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Challenging quad in NGC281 BU1

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#1 Darren Drake

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Posted 09 October 2019 - 10:19 AM

The Burnam 1 quadruple star is a challenging 4 star system.  The first 3 are easy but the 4th can be very elusive.   How many here have seen that 4th star and what is the min aperture needed to see it?  I saw it coming in and out last night in my 18 but suspect an 8 can do it.  Thanks


Edited by Darren Drake, 09 October 2019 - 10:24 AM.


#2 dmdouglass

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Posted 09 October 2019 - 12:14 PM

Darren...

 

Interesting "Challenge" ... and of course, you are looking right into the middle of The PacMan Nebula.

My "observations" are all images... camera sees MUCH better than my old eyes.

I have an old image from 2013 that i looked up...

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BU-1 Crop from 2013.jpg

 

Here is the Stelle Doppie information for this one.  

For "The fourth star" , my assumption is that your question is talking about the AD pair, with the "D" star at Mat 12.1.  

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BU-1.png

 

Will have to consider a "re-Image" and see what i can resolve...  (with, maybe, some better focus :) )


Edited by dmdouglass, 09 October 2019 - 12:16 PM.


#3 mccarthymark

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Posted 09 October 2019 - 12:19 PM

I observed BU 1 AB (which is what I assume you mean) with a 12.5" in mediocre (5-6/10) seeing: 

 

BU 1: !! Right triangle of equal stars; the foot star has a very faint, 2-3 delta mag star very close ~1", faint split.  Some fainter stars wreathed about it. [AB seen, while AC, AD appear to be the other triangle stars.  17 visible stars in the system, which I suppose ought to be called a cluster.] -- Pac Man cluster
00H 52M 49.22S +56° 37' 39.5" P.A. 83 SEP 1.5 MAG 8.58,9.33 SP O6.5V DIST. 3030.3 PC (9884.84 L.Y.)

 

The B star appeared much fainter to me than the data, but I sometimes get these estimates a little off.

 

Interestingly Stelle Doppie says this is not physical


Edited by mccarthymark, 09 October 2019 - 12:20 PM.


#4 fred1871

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Posted 09 October 2019 - 08:45 PM

Darren, if by the 4th star you mean the tight AB pairing, mags 8.58 and 9.33 at 1.5", I recorded it as visible "a tiny point just separated from A" with a C8 at 200x back in the 1990s when I was observing from San Diego, Ca. So, yes, it's visible with an 8-inch. On a previous night of sub-standard seeing it didn't show (smudge seeing); with the steadier night when I saw it, I didn't think it difficult. I'd expect a good 6-inch refractor to show it.

 

The C8 also showed the dim wide-ish FG pair, mags 11.3 and 12.2, offset from the main group. Likewise the mag 12.1 E component, all at 135x.

 

I was surprised to discover that BU 1 is absent from the Cassiopeia listing in Sissy Haas's book Double Stars for Small Telescopes. Slightly too faint, perhaps? A pity, because on both nights I observed it I noted it as a fine object. Perhaps for a 4-inch it would be less effective due to the low magnitudes for that aperture.



#5 gfeulner

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Posted 09 October 2019 - 09:12 PM

I can routinely see ABC and D in my TEC 140 at around 250x if I'm at my dark observing site and if the seeing is steady. Any turbulence and the D star is very difficult or impossible to see. I'll have to look for the E star next chance I get.

Gerry




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