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Observing >> Deep Sky Observing

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jacobmarchio
sage


Reged: 08/30/12

Loc: Alabama
Can't Split The 6 Trapezium Stars
      #5534356 - 11/22/12 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?


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starrancher
Carpal Tunnel
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Reged: 06/09/09

Loc: Northern Arizona
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5534358 - 11/22/12 07:35 PM

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

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helpwanted
Post Laureate
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Reged: 07/04/07

Loc: Phoenix, AZ
Re: Can't Split The 6 Trapezium Stars new [Re: starrancher]
      #5534362 - 11/22/12 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.

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jacobmarchio
sage


Reged: 08/30/12

Loc: Alabama
Re: Can't Split The 6 Trapezium Stars new [Re: helpwanted]
      #5534381 - 11/22/12 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.

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JasonBurry
sage


Reged: 04/27/12

Loc: Cape Spencer, NB, Canada
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5534943 - 11/23/12 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


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Rich (RLTYS)
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Reged: 12/18/04

Loc: New York (Long Island)
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5535110 - 11/23/12 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)


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BillFerris
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Reged: 07/17/04

Loc: Flagstaff, Arizona, USA
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5535332 - 11/23/12 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


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Sarkikos
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Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: Can't Split The 6 Trapezium Stars new [Re: BillFerris]
      #5535463 - 11/23/12 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.


Mike


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Sasa
professor emeritus


Reged: 11/03/10

Loc: Ricany, Czech Republic
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5535817 - 11/23/12 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.


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Tony Flanders
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Reged: 05/18/06

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Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5535861 - 11/23/12 05:04 PM

Quote:

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.

Edited by Tony Flanders (11/23/12 08:48 PM)


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azure1961p
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Reged: 01/17/09

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Re: Can't Split The 6 Trapezium Stars new [Re: Tony Flanders]
      #5535925 - 11/23/12 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


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rtomw77
Pooh-Bah
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Reged: 10/06/04

Loc: Deer Valley, AZ
Re: Can't Split The 6 Trapezium Stars new [Re: azure1961p]
      #5536636 - 11/24/12 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


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Daniel Mounsey
Vendor (Woodland Hills)
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Reged: 06/12/02

Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5536824 - 11/24/12 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.com/photos/reid2008/3808964245/


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jacobmarchio
sage


Reged: 08/30/12

Loc: Alabama
Re: Can't Split The 6 Trapezium Stars new [Re: Daniel Mounsey]
      #5537364 - 11/24/12 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.

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Happy Birthday Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5549000 - 12/01/12 03:45 PM

Here are some finder charts:
http://www.astropix.com/HTML/B_WINTER/TRAPEZ.HTM
and
http://www.laughton.com/paul/rfo/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.


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simpleisbetter
Carpal Tunnel
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Reged: 04/18/11

Re: Can't Split The 6 Trapezium Stars new [Re: Starman1]
      #5549021 - 12/01/12 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.com/trapezium-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.


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jacobmarchio
sage


Reged: 08/30/12

Loc: Alabama
Re: Can't Split The 6 Trapezium Stars new [Re: simpleisbetter]
      #5549422 - 12/01/12 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.

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Erik Bakker
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Reged: 08/10/06

Loc: The Netherlands, Europe
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5549814 - 12/02/12 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.


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jacobmarchio
sage


Reged: 08/30/12

Loc: Alabama
Re: Can't Split The 6 Trapezium Stars new [Re: Erik Bakker]
      #5551928 - 12/03/12 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


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kansas skies
sage


Reged: 12/02/12

Loc: Kansas, USA
Re: Can't Split The 6 Trapezium Stars new [Re: jacobmarchio]
      #5555739 - 12/05/12 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.

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