orion

[alhiggs]

I can't remember if this is true or not is it hard to see 4 stars of trapezium cluster in m42 If so I saw 4 of them last night

[MarsG76]

The 4 trapezium stars (A-D) are easy to see, E and F are hard...

 

[Doc]

The trapezium consists of 6 visible stars, four of them are easy the other two very hard. There is actually 10 stars I think but three are almost impossible.

 

 

 

 

 

 

[furrysocks2]

I've been trying to get E and F recently - not giving up.

Here are the magnitudes and angular separations...

 

[alhiggs]

thanks guys apreciated

[Stu]

1 hour ago, alhiggs said:

I can't remember if this is true or not is it hard to see 4 stars of trapezium cluster in m42 If so I saw 4 of them last night

It depends what you are using to observe with?

[des anderson]

Well done,not everyone has seen the Trapezium, I overlooked it for ages until someone showed me where look for it when I first started. Des 

[Stu]

15 hours ago, Stu said:

It depends what you are using to observe with?

@alhiggs Let us know what you were observing with. If it was the 20x80 binos then you were probably right on the limit for splitting the Trapezium. A little above this mag and they become easier, but splitting all four is not always trivial at x20.

Let us know how they appeared, and we can probably advise better. If they were a very tight grouping of stars that you could just resolve as four, then yes, you likely saw it. If there was significant space between them then I suspect you were looking at other stars. It's easy to get confused without a sense of scale.

Here are some charts which show approximately the field of view you should get, I've assumed 3.2 degrees.

Note that the Trapezium is the unresolved clump of stars in the centre. I put a 0.25 degree circle on in the 3rd image and then zoomed into this in the 4th and 5th image, so you can start to see the Trapezium resolved. Is this how it appeared?

[Ed in UK]

Really pleased this subject has been posted as I am a complete beginner to Star Gazing/Astronomy. Only managed two session so far with my scope (Skywatcher 130EQ2) and the M42 was one of the first subjects I looked at. I recall seeing stars in the center but need to look closer now to make sure that I've seen the Trapezium, but it certainly rings a bell with me. 

So much to see out there.

@alhiggs if using a scope try looking at  Mizar & Alcor in the Big Dipper handle. With binoculars you can see the two stars, but with a scope you can see them both clearly along with third fainter star. Look really closely at Mizar (The brighter of the two iirc) and you should see a much smaller star next to it.

[Luna-tic]

I split the four easily last night at slightly less than 60X with an f/5.9 80 APO, and we had the club's big 25" f/5 Dob out and had "F" in and out, but never saw "E", we were at the limits of the seeing, I suppose.

[Stu]

27 minutes ago, Luna-tic said:

I split the four easily last night at slightly less than 60X with an f/5.9 80 APO, and we had the club's big 25" f/5 Dob out and had "F" in and out, but never saw "E", we were at the limits of the seeing, I suppose.

I normally find E significantly easier than F. Should be quite easy in a larger scope but they are much more susceptible to poor seeing I guess.

I did see them both beautifully resolved in a lovely scope recently.

[Luna-tic]

I could only imagine that since 'F' is slightly brighter, that's why we could see it and not 'E'.

Is there info on the period of  B's binary companion, which I would assume would vary its brightness dependent on whether the companion is eclipsed or in conjunction or to one side?

[rockystar]

I had E a couple of weeks ago, for the first time.  It was in and out with averted vision, but definitely there - and only seen because I knew where to look.  I couldn't get F though. 

[Ricochet]

Picking the right eyepiece is probably the key to picking out e and f. You want to have an exit pupil a touch over 1mm so that you darken the background as much as possible without diminishing the stars by pushing light out into their airy disks. 

[F15Rules]

5 hours ago, Luna-tic said:

I could only imagine that since 'F' is slightly brighter, that's why we could see it and not 'E'.

Is there info on the period of  B's binary companion, which I would assume would vary its brightness dependent on whether the companion is eclipsed or in conjunction or to one side?

I'd agree with Stu's remarks, I haven't heard before of F being visible while E isn't. Although E and F are of similar brightness, F is close to a much brighter companion, C, mag 5.1, and E is close to a fainter companion, A, variable between 6.7-7.5.

Therefore, F tends to be harder to see being close to a much brighter star than E is..

I have seen both readily with a good 4" refractor on a steady night, but more often than not F is an averted vision catch, while E can often be seen with direct vision..I find a power of between x60 and x100 best?.

Dave

[Stu]

6 minutes ago, F15Rules said:

I'd agree with Stu's remarks, I haven't heard before of F being visible while E isn't. Although E and F are of similar brightness, F is close to a much brighter companion, A, mag 5.1, and E is close to a fainter companion, C, variable between 6.7-7.5.

Therefore, F tends to be harder to see being close to a much brighter star than E is..

Dave

Dave, the labeling I can see seems to be illogical, in that the fainter of the two is A, with C being the mag 5.1 nearest to F. Is that correct?

[F15Rules]

Stu,

It's not logical, but it is correct..the following quoted from Wikipedia.

It could be that A, being variable, may have faded since it was first designated as A?

The map on the page from which the quote is taken is the same as the one shown in the top of the thread☺..

Dave

"Theta1Orionis A (θ1 Ori A) is a variable trinary star in the constellation Orion. Its apparent magnitude range is 6.72 to 7.65 with a period of 65.432 days. It is one of the main stars in The Trapezium in Orion, along with B, C, and D, as well as the fainter E".

[Luna-tic]

A through D are labeled in the order of their Right Ascension; not sure why E through I are different, unless it's the order in which they were first seen.

I really can't say why we could see 'F' and not 'E', but I'm sure it was 'F' we saw. It was next to the brighter 'C', but it was in and out, mostly out. We had a 20mm EP; sure, but I think it was a Nagler (2"). In a Dob with a 3175mm focal length, that gave a magnification of 158X, and with a 25" (635mm) mirror, it was a pretty darn bright image.