37 replies to this topic

[javad]

Hi all,

 

Last night I decided to give a shot to Sirius B. Seeing was mediocre. For a few minutes the seeing improved and I am confident that I saw a dim and small star at about 2 o'clock position from Sirius. Then I could no longer see it again no matter what, despite Sirius getting higher. Maybe the seeing worsened? 

 

Location: 40*N, 50*E

Time: 01:00h

 

How likely is it that it was actually the Pup?

[Astrojensen]

 

How likely is it that it was actually the Pup?

We have no way of saying, before we know what telescope and magnification you used. Also, a description like "2 o'clock" is meaningless, since it depends on a whole range of factors, only a few of which are mentioned in your post. It's better to describe the position of the companion in relation to the motion of Sirius itself in the eyepiece, IE whether it was trailing after Sirius in the eyepiece or ahead of it, and whether it was to the north or south of the east-west line of diurnal motion. This method eliminates any uncertainties. 

 

 

Clear skies!

Thomas, Denmark

[javad]

We have no way of saying, before we know what telescope and magnification you used. Also, a description like "2 o'clock" is meaningless, since it depends on a whole range of factors, only a few of which are mentioned in your post. It's better to describe the position of the companion in relation to the motion of Sirius itself in the eyepiece, IE whether it was trailing after Sirius in the eyepiece or ahead of it, and whether it was to the north or south of the east-west line of diurnal motion. This method eliminates any uncertainties.


Clear skies!
Thomas, Denmark

Sorry for omitting crucial details

I used a 10" f/5 dob with a 7mm eyepiece, about 180x magnification. The companion was trailing Sirius.

Here is a rough sketch from my memory.

I indicated West as such because was following that direction. But probably it is off, feel free to correct me.

I suck at drawing, please excuse the low quality.

Attached Thumbnails

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Edited by javad, 03 December 2021 - 01:30 AM.

[ziggeman]

I once 'saw' it too. in a c14. And took a photo and send it with postage mail over the atlantic. (internet was barely invented), to a guy named Brian Marsden.

Even though they had a photo they couldnt be certain it was Sirius b. The photo was to unclear with glares they said. This happened in the 70s.

I will try again one day!

[Sarkikos]

Sorry for omitting crucial details

I used a 10" f/5 dob with a 7mm eyepiece, about 180x magnification. The companion was trailing Sirius.

Here is a rough sketch from my memory.

I indicated West as such because was following that direction. But probably it is off, feel free to correct me.

I suck at drawing, please excuse the low quality.

The Pup is pretty easy to see in a 10" f/5 Dob, given decent seeing.  I've seen it many times in my 10" f/4.8 Dob.

 

The Pup is about 11" roughly E from Sirius, and so should be trailing Sirius.  I think you saw the Pup. 

 

Mike

Edited by Sarkikos, 05 December 2021 - 09:27 AM.

[Konstantin 1980]

I observed the Sirius satellite even during the day, with my 254 mm telescope. I also took a photo. The state of the atmosphere and the correct magnification are of prime importance. The minimum aperture in which I saw the satellite after sunrise (!!) is 140 mm. Sirius was 19 degrees high.

[Sarkikos]

We didn't have to take the picture as proof.  I would have believed you. 

 

Mike

[javad]

The Pup is pretty easy to see in a 10" f/5 Dob, given decent seeing. I've seen it many times in my 10" f/4.8 Dob.

The Pup is about 11" roughly E from Sirius, and so should be trailing Sirius. I think you saw the Pup.

Mike

Best news this morning! Thanks. The pic you attached is close to what I saw too!
I also saw for the first time Trapezium E and F stars that night. What a night!)

Edited by javad, 06 December 2021 - 01:20 AM.

[Sarkikos]

Yes, if the seeing is decent, the Pup and the Trap E and F are pretty easy to see in a 10" f/5 Dob.  Some observers call a 10" Dob "the smallest of the big telescopes."

 

Did you notice the color of the Pup?  For me, it always had a pale blue color.

 

Mike

Edited by Sarkikos, 06 December 2021 - 09:23 AM.

[Voyager 3]

Your sketch too is very much like how it appears in the eyepiece .. and yes , the pup will always trail behind the primary without tracking .
Hmm looks like you did it!

[javad]

Yes, if the seeing is decent, the Pup and the Trap E and F are pretty easy to see in a 10" f/5 Dob.  Some observers call a 10" Dob "the smallest of the big telescopes."

 

Did you notice the color of the Pup?  For me, it always had a pale blue color.

 

Mike

Yes it is a decent machine I am glad I built my 10"just  before this supply shortage. 

I think I remember the pup being white, next time I see it, I will pay close attention.

 

In summer I could easily split Izar, in theory Pup should be easier?

[javad]

Thanks everybody for your comments, I used to think double star observing was boring, could not have thought it would be this fun!

[Mr.Furley]

Izar is much easier to split than Sirius in my experience.. that little guy gets lost in the glare of the primary if the seeing is shaky at all. I will definitely have to give it another shot next time im out late enough.

[Bigzmey]

Not to rain on anyone parade but there is a 11.2 mag field star at 111" separation from Sirius A at PA=64.5 deg. It is much easier to spot compared to Sirius B at 11.3" separation and pretty much the same PA=64.7 deg.

 

I bet majority of Sirius splits are mistaken identity. If you can't positively identify both that field star and Sirius B, you can't claim that you have split Sirius. 

[Sarkikos]

Not to rain on anyone parade but there is a 11.2 mag field star at 111" separation from Sirius A at PA=64.5 deg. It is much easier to spot compared to Sirius B at 11.3" separation and pretty much the same PA=64.7 deg.

 

I bet majority of Sirius splits are mistaken identity. If you can't positively identify both that field star and Sirius B, you can't claim that you have split Sirius. 

An 111" separation is nearly 2 minutes, and ten times larger than the separation of Sirius A from Sirius B.  Javad was observing with a 10" f/5 Dob and a 7mm eyepiece.  He didn't mention the type of eyepiece.  Let's say something like a Plossl.  That would be about a 50 degree AFOV.  A Delite would be 62 degree.  In either case, the star at 111" (about 2') separation would be maybe 1/5 of the way from Sirius B at center of field to edge of field.  That star would be well away from the glare of Sirius, and not as close as in Javad's drawing.  I think Javad saw the Pup.

 

I've never mistaken any other star for the Pup.  It is a pale blue star nestled in close to Sirius A.

 

Mike

[Bigzmey]

An 111" separation is nearly 2 minutes, and ten times larger than the separation of Sirius A from Sirius B.  Javad was observing with a 10" f/5 Dob and a 7mm eyepiece.  He didn't mention the type of eyepiece.  Let's say something like a Plossl.  That would be about a 50 degree AFOV.  A Delite would be 62 degree.  In either case, the star at 111" (about 2') separation would be maybe 1/5 of the way from Sirius B at center of field to edge of field.  That star would be well away from the glare of Sirius, and not as close as in Javad's drawing.  I think Javad saw the Pup.

 

I've never mistaken any other star for the Pup.  It is a pale blue star nestled in close to Sirius A.

 

Mike

Mike, following your line of thoughts, 50 deg EP at 180x will produce TFV of 16.7' Here is a screenshot from SkySafari Por 6 simulating this FOV. Crosshair shows the 11.2 mag field star at 111" separation. You can't even see Sirius B in this view

 

 

Considering how far Sirius glow extends, to me the faint star in the OP sketch is too far to be the Pup at 180x. Sirius is one of the toughest splits out there. If you want to be true to yourself one need to verify the PA and distance using field stars as reference.  

 

Experienced observers I trust never take it lightly. They report ~10% success rate (largely depending on seeing), if some one says it is easy, no matter with what aperture something is amiss. 

[Bigzmey]

This observation is much closer to my experience. See how close the Pup at 489x to the Sirius? It is basically sitting within the Sirius A glare. And further away is the field star I was referring. At 180x it will be ~3 times closer to the Sirius A disk.

 

https://www.cloudyni...us-b-the-pup/  

[Sarkikos]

Mike, following your line of thoughts, 50 deg EP at 180x will produce TFV of 16.7' Here is a screenshot from SkySafari Por 6 simulating this FOV. Crosshair shows the 11.2 mag field star at 111" separation. You can't even see Sirius B in this view

 

Screenshot_20211209-174210_SkySafari 6 Pro.jpg

 

Considering how far Sirius glow extends, to me the faint star in the OP sketch is too far to be the Pup at 180x. Sirius is one of the toughest splits out there. If you want to be true to yourself one need to verify the PA and distance using field stars as reference.  

 

Experienced observers I trust never take it lightly. They report ~10% success rate (largely depending on seeing), if some one says it is easy, no matter with what aperture something is amiss. 

Yes, I set up my SkySafari Pro 7 to simulate the same thing earlier this evening.  The split to the star that is 111" away is comparatively far from Sirius A and very easy to see.  Now imagine a star 1/10 of that distance.  

 

But you're going by a screenshot from SkySafari.   Can you trust that the size of the glare from Sirius on SkySafari exactly matches what you will see through a specific telescope?  I take what SkySafari shows me in images of stars and DSO with a great big grain of salt.  SkySafari isn't designed for a specific telescope, by for a wide range of telescopes.  We are talking about a separation of 11" in a 10" telescope.  Whether or not the observer can split the Pup at that scale in a 10" aperture depends a lot on the quality of the sky, the telescope and the observer.

 

All I can say is, if an amateur astronomer doubts that they can see the Pup at a certain magnification, increase the magnification.  This is what you should do.

 

I've seen the Pup plenty of times with my 10" f/4.8 Dob.  I never mentioned any smaller aperture.  In fact, my 10" is the only telescope I've ever seen the Pup through.  It does take good seeing to split it.  But as long as the seeing was good, it wasn't difficult to see it.  

 

Mike

Edited by Sarkikos, 09 December 2021 - 09:45 PM.

[Sarkikos]

I know for a fact that I've seen the Pup with a 5mm XO in my 10" f/4.8 Dob.  That's 240x.  I know it is possible, because I've done it.  The star was pale blue and very close to Sirius B and following it.  The split was easier in my 2.58 XO, but I did see it also in the 5mm.  Was it difficult?  "Difficult" is on a continuum.  I've split more difficult doubles - comparatively speaking - through my Canon 10x42 IS binos. 

 

So did Javad see the Pup or the False Pup at 180x with a 7mm eyepiece?  It's difficult to judge from a drawing.   I say he should experiment with a higher power eyepiece - or use a Barlow - on a night of good seeing, and try to see if he can see a pale blue star closer to Sirius B.  

 

Mike

Edited by Sarkikos, 09 December 2021 - 09:44 PM.

[Bigzmey]

The screenshot from SS6p was just for illustration purpose only. But I know from my experience that bright star glow may extend and shrink based on the viewing conditions. But what about Special Ed's sketch?

 

https://www.cloudyni...us-b-the-pup/ 

 

As I mentioned this matches well what I saw with my 8" SCT. His was at 489x. Mine was at 300x, but in both cases The Pup was sitting within the glow from Sirius. I heard the same account from few other observers. In the OP sketch there is too much black space between the Sirius and the Pup for my liking. 

[Bigzmey]

So did Javad see the Pup or the False Pup at 180x with a 7mm eyepiece?  It's difficult to judge from a drawing.   I say he should experiment with a higher power eyepiece - or use a Barlow - on a night of good seeing, and try to see if he can see a pale blue star closer to Sirius B.  

 

Mike

There! Definitely revisit and use the False Pup as a reference for the real one.  

[Sarkikos]

Yes, I think Javad should definitely try again with higher power, at least 250x, and around 500X would be even better to make sure he made the split.  It is easier to first see a split at a higher magnification, and then try again at a lower power. 

 

With good seeing, around 500x should not be very difficult to pop the Pup with a decent 10" Dob.  I think there are plenty more difficult objects for a 10" scope.  For instance, I thought the Horsehead was much more difficult to see.  A different type of object, but you get the idea.

 

Best of luck to Javad! 

 

Mike

Edited by Sarkikos, 09 December 2021 - 09:57 PM.

[John Fitzgerald]

I thought I saw the pup last year with a fairly low power, and later doubted it quite a lot.  At 11", it's similar to the separation of Rigel, which is 9".  It will look closer than the companion of Rigel though, due to more bloating and irradiance.

[Mr.Furley]

Yeah Rigel pops pretty easy for me at 180x, I have not had success on Sirius at 250x+ yet. Much more difficult. I expect when I do catch it the pup will be barely there in the glare.

[Achernar]

Hi all,

 

Last night I decided to give a shot to Sirius B. Seeing was mediocre. For a few minutes the seeing improved and I am confident that I saw a dim and small star at about 2 o'clock position from Sirius. Then I could no longer see it again no matter what, despite Sirius getting higher. Maybe the seeing worsened? 

 

Location: 40*N, 50*E

Time: 01:00h

 

How likely is it that it was actually the Pup?

Sirius B lies about 11 arc-seconds to the east-southeast of the bright primary star. If your telescope is not driven, next time you think you found the white dwarf, see if it lags behind Sirus A. It is blue white in color.....if you see a pip of light that looks like that that follows Sirius A it means you probably found it. Although it's at magnitude 8.5, it looks a lot fainter due to the heavy glare from Sirius A. It can also be lost in a diffraction spike. The good news is you don't need a large  telescope to see it, but you do need a telescope of good optical quality and the same is true for your eyepieces. Good seeing is also important. If the seeing is poor, it is not the night to find Sirius B. However, there IS another white dwarf in a triple star system you can see even with a small telescope, 40 or Omicron 2 Eridani B. At tenth magnitude and lying over 80 arc-seconds away from the fourth magnitude primary, it is visible in small telescopes. While this white dwarf is white, the primary star is a fairly Sunlike orange star, and the other star orbiting the white dwarf is a small red dwarf. The system lies 16 light years away.

 

Taras
 

Edited by Achernar, 17 December 2021 - 09:00 PM.