopes to split these two?