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Sirius A and ...... Sirius B !!!

John

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John

John

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I'm back in again after a concentrated session of 90 minutes on Sirus with my 12" Orion Optics dobsonian.

After many attempts with many scopes, I've no doubt that I was, at last, able to see Sirius B tonight - the infamous "Pup" star :grin:

The success first came with a 5mm Baader Genuine Orthoscopic eyepiece which was giving 318x and a pretty "tight" image of Sirius A. The curved secondary supports in the scope remove the normal 4-way diffraction spikes but the Dog star still showed a fine circlet of tiny spikes. And there, buried in this fine halo was a small glimmering point of light that came and went but, importantly, appeared at a constant distance from Sirius A, following in it's wake as it crossed my field of view, more or less due east of the main star. I watched fascinated as the pair crossed the field and disappeared behind the field stop. I nudged the scope to reposition them back on the opposite side and watched the show again, and again. The B star was not always visible during these transits but it did show constantly for a few seconds at a time when the seeing settled slightly.

I then replaced the 5mm ortho with the 6mm BGO and repeated the exercise. Same result and perhaps a little easier to discern the faint B star as Sirius A was defined a little more tightly. I then tried a number of eyepieces around those focal lengths, 6mm BCO, 6mm Circle-T ortho, 5mm Pentax XW and the 6mm Ethos.

The companion to Sirius A was never exactly easy to see but it was more obvious with the Baader orthos, a little more challenging with the 5mm XW and tough to more than glimpse occasionally with the Circle-T ortho and Ethos. More powerful eyepieces seemed to expand the halo around Sirius A so that B was drowned out although I did manage to spot it a couple of times with the 10mm Baader Classic Ortho + Baader 2.25x barlow for 4.4mm, which I was quite impressed by.

I thought the angular relationship between the A and B stars seemed right from the charts I've seen of their current positioning. For a sense of "scale" to judge the separation I used Castor which has a separation of around 4 arc seconds at the current time. The separation of the Sirius A & B pair appeared to me to be around twice that of the bright Castor pair. Again this appears about right as currently the data I have indicates a separation of around 8 arc seconds.

If this had been a fleeting glimpse I would not have been convinced but the fact that I was able to repeat the observation quite a number of times, consistently, with a number of different eyepieces leaves me confident that I have, at last, been able to "see the Pup" :smiley:

And that's a good feeling :grin:

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John

John

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Thanks James :smiley:

Yes Mark, FLO have kindly lent me a set of the Baader Classics (3 orthos, 1 plossl and a barlow) and some Bader Genuine Orthos to compare with them. In this instance the BGO's scored first but the BCO 6mm was right up there too. You really need eyepieces that have an absolute minimum of light scatter with this object and good orthos are excellent for that :smiley:

The scope played a big part too - I'm so lucky to have found this Orion Optics 12" F/5.3 and that Shane has created such a nice mount for it. I'm hugely looking forward to taking it too SGL8 :grin:

The southern horizon at Lucksall is less cluttered than mine is here - I may be able to get an even better view !

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alan potts

alan potts

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Great News and a great report. It is very interesting to have read the part about the eyepieces, maybe I will buy one after all.

I also find it interesting of the diffent approach I tend to look for it with a magnification of around X100-150 in most scopes. I have never seen it using the amount power you had on. I know it makes so much difference with it being higher for me, when I was in Hull it was barely over the roof tops of 100 yard distant houses.

Well Done I am so pleased to hear this!

Alan.

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Marki

Marki

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What a thoroughly enjoyable read, John. And congrats! Regretfully I was too tired to enjoy much last night, and constantly irritated by cloud dodging whenever I went out. Sirius was pretty low for me over a neighbour's offshot kitchen, so no dice again! However, you've inspired to me to keep on trying, or at least to consider swapping all my fracs for a well built 12" dob :grin:!

The comparison of the eps is very interesting too. The BGOs really seem to score well - and I regret not buying the full set when I had the chance!

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Angus Wright

Angus Wright

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Very interesting account of an observation of Sirius B. I can say that it is an object that is on my 'must see one day' list. As the angular separation is currently increasing for the next few years so it should get a bit easier, up to about 2025 I think.

Sent from my iPad using Tapatalk HD

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John

John

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Thanks folks :smiley:

You are right Angus, it's not a particularly close pair at the moment but it's that massive brightness difference that provides the challenge.

The Pup is a very interesting object - it's just a bit smaller than the Earth but has 98% of the mass of the Sun - a white dwarf I believe.

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Damo636

Damo636

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Many congratulations John, that's an extremely tough cookie to crack :icon_salut:

I've never managed it myself but your success will help breathe new life into my half hearted attempts.

PS. Any pics of the 12" on its new mount? :smiley:

Edit: Just found pics in the Members Equipment forum :rolleyes:

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John

John

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John

Thinking about it, I think the key factor was the arctic blast we have just had in my experience the seeing and transparency are always at their best in these conditions.

Cheers

Ian

Thanks Ian - "its an ill wind that blows nobody any good" then :smiley:

It's funny how having something really gripping to concentrate on, like the possibility of splitting Sirius, seems to ward off the cold to some extent :smiley:

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lunator

lunator

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Thanks Ian - "its an ill wind that blows nobody any good" then :smiley:

It's funny how having something really gripping to concentrate on, like the possibility of splitting Sirius, seems to ward off the cold to some extent :smiley:

John

I used to joke with my non-astronomy friends that astronomers were the only people who were happy when the wind blew directly from the North :)

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