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Can't Split The 6 Trapezium Stars

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#1 jacobmarchio

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Posted 22 November 2012 - 07:30 PM

Hi all,
I was out observing last night. It was simply beautiful; seeing was excellent and could sport high magnification. Most of my observing time was spent on the moon. As the moon was still up, I knew I wouldn't get much detail in M42, so I decided I would try to get all 6 stars in the trapezium (I had failed before, due to seeing etc.). Four of the stars were easy, even at low magnification- but even when I push my magnification to 208x (and seeing still excellent) I only see the 4. Do I need even more magnification, or am I just expecting to much from my 6" F/5 Newtonian?

#2 starrancher

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Posted 22 November 2012 - 07:35 PM

Light pollution and or moon glow can kill the faint guys .

#3 helpwanted

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Posted 22 November 2012 - 07:38 PM

I am going off the top of my head, but I think E & F are both around 12th magnitute, so light pollution can easily kill both.

#4 jacobmarchio

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Posted 22 November 2012 - 07:59 PM

Thanks for the response guys. I'm on the edge of a yellow/green zone, so not too much lp... the moon was up and shining brightly, so that may be it. I didn't think the moon would affect the Trapezium so much... oh well. Will have to try with no moon.

#5 JasonBurry

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Posted 23 November 2012 - 07:22 AM

I observe from a green/blue zone with an 8" reflector. 200x is what I've used to bring out the E and F components, but they're quite easily overwhelmed by the glare of the A-D stars.

I last observed them early this week. Star E was fairly easy, but still took some moments of concentration to bring out. Star F showed only intermittently with the seeing that night.

I think transparancy and seeing are most important here. They are tiny points of light compared to A-D.

J

#6 Rich (RLTYS)

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Posted 23 November 2012 - 09:32 AM

Seeing conditions can also have a major effect on seeing 6 stars. With my 10" refl sometimes it's easy other times I just can't do it.

Rich (RLTYS)

#7 BillFerris

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Posted 23 November 2012 - 11:50 AM

The E and F stars (both 10th magnitude) should be visible in your 6 inch under dark skies with good seeing. Both are separated by about 4 arcseconds--well within the resolution limit of a 6 inch aperture--from their brighter neighbors. Often, the biggest challenge is digging the fainter stars from the glare of the brighter. F is about 100-times fainter than C. The difference in brightness between A and E isn't as great but is still enough to make detection of the fainter star a bit of work. Keep at it.

Bill in Flag

#8 Sarkikos

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Posted 23 November 2012 - 01:01 PM

You just need to catch them on a moonless night with good seeing and good transparency at a dark site. Then it's easy.

:grin:
Mike

#9 Sasa

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Posted 23 November 2012 - 04:14 PM

Jacob, it reminds me when I was trying to observe more than 4 stars in Trapezium for the first time. At that time, I was using as well 150mm Newton (f/5). It took me about 20-30 minutes of trying different magnifications, eyepieces and barlow combinations before I noticed star E (for record, this was at 176x: Pentax XF8,5 + Barlow XCel ED 2x). Once I knew what should I be looking for, I saw it also in other eyepieces which I was trying that night: 4mm University ortho (188x) and then even in Pentax XF8.5 alone (88x).

With two years of more experience, I'm able to see occasionally star E in my 80mm refractor (AS80), if the conditions are good. With 100mm ED refractor, I could also glimpse from time to time star F as well.

So the moral is, keep trying. Once you crack them it will be much easier to notice them next time.

#10 Tony Flanders

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Posted 23 November 2012 - 05:04 PM

I was out observing last night. It was simply beautiful; seeing was excellent and could sport high magnification. Most of my observing time was spent on the moon. As the moon was still up, I knew I wouldn't get much detail in M42, so I decided I would try to get all 6 stars in the trapezium (I had failed before, due to seeing etc.). Four of the stars were easy, even at low magnification- but even when I push my magnification to 208x (and seeing still excellent) I only see the 4. Do I need even more magnification, or am I just expecting to much from my 6" F/5 Newtonian?


I'm a little surprised you couldn't see them -- especially E, which I find a lot more prominent than F.

I doubt the Moon had much to do with it. The stars are plenty bright for a 6-inch scope; the problem isn't the faintness of E and F but the brightness of A and C.

As others have said, they're a lot easier to see once you know what to look for.

#11 azure1961p

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Posted 23 November 2012 - 05:37 PM

I've *played* with the trap and my 8" in 6/10 and 7/10 seeing under magnitude 5 sky's. The short of it is, if you can't see clean diffraction rings around the 4 trap stars the others are going to be tough to impossible even at 60x per inch. Generally garbage seeing leaves me with neither e nor f while mediocre brings both with patience and attention and good seeing had them held linger and far more often.

A trick. Here too isknowing WHERE to look. I gazejust *above* the trap +or south rather) by maybe 15 arc seconds and the fainter ones show peripherally. The fainter o e can be stubborn. In the 8" 200x is my favorite for this though even 140x can detect it. At 200x though nice diffraction patterns make an exquisite view.

Pete

#12 rtomw77

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Posted 24 November 2012 - 04:25 AM

Another trick is to observe within a time period of several hours of when Orion is due South and at its highest point for the night. This is the only way I can see E and F through the Phoenix light dome.

Tom

#13 Daniel Mounsey

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Posted 24 November 2012 - 08:53 AM

Seeing E and F is exactly the same as seeing the Tettigoniidae insect in this photo. Once you know where to look, you'll spot them.
http://www.flickr.co...008/3808964245/

#14 jacobmarchio

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Posted 24 November 2012 - 03:09 PM

Thanks for the tips! Will try, but the moon is waxing full, so it might be a while before the moon and weather cooperate. :p

#15 Starman1

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Posted 01 December 2012 - 03:45 PM

Here are some finder charts:
http://www.astropix....NTER/TRAPEZ.HTM
and
http://www.laughton..../trap/trap.html
Note, I've seen these from my rooftop in LA with a 6" f/5, so perhaps seeing wasn't as good as you think. The F star, especially, requires that the brightest Trap star be a tiny little point. 200X is more than enough power to see them.

#16 simpleisbetter

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Posted 01 December 2012 - 04:02 PM

I agree, seeing and cooldown are very important. Any thermals and you'll be chasing E & F. Here's another link showing info on the Trap.
http://cityastronomy...rapezium-lg.jpg

Curiously, I seem to almost always see F first, and more often than E; not sure why, but it happens in both my current C6R and my former 4" f/7.

#17 jacobmarchio

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Posted 01 December 2012 - 09:25 PM

Thanks for the star charts. I'm pretty sure the seeing was quite good, and my scope was fully cooled. It is possible I just didn't know where to look, or the high, bright moon washed them out. Will try when conditions are good.

#18 Erik Bakker

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Posted 02 December 2012 - 04:59 AM

Jacob,

Most importantly, you need good seeing AND good transparency. Under those conditions, I saw all 6 in my 70mm fluorite at 140x. A bit more aperture and magnification help of course. But a fully cooled 6" and 208x is definitely enough. Just wait for better conditions.

#19 jacobmarchio

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Posted 03 December 2012 - 12:14 PM

Hi again,
I tried again last night, good seeing, cooled scope, moon up. Failure.

Again, the conditions were against me. The moon was up. I don't know if this helps, but the faintest star, the "B" star, was very dim, if that gives you any idea of the Moon's affect. Also, I forgot to take a print of one of the trapezium star charts, and couldn't exactly remember which stars they were by. And the different orientation of the Newt was throwing me off a bit :p

#20 kansas skies

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Posted 05 December 2012 - 02:09 PM

I was able to spot the E and F components last night with a 4" refractor (f/10 achromat) at 100X. I usually can see E without too much difficulty, but I find that F requires very steady seeing conditions to separate it from C. Still, it will usually show itself as an elongation of C. Also, the F component seems to be much more difficult to isolate in my 8" SCT due to excessive glare from C - Bill.

#21 Bill Barlow

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Posted 05 December 2012 - 08:02 PM

I could easily see both the E and F stars in my Meade 12 ACF between 150x-200x. This was when the Orion Nebula was only about 20 degrees above the horizon. I guess the higher resolution of the 12" scope helped me out a lot.

Bill

#22 MikeBOKC

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Posted 05 December 2012 - 09:09 PM

E and F are just about always there in my CPC1100, unless seeing is really doggy. Then, they tend to fade in and out. Under 10 inches I think you need fairly still air.

#23 drbyyz

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Posted 09 December 2012 - 11:27 AM

Gave this a shot last night after reading this thread yesterday. Seeing was kinda iffy, but not too awful. My skies also aren't the greatest. Was able to make out E pretty easily, but it was definitely flickering in and out of my vision. No luck at all on F. Going to try again on a better night.

#24 REC

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Posted 09 December 2012 - 01:36 PM

For me, that's a tough one for my 8" SCT. Generally feel lucky if I can just get E steady without blinking in and out. But when I do, I know I'm going to get a knock out view of the nebula! Definitely a seeing issue here.

Bob

#25 jacobmarchio

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Posted 09 December 2012 - 07:44 PM

Yeah, my skies are pretty bad right now... mostly clouds ever since the beginning of December, and the forecast doesn't look too good either. :p






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