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Can't Split The 6 Trapezium Stars

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#26 bandhunter

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Posted 16 December 2012 - 10:29 PM

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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#27 jrbarnett

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Posted 17 December 2012 - 11:56 PM

Nah. E and F are much brighter than that (about Mag 10 each), and typically are easy under suburban skies with average seeing in a 4" refractor.

I find poor baffling/glare suppression to be the biggest culprit in not seeing all six in moderate aperture scopes. The other challenge is observer expectations. Warm up on Polaris then Rigel. Train your eye to pick out a little "diamond chip" star next to a much brighter companion. Use a finder chart so that you know exactly where to look. I bet they were there in the 6" f/5 if he knew exactly where to look.

http://www.astropix....NTER/TRAPEZ.HTM

Regards,

Jim

#28 blb

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Posted 18 December 2012 - 12:49 PM

Nah. E and F are much brighter than that (about Mag 10 each), and typically are easy under suburban skies with average seeing in a 4" refractor.

I find poor baffling/glare suppression to be the biggest culprit in not seeing all six in moderate aperture scopes. The other challenge is observer expectations. Warm up on Polaris then Rigel. Train your eye to pick out a little "diamond chip" star next to a much brighter companion. Use a finder chart so that you know exactly where to look. I bet they were there in the 6" f/5 if he knew exactly where to look.

http://www.astropix....NTER/TRAPEZ.HTM

Regards,

Jim


Vrey good advice Jim. If you can see the companion stars for Polaris and Rigel you should be able to see the E and F stars in the Trapezium, but you may need to use some averted vision to find them at first. Averted vision will place the stars in a more sensitive part of the eye, so they will be a little easier to see the first time. Also do a star test to be certain that your scope is well collimated. That may prevent you from seeing them too.

#29 Ain Soph Aur

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Posted 31 December 2012 - 09:31 PM

I've had E & F through my 4" f/13 Carton quite a few times from my backyard red/orange transition zone under good conditions this year, and not so much other times even when I thought conditions were excellent.

I have glimpsed E twice this fall in an excellent 60mm f/20 from a green zone, but neither from my backyard (yet) after quite a few times of trying. I usually only have the 60mm out at home for lunar viewing when the dark sky conditions aren't so good.

#30 bremms

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Posted 31 December 2012 - 10:56 PM

E and F are all about scattered light and seeing. Years ago, never had any trouble if the seeing was good from a green blue site with a very good 6 inch f8. Hard in a C8 due less contrast. Seeing is VERY important.

#31 Walter C

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Posted 01 January 2013 - 10:27 PM

New to this forum, 40+ years into astronomy.

I use a 10" Newt with a mirror that needs a good re-coating real bad.

Several weeks ago I saw the "E" star with no problem using a 20mm Plossl. It was a cool clear night with no wind below or high. Our dark sky site isn't totally dark, but, dark enough. Stars were points even at higher powers. I looked at Jupiter with 240x plus and was please to see 3 or 4 bans and the red spot with ease.

I took a stab at "E" with the very high power, but, it just was too fuzzy. The lower power 20mm and then with a 16mm Koneg II made the stars appear to be periods.

My opinion, stable air conditions are more important than the dark sky (which is very important) when it comes to "E".

#32 planet earth

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Posted 03 January 2013 - 04:34 AM

Sometimes in my light polluted area I will see E and F easily in a 6 f8 at X150, other times I can barely see E with a 12 f5 roughly same power.
Haven't really tried enough times with my 4.5 f8, but so far no luck.
Try try and try again.....
Sam

#33 jacobmarchio

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Posted 04 January 2013 - 12:30 PM

Ok, I've got a question: how far apart would the separation be at around 200x?

Haven't had good conditions for a while, patiently waiting... it seems like constant cloud.

#34 Starman1

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Posted 04 January 2013 - 02:49 PM

Here is a map of the Trapezium and its associated stars:
Theta Orionis

#35 Lane

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Posted 04 January 2013 - 04:38 PM

I have seen E and F with my TMB 92L several times now in a blue zone, but it does take a bit of patience to find them. F always seems to be harder though when the atmosphere is not cooperating. I have failed to find it on several occasions with that little scope.

#36 BillFerris

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Posted 04 January 2013 - 08:58 PM

Ok, I've got a question: how far apart would the separation be at around 200x?


E and F are separated by about 4 arcseconds, respectively, from stars A and C. At a magnification of 200X, the apparent separation would be (4x200) 800 arcseconds. This translates to (800/60) 13.3 arcminutes...not quite half the size of a full Moon to the naked eye.

Bill in Flag

#37 dpwoos

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Posted 06 January 2013 - 12:10 AM

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?


This is a perfect example of the value of joining your local astro club and observing with other folks and other scopes. Both E and F are fairly easy to see in bigger scopes (10"-14"), and once you see them once then I bet you will be able to see them in your 6", assuming your optics are up-to-snuff and working correctly. In my 6" f/8 when the sky is cooperative they are both so obvious that it is a wonder that they aren't always so easy to see. And, when the sky isn't cooperative then E is much harder to see, and F is simply not there.

#38 kansas skies

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Posted 06 January 2013 - 11:05 PM

I was experimenting a little with trying to separate these components a couple of nights ago. I was using a 4" f/15 refractor with a 17mm Celestron Silvertop Plossl (this seemed to be the best magnification for showing a nice pinpoint E component under the conditions at the time). The F component was lost most of the time in the glare of C. The seeing was a little rough, but the F component would occasionally show itself during moments of better seeing. I tried averted vision, but it didn't seem to work well here. I think this was because averted vision just emphasized the glare of the brighter component, and in my opinion, made things worse. For this reason, I think the best way to separate the components is to use a magnification that allows for E to be seen clearly and then just be patient.

Bill

#39 Atl

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Posted 07 January 2013 - 01:03 PM

They are awfully small and at first you won't see them...but once you do they are quite obvious. It was a challenge at 100x on my 12.5" dob....but they are distinct and clear.

#40 CelestronDaddy

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Posted 10 January 2013 - 09:41 PM

Conditions in my area have not been good at all and we just finished 2 days of rain. Tonight however looked good on my clear sky chart so I set up early and went out around 6:45pm. Around 7:30 I tried the Trapezium and at about 137x to 150x I was able to see E without too much trouble. Couldn't pick up F though. It seems to be harder so I need to keep trying, g....

#41 azure1961p

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Posted 11 January 2013 - 12:37 PM

I've found 200x with my 8" is ideal. I can rsolve them at lower mags but the airy discs are well defined at 200x and so it looks text book. Averted vision is very important, look just a few arc seconds above the trap on the e f side of the trapezoid asterism and that's how I see them simultaneously. But as mentioned in poor seeing both can be utterly erased out of existence.

Pete

#42 CelestronDaddy

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Posted 11 January 2013 - 04:09 PM

I've found 200x with my 8" is ideal. I can rsolve them at lower mags but the airy discs are well defined at 200x and so it looks text book. Averted vision is very important, look just a few arc seconds above the trap on the e f side of the trapezoid asterism and that's how I see them simultaneously. But as mentioned in poor seeing both can be utterly erased out of existence.

Pete


Pete - I'll keep trying for F and maybe I'll catch it when conditions are better. I don't have a barlow right now so the best I can do with EP is around 150x. I think my next purchase will be a decent 2x barlow instead of a higher power EP. I tried using averted vision but just couldn't get F. Do you utilize a barlow of some sort or just higher power EP's? Maybe my 53 year old eyes aren't cooperating :lol: E faded out sometimes but for the most part I could readily pick it up... Tony

#43 drbyyz

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Posted 12 January 2013 - 08:16 PM

Finally "logged" F last night under decent conditions at 167x.

#44 CelestronDaddy

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Posted 12 January 2013 - 09:00 PM

Way to go! Glad you got it, g... :waytogo:

#45 jacobmarchio

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Posted 15 February 2013 - 10:47 AM

Hi all,
Sorry for the long delay in posting, we've had some bad weather for a long time. Anyway, got them last night :)! The moon was up, and I used my C9.25. The corrector had some dew, so I'm sure that didn't help. Used a magnification of 235x (25mm Plossl w/ 2.5x PowerMate). Pretty positive about both of them. They are a lot dimmer than I thought- but maybe the moon and a dewy corrector caused this. Went over to try it in my 6", but the secondary was literally dripping with dew, so I couldn't there. The sct corrector gradually got more dew through the night. I will say that having a tracking mount and a chair helps!

#46 Starman1

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Posted 15 February 2013 - 11:14 AM

Hi all,
Sorry for the long delay in posting, we've had some bad weather for a long time. Anyway, got them last night :)! The moon was up, and I used my C9.25. The corrector had some dew, so I'm sure that didn't help. Used a magnification of 235x (25mm Plossl w/ 2.5x PowerMate). Pretty positive about both of them. They are a lot dimmer than I thought- but maybe the moon and a dewy corrector caused this. Went over to try it in my 6", but the secondary was literally dripping with dew, so I couldn't there. The sct corrector gradually got more dew through the night. I will say that having a tracking mount and a chair helps!

Though it won't prevent dew forever, a dew shield on the SCT will help.
Most are poorly designed. A good dew shield should be:
--insulating. Where it wraps around the scope it should insulate the cell of the corrector from cooling against a cold atmosphere
--be very non-reflective inside. Flocking is good.
--be at least 1.5X the aperture in length. Many commercial dewshields are too short.

Even here in southern California, an SCT without a dewshield starts dewing over in 20 minutes. With a dewshield, maybe by 3-4am.

It also helps to keep the corrector clean and free from dust.

#47 jacobmarchio

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Posted 15 February 2013 - 01:16 PM

I do have a dew shield (it's an Astrozap shield), and it was on :grin: Believe it or not, it started dewing up while I was aligning the mount :shocked:. I guess it takes more than a dew shield to even delay dew here.

#48 Starman1

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Posted 15 February 2013 - 01:25 PM

I do have a dew shield (it's an Astrozap shield), and it was on :grin: Believe it or not, it started dewing up while I was aligning the mount :shocked:. I guess it takes more than a dew shield to even delay dew here.

Yeah, I grew up in Indiana, where the dew point was reached when the temperature fell 2 or 3 degrees. Out here the temperature has to fall 20 degrees or more to reach the dewpoint, indicating the lesser amount of atmospheric water vapor.

Sometimes it helps to keep the scope horizontal, if the dewpoint is already reached, for a half-hour after the heaviest dewing. The relative humidity often drops then.
But it sounds like you needed a heated dewshield, or at least I can foresee one in your future.

#49 la200o

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Posted 15 February 2013 - 03:21 PM

I couldn't use my CPC without a heated dewshield here in Michigan.

Bill

#50 nevy

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Posted 18 February 2013 - 04:08 PM

In my 12" dob the E star is easily seen , I could never see the F star until I installed a fan blowing on the back of the mirror , now it's there , if the fan isn't running I noticed it would be hidden by a bit of flairing from the main star , also I've seen for the first time , the pup ( companion to Sirius ) a few nights ago , the first time I tried the scope with the new fan running.






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