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MimasDeathStar

Splitting the Trapezium with a 130mm scope

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Just wanted to ask an open question to all of the above. As yet I have not got past A to D. Halfway through this thread I notice that #chiltonstar said that a good night exposes the F star an excellent night the E star.

This seems to be echoed by further posts. Don’t want to sound obvious but why is the alphabetical E star harder to see than F? Surely someone looked through a telescope back in the day and said “look a fifth star in the trapezium” the E star!!!

Why are they out of order to the views recorded on this forum? Surely if it is A B C D star then the next easiest is E followed by F not the other way round.

Marvin

 

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22 hours ago, Barry-W-Fenner said:

Just been out for an hours viewing. No moon and good seeing and I managed both E & F at x150 mag.  E was fairly easy to spot tonight with F popping in and out of view. I am chuffed to bits at spotting them!

The rigel split was very easy to get tonight at x150!

Managed some great targets in the hour I was out, a real quality bit of time at the eye piece!

Baz 😁

 

Funny how you can go right off people ;)

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3 minutes ago, Captain Magenta said:

Funny how you can go right off people ;)

You can’t blame people for great skies, but ‘I know just what you mean’ AHHHH.

Barry-W-Fenner you are the astronomer! I think the term is you are the man but who knows who any one is on here and I don’t want to appear gender bias.

If the B-W-F has cracked the trapezium wide open then ‘they’ get my applause.

Marv

just as a foot note the B to the W to the F said E star easy then F star! What’s going on!

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Come down here for a holiday folks, you'll all see E & F easy peasy! 😀

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Just now, Geoff Barnes said:

Come down here for a holiday folks, you'll all see E & F easy peasy! 😀

But why is E and F reported the wrong way round alphabetically? Besides I have been to Melbourne, a huge light polluted city. Very nice though and I did enjoy the botanical gardens and war museum.

I bet a two hour trip into the country side must give you some great skies. But we are deviating. Back to E and F in the northern hemisphere.

M

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42 minutes ago, Geoff Barnes said:

Come down here for a holiday folks, you'll all see E & F easy peasy! 😀

I will have to look you up Geoff next time I am there in Melbourne, visiting my Daughter and her family. I have been several times now and made do with my bins , which was pretty good. The last time we all rented a house in Daylesford for a holiday and the night sky there just blew me away.

Edited by Saganite
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50 minutes ago, Marvin Jenkins said:

Just wanted to ask an open question to all of the above. As yet I have not got past A to D. Halfway through this thread I notice that #chiltonstar said that a good night exposes the F star an excellent night the E star.

This seems to be echoed by further posts. Don’t want to sound obvious but why is the alphabetical E star harder to see than F? Surely someone looked through a telescope back in the day and said “look a fifth star in the trapezium” the E star!!!

Why are they out of order to the views recorded on this forum? Surely if it is A B C D star then the next easiest is E followed by F not the other way round.

Marvin

 

E is easier to see than F I find. The distances between the E & F stars and their partners A and C is pretty much the same (4.5 arc seconds and 4.6 arc seconds) but C is somewhat brighter than A and thus the C - F pair is a more uneven brightness pair and therefore harder to split.

Uneven brightness between components of a binary system makes them harder to split even if the separation between is relatively unchallenging. Sirius A and B being the most extreme example.

Observing them at the altitudes they reach in the UK also adds to the challenge of course.

Image result for trapezium cluster

 

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13 minutes ago, Marvin Jenkins said:

Just wanted to ask an open question to all of the above. As yet I have not got past A to D. Halfway through this thread I notice that #chiltonstar said that a good night exposes the F star an excellent night the E star.

This seems to be echoed by further posts. Don’t want to sound obvious but why is the alphabetical E star harder to see than F? Surely someone looked through a telescope back in the day and said “look a fifth star in the trapezium” the E star!!!

Why are they out of order to the views recorded on this forum? Surely if it is A B C D star then the next easiest is E followed by F not the other way round.

Marvin

 

It's a fair point Marvin.

I've always thought the received wisdom is that E is easier than F..however, E is somewhat fainter than F (see below), so you would think F would be easier to see?

I think though that the seeing is the key factor, although transparency is also important: when I can see both E and F, the F star can seem to be slightly fainter than E.. but now and again, if the transparency is good, but the seeing is not great, I can see F but not E..                                                                                                            Here, it gets a bit confusing, as the A star is NOT the brightest of the A-B-C -D Trapezium four: actually, the C component is about a magnitude brighter than A: now, since the F star is close to the brightest C star and E is close to the fainter A star, then F can get lost in the glare of the bright C star  ( rather as The Pup companion of Sirius can easily be list in the glare of Sirius itself), when the atmosphere is more unsteady or turbulent, whereas E, being close to the fainter A component can more often be glimpsed when F cannot.                                                                        I found this on the net, which may help..  (credit: Astropix com, my italics and bold type ref seeing, optical quality and skill) -                                                      

"The four brightest stars in the Trapezium (A, B, C and D) are easily visible in a four-inch telescope with decent optical quality under good seeing conditions. They range in brightness from about magnitude 5 to magnitude 8. All are hot class O and B stars.

With more magnification and good seeing conditions, two fainter stars, E (mag 11.1) and F (mag 10.12) can also easily be seen in moderately sized amateur instruments. These stars are part of the Trapezium's multiple-star system. Because of their proximity to the much brighter stars in the Trapezium, their visibility in a telescope is more dependent on good seeing, optical quality, and observer skill.

Three other faint stars, G, H and I are also part of the system, but are too faint to be seen except in very large amateur instruments. Other fainter stars are also involved in the system.

Many of these stars are themselves binary and multiple star systems.

Trapezium

θ Orionis - The Trapezium Multiple Star System

Star

Magnitude

Notes

A

6.72 - 7.65

Eclipsing Binary in 3-star system

B

7.9 - 8.65

Eclipsing Binary in 5-star system

C

5.13

Spectroscopic binary star

D

6.71

Double star

E

11.1

Spectroscopic binary star

F

10.12

Binary star

I hope that makes sense🙃😊.

Dave

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24 minutes ago, Marvin Jenkins said:

But why is E and F reported the wrong way round alphabetically? Besides I have been to Melbourne, a huge light polluted city. Very nice though and I did enjoy the botanical gardens and war museum.

I bet a two hour trip into the country side must give you some great skies. But we are deviating. Back to E and F in the northern hemisphere.

M

I don't see that it is. I find E easier than F, so that makes some sense. What doesn't make sense is that F is slightly brighter than E (10.2 vs 10.3) so for that reason they seem a bit out of sorts, but then A to D are not in brightness order so that doesn't help either! They seem to be in order West to East..  

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34 minutes ago, Geoff Barnes said:

Come down here for a holiday folks, you'll all see E & F easy peasy! 😀

How are you fixed next July Geoff??😁😎

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8 minutes ago, John said:

Uneven brightness between components of a binary system makes them harder to split even if the separation between is relatively unchallenging. Sirius A and B being the most extreme example.

John, you posted just before me! Well put!👍😊

Dave

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1 hour ago, Saganite said:

I will have to look you up Geoff next time I am there in Melbourne, visiting my Daughter and her family. I have been several times now and made do with my bins , which was pretty good. The last time we all rented a house in Daylesford for a holiday and the night sky there just blew me away.

Be good to catch up @Saganite

Just PM me when you're out here! :)

1 hour ago, F15Rules said:

How are you fixed next July Geoff??😁😎

Hi Dave, should be here. It will be mid winter, so no Orion visible, but darker skies and lots of southern goodies to see!

Give me a hoy if you're coming out. :)

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