Polaris B Or Not To Be?

[cloudsweeper]

I started by revisiting the lovely Y/B pairing of Almach, then directed the 8SE to Polaris.  (Just hadn't got round to it before!)

At x56, I saw the very bright A star, and close by was a fainter, clear star, well out of the glare.  I thought that was the B star, but it sat at about 1 or 2 o'clock. 

The problem is relating what I saw with the stated Position Angle of 233deg.  How do you figure the PA when looking straight at north?  (It would work if north is down, towards Polaris, and east is to the left viewed through the Cat.)

Stellarium and Sky Safari are no help at all.

Can anyone confirm (or refute) that I actually saw the B star?  Thanks!

Doug.

 

 

 

[Nik271]

Hi Doug,

Polaris B should look slightly blue and relatively easy to spot with 8SE. Here is a photo I took recently with a 180mm Mak which I think shows the color  well. (Polaris A itself is blown out, should be tighter in the eyepiece).

I don't think there is any other star nearby to confuse it with.

Nikolay

 

 

[cloudsweeper]

Thanks Nikolay @Nik271 - Yes, the 8SE would easily pick up the faint secondary, and there was nothing else near the primary.  But sitting at about 1 o'clock, it doesn't seem to tally with various sources.  Further viewing needed!

Doug.

[Captain Scarlet]

It sounds from your description it was definitely Polaris and its little companion. I always use Polaris as an alignment star, and use that tiny blue dot to ascertain that it’s Polaris I am actually looking at through the main scope, as so many more stars appear that it would otherwise not be obvious. 19 arc seconds is the split I think, close enough to be sure but almost never to close to not see. Lovely sight IMO.

Position angle would depend on what time and what diagonal/mirror config you had I think.

Incidentally I tried for it once side-by-side with a 200 newt and a Leica 62mm spotting scope. It was very obvious through the 200p, but I couldn’t see it through the 62mm.

Cheers Magnus

[cloudsweeper]

Thanks Magnus @Captain Magenta - good point! - I never thought that with the target being at the NCP, the view might change considerably.  (I think...)

I'll try for another look tonight, but as you and Nikolay said, it does seem likely that I saw it yesterday.  Just sought confirmation!

Doug.

 

[Paz]

Here's what it would look like from an alt/az perspective at about 9pm with a mirror diagonal. The secondary would be around 2 o'clock.

Edited January 8, 2021 by Paz

[cloudsweeper]

Thanks Paz @Paz - that clinches it then.  Looks like a shot from Sky Safari.  Wonder why I couldn't see the target (secondary, that is) on that app??

Further point of interest:

I had another look on the 6th.  Tending to be lazy about these things, I just did a one-star alignment using Polaris.  Directing the mount to other targets sent it miles away.  It's like defining an origin without specifying the axes I suppose, so I reckon one-star can't be used with Polaris.

Doug.

[Paz]

3 hours ago, cloudsweeper said:

Thanks Paz @Paz - that clinches it then.  Looks like a shot from Sky Safari.  Wonder why I couldn't see the target (secondary, that is) on that app??

Further point of interest:

I had another look on the 6th.  Tending to be lazy about these things, I just did a one-star alignment using Polaris.  Directing the mount to other targets sent it miles away.  It's like defining an origin without specifying the axes I suppose, so I reckon one-star can't be used with Polaris.

Doug.

I wonder why you can't see the secondary in sky safari, funnily enough I can't see the secondary of Rigel in my app. I've got the pro version (don't ask me why, it's got way more than I need).

If you wanted to explain the PA of a secondary for a star that was at perfect north I guess you could use the right ascension reference to do it.

[mikemarotta]

On 06/01/2021 at 04:50, Nik271 said:

Hi Doug, I don't think there is any other star nearby to confuse it with. Nikolay

 

On 06/01/2021 at 04:23, cloudsweeper said:

At x56, I saw the very bright A star, and close by was a fainter, clear star, well out of the glare.  I thought that was the B star, but it sat at about 1 or 2 o'clock. 

The problem is relating what I saw with the stated Position Angle of 233deg.  Doug.

Here is my sketch of Polaris. I had been using an architect's stencil for the nice little circles, but I lost it in the grass, so the stars are irregular by my handiwork. Just for one thing about your concerns: how to you align your eyepiece and prism to assure that you are squared up with the sky? If you are little off, or you turn it to be comfortable, you change the apparent angles, right?

I draw circles that are proportional to my field of view. I also view with two eyes so that I can hold a millimeter ruler at a convenient distance. I also speak out loud what I see.

 

Edited January 12, 2021 by mikemarotta
reduce graphic

[cloudsweeper]

Mike @mikemarotta - I don't tend to rotate the star diagonals in the fracs and SCT.  The Dob of course is a different matter where your viewing angle is constantly changing.  Confusion arises (I think) from the star being very close to the NCP.  And that also created the issue with aligning GoTo using only Polaris.  

Doug.