Opening the Trapezium.

[cotterless45]

Often a lot of head scratching and nay saying as to where these extra stars, E and F hide out. Found this , E is the easiest, Nick.

[wookie1965]

Only ever seen E and F once on a crisp December night about 2 am in the 6" I had, waiting for another night to see if I can tease them out in the Tal or the 8".

[Stu]

Handy chart Nick. E I've seen plenty of times, F is very fickle, particularly in smaller apertures, needing very good seeing and the right mag I find.

[JOC]

a,b,c, and d I have no problems with (and aren't they pretty?), I am not aware of seeing e and f yet.  However, this winter I have more experience, a collimated 8" Dob (that I can now keep collimated when it needs it) and a flash new 5mm Pentax XW EP (I have high hopes for this).  Give me the right conditions and who knows I might get lucky this year.

[F15Rules]

6 hours ago, Stu said:

Handy chart Nick. E I've seen plenty of times, F is very fickle, particularly in smaller apertures, needing very good seeing and the right mag I find.

Agree, Stu..although I've also seen F a number of times, E is far easier. That one extra magnitude of faintness and "F"s proximity to "C" at only 4 arc secs really makes it challenging unless the sky is particularly transparent, I find.

Without wanting to reopen the frac/reflector debate, I do think this type of object is one where fracs have the advantage ie. stellar tight point spot size..but, in viewing M42 as a whole, of course an 8" dob should show a much brighter image with more detail:-).

I for one never tire of just gazing at  the Trap, whether 4,5 or 6 members are visible☺.

Dave

[Doc]

Seen all 6 in a 12" and a 16" dob. Now I have a 5" triplet I have only ever seen ABCD & E, have yet to see F in the 5" refractor. 

[Dave Smith]

One of the first targets with my new 250px dob and 10mm xw eyepiece was the trapezium. Only 4 visible at first attempt but did manage E on the second night and a recollimation. No sign of F however.

Dave

[John]

That is a useful chart. I can get E & F regularly with my scopes of 120mm and upwards (can't miss them in the 12" dob !) and on good nights with my 102/100 mm fracs. G should be possible with the 12" dob in principle although, as ever, reality might have other plans

Interesting piece on the Trapezium here:

https://maas.museum/observations/2010/02/23/harry-zooms-in-on-the-trapezium-the-heart-of-the-great-nebula-in-orion/

[Moonshane]

Aperture and seeing are key factors. Great asterism.

[timwetherell]

Definitely possible in a 140mm refractor under the right seeing. Triton is the same, seen it lots of times in 8" scopes and on a good night it's right there. on a bad night, it's just not!

 

[Moonshane]

Never managed any of the ice planet moons

Maybe one day!

[John]

I got Triton with my 130mm frac. Not in a smaller aperture than that, so far, though.

Your 12" dob should do the trick Shane, on both Triton and at least a couple of the Urianian moons. Lots of mag needed though, I find.

[Pig]

I seem to remember seeing the E when I had my 9.25, but it was quite a while ago and I may just be kidding myself ? What kind of magnification would be most suitable?

[Moonshane]

You' get F too with a 9" scope. Around 150x is a good guide I reckon.

[John]

50 minutes ago, Pig said:

I seem to remember seeing the E when I had my 9.25, but it was quite a while ago and I may just be kidding myself ? What kind of magnification would be most suitable?

I find around 150x - 200x seems to work well.

 

[alan potts]

I am still trying for the alphabet extensions of G and H, but without luck so far. I feel I have an advantage with living further south on these E and F as I find them fairly easy most of the time with the 190mm M/N.

[Pig]

Cheers guys, I will give it a go on the next clear night ? If judging by the weather of late should be quite soon. NIcks’s map should help as what I had seen was inside the square !

[alhiggs]

so basicly  down to time location in the sky and if I'm right in thinking what magnitude the star is will determine if you see it or not 

[Moonshane]

On 22/11/2017 at 18:15, Moonshane said:

Aperture and seeing are key factors. Great asterism.

 

[Piero]

After numerous attempts, I never managed to really convince myself that I have seen E and F with the TV60. I should give them a go with the HR 2.4mm. MAYBE that will do the trick!  

Having bought the Tak just this year, I only observed the Orion nebula a couple of times. E was visible at around 130x. I reckon F would also have been feasible that night with a bit more mag, but I forgot the zoom and spacers at home and it was already 2.30am.

With the 8" dob in Italy, E and F are visible every time. 

[John]

1 hour ago, alhiggs said:

so basicly  down to time location in the sky and if I'm right in thinking what magnitude the star is will determine if you see it or not 

E & F Trapezium effectively form double stars with A and C Trapezium respectively, as per the diagram in the opening post in this thread. The separation between these pairs is A - E = 4.9 arc seconds and C - F = 4 arc seconds. Close but should be reasonably straightforward splits at around 100x in most scopes. However there is quite a large brightness difference between these pairs which makes the split harder and also the surrounding nebulosity adds to the challenge. What might be rather routine double stars in the "open sky" become rather challenging within the setting of the Orion Nebula.

I often use seeing Rigel's companion star and also being able to see the magnitude 10 4th member (star C) of the Sigma Orion multiple as good indicators of whether E & F Trapezium are going to be visible.

 

[Astro Imp]

Interesting comments by @John regarding the surrounding nebula adding to the difficulty of splitting E & F. Castor is an easy split to me at similar separations but the trapezium is a challenge, I have occasionally seen E but still waiting for F. 

[niallk]

Seeing was quite good last night here, and I had the sharpest views of the trap ever.  E and F were obvious pin points with steady 'black' space between them and the bright A-D stars, using a 17E in my 15" giving ~115x.  At 330x, I could see that my mirror wasn't fully cooled.  The jetstream had kindly and dramatically diverted south of Ireland last night, which is why I headed out to see what I might see despite the moon:

I've never seen the trap like this - I was even detecting some very subtle pink along the leading edges of the outstretched 'arms' in the strongly green nebulosity, with extra fine intricate detail in the dust.  The moon had risen, but was partly covered by cloud - in fact Orion was the main section of the sky open to me that was free of some high thin cloud that closed in as soon as I set up the scope.

I got excited that I'd seen the Pup, but checking charts around Sirius later, er no!! - it was another faint star but not close enough to be the Pup.  No real luck on the Flame.

I find what I see in M42 highly variable with conditions - always worth revisiting time and again!

[Stu]

6 minutes ago, niallk said:

I got excited that I'd seen the Pup, but checking charts around Sirius later, er no!! - it was another faint star but not close enough to be the Pup.  No real luck on the Flame.

Tee hee, I've done that before, spent a long time struggling to glimpse something, feeling like I've got a star appearing regulating at the same point, only to check and see it is in the wrong place!! I'll get it one day!

Exciting to see tinges of pink in M42. I've heard of other colours being see in much larger dobs in the US, but if the conditions are right, and you have good eyes then it is likely to be possible. I even suspect having the moon around can help as it keeps your cones stimulated and makes it easier to detect colour. Nice one.

[John]

I managed Trap E & F with my Tak 100 last night. Good stuff although lots of light cloud patches made it a bit "GO / NO GO"

Switched to the Vixen ED102SS later for stunning lunar views.