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The Trapezium - viewing E and F and Sirius B

Mark at Beaufort

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Mark at Beaufort

Mark at Beaufort

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I have some Hutech orthoscoptic eyepieces on test mainly to try and view Sirius B. To be honest I have never tried these EPs in the past mainly because of the tight eye relief so it was interesting to use the 6mm and 9mm last night.

I set up the 180mm Mak and the 10" Dob side by side so that I could view Jupiter with the Mak and try to view Sirius with the Dob. There was a lot of dew last night so the 12v was in high demand.

I placed the 9mm Hutech into the Dob giving a mag of 133x and looked at the Trapezium. The first thing that I noticed was that star E was very clear. Suddenly I saw star F close to star C - it came in and out of view but for a moment it was there. Unfortunately it was around 9pm and I started to get cloud moving in from the West so decided whilst I had the chance I would quickly view Sirius.

I placed a red 25 filter into the 6mm Hutech and looked at Sirius. The star appeared much sharper but although I only had a few minutes I could not detect Sirius B. However, I am sure using a red filter is the way to go.

Had to finish around 9.15pm too much cloud and the battery for the 12v hairdryer ran out. It was annoying because around 11pm the sky was crystal clear so I had a session with the 15x70 binos.

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John

John

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Interesting report Mark. I saw E & F Trapezium last night with my ED120 refractor but I could not detect Sirius B even with good orthos. I also used a red filter last night and it does tighten up star images quite a bit but in the ED120 I suspect the lower transmission just put the Pup star below the viewing threshold.

It's a sort of balancing act with these really unequal brightness doubles it seems to me - power is needed, but not too much, some filtering helps, but not too much, you need some aperture but minimal diffraction. Oh, and you need steady seeing conditions too !

I reckon you will get that pesky Pup star though :smiley:  

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  • 2 weeks later...
John

John

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I've gotten E and F visually with my 4" refractor. Can't get them every time, and they're definitely faint, but it can absolutely be done.

I agree. The 4" Vixen is the smallest aperture that I've managed to see E & F with and, as you say, they are not always visible with that aperture. 

With my ED120 refractor they are routinely seen unless the seeing conditions are notably poor.

As I've posted a few times on here, the magnification needs to be just right to see them clearly - not to much and not too little. It needs a little experimentation to find the "right" eyepiece for the scope and conditions. It's nice to have a few options to play with  :wink:

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John

John

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I have seen E&F in my 150p with 8mm BST only a couple of times though because had to be really a still night and really clear never tried the pup.

I have to be honest and say that the Pup is a much harder challenge for a number of reasons, notably the extreme brightness difference between it and Sirius A and their relatively low elevations from the UK. So far, I've only managed to see it with my 12" scope on nights of reasonably steady seeing.  

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wookie1965

wookie1965

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I have to be honest and say that the Pup is a much harder challenge for a number of reasons, notably the extreme brightness difference between it and Sirius A and their relatively low elevations from the UK. So far, I've only managed to see it with my 12" scope on nights of reasonably steady seeing.  

Might be out of my viewing then in my 6inch i will give it a go when i get a really good night but i wont be disappointed if i cant resolve it.

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chiltonstar

chiltonstar

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Might be out of my viewing then in my 6inch i will give it a go when i get a really good night but i wont be disappointed if i cant resolve it.

Can be done with 6" or smaller  but takes a night of exceptional seeing. I've done it a few times now with 5", once with a quality ED80, never managed with my 4" 'frac.

At the moment, seeing the night sky at all seems to be pretty exceptional!

Chris

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Joves

Joves

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I have to be honest and say that the Pup is a much harder challenge for a number of reasons, notably the extreme brightness difference between it and Sirius A and their relatively low elevations from the UK. So far, I've only managed to see it with my 12" scope on nights of reasonably steady seeing.

I agree, John. For me, spotting the Pup was a whole 'nother challenge. Would the difficulty of these two objects be considered even in the same league? My experience was that E and F were a slight challenge, but almost immediately doable. The Pup, however, took several attempts and has only been able to be seen by these eyes, once I might add, in my 10" SCT. Admittedly, I have only tried it once with the 10", so am not sure if I could make a routine of it with reasonable seeing.

Orion is positioned pretty high in the sky also, I'd say roughly around 75 degrees, so I'm sure that is helping with E and F considerably also.

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alan potts

alan potts

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Nice report Mark, keep at it you will get there, I found it fairly easy the other night with the maksutov but could not crack it last night with the 70mm ED despite over two hours work.

I don't know if you have read my other reports on Sirius but I can't crack it when viewing it below 20 degrees elevation, once is get about about 24 degrees it becomes much less of a pain.

Alan

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NickK

NickK

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I think I have confidence in the Pentax (675mm f6.38)- visually it's capable. EPs are usually 5,13, or 32mm Baaders Hyperions. I have a 2x and now a 5x powermate that I'm eager to try! I've imaged at 2x (1340mm f13) but although most DSOs will be out for the 5x I'm hoping that M42 core stars will be bright enough (5x = 3375mm at f32.2.. dawes limit is another matter...

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NickK

NickK

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Good job - I managed to get E&F by imaging at 1340mm and a bit of post imaging prodding - 4" refractor isn't enough to get them separate visually usually!

I'll correct that - saturday night I managed to get them both running with the 5x power mate and 13mm hyperion. The atmosphere seems to dictate when they can be seen but saturday night I had a crystal clear portion of the night with almost zero turbulence (not had that before except in Hawaii!).

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John

John

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I'll correct that - saturday night I managed to get them both running with the 5x power mate and 13mm hyperion. The atmosphere seems to dictate when they can be seen but saturday night I had a crystal clear portion of the night with almost zero turbulence (not had that before except in Hawaii!).

Good result. I've resolved E & F with my Vixen ED102SS refractor a few times on nights of really good seeing but my ED120 refractor shows them routinely. Getting the power "just right" seems critical with these scopes but the 12" dob is much less fussy in this respect, understandably with that much more aperture and resolution to play with.

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Stu

Stu

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Since I have moved to a darker sky site I have found my 8" dob shows them well a medium magnifications. I always found them hard to see from London with the same scope.

Cheers

Ian

I can get E in my 4" on good nights, but haven't managed F. I'm sure, as you say, the London skies and lovely vapor trails don't help!

Stu

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iksobarg

iksobarg

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Had to finish around 9.15pm too much cloud and the battery for the 12v hairdryer ran out. It was annoying because around 11pm the sky was crystal clear so I had a session with the 15x70 binos.

Nice post. Sorry about your battery and weather.

Mark, how strongly can you recommend 15x70 binos? I spose you have more than one set? I'm looking for a set for general purpose. Thanks!

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John

John

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Nice post. Sorry about your battery and weather.

Mark, how strongly can you recommend 15x70 binos? I spose you have more than one set? I'm looking for a set for general purpose. Thanks!

A good place to ask this would be the binocular section  :smiley: : 

http://stargazerslounge.com/forum/133-discussions-binoculars/

This thread is about viewing E & F Trapezium in M42 and Sirus B.

Thanks  :smiley:

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Marki

Marki

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Managed E recently (monday) with my 6" 'frac, but really struggled with F even high power. Its odd, as I've seen F before, even with a 4" frac (had some great views last winter in crisper air). Guess its down to the air conditions - too much light spill in murky air to really pick it out. Still not cracked Sirius B though, even on nights when I can see Rigel's companion... .

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Stu

Stu

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Managed E recently (monday) with my 6" 'frac, but really struggled with F even high power. Its odd, as I've seen F before, even with a 4" frac (had some great views last winter in crisper air). Guess its down to the air conditions - too much light spill in murky air to really pick it out. Still not cracked Sirius B though, even on nights when I can see Rigel's companion... .

I really struggle with F from my location too, think it must be local seeing conditions. I have regular aircraft heading into Heathrow coming overhead which doesn't help.

Rigel I find relatively easy, even in the 76 when conditions are good, nothing like as hard as the pup! Might give it a go with the Vixen tonight.

Stu

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