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Time to get serious about Sirius


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Pretty sure I got it tonight with the 200p. Barlowed the Hyperion IV zoom at 8mm with the dedicated 2.25x at (I think) 337x. A very faint speck of light  trailing Sirius A at around the 4 o clock position Dob view.

It came and went with the seeing but I went back to it after a look around Orion and it was in the same position. 

Got the best views yet of Trapezium E&F tonight at 150x as well. 😎

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'Tis the season that Sirius is getting reasonably well positioned (well, as good as it gets here in the UK) and it is a good time to take on the challenge of splitting it and seeing the elusive "Pup"

Got the little blighter ! First time I've managed it with the ED120. Quite hard and I repeated the observation about 10 times with 2 different eyepieces to make sure. The "Pup" star was not consi

Last evening it was minus 6 deg C, but the seeing was generally very stable. It got the Tak TSA 120 out before dusk and got on with variable star work in the observatory until 21.30. Turning Tessa tow

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6 minutes ago, Dark Vader said:

Pretty sure I got it tonight with the 200p. Barlowed the Hyperion IV zoom at 8mm with the dedicated 2.25x at (I think) 337x. A very faint speck of light  trailing Sirius A at around the 4 o clock position Dob view.

It came and went with the seeing but I went back to it after a look around Orion and it was in the same position. 

Got the best views yet of Trapezium E&F tonight at 150x as well. 😎

Excellent - well done DV :smiley:

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I'm very happy to say that last night (27 Feb) I finally managed to see the Pup! I'm so thrilled by it 🙂 

I spent nearly 2 hours observing from 7:30 to 9:30pm and managed to see it both with or without diagonal and with both 10mm and 6mm eyepieces giving 270x and 450x respectively. As other have said the position of the Pup is at 4o'clock without diagonal (Dob view) and at 2 o'clock with a diagonal (refractor or Mak view).

At these magnifications the separation is not the issue but the glare from the main star. I came to realize that my EP have too much light scatter around Sirius A which hides the Pup very well.

So here is my method, I repeated this many times and it always produced the Pup. Once I saw it I was able to follow it as it drifted across the FoV.

I'm using a manual EQ5 so my view drifts to the west. With GoTo this might be easier as you can put Sirius A anywhere in the FOV you like and it will stay there.

The idea is to hide Sirius A at the south or southwest edge of the FoV. The Pup is ENE of Sirius A so it should 'pop out' as soon as your eye adapts to the darker background. Once you get the angle correct you should have 2-3 seconds in manual mode to observe it as it drifts west. I made a small diagram:

2143236399_SiriusB.thumb.png.8570dc59d197bfa48894406ff296f50a.png

Its important to use a EP without any vignetting or edge distortion. I managed this first with the 6mm red line Svbony EPs but in retrospect could have just used a good Plossl. It worked also at 270x with the 10mm EP but it was trickier as the separation between the main star and the Pup is then visually smaller.

For tonight I will make an occulting bar at the fieldstop, orient it NW-SE and put Sirius A under it. Should give me more time to enjoy the view :)

Good luck, everybody!

Nik

 

 

 

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Excellent Nik :thumbright:

Your "cunning plan" worked a treat :smiley:

Light scatter from Sirius A is the big issue with this challenge. Last night I noticed that this was quite variable. There were times when the Sirius glare would suddenly inflate for a while masking the Pup star entirely. I assume that this is due to an unstable air mass of some sort ?. I have also found that sometimes "looking too hard" can cause the eye to become moist and that creates it's own very local Sirius scatter as well.

 

Edited by John
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Nice Nik. I tried this in my 100mm f13 last night (moving Sirius just off the ep field of view). I can't swear to split, but I was getting hints of its presence at 260x with a 5mm baader genuine ortho. Tried again at 292x with a 10mm ortho and 2.25 barlow, but if any thing that made it harder. So, I 've got closer than I've been before, but tantalisingly this is not a definite for me yet. The pup escapes again... .

I find this scope will certainly show the Rigel double and the E and F in the Trapezium (altough it struggled with this last night), and can just split Zeta Cancri (just... barely managed it last night at x260 in moments of good seeing and slightly cleaner at 292x later on when it was higher in the sky). Based on this, I think it should get Sirius B, or is 4" too small? Has anyone had any luck with a filter to reduce the glare at all?

Edited by Marki
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I've tried filters of various types but without success. While the glare from Sirius A subsides, Sirius B seems to get dimmed to the point where it just drops below visibility. Plus the filter itself adds a little more scatter to Sirius A. It seems to be a fine balancing act :rolleyes2:

Last night was the first time in a few years of trying that I've split Sirius with my ED120. The next challenge is to try to get it with the Tak FC100.

 

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