Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

Trapezium E & F with 100mm and other delights


Recommended Posts

Just a short session tonight with the 100mm refractor.

Mars was hard work to be frank. Mediocre seeing, small disk plus a cold night with heating plumes abounding took their toll so it was only really possible to see vague dark markings on the small disk at 191x.

The Moon was somewhat better and some lovely detail was on show along the terminator provided that I stuck to sub 200x magnification. Above that and the seeing held things back.

Orion well up and very inviting as ever.

Rather surprised (given the conditions) that I could pick out both the E & F stars in the Trapezium cluster. The optimum magnification for this seemed to be 113x (8mm eyepiece) more than that made the task a little harder and less didn't show them. Proved once again that there is a "goldilocks" magnification for teasing these fainter members of this famous group of young stars out of the nebulosity in which they are embedded.

Alnitak (Zeta Orionis) was also rather well split at 191x given the conditions. 2.2 arc second gap but quite a brightness difference and a subtle tint variation between the stars in this pair with the fainter (mag 3.7) star seeming pale yellowish compared with the white of the brighter (mag 1.9) primary star. The third component, C, was also visible a little further off which is mag 9.6.

Nice session, despite the seeing :icon_biggrin:

Seasons greetings to all :icon_biggrin:

 

 

Edited by John
  • Like 24
Link to post
Share on other sites
  • Replies 28
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Just a short session tonight with the 100mm refractor. Mars was hard work to be frank. Mediocre seeing, small disk plus a cold night with heating plumes abounding took their toll so it was only r

... went out again after dinner and the seeing was considerably less bad. Bagged them both immediately. The E much clearer to me than the  F but no doubt about both. Spent quite a while on them and mo

I’ve tried to see them in an 80mm ED, Mak127, C5 & ST120... nothing. Second time out on M42 with the 10” dob and there they were, clear and repeatedly obvious (swapping between 14mm eyepieces).

Nice session John. I’ll remember your Goldilocks magnification when I’m next our with my 100mm frac. We’ve had so much bad weather it’s been many weeks since I have been out, in fact I have not yet observed M42 or anything in Orion this year. I was hoping to get in plenty of observing during my two week break - there’s still time. 🤞

  • Thanks 1
Link to post
Share on other sites

I have only ever seen E and F on a winters night crisp and clear with my very first scope a 150p, just waiting for the same kind of night get them in the refractor.

Nicely done I dont think I could get them in my Tal but you never know.

  • Like 1
Link to post
Share on other sites
Posted (edited)
5 minutes ago, wookie1965 said:

..... but you never know....

I think that is a good motive for many observers :icon_biggrin:

 

Edited by John
  • Like 1
Link to post
Share on other sites
On 25/12/2020 at 00:00, John said:

Rather surprised (given the conditions) that I could pick out both the E & F stars in the Trapezium cluster. The optimum magnification for this seemed to be 113x (8mm eyepiece) more than that made the task a little harder and less didn't show them. Proved once again that there is a "goldilocks" magnification for teasing these fainter members of this famous group of young stars out of the nebulosity in which they are embedded.

I found very much the same a few nights prior to your observation... managed to clearly see the E and F stars, using the both the Delos 14 and XW 14 in the Bresser 10” dob. With the TV Paracorr in place, the magnification was 104x. Going to either XW10 or XW20, the stars were not visible, so it seems a certain magnification is appropriate 👍

I’m just very happy that I was able to see them in my first session on M42 using the new dob 😀

  • Like 4
Link to post
Share on other sites

I had a go last night with my Skymax 180 and maybe maybe maybe imagined the E for a fleeting moment. At around 150x. Personally I won’t take it as a “tick” (still haven’t bagged them) but I’ll take the tease and persevere. A week of clear nights forecast so I should get plenty of chances.

M

  • Like 3
Link to post
Share on other sites
17 minutes ago, Captain Magenta said:

I had a go last night with my Skymax 180 and maybe maybe maybe imagined the E for a fleeting moment. At around 150x. Personally I won’t take it as a “tick” (still haven’t bagged them) but I’ll take the tease and persevere. A week of clear nights forecast so I should get plenty of chances.

M

I tried again (on New Years Eve) but this time with my Skymax 127... nothing at any magnification (XW 20 thru XW 7), apart from the four (A to D) stars, so I guess aperture is also important for these too. Keep trying, as you should have the aperture with the Skymax 180... good luck 🤞

I did work through a few doubles in Orion through and they all split nicely 👍

Had to stop after an hour though, as the scope body (including dew shield) were covered in a thin layer of ice 😮

 

Edited by HollyHound
Link to post
Share on other sites
Posted (edited)

Over the years I've found that getting both the E & F stars in my 102mm / 100mm refractors quite challenging. The E star is the most readily seen but the F can be pretty elusive at that aperture. At 120mm (refractor) both these stars are more regularly seen, once the magnification is right. At 130mm (refractor again) they are pretty straightforward unless the seeing is very mediocre. With my 12 inch dob E & F are unmissable - very obvious even in so-so seeing.

Anyone managed to see G, H or I yet ?

Orion's Firepit

Here is a nice Sky & Telescope article by Bob King on this topic and a bit more besides:

https://skyandtelescope.org/observing/star-trapping-in-orions-trapezium/

 

Edited by John
  • Like 2
  • Thanks 1
Link to post
Share on other sites
38 minutes ago, John said:

With my 12 inch dob E & F are unmissable - very obvious even in so-so seeing.

I would certainly agree that in my 10” dob, the E & F were very clearly visible that night, at the right magnification, whereas I’ve never seen them in any of my (smaller aperture) scopes.

Quote

Anyone managed to see G, H or I yet ?

I did try, but not a chance of seeing these...will keep trying, although I suspect it’s beyond even this scope 🤞

Edited by HollyHound
  • Like 1
Link to post
Share on other sites

Had a shot tonight, while waiting for the moon to appear over the rooftops. The seeing was pretty poor, though. 8" dob.

I think I was getting the E star. Between x100 and x150 something was shimmering in and out with averted vision. The poor seeing made everything tricky; focusing was problematic, especially using the zoom lens. I'd like to try again on a better night. If what I thought I was seeing appears steadily then, I'll say I saw it tonight. No sign of F at all.

Alnitak was a pulsating blob and no hope of splitting anything.

The moon appeared and simultaneously so did the clouds, so back inside now with a nice Rioja.

Edited by Pixies
  • Like 2
Link to post
Share on other sites
30 minutes ago, Pixies said:

Had a shot tonight, while waiting for the moon to appear over the rooftops. The seeing was pretty poor, though. 8" dob.

I think I was getting the E star. Between x100 and x150 something was shimmering in and out with averted vision. The poor seeing made everything tricky; focusing was problematic, especially using the zoom lens. I'd like to try again on a better night. If what I thought I was seeing appears steadily then, I'll say I saw it tonight. No sign of F at all.

Alnitak was a pulsating blob and no hope of splitting anything.

The moon appeared and simultaneously so did the clouds, so back inside now with a nice Rioja.

If it is cold where you are as it is here, there will be a lot of heat rising from rooftops of houses I reckon, which is not good for this sort of task :rolleyes2:

A couple more glasses of Rioja and you might be able to see F though to Z ! :wink:

 

  • Like 2
  • Haha 2
Link to post
Share on other sites
8 minutes ago, John said:

If it is cold where you are as it is here, there will be a lot of heat rising from rooftops of houses I reckon, which is not good for this sort of task :rolleyes2:

A couple more glasses of Rioja and you might be able to see F though to Z ! :wink:

 

There's still snow on the ground and I'm looking over a row of old Georgian houses, so undoubtedly, yes. Also, the jet stream is doing 100mph above us just now, too.

Perhaps not F to Z, but I reckon Epsilon Lyrae is now "Triple Triple".

  • Haha 2
Link to post
Share on other sites
9 hours ago, John said:

If it is cold where you are as it is here, there will be a lot of heat rising from rooftops of houses I reckon, which is not good for this sort of task :rolleyes2:

Good point and actually that’s something I’d forgotten about... quite fortunate here that we have only one house (the farmhouse directly SW) anywhere within 1/2 mile of us, just some trees to the East, barns (full of cows) to the West, but pretty much open fields all round.

When the lights in Thornbury go off towards midnight, I think it’s pretty much Bortle 4 here, as there are no streetlights at all.

All these could help explain why E & F were so solidly visible I suppose 🤔

  • Like 2
Link to post
Share on other sites
47 minutes ago, Captain Magenta said:

I’m going to cheat tonight and deploy the 12” newt...

That’s not cheating, that’s using the right tool for the job 👍

  • Like 2
Link to post
Share on other sites
2 hours ago, Captain Magenta said:

I’m going to cheat tonight and deploy the 12” newt...

That's a good approach. Once you have seen them with a larger aperture, finding them with smaller apertures becomes a little bit easier.

 

 

  • Like 2
Link to post
Share on other sites

I'm not sure what i'm doing wrong.

Never yet got close to either the 'E' of 'F' components in  either of my current 2 refractors (105mm / 140mm) which have been in use since September 2019.

I've only actually positively identified the 'E' just the once, and that was around 5 years ago in a previous scope (a 132mm refractor) but even then it wasn't obvious.

I've never seen the 'F' at all.

So i either 'need to get out more' or.......its down to grotty Derby seeing or maybe just my 53 year old eyes ?  Perhaps my eyesight simply isn't up to it ?

It also might explain why i've never got anyway near the 'Pup Star' or Triton or any of the Uranian moons.

I can however, see Epsilon Lyrae double double, and have had some lovely views of that last autumn when it was high in the sky.

I'm planning a new custom built 10" Newtonian later in the year. Maybe that extra aperture will help.

I do enjoy my current double star observing though, and will continue to try for these elusive targets.........

Good topic, thanks for posting 🙂

 

  • Like 3
Link to post
Share on other sites

I have seen G. It was through the 12" (ish) Dob that our club owns (which I helped to build) usinf Pentax XL eyepieces and it was a brilliant night years ago now. E and F were obvious, and myself and another observer took turns spending ages seeing what else we could see, and we both agreed that we could see another star. We refered to a chart of the components, and it was the G star.

I wonder if I'll be able to catch E and F tonight in my 100mm? Fingers crossed.... !

  • Like 3
Link to post
Share on other sites
2 hours ago, Space Hopper said:

I'm not sure what i'm doing wrong.

Never yet got close to either the 'E' of 'F' components in  either of my current 2 refractors (105mm / 140mm) which have been in use since September 2019.

I've only actually positively identified the 'E' just the once, and that was around 5 years ago in a previous scope (a 132mm refractor) but even then it wasn't obvious.

I've never seen the 'F' at all.

So i either 'need to get out more' or.......its down to grotty Derby seeing or maybe just my 53 year old eyes ?  Perhaps my eyesight simply isn't up to it ?

It also might explain why i've never got anyway near the 'Pup Star' or Triton or any of the Uranian moons.

I can however, see Epsilon Lyrae double double, and have had some lovely views of that last autumn when it was high in the sky.

I'm planning a new custom built 10" Newtonian later in the year. Maybe that extra aperture will help.

I do enjoy my current double star observing though, and will continue to try for these elusive targets.........

Good topic, thanks for posting 🙂

 

I’ve tried to see them in an 80mm ED, Mak127, C5 & ST120... nothing. Second time out on M42 with the 10” dob and there they were, clear and repeatedly obvious (swapping between 14mm eyepieces).

I have 54 year old eyes, admittedly quite good skies here (mostly), but limited experience... so I reckon it’s got to be that 10” aperture and if you’re planning on getting or making one of these, you should be able to see it at last 🤞😃

  • Like 5
Link to post
Share on other sites

Well certainly not for me yet tonight, despite the 12”. Seeing is appalling, Rigel and alnitak like kaleidoscopes. View much worse than with Mak the other night. Oh well, decent forecast for next 4-5 nights so I’ll persevere...

  • Like 1
  • Sad 2
Link to post
Share on other sites

... went out again after dinner and the seeing was considerably less bad. Bagged them both immediately. The E much clearer to me than the  F but no doubt about both. Spent quite a while on them and moved briefly on to Mars and the moon both of which confirmed the seeing was still far from good. Very pleased though.

  • Like 5
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.