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Cosmic Challenge: Zeta (ζ) Cancri

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#51 DavidN

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Posted 01 April 2021 - 12:42 AM

Finally had clear skies recently here in the Pacific Northwest, and this was one object I wanted to get a good look at. It split very nicely in my 5” Mak-Cass with a 7mm Nagler 

(220x). Seeing was a bit iffy, but when things settled down it was a very clean split that was easier than I expected.

 

Nice challenge object this month! If you haven’t tried it yet, give it a try.


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#52 PhilH

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Posted 03 April 2021 - 11:33 AM

Thanks, everyone, for the great comments about this challenge.  There was more chatter here than any previous challenge to my knowledge!  Keep 'em coming! waytogo.gif


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#53 PhilH

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Posted 03 April 2021 - 11:36 AM

Ahhhh my favorite. Phil, it's always an honor having you around. 

Steady skies!

DoctorD

Thanks, DoctorD.  The honor is mine.  smile.gif


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#54 Daniel Mounsey

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Posted 06 April 2021 - 07:47 PM

Thanks, DoctorD.  The honor is mine.  smile.gif

Phil,

I still can't get over how long you've been at this. Many years ago in the early 90's I acquired your first edition of Star Ware which I think was about 1994. It was an absolute treasure-trove and I still cherish it to this day as well as the other revisions. I picked it up at a local bookstore and was amazed at all the information you had about so many telescopes. waytogo.gif


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#55 Astrojensen

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Posted 07 April 2021 - 11:29 AM

Thanks, everyone, for the great comments about this challenge.  There was more chatter here than any previous challenge to my knowledge!  Keep 'em coming! waytogo.gif

I guess this shows both how underrepresented double stars are today and how much love there still is for them, at least the brighter, showier pairs. 

 

 

Clear skies!

Thomas, Denmark


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#56 argonbeam

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Posted 10 April 2021 - 05:33 PM

I am a relative newbie but am coming to like these double stars in light pollution (I can't see any of Cancer, even M44, naked eye from my viewing area) because most nights I have come to realize I just am not going to see many galaxies and these doubles can be a nice challenge. I have an 8" dob but my highest mag available right now is 150x (8mm). I can get a clean split of the components at 34x but haven't been able to split the much tighter pair. There is some elongation at 150x. Haven't done any back of the envelope calculations, but appears I will need a bit more magnification to split the tighter pair. Thank you Phil for a fun challenge. 


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#57 radiofm74

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Posted 11 April 2021 - 01:06 AM

I guess this shows both how underrepresented double stars are today and how much love there still is for them, at least the brighter, showier pairs. 

Spot on! Hunting and splitting multiples is a thrilling challenge (as this whole Tegmine endeavour showed me), extremely instructive and rewarding, and I've come to regard it as my "moonlit night" DSO activity. Faint fuzzies and even bright clusters just suffer too much under the combined effect of the Moon and light pollution. It's now cloudy here and I'm putting together a nice "beyond Messier" observing program. Today I'll work on doubles!

 

I am a relative newbie but am coming to like these double stars in light pollution (I can't see any of Cancer, even M44, naked eye from my viewing area) because most nights I have come to realize I just am not going to see many galaxies and these doubles can be a nice challenge. I have an 8" dob but my highest mag available right now is 150x (8mm). I can get a clean split of the components at 34x but haven't been able to split the much tighter pair. There is some elongation at 150x. Haven't done any back of the envelope calculations, but appears I will need a bit more magnification to split the tighter pair. Thank you Phil for a fun challenge. 

From memory: I had to go up to ≈250-280x to split Zeta1. You need a Barlow my friend ;D – and a steady sky. 


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#58 Special Ed

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Posted 11 April 2021 - 12:25 PM

Guess I'm late to the party but I've been enjoying reading the responses to Phil's challenge while I waited for an opportunity to see Zeta Cancri for myself.  It appeared as a creamy white double at low power.  Zeta-1 appeared elongated at 163x and 198x and was resolved (according to David Knisely's definition posted above) at 326x.  I suspected a notch at 244x but had to go to 326x to confirm. 

 

It might be cheating to use a 14" scope, but the seeing wouldn't allow me to go any higher to see the split.  In brief moments of settled air I thought I could see the split at 355x and 391x but it might have been averted imagination so I didn't include that view in my sketch.  The seeing made the stars appear somewhat bloated at higher magnifications.

 

Thanks for the challenge, Phil!  This is the first time I've looked at Zeta Cnc.  Btw, I have the 3rd and 4th editions of Starware--it's a very good reference.

 

Zeta_Cancri_2021.04.10_v1.jpg


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#59 PhilH

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Posted 20 April 2021 - 03:53 AM

Guess I'm late to the party but I've been enjoying reading the responses to Phil's challenge while I waited for an opportunity to see Zeta Cancri for myself.  It appeared as a creamy white double at low power.  Zeta-1 appeared elongated at 163x and 198x and was resolved (according to David Knisely's definition posted above) at 326x.  I suspected a notch at 244x but had to go to 326x to confirm. 

 

It might be cheating to use a 14" scope, but the seeing wouldn't allow me to go any higher to see the split.  In brief moments of settled air I thought I could see the split at 355x and 391x but it might have been averted imagination so I didn't include that view in my sketch.  The seeing made the stars appear somewhat bloated at higher magnifications.

 

Thanks for the challenge, Phil!  This is the first time I've looked at Zeta Cnc.  Btw, I have the 3rd and 4th editions of Starware--it's a very good reference.

 

attachicon.gifZeta_Cancri_2021.04.10_v1.jpg

Very nice sketch.  And thanks also for the kind words about Star Ware.  Of all the books I have written, I must admit that was my favorite one to research.
 


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#60 PhilH

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Posted 20 April 2021 - 03:58 AM

Phil,

I still can't get over how long you've been at this. Many years ago in the early 90's I acquired your first edition of Star Ware which I think was about 1994. It was an absolute treasure-trove and I still cherish it to this day as well as the other revisions. I picked it up at a local bookstore and was amazed at all the information you had about so many telescopes. waytogo.gif

Ha, yes I really am that old!  First book was Touring the Universe through Binoculars in 1990, while my first published article was in 1985 ("A Messier Marathon" in S&T's January 1985 issue).  Wrote that one on the old Smith-Corona.  Yikes!!


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#61 radiofm74

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Posted 20 April 2021 - 04:00 AM

Ha, yes I really am that old!  First book was Touring the Universe through Binoculars in 1990, while my first published article was in 1985 ("A Messier Marathon" in S&T's January 1985 issue).  Wrote that one on the old Smith-Corona.  Yikes!!

Sorry to go OT but I juuuust got Touring the Universe through Binoculars, and it's become instantly the indispensable companion to plan binocular (and even telescopic) forays!


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#62 PhilH

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Posted 21 April 2021 - 03:12 AM

Sorry to go OT but I juuuust got Touring the Universe through Binoculars, and it's become instantly the indispensable companion to plan binocular (and even telescopic) forays!

Thanks, radiofm74.  I am happy that you find TUB useful.  Don't know if you know, but >20 years ago, a buddy named Dean Williams and I collaborated to create companion software Touring the Universe through Binoculars Atlas (TUBA, for short).  Although originally designed to work with Windows 98, it works fine with all subsequent Windows OSs, including Win10. It's free for downloading, if you're interested.  (Sorry, no Mac version is available.) You'll find info on my web site.


Edited by PhilH, 21 April 2021 - 03:13 AM.

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#63 radiofm74

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Posted 21 April 2021 - 04:36 AM

Thanks, radiofm74.  I am happy that you find TUB useful.  Don't know if you know, but >20 years ago, a buddy named Dean Williams and I collaborated to create companion software Touring the Universe through Binoculars Atlas (TUBA, for short).  Although originally designed to work with Windows 98, it works fine with all subsequent Windows OSs, including Win10. It's free for downloading, if you're interested.  (Sorry, no Mac version is available.) You'll find info on my web site.

Thank you Phil! I am a Mac user but I'll hack my wife's PC to use it ;D


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