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Rigel and Sirius - Omni XLT 102 ED

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#1 greyfox

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Posted 14 January 2013 - 10:42 PM

Evening all:

Just hauled my Omni XLT 102ED in from its first night out in well over a year. Tonight was my first ever attempt at the Pup. But first things first!

I've been looking at Rigel for many years, but have just recently dedicated myself to the double star field. The companion was unknown to my 8" Dobsonian, so it was time to try it with the Omni. In the fading twilight, I acquired Rigel and plopped in my 24mm Panoptic. Squaring her up, I then swapped to my Nagler 7mm T6, giving approximately 128x. Sure enough,
after just a couple seconds, the companion popped into view plain as day!

I tried hunting the glare around Rigel with the Panoptic, but 38x is just not enough for Rigel "B".

Now the Pup. With the knowledge of the seperation fresh in my brain, I pointed the scope at Alpha Canis Majoris. After 2 hours of staring, tracking the star through clouds, and stopping my aperture down a bit, I saw no trace of "B" in my 138x Nagler 7mm. I thought I saw glimpses of something, but I can't be sure tonight.

For those who still havent seen Rigel, try a smaller scope. My 8" never showed it, but my 4" OXLT120ED showed it the first time.

BJK

#2 Kon Dealer

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Posted 15 January 2013 - 09:59 AM

Like you my 4" shows Rigel B quite easily, whilst I often struggle with my 8SE.
On the other hand I cannot see The "F" star in the trapezium with my 4", but can with my 8SE.
I suspect it is all to do with what I would call the "resolution/glare" ratio.

#3 7331Peg

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Posted 15 January 2013 - 02:18 PM

You can also see Rigel's secondary in a good 60mm refractor as well. One of the amazing things about refractors is how much less aperture you need to split a difficult star in comparison to what is required for an SCT or a reflector.


John :refractor:

#4 greyfox

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Posted 15 January 2013 - 02:34 PM

John:

Absolutely LOVE your blog. Awesome work!

Brad

#5 Bonco

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Posted 15 January 2013 - 04:19 PM

You can also see Rigel's secondary in a good 60mm refractor as well. One of the amazing things about refractors is how much less aperture you need to split a difficult star in comparison to what is required for an SCT or a reflector.


John :refractor:

John, I certainly agree Rigel can be viewed in a 60mm refractor. I first proved that when the humble 60mm f9 guidescope on my 10 inch Newt was tried on Rigel. Even with an old not so good .965 eyepiece, Rigel and its beautiful companion were seen in a nice dark field. After that I purchased other 60mm scopes like a Lafayette f13 and a Unitron f15. Can't remember anytime that I couldn't split Rigel with these telescopes. BTW, the same for the famous double double in Lyra, very easy in a 60mm. Bill

#6 7331Peg

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Posted 15 January 2013 - 08:09 PM

Yeah, I agree completely on Epsilon Lyrae, Bill. As long as the seeing is reasonable, that pair of stars is a real thrill in a 60mm refractor.

On Rigel, the secondary appears as just a puff of white light. It has to be one of the most amazing and satisfying splits I've enjoyed in a 60mm scope. I've been riveted to an eyepiece for fifteen to twenty minutes at a time just staring at that thing.

Thanks for the compliment, Brad. Looks like I've finally got a string of a few clear nights this week, so hopefully I can dig up some new material for that blog!


John :refractor:

#7 rflinn68

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Posted 27 January 2013 - 11:35 AM

Thats odd...I see it clearly with both my 10" dob and my 10" SCT. I've just recently got into double star observing however, and these were seen using my newly aquired WO binoviewers. Rigel b stuck out like a sore thumb the other night in the 10" Meade. I really love the binoviewers and have seen much more with them. Next time I have my 65mm apo out I'll take a gander to see what it shows.

#8 azure1961p

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Posted 27 January 2013 - 12:06 PM

Rigel is routine with my 8". Infact if it isn't showing its just a real lousy night.

Pete

#9 Atl

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Posted 27 January 2013 - 01:07 PM

I got the pup with my 12.5" last night after looking nearly every night for a month. I posted about it in the eyepiece forum but was unceremoniously I informed I was probably seeing a double image. Is Sirius b that hard to split?

I split Rigel the first time with a C90...thought it was no big deal...then it never happened again. My dob does it easily even in poor seeing.

#10 David Knisely

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Posted 27 January 2013 - 01:41 PM

I got the pup with my 12.5" last night after looking nearly every night for a month. I posted about it in the eyepiece forum but was unceremoniously I informed I was probably seeing a double image. Is Sirius b that hard to split?

I split Rigel the first time with a C90...thought it was no big deal...then it never happened again. My dob does it easily even in poor seeing.


Yup, Sirius-b is really hard to see. The smallest aperture I have ever gotten a decent view of it in was an 8 inch classical Cassegrain at Hyde Observatory many years ago, although at the time, it was somewhat easier to see in our 14 inch Celestron SCT. It requires exceptionally-stable seeing and a set of reasonably-good optics to get the "pup" to show up very well, as the glare from the primary makes the companion really hard to see. Clear skies to you.

#11 Achernar

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Posted 27 January 2013 - 09:20 PM

I've seen Rigel B in telescopes as small as a 60mm refractor, and I see it routinely with my 6-inch Dob unless the seeing is very bad. Sirius B is another story, it is 10,000 times fainter than Sirius A even though it's over twice as hot at the surface. Right now it's about 10 arc-seconds due east of Sirus A, and if the seeing is good or better, you have a crack at it with a 6-inch for sure. I just spotted it tonight right in fact with my 6-inch F/8 at 260X. You need to use as much magnification as your telescope and seeing will bear, and you want eyepieces that scatter as little light inside of them as possible. Scattered light hides Sirius B, which looks like an 11th magnitude bluish pip of light even though this Earth sized but Solar mass white dwarf's true magnitude is 8.5. It's apparent faintness is due to the extreme glare of Sirius A, which in about 20 or 25 years will hide Sirius B from view until it pulls away from the primary again in it's 50 year orbit. The average separation is 2 billion miles, and that always keeps it near Sirius A. If your refractor's optics are of excellent quality, you might find it. It eluded astronomers for over two decades before Alvan Clark found it while testing a newly completed 18 1/2-inch telescope on Sirius. Fortunately, we don't need an 18-inch to see it today.

Taras

#12 azure1961p

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Posted 27 January 2013 - 10:16 PM

I swear during winter time in Connecticut the bad seeing is tethered to the ground till May. Cleardarkskys.com has the green and grey poor seeing mapped ovr the northeast so long I think its burned into the program. I've never gotten good enough seeing to see the pup. Never. If it isn't poor elevation than its typical 4-5/10 Pickering seeing so typical when its cold.

Pete

#13 HellsKitchen

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Posted 13 February 2013 - 11:17 AM

Rigel B is easy, It is obvious in my 8" in the worst seeing, any 8" that struggles with it must have some sort of serious optical flaw. Infact, my 4.5" newt will show it regardless of seeing. Sirius B and Antares B are both much more challenging.

#14 leviathan

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Posted 13 February 2013 - 01:31 PM

Sirius B is difficult to see because of too bright Sirius A. If you'll manage to block it somehow and you know where to look, you'll find it.

#15 CelestronDaddy

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Posted 14 February 2013 - 09:49 PM

Finally had some decent sky in my location tonight. Maybe a 7/10. I wanted to try Sirius B and Rigel tonight. I let my 6E acclimate for about an hour and started out with the trapezium. E and F were seen at 136X and F was fairly constant so I knew conditions were good for me. So I moved to Rigel and it was an easy split at 136X and 60X. Nice contrast. I then tried Sirius and thought I had a glimpse of B but not enough to be certain. Sirius B is a difficult one because of the huge difference in magnitudes. Will have to keep trying :grin:

#16 jrbarnett

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Posted 20 February 2013 - 10:56 PM

Sirius B is actually easier in small aperture than large. The split is huge (10 arc seconds) so resolution is irrelevant. Suppression of glare and stray light, and beating the seeing are key. It's easiest in a 3-incher for me. Haven't tried it in a 60mm yet, but I will next time I'm out.

I always find it to be much easier in refractors too than obstructed scopes. Part of it is the aperture - refractors lack it - and the other part is better baffling and stray light control than in an obstructed design. In fact, I think apertures over about 6" are a hindrance on the Pup whenever it is more than about 7 arc second of separation from A as they are more affected by seeing and the extra resolving power they bring is of no benefit on the target.

Regards,

Jim

#17 ziridava

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Posted 23 February 2013 - 01:26 PM

Hello
I'm in doubts if I ever saw Rigel's companion in my 60mm refractor but I'm sure I saw it in my 76mm F/9 Newtonian at over 100x.
In my 125mm F/7 Dobsonian I always see Rigel's companion if seeing is at least 6 on Pickering scale.
Last time I saw it was last week,125mm Dobsonian, home-made Keplerian ocular of 15mm focus, 57x.

Mircea

#18 mdowns

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Posted 23 February 2013 - 02:35 PM

Fellow cnighter Mike Reily and myself got together a couple of weeks ago and found the pup with relative ease in both his 6"f6 rfr and his meade 125. I say relative because thats what it is. Frist glance didnt really reveal anything but playing with the mags(we bumped them up alot) and positioning Sirius just out of the fov made all the difference. as mentioned above,the seperation is significant,just overwhelmed by the light of the primary.

#19 CelestronDaddy

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Posted 23 February 2013 - 09:24 PM

Mircea, I've been able to split Rigel with my 80mm refractor in the past. I need to try Sirius and see if I can split it with the refractor.

#20 dlapoint

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Posted 25 February 2013 - 11:23 PM

I think might have viewed sirius b tonight with my 6" achromat stopped down to 4 inches. There was a light haze in the air which seemed to make it easier to pick out. I've looked at picks on line and they match what I seen. I will try with the ed100 tomorrow night.

#21 Ain Soph Aur

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Posted 26 February 2013 - 12:14 AM

I have seen Sirius B many times this Winter with the 4" f/13 Carton achro. It is much easier to catch it at twilight...

#22 Rutilus

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Posted 26 February 2013 - 04:45 PM

Another Carton 4" f/13 user here. Even at 18 degrees altitude, I have been able to observe the Pup on quite
a regular basis over the last few months.

#23 CollinofAlabama

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Posted 09 March 2013 - 12:52 AM

Interesting observations! I split Rigel easily with my Chinese 102ED F/7 the other night, but, at least at 100x, had no such luck with Sirius. I'll have to try higher power when my skies can handle it, and maybe pull out my AT80ED. Can't hurt to have more options on the table. No long refractors for me; I'm a newt guy who likes the eyepiece comfortably placed. 712mm of focal length is about all I'll own for a scope with the wrong end pointed down. Hopefully one of these will work. But there's always 2014 and 2015 if they can't seem to do it in 2013. :lol:

Brandon in TN, thanks for the twilight hint. I'll have to attack the Dog Star immediately after chasing down PANSTARRS next week.






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