The trapezium

[alan potts]

Firstly, I didn't know where to put this, here or in the Reports section. If it needs moving please feel free.

This must be one of the most looked at parts of our winter night sky and rigthly so. I spent 2 and a bit hours on it last night with the 12 inch LX, it don't seem to get so much light time these days. When I bought it I was building my house here in Bulgaria, with all the work I was doing, lifting this and carring it outside was a piece of cake. Now I have finished I am not as strong as I was a few years back, I still have some concrete to mix and some bricks to arrange into a neat pile and then call it an observatory.

The trapizium itself it a fairly easy obect in even a small scope, I have done it without trouble in my 70mm ED refractor and can see the 4 stars well, but that's all. It was John that pointed out to me there are more trasures hidden away within the nebulosity. These are known as the 'E' and 'F' stars, both around the eleventh magnitude, I find 'E' star easy even in a 115mm refractor but due to 'F' being close to a much brighter star it is more of a test. I firmly believe seeing needs to be pretty good to pull off both in a smallish scope, the trapezium is 11 degrees higher in the sky for me so I have it much better placed.

Now last night was fairly good seeing and I had the LX outside. the air was very clear as I could see right down to the horizon without any optical aid, there was however some air tubulence of some type that was spoiling the show, it was not the scope as it had been out for at least 2 hours. Or was it, I sometimes wonder about cooling of scopes, outside at minus 2 with the sun on it for a while, did this cause the poor seeing for a hour or so, because it went away.

It was pointed out to me that the key to the first two extra stars 'E&F" was getting the power just right, I tried a few eyepieces giving magnification from X90-X152. I settled in the end for the 24mm Panoptic giving X124, I also cross-checked this with a Meade 24mm UWA, just for fun. After an hour much better air condition was on the menu, was this the scope or sky, I just don't know and never will. Around this time the 'F' star just popped into view, one minute it wasn't there then it was, it seems much closer to the main star than the charts suggest. What I did next was to place the Meade 24mm UWA in the same scope, having done that I found it very difficult to see the 'F' star, interresting indeed. This was putting what is considered a high quality eyepiece against one of the best ever made, clearly there is a difference.

Then I swapped eyepieces up and down the power range, going to 20mm nagler at X152 made 'F' vanish and 'E'harder to see and dropping to X90 in the shape of a UWA 30mm Meade did much the same on a smaller scale. How true the get the magnification right seems to be, I have to say the power was in the sweet spot a little lower on the the 115mm refractor, so it is not the same for every telescope. It would be nice to hear what magnification other site members use to view the same group?

Then I spent an hour or so looking for two more little gems in the trinket box the 'G' and 'H' stars. I did start to see a star that was around the magnitude 13-14 to the East of the 'A' star, I am sure that it was there but I could not see it all of the time, again swapping eyepieces around but in the end sticking to the Panoptic, it is some eyepiece. When I later checked the chart kindly sent to me by John it was clear I was not seeing either of these stars, maybe I found the 'J' star. It would be nice to hear from anyone that has seen these to fainter stars both of which are around the 16th magnitude. However I feel myself that a scope of 16-18 inches will be the minimum size that one could see these with but you never know.

If you have a clear sky tonight or even this month have a look for the 'E' and 'F' stars, they may well be a bit more difficult from England than for me.

Clear skies,

alan.

[Space Dragon]

Alan

With my 925 and 24mm Pans in a Bino, E is obvious on most nights but I'm not convinced I've seen F yet. This is from a suburban site as the weather has not made it worth getting in the car this winter.

It might be better in a couple of months when Orion gets a bit higher in the sky, tonight is forecast as clear so I'll have another go as late as I can.

[James]

I've seen the E star fairly often, the F star is much trickier, I've seen it a few times over the years. With my 14" Flextube from Exmoor I 'think' I've seen the G star once but if I'm to be honest I suspect it was more a case of averted imagination...

Like Alan I think that magnification is critical for these stars - I tend to never go above 160x (10mm Pentax XW) on this object and usually try around the 110x mark.

Like you Alan I find the F star appears much closer to the nearest bright star than the charts suggest - perhaps it's an optical illusion.

James

James

[alan potts]

James,

I think it is all down to a chart is there in front of you and much larger, scale of it all.

Space dragon,

I cracked both of these 'E' and 'F' a couple of weeks back with the 190mm M/N, I would have thought you could see them with your 9.25 SC, it could just be a case of 11 degrees latitude making it that much easier.

Alan.

[Space Dragon]

I think I'll use "averted imagination" as James suggested, that seems to work when all else fails........It's almost more difficult to be sure you've seen something when you know where it should be.

I found E without knowing where it should be but now i know where F should be.....I keep thinking I may have seen it...if you know what I mean.

[alan potts]

Space Dragon,

Averted imagination, are good words. I was doing a lot of looking at Sirius just after Christmas time, we had a number of nights where the 'Pup' star was easy to see with both the 115mm and the 190mm. I normally use around X100 keeping a clean image to me is the key. Averted imagination takes the stage, I got to even thinking I could see it with a 35mm Panoptic in the tube (X28), which of course it totally mental. I even checked it the following night for over half an hour, I could see something, but what.

I was looking for an hour before hitting a sweet spot in either conditions or scope temperature, then it was clear.

Alan

[chiltonstar]

I've seen the "E" component quite often (5" Mak), but haven't yet licked the "F" star - I think you are right about latitude, but seeing is all-important as well, at least in this benighted, fog & rain blighted land!

Chris

[freeflyjay]

i thouht there were only 3 untill a 4th poped into view with a better eyepiece, but with the light pollution from my yard don`t think i`ll get e and f

[Jessun]

Nice report Alan!

/Jesper

[Robstargazer15]

Ive seen star E with the threshold of vision. Star f has been seen with imagination, no defiite sighting yet.

The four bright stars of the trapezium outshine them.

Will a filter dim the bright stars and make the e and f stars more visible?

[alan potts]

Rob,

I don't know the answer to the filter question but I would have thought that there is a filter that will help. I will leave that to someone who knows as my idea of a filter is wearing a pair of Raybans when looking at the moon, it is a good job no one can see me.

Alan.

[Plantins]

I've had a few C14's, the one I have now has the Starbright coatings and the primary has a very smooth figure. I have seen the E & F stars everytime I've looked at M42/Trapezium with this scope, even with a 3/4 moon up.

I had a brand new C14 Edge and tested this on the Trapezium alongside my C14 Starbright. The Starbright nailed the E & F stars as always but the C14 Edge only had the E star, no F. The nebulosity in the C14 Edge seemed nicer and took on a more 3d effect and the colour of the nebula was green rather than the grey in the Starbright C14. I put the 3d effect and green colour down to the XLT coatings which are more advanced and are better than the Starbright coatings.

My C14 prior to these was a grey tube version with the XLT coatings, not once did I see the E or the F stars with this scope. The M42 nebula again though was Green coloured and very 3d.

Eyepiece used on all the scopes was a 31mm Nagler producing 126x mag and a TeleVue Everbright diagonal.

Although over the years coatings have improved on mass produced scopes which really does improve performance and light throughput. I think the difference with the Starbright coated C14 is the figure on the primary mirror is better than the other two. That is the only conclusion I can think of.

[John]

Nice and detailed report Alan

It's good to apply some power to the central regions of M42 to search for E & F. Even if you don't spot them the nebulosity around the Trapezium takes on an different and fascinating appearance which is worth studying in itself. I believe the dark "lane" that seems to project into the heart of M42 is known by some as the "fishes mouth". It seems to lead to eye towards the Trapezium stars. It has been mistaken for the Horsehead Nebula from time to time !

Personally I can see E quite often with my 4" refractor but I've only managed F a couple of times with that scope. My ED120 shows both quite regularly although F does have a habit of seeming to fade in and out from time to time as the seeing fluctuates. Through my 12" dob they were both very clear on Saturday night.

Eyepiece that have good light transmission and little scatter are good for these challenging objects.

[Mark at Beaufort]

An enjoyable thread to read - thanks Alan.

A few days ago we had a very clear and transparent night so I set up the 10" Dob to view Jupiter and the shadow transit of Io. The view was so good I decided to view the Trapezium with my 3-6mm Nagler zoom and my 8mm Ethos with a 1.6x barlow.

As others have said star E was easy but F was so much more difficult. I was able to see star F from time to time with the zoom set at 6mm (200x) and the Ethos combination at (240x).

Alan as you report its a number of factors that determine whether you can see star F. By the way I have never seen any of the other stars.

Mark

[nightfisher]

Good report Alan, i JUST glimpsed the E star the other evening with my Tal 100 f10, i keep meaning to set the 180 mak up for go at the trapezium, just dont seem to get the time, i have yet to spot the f star, but i dont think the Tal will do it

[Mike73]

I've just had a quick look at Jupiter and the air seems fairly steady tonight so I'II have a crack at this later, I'II have to stick with the frac as I think I'II get blown across the garden if I use the dob!

[alan potts]

FOLLOW UP TO THE MAIN REPORT FROM LAST NIGHT.

I have just had a go with the 70mm ED which is not the best piece of glass ever made but it is not bad either.

The night was started with, I won't bother, to my word look at the sky and finishing with was it worth it for 50 minutes, of course it was. Now I just grabed this scope as I know it cools very fast and I was really wanting to check out what the scope was like and how well it shows the Trapezium. This was largely on the back of a thread I was reading about two weeks back when one member thought there were only 3 stars in this.

As one or two of the members that have posted here have said in agreeing with me, conditions are a big factor, part of the conditions are also where I live in relation to many that will read this.

I have to say the 70mm showed the four stars very easily indeed even with a magnification as low as X16, I know I could have gone lower and still seen all four stars. I must point out without trying to be cleaver I am using only Televue eyepieces, 24mm Panoptic, 16mm Nagler 10mm delos and 6mm Delos. This could be important when looking in anything but top conditions as I find these eyepieces just seem to control everything that bit better than others.

I can only conclude that the member who had a problem with only seeing three stars was either a victim of the constellation being lower than I have it, poor seeing or he may have been using a smaller scope with a stock eyepiece.

clear skies

Alan.