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TegiriNenashi
super member


Reged: 12/20/10

Rigel B vs. Sirius B
      #4496974 - 04/04/11 11:16 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)?


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Rigel B vs. Sirius B new [Re: TegiriNenashi]
      #4497190 - 04/05/11 12:55 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


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Rigel B vs. Sirius B new [Re: jrbarnett]
      #4497487 - 04/05/11 07:30 AM

Quote:

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

Edited by Jon Isaacs (04/05/11 07:34 AM)


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Bonco
Post Laureate
*****

Reged: 04/17/06

Loc: Florida
Re: Rigel B vs. Sirius B new [Re: Jon Isaacs]
      #4498601 - 04/05/11 05:00 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


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Rich (RLTYS)Moderator
Post Laureate
*****

Reged: 12/18/04

Loc: New York (Long Island)
Re: Rigel B vs. Sirius B new [Re: Bonco]
      #4499742 - 04/06/11 06:12 AM

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

Rich (RLTYS)


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Asbytec
Guy in a furry hat
*****

Reged: 08/08/07

Loc: La Union, PI
Re: Rigel B vs. Sirius B new [Re: Rich (RLTYS)]
      #4499928 - 04/06/11 09:06 AM

Same experience, Rich.

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desertstars

*****

Reged: 11/05/03

Loc: Tucson, AZ
Re: Rigel B vs. Sirius B new [Re: Asbytec]
      #4499962 - 04/06/11 09:27 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.

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dscarpa
Post Laureate
*****

Reged: 03/15/08

Loc: San Diego Ca.
Re: Rigel B vs. Sirius B new [Re: TegiriNenashi]
      #4500805 - 04/06/11 03:46 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

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lionel
sage


Reged: 08/12/07

Loc: Delaware
Re: Rigel B vs. Sirius B new [Re: Rich (RLTYS)]
      #4501071 - 04/06/11 06:08 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


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Mike Spooner
Vendor (mirrors)


Reged: 08/06/10

Re: Rigel B vs. Sirius B new [Re: Jon Isaacs]
      #4525084 - 04/17/11 09:01 PM

Quote:

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


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kcolter
sage
*****

Reged: 06/04/03

Loc: Missouri, USA
Re: Rigel B vs. Sirius B new [Re: Mike Spooner]
      #4525788 - 04/18/11 08:04 AM

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

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Homunculus
member


Reged: 03/14/11

Re: Rigel B vs. Sirius B new [Re: Mike Spooner]
      #4525928 - 04/18/11 09:40 AM

Quote:

Quote:

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

J.


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demetry
member


Reged: 01/08/06

Loc: South Carolina
Re: Rigel B vs. Sirius B new [Re: Homunculus]
      #4533015 - 04/20/11 10:46 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.

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Mike Spooner
Vendor (mirrors)


Reged: 08/06/10

Re: Rigel B vs. Sirius B new [Re: demetry]
      #4538421 - 04/23/11 09:50 AM

Quote:

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!

Best,
--Mike


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demetry
member


Reged: 01/08/06

Loc: South Carolina
Re: Rigel B vs. Sirius B new [Re: Mike Spooner]
      #4539768 - 04/23/11 09:58 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.


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Dean Norris
Carpal Tunnel
*****

Reged: 11/05/08

Loc: Santa Cruz, Ca
Re: Rigel B vs. Sirius B new [Re: demetry]
      #4539826 - 04/23/11 10:26 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


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magnus
professor emeritus


Reged: 03/17/04

Loc: Visby, Sweden
Re: Rigel B vs. Sirius B new [Re: Dean Norris]
      #4539959 - 04/23/11 11:26 PM

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


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lionel
sage


Reged: 08/12/07

Loc: Delaware
Re: Rigel B vs. Sirius B new [Re: magnus]
      #4540124 - 04/24/11 01:08 AM

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

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


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Rutilus
Carpal Tunnel


Reged: 12/17/10

Re: Rigel B vs. Sirius B new [Re: lionel]
      #4540402 - 04/24/11 07:28 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.


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magnus
professor emeritus


Reged: 03/17/04

Loc: Visby, Sweden
Re: Rigel B vs. Sirius B new [Re: Rutilus]
      #4542492 - 04/25/11 04:58 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


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