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Rigel B vs. Sirius B

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#1 TegiriNenashi

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Posted 04 April 2011 - 10:16 PM

Just to confirm, what I saw (and didn see) couple of days ago, I understand that Sirius is much tougher to crack than Rigel (with 10" at 200x), is this right? I was unable to split Rigel on really bad condition only. I understand that angular separation is about 10" for both systems, so the view would be very similar, but brightness difference is much higher for Sirius?

If you'd assign difficulty level, what it would be, something like 9 vs. 5 (out of 10)?

#2 jrbarnett

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Posted 04 April 2011 - 11:55 PM

Currently? I'd rate Sirius as a 5/10 and Rigel as a 3/10 in a 3" or larger scope at ~100x.

Sirius B was easy and obvious under 6/10 seeing skies in a 3" f/6 LOMO triplet at just 70x last Friday night at ~34-deg N (Mojave Desert in California).

Difficulty in a 10-incher, likely has more to do with seeing, collimation and thermal stability of the scope, not the magnification and certainly NOT the aperture.

Regards,

Jim

#3 Jon Isaacs

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Posted 05 April 2011 - 06:30 AM

Currently? I'd rate Sirius as a 5/10 and Rigel as a 3/10 in a 3" or larger scope at ~100x.

Sirius B was easy and obvious under 6/10 seeing skies in a 3" f/6 LOMO triplet at just 70x last Friday night at ~34-deg N (Mojave Desert in California).

Difficulty in a 10-incher, likely has more to do with seeing, collimation and thermal stability of the scope, not the magnification and certainly NOT the aperture.

Regards,

Jim


Splitting Sirius in a 3 inch telescope is a remarkable observation and not one to be taken lightly. Sirius B is considered one of the most difficult splits people commonly attempt, not because it is tight but because of the 10 magnitudes difference in brightness. Rigel is relatively easy in a 80mm telescope, conditions have to be excellent to split Sirius even with it's current wider separation. The B star easily gets lost any atmospheric scatter from the A star.

Rigel:

A-BC
Component 1 magnitude: 0.30
Component 2 magnitude: 6.80
Separation: 9.6

Sirius:
Component 1 magnitude: -1.46
Component 2 magnitude: 8.50
Separation 9.2

Over the years I have split some very tight unequal double stars but never split Sirius and let me tell you I have tried many times with a variety of telescopes under a variety of conditions. The original poster should not be disappointed that the split was not made, it is tough.

Jon Isaacs

#4 Bonco

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Posted 05 April 2011 - 04:00 PM

I think the difficulty between Sirius and Rigel is huge. I always split Rigel with 60mm and larger scopes. I've only seen the pup a couple of times with a 10 inch and never (yet) in anything smaller. It's a challenge for sure especially during less than perfect viewing conditions. As the pair opens up no doubt we'll get more reports of success with smaller telescopes.
Bill

#5 Rich (RLTYS)

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Posted 06 April 2011 - 05:12 AM

I have never quite understood how or why people compare splitting Sirus with Rigel :confused:. Rigel is so much easier to split and despite having tried numerous times I've never been able to split Sirus. :bawling:

Rich (RLTYS)

#6 Asbytec

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Posted 06 April 2011 - 08:06 AM

Same experience, Rich.

#7 desertstars

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Posted 06 April 2011 - 08:27 AM

Same here. It's a poor night of seeing indeed when my old 60mm refractor doesn't reveal the companion of Rigel. Under the best conditions I've yet to be absolutely sure of the Pup in an 8" reflector.

#8 dscarpa

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Posted 06 April 2011 - 02:46 PM

I saw Sirius B once in my WO ZS110 in my suburban location useing a 9T6 and 3X TV barlow for 250X, seeing was excellent. It was very difficult, I'd give it a 10. Rigel is a cakewalk unless conditions are terrible, for me it's a 3. David

#9 lionel

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Posted 06 April 2011 - 05:08 PM

There really is no comparison as far as difficulty, but splitting Rigel can help you with the much greater challenge of splitting Sirius.

Sirius' separation is similar to Rigel's. If you have not seen the Pup before then Rigel's separation is a useful indicator of how far the Pup will appear from Sirius in a given eyepiece. That distance combined with its due east position angle will tell you exactly where it should be.

If you're trying to view the Pup from greater than 40 degrees N latitude, wait for a night of good seeing (both E & F Trap stars constantly visible) and make the attempt when CMa is close to the meridian. Use high power....above 300x - to pull the faint Pup out of Sirius' glare field.

That's how I saw the Pup last winter...

Lionel

#10 Mike Spooner

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Posted 17 April 2011 - 08:01 PM

Over the years I have split some very tight unequal double stars but never split Sirius and let me tell you I have tried many times with a variety of telescopes under a variety of conditions. The original poster should not be disappointed that the split was not made, it is tough.

Jon Isaacs


Last couple of nights I've had excellent seeing from central AZ. I was able to see the pup with 8" f/6 at 400x without undue difficulty. I also spied it for a brief period using a 7.3" @ about 460x. It was getting pretty dim in the smaller scope. Didn't really try at lower magnifications.
Currently, these are the smallest scopes I definitely have seen it through though I thought I saw it years ago when it was much closer but with absolutely superb conditions and a super 6". I recall I couldn't see it with anything but a beautifully polished Zeiss eyepiece.

Best,
--Mike Spooner

#11 kcolter

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Posted 18 April 2011 - 07:04 AM

Yeah, Mike, it's easy when you're using a Spooner mirror <g>.

#12 Homunculus

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Posted 18 April 2011 - 08:40 AM

Over the years I have split some very tight unequal double stars but never split Sirius and let me tell you I have tried many times with a variety of telescopes under a variety of conditions. The original poster should not be disappointed that the split was not made, it is tough.

Jon Isaacs


Last couple of nights I've had excellent seeing from central AZ. I was able to see the pup with 8" f/6 at 400x without undue difficulty. I also spied it for a brief period using a 7.3" @ about 460x. It was getting pretty dim in the smaller scope. Didn't really try at lower magnifications.
Currently, these are the smallest scopes I definitely have seen it through though I thought I saw it years ago when it was much closer but with absolutely superb conditions and a super 6". I recall I couldn't see it with anything but a beautifully polished Zeiss eyepiece.

Best,
--Mike Spooner


It's not tough! A few people on this thread have seen it with a 3" refractor at 70x. James Mullaney also said as much in a recent edition of Sky & Tel. Go figure :grin:

J.

#13 demetry  Happy Birthday!

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Posted 20 April 2011 - 09:46 PM

This season I learned to find the Pup with my 16" Spooner refigured Meade mirror. (Thanks, Mike!) Afterwards, it has become easy to find with my 5" refractor with very good seeing. Rigel B is way much easier to split because of the much less difference in magnitude from the primary.

#14 Mike Spooner

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Posted 23 April 2011 - 08:50 AM

This season I learned to find the Pup with my 16" Spooner refigured Meade mirror. (Thanks, Mike!) Afterwards, it has become easy to find with my 5" refractor with very good seeing. Rigel B is way much easier to split because of the much less difference in magnitude from the primary.


Hi Demetry!

Hope you get some good views of Saturn with the 16". We've had some good seeing here lately but seems like I'm working a lot of the best nights! :confused:

Best,
--Mike

#15 demetry  Happy Birthday!

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Posted 23 April 2011 - 08:58 PM

Mike, thanks for the reply. Please see the pm sent to you.

Jon, Have you pointed your 20" reflector to Sirius? I bet you'll find the Pup that way. From then on it will be easy when the seeing allows.

#16 Dean Norris

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Posted 23 April 2011 - 09:26 PM

On this forum we could have a poll where you would list the scope and magnification you used to split Sirius.
I was fortunate to see it in my 10" on a clear and steady January night. Though this year no such luck.

Dean

#17 magnus

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Posted 23 April 2011 - 10:26 PM

...and how high above horizon Sirius can possibly be observed from a given place ;)
Magnus 57*N.

#18 lionel

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Posted 24 April 2011 - 12:08 AM

I hear you Magnus...those folks in California don't appreciate what a challenge it is for northerners :grin:.

I'm guessing Sirius' altitude is about 16 degrees above your horizon. That's got to make a split pretty much out of the question for you.

At my site Sirius reaches a maximum altitude of about 32 degrees. Combined with winter viewing that is almost always through the jetstream, it's no surprise it is a very difficult challenge even in my superb 10" DK. I consider myself lucky to be the first person in my large observing group to see the Pup.

Lionel

#19 Rutilus

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Posted 24 April 2011 - 06:28 AM

In the past year using a 4 inch refractor, I've managed to see the Pup twice when at an altitude of 16 degrees.
Very difficult and the conditions have to be excellent.

#20 magnus

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Posted 25 April 2011 - 03:58 AM

Congrats to Lional & Rutilus.
Next winter I will have a real serius try to see the Pup with my 8"f/6 OOUK, but doubt I can sucess.
Rigel on the other hand is a walk in the Park, even in my C80ED.
/Magnus

#21 John Van Allen

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Posted 14 February 2013 - 06:46 AM

At my location here in the Dominican Republic Sirius is nicely placed for observing at around 54° altitude at around 1030 at night. Using my Questar 3.5 with an 8mm eyepiece and the 2x internal lens I believe I saw the pup once but still have a question mark in my log book. The city of Santo Domingo has a lot of light pollution as well as other kinds of pollution. There are some very high mountains here and I am planning a trip to do Sirius Splitting (no pun intended), Rigel is easy with the Q and with an O111 filter even easier. I believe I saw the pup using this filter but with only 3.5" aperature the images get very dim. One other thing is at play here, the age of my eyes. At 66 my eyes aren´t the same as at 26 and after a few minutes of intense concentration they start misbehaving like watering. Finding the sweet spot in the eyepiece is tricky with the mileage these eyeballs have. Any suggestions re eye exercises, vitamins, etc would be appreciated.
Regards
John

#22 nirvanix

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Posted 14 February 2013 - 11:05 AM

Rigel B turns out to be an excellent measure of seeing conditions for me. When seeing is excellent I can split it at ridiculously low powers, but when seeing is really bad can't split it at all because daddy is doing the flash dance all over the place. I wonder if there is a linear relationship between magnification needed for the split and seeing? Maybe I'll get out some graph paper and find out. :p

#23 Pete-LH

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Posted 15 February 2013 - 06:04 AM

Hi everyone and Lionel,
No success yet ...
Rigel has been no problem even down to a 60mm f/11. Quite beautiful so I've given it a shot every time out this fall to get an idea of the conditions. I've tried Sirius in the past with no luck but was inspired by the posts here so I thought I'd give it a Sirius (sorry) try last night.
I set up my FS-102 and with a 5mm Ortho thought I caught a glimpse briefly. To reduce the glare I stopped down with the Tak manhole cover and had a beautiful Airy disc with two concentric diffraction rings. I stared at it for a while but no Sirius B. So I went on to Beta Monoceros which I've been obsessed with lately, then over to M48 and called it a night. The spirit was willing but the body was weak and my bed was calling.
Lionel, Fred is talking about the RV lot on Sunday so maybe we can give it a shot there?






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