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Sirius B observed

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#26 Astrojensen

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Posted 17 January 2019 - 03:13 PM

I split Sirius last year with my 10" Dob.  It definitely helps that Sirius B is approaching maximum seperation.  Here is the sketch I made of it.

Based on the cardinal directions in your sketch, you either didn't see Sirius B or you got the directions on the sketch wrong, as you show B to be West of Sirius, but in reality it is East of Sirius. When seen in the eyepiece, Sirius B is trailing behind Sirius, almost directly to the East, but slightly to the North of the E-W line.

 

 

Clear skies!
Thomas, Denmark


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#27 Astrojensen

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Posted 17 January 2019 - 03:21 PM

Thomas, the last sentence was the one I noticed especially, when re-reading this thread. 6"-8" apos at or near periastron? Doesn't seem likely. At closest approach the separation of Sirius A and B is about 2.5", less than a quarter of the current 11". The glare factor I'd expect to get worse at a faster rate than the reducing separation. At 11" it's relatively attenuated.

 

Given the 10 mags brightness difference, Sirius at periastron will be rather like trying to see Procyon B, mentioned earlier in this thread, which I've found was observed with less than the Lick 36-inch: from memory, though I'll look for the information again, it was with a 67cm refractor by, I think, van den Bos in South Africa. With much less aperture than that it doesn't seem to be possible.

Well, Leo Brenner (who is rather infamous, but many of his observations have been confirmed by spacecraft images) claimed to have seen Sirius B in a 7" when it was near periastron. Given the fact that he was observing from a superb location at a Mediterranean site and that I read very convincing visual reports of sightings with scopes as small as 80mm already in 2003-5, I don't consider it *completely* unlikely to be possible to see Sirius B near periastron with a 7". 

 

But that's just my gut feeling, not cut-in-stone facts. I think it would be fun to follow Sirius B for as long as possible with an 8" high-end apochromat from a site with superb seeing. Sadly, I am not in possession of either.

 

 

Clear skies!
Thomas, Denmark


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#28 fred1871

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Posted 17 January 2019 - 11:54 PM

Thomas, do you have a reference for he Leo Brenner sightings?

 

For the 2003-5 period, were these reports in Sky & Telescope (which is keen to carry all manner of Sirius stories), or reports here on CN?



#29 InkDark

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Posted 18 January 2019 - 10:14 AM

Magnification was around 67x. 

 

 

Clear skies!
Thomas, Denmark

I guess we don't have the same skies and the same scope 'cause I need a bit more to split Rigel.

 

I'll have to try again and get my eye use to the task.



#30 fred1871

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Posted 18 January 2019 - 08:46 PM

Thomas, my reason for asking about Leo Brenner's claim was to get a date (no doubt listed in the publication) so as to establish the separation of Sirius A and B at that time.

 

Regarding the 2003-2005 observation claims, the separation for Sirius at the time is in the 6"-7" range, not the 2.5" for periastron. One would also need to evaluate the observations, because if there's only one out of say twenty observers who claim success while using 80mm, it becomes an outlier, and doubtful. At best, it means exceptional eyesight.

 

There's also the possibility of internal reflections in the optics, a point noted by an observer in another current thread here on CN regarding Sirius. Some observers don't check for that.

 

Finally, we had the experience a few years ago with another double of various folk being very certain they'd seen the companion star, and describing where it was. When a new speckle measure was made (professional observer, 4-metre scope, etc) it showed that all but one of the observers claiming to have seen the companion were getting a false positive. And there was no reason to think they were making it up. The one observer who did succeed had been uncertain whether the (extremely difficult) companion star was definitely seen: but his observations accurately fitted the real position. Others had expected a wider separation, based on a measurement that turned out to be wrong. Perhaps that had an unconscious and unintended effect on their observing attempts.

 

With Sirius, of course, we know with good accuracy the separation and angle. With a bit of observing practice it's possible to know, given the scale at a particular magnification, and working out the angle as seen, where to look. The angle seen in the eyepiece seems to be a problem for some. Establish West -  where the drift is towards. North and South can be found by using the slow motion controls or nudging the scope (Dobs, etc). The PA (position angle) is currently about 70 degrees, so a little bit northwards from directly East. Sirius B will trail in the field, following Sirius, offset slightly Northwards from the E-W line.

 

Clockface descriptions in isolation don't tell you the direction. With a refractor, SCT, Mak, using a diagonal which can be rotated will change the angle; your head angle can change it too. And with Newtonians the angle on the sky, Sirius, telescope, head, will affect the angle in the eyepiece. That's why establishing your directions in the eyepiece, as above, gives you what's needed.


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#31 Astrojensen

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Posted 19 January 2019 - 04:35 PM

I'll try and dig up the old issue of Sky and Telescope again. I do recall that the article mentioned that he had done it "close to periastron" and I'm not sure a more accurate date was mentioned.

 

My late friend Per Darnell had, incredibly, all the old issues of "Astronomische Rundschau", which Brenner published and in which he showed his observations. I've actually leafed through them and read a little here and there, but can't remember any details, except the absolutely stunning drawings of Jupiter and Saturn. Sadly, I don't know what has happened to Darnell's library after his passing. 

 

 

Clear skies!
Thomas, Denmark



#32 Uwe Pilz

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Posted 20 January 2019 - 01:20 AM

I don't think that we should take the observations of Leo Brenner too serious. His live was at least adventurous, full of lies. Astronomische Nachrichten refused to print anything of him in the later times.

 

Here

http://www.geocities...ac/Prog/S_T.pdf

ist the Syk and Telsecope Article form 1995

 

The 

Mitteilungen der Astronomischen Vereinigung Karlsruhe gave a summary of his life, in German of course. I give the most important sentences here  – again in German, but Google translator helps perhaps. If you don't understand anything, please ask me.

 

Der gute Eindruck, den Brenner anfangs auf seine Zeitgenossen machte, ist nicht
schwer zu verstehen. Im Jahre 1895 gab es nur wenige Beobachter, die systematisch die
Planetenoberflächen beobachteten, und dies hauptsächlich beschreibend, beschränkt auf die
visuelle Kontrolle und auf Zeichnungen. Die glänzenden Beispiele von G.V.Schiaparelli und
Persival Lowell boten aufregende Aussichten auf Entdeckungen für einen Beobachter mit
gutem Auge, der an einem erstklassigen Beobachtungsplatz arbeitete.

Aber die Entdeckungen, die Brenner so überzeugend ankündigte, wurden immer extremer:
Von seinen zahlreichen Zeichnungen der Venusoberfläche mit dunklen Markierungen leitete
er 1895 eine Rotationsperiode des Planeten von 23 Stunden, 57 Minuten und 36.2396
Sekunden ab. Im Jahr darauf korrigierte er den Wert für die Sekunden auf 36.3773. Ebenfalls
im Jahr 1896 verkündete er triumphierend die Rotationsperioden von Merkur und Uranus zu
23.25 Stunden beziehungsweise 8 Stunden 17 Minuten. Heute wissen wir, dass Brenners
Wert für Merkur falsch war. Aber, peinlicherweise ist die von ihm angegebene Periode für
Uranus fast exakt die Hälfte des besten obwohl immer noch unsicheren derzeit bekannten
Wertes. Vergleichsweise bemerkenswert war Brenners Atlas des Mars, den er aufgrund seiner
Beobachtungen in den Jahren 1896 und 1897 angefertigt hatte; er zeigte nicht weniger als 164
Kanäle, die meisten davon zum ersten Mal. Achtzehn davon liefen in verschiedenen
Richtungen von einem dunklen Fleck aus, dem Trivium Charontis. Brenner erhob später den
Anspruch, 34 Marskanäle allein mit einem 3-Zoll Refraktor entdeckt zu haben.

Und da war noch die Sache mit dem Sirius-Begleiter, der im Jahre 1894 sein Periastron
durchlief. Zwischen März 1891, als S.W.Burnham seine letzte Messung mit dem 36-Zoll
Refraktor auf dem Lick-Observatorium gemacht hatte und dem August 1896, als R.G.Aitken
ihn mit demselben Teleskop wieder sah, war der schwache Begleiter in dem hellen Glanz des
Sirius unbeobachtbar. Nichtsdestoweniger publizierte Brenner in den "Astronomischen
Nachrichten" Mikrometer-Messungen, die er mit seinem 7-Zoll Refraktor in zwei Nächten im
März 1897 gemacht zu haben vorgab.

Die freundlichste Deutung dieser verschiedenen erstaunlichen Beobachtungen von Brenner ist
die, dass er nicht unterscheiden konnte zwischen dem, was er sah, und dem, was er sehen
wollte. Die Astronomen, die seine Beobachtungen zunächst beifällig zur Kenntnis nahmen,
distanzierten sich nach einer Weile von ihm, und Heinrich Kreutz, der Herausgeber der
"Astronomischen Nachrichten", lehnte es zum Schluss ab, irgendetwas von Brenner zu
drucken.

 

 


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#33 Asbytec

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Posted 20 January 2019 - 07:11 PM

It was almost conspicuosly easy, even if I couldn't see it all the time, due to turbulence at the low altitude, but it remained visible in the same, correct location, as a small, flickering speckle, as I moved Sirius around the field. 

 

 

Clear skies!

Thomas, Denmark

That's amazing, Thomas. My first attempt with an 8" at 300x under modest seeing. I thought Sirius B was easy, too. Kind of anticlimactic. But it turned out to be a nearby field star instead. It took another night of good seeing to just barely catch a few glimpses of it as Sirius hit the field stop. I was also looking form some indication of it, as you mentioned a steady speckle that persisted. Or maybe a tiny point, or a small bloating of a diffraction ring. Something. I got a few maybe sightings, and maybe some of them were not spurious. But, not sure enough to call it. 

 

It makes me wonder why large apertures may have some difficulty with the Pup. One thing that comes to mind is larger apertures gather a lot of light and show a nice expanse of diffraction rings in good seeing and a lot of spiking and speckling in worse seeing. They also gather the sky glow from Sirius. Of course, my scope is obstructed, too, with it's associated rings. Last night I caught it  under high thin overcast with a full moon, so that certainly didn't help things. But, apparently it didn't make it impossible, either. An 8" has plenty of resolution, maybe too much light grasp for Sirius but not for dimmer field stars, and maybe some obstruction effects. 


Edited by Asbytec, 20 January 2019 - 07:12 PM.

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#34 fred1871

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Posted 23 January 2019 - 06:45 AM

Uwe, thank you for the Sky & Telescope article link. Very informative. I had read it many years ago, but it was good to see it again.

 

I then had a look at the Orbit diagram for Sirius, which appears in the 6th Orbit Catalogue, available online from the US Naval Observatory as part of the catalogs collection that includes the WDS. There's only one past measure marked in the periastron region, which I suspect is Leo Brenner's claimed measure. Otherwise, nothing in the closest part of the orbit. Once the separation approaches 4" the measure attempts re-commence.

 

So I suspect that observations during the very closest part of the orbit will remain a very difficult territory no matter what instruments are brought to bear. The brightness difference of Sirius A and B, near enough 10 magnitudes, will exclude speckle imaging in its current forms.


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#35 Miranda2525

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Posted 23 January 2019 - 05:55 PM

I was honestly a little surprised by how easy it was. I've seen Sirius B each year now three years in a row, when it's high in the morning autumn sky. It's much, much easier, when it's not high in a dark sky, where the brilliance of Sirius itself is overpowering the feeble flicker of the companion. 

 

Very high quality optics obviously helps, as does the binoviewer, at least for me. 

 

 

Clear skies!
Thomas, Denmark

Congratulations!

 

I have still yet to see it. I'm thinking  maybe the binoviewers helped?  I notice that when I use my binoviewers, I always see faint stars better than when I use only one eye.


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#36 Astrojensen

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Posted 24 January 2019 - 11:18 AM

Congratulations!

 

I have still yet to see it. I'm thinking  maybe the binoviewers helped?  I notice that when I use my binoviewers, I always see faint stars better than when I use only one eye.

The binoviewer clearly helped. I've done comparisons with and without binoviewer and Sirius B was definitely easier to see with the bino than with a single eyepiece.

 

I think that is because seeing Sirius B itself is not actually a detection challenge, as it is magnitude 8.5, according to the photometer and the number of photons arriving. Instead it becomes a contrast challenge, detecting the tiny, faint speck next to the bright beacon of Sirius itself and when it comes to contrast detection, a binoviewer offers 41% better contrast than a single eyepiece, if both eyes work equally well. 

 

 

Clear skies!
Thomas, Denmark 


Edited by Astrojensen, 24 January 2019 - 11:22 AM.

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#37 John Fitzgerald

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Posted 24 January 2019 - 11:20 AM

I'm going to try to see Sirius B again extensively this winter/early spring once the 6" APO comes in.


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#38 Astrojensen

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Posted 24 January 2019 - 11:25 AM

I'm going to try to see Sirius B again extensively this winter/early spring once the 6" APO comes in.

Early spring evenings, when Sirius rides high in the south, right after sunset, is a really great time to see B. Start as soon as you can see Sirius itself and just keep looking, until it pops up, when the conditions are just right. Since you also need fairly good seeing, you may need to try several evenings, until you finally come across an evening, where everything fall into place.

 

 

Clear skies!
Thomas, Denmark


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#39 Miranda2525

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Posted 24 January 2019 - 06:55 PM

The binoviewer clearly helped. I've done comparisons with and without binoviewer and Sirius B was definitely easier to see with the bino than with a single eyepiece.

 

I think that is because seeing Sirius B itself is not actually a detection challenge, as it is magnitude 8.5, according to the photometer and the number of photons arriving. Instead it becomes a contrast challenge, detecting the tiny, faint speck next to the bright beacon of Sirius itself and when it comes to contrast detection, a binoviewer offers 41% better contrast than a single eyepiece, if both eyes work equally well. 

 

 

Clear skies!
Thomas, Denmark 

Those other points you made make sense too. Thanks for your post!

 

And again congratulations!  May your skies always be clear and eventful! 



#40 Luna-tic

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Posted 25 January 2019 - 11:49 PM

I managed to get Sirius B tonight, along with several other close splits; the seeing and sky clarity was incredible tonight from my location (N35*38'46"/W81*15'5"), seemed to be better than Astrospheric indicated it would be. I went "double hunting" tonight, slewing to every one listed on the Synscan HC that wasn't behind a tree. I used a 13mm Ultima EP in my Edge 8, giving me 154X.

 

I split Sirius B, but wasn't sure it was really "B", so I moved 'A' to the field stop in the EP, occulting the bright star, and sure enough, could see 'B'. I also split Rigel, and got 'E' and 'F' in the Trapezium. The real highlight of the night for me was seeing Beta Monocerotis for the first time. Beautiful and really close triple. I also looked at Castor tonight, and I'm pretty sure I saw the 'C' pair (as a single, of course) very faint and a bit distant from 'A' and 'B'.


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#41 flt158

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Posted 26 January 2019 - 08:44 AM

I managed to get Sirius B tonight, along with several other close splits; the seeing and sky clarity was incredible tonight from my location (N35*38'46"/W81*15'5"), seemed to be better than Astrospheric indicated it would be. I went "double hunting" tonight, slewing to every one listed on the Synscan HC that wasn't behind a tree. I used a 13mm Ultima EP in my Edge 8, giving me 154X.

 

I split Sirius B, but wasn't sure it was really "B", so I moved 'A' to the field stop in the EP, occulting the bright star, and sure enough, could see 'B'. I also split Rigel, and got 'E' and 'F' in the Trapezium. The real highlight of the night for me was seeing Beta Monocerotis for the first time. Beautiful and really close triple. I also looked at Castor tonight, and I'm pretty sure I saw the 'C' pair (as a single, of course) very faint and a bit distant from 'A' and 'B'.

Perhaps you might give Zeta Cancri a go some time Luna-tic. 

It is otherwise called Tegmine. You might split it at 154X. 

But then again you probably will require something close to 200X or higher. 

Congratulations on seeing Sirius B.  

 

Aubrey. 



#42 Luna-tic

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Posted 26 January 2019 - 02:37 PM



Perhaps you might give Zeta Cancri a go some time Luna-tic. 

It is otherwise called Tegmine. You might split it at 154X. 

But then again you probably will require something close to 200X or higher. 

Congratulations on seeing Sirius B.  

 

Aubrey. 

Actually, I meant to. I went out just after full dark, Cancer was still low and I have trees blocking my low eastern view. I saw Z Can on the HC but forgot to go back to it later that night when it was high enough. I definitely won't miss it the next time. I checked it out in Stellarium, looks about as close a split as does Beta Mon, but after reading about the Z Can system, it's a bit confusing, lots more than the eye, or telescope, can see; at least five stars, and I can't get a grasp of what is A, B, and C.Two of one pair are listed as 5.06 arc-sec apart, which isn't as close as the smaller gap in the Beta Mon triple (3.9 arc-sec), which I split at 154X.  At any rate, I'll have a go, probably tonight, as it's supposed to be as good as last night. If it's as good seeing as last night, the air will support more than the 154X I was using. I tried a 2.5X Barlow last night with the 13mm EP, which gave me 384X but it was too much to see E and F in the Trapezium. I didn't try anything in between; I have a 10mm Hyperion I can try, it will give me 200X, or I can try the Barlow again with a 20mm, which will give me 250X. Anyway, it gives me a great excuse to set up again.


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#43 Luna-tic

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Posted 27 January 2019 - 11:10 AM

Perhaps you might give Zeta Cancri a go some time Luna-tic. 

It is otherwise called Tegmine. You might split it at 154X. 

But then again you probably will require something close to 200X or higher. 

Congratulations on seeing Sirius B.  

 

Aubrey. 

I did, Aubrey, the night following your post. I started a new thread on the Double Star Observing forum since it didn't really fit here, about my results. Thanks for setting up a great evening.

https://www.cloudyni...-and-then-some/


Edited by Luna-tic, 27 January 2019 - 11:11 AM.



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