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Wildthing
super member
Reged: 11/07/07
Posts: 192
Loc: Muncie, IN
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What is the best scope for viewing and splitting doubles?
A Refractor or a SCT?
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Clear Skies, Donnie / Muncie, IN
Equipment:
Stellarvue SV-102ED f/6.95
Celestron CPC 800 XLT
Orion 100mm f/6 Achro
Mounts:
TV Gibraltar w/Sky Tour
Celestron CG5-GT Mount
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Hrundi
Pooh-Bah
Reged: 02/06/08
Posts: 1237
Loc: Estonia
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Very large aperture newtonian is my guess.
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Covey32
scholastic sledgehammer
Reged: 12/09/04
Posts: 921
Loc: Georgia
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I have a 6" Intes Maksutov on an Ioptron Mini Tower that I use for doubles, and it beats my 120mm ED refractor for both resolution and portability.
My C8 is nowhere near as good. (at least to my eyes)
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Hank
12.5" Mag1 Portaball
Orion 120mm F5 Refractor
Skywatcher 120ED F7.5 Refractor
1982 Celestron C8 Orange tube
Celestron ED80 Refractor with Lunt 50mm HA
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Erik Bakker
professor emeritus
Reged: 08/10/06
Posts: 532
Loc: Haren, The Netherlands, Europe
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Esthetically, a good refractor cannot be beaten for doubles that are within it's reach. After that a bigger closed tube mirror or compound telescope with very good optics takes over. And the smaller the central obstruction, the better. But start with smooooth and well figured optics in a properly designed tube with respect to thermal characteristics.
Clear skies,
Erik
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Visual astronomer, main instruments:
Fully mounted Questar 7 P-BB
Celestron C 102F f/8.8 fluorite
Vixen FL 70S f/8 fluorite
Celestron C 55F f/8 fluorite
Sets of Zeiss, TeleVue and Brandon eyepieces
Zeiss 7x50 Marine B/GA
Zeiss TM german equatorial
Gitzo 224 with Manfrotto 501 fluid head
Unitron alt-az mount
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EdZ
Professor EdZ
Reged: 02/15/02
Posts: 14731
Loc: Cumberland, R I , USA42N71.4W
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Quote:
What is the best scope for viewing and splitting doubles?
A Refractor or a SCT?
Here's are links to some very useful discussions on the same topic. these are linked for our Best Of threads and these now reside in our archive
Diffraction: Refractors vs. Reflectors
Magnitude, Color and Obstruction affect resolution
there are factors that in some instance make each scopee a better choice for the intended target. So, one is not better than the other, each has advantages for different types of doube star targets.
edz
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Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21
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David Knisely
Postmaster
Reged: 04/19/04
Posts: 8279
Loc: Beatrice, Nebraska
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Quote:
What is the best scope for viewing and splitting doubles?
A Refractor or a SCT?
Neither; the best scope for viewing and splitting doubles is the one you use. All scopes have their advantages and disadvantages, but the truth of the matter is that with doubles, almost any scope of halfway decent quality will work very well. I might argue for certain designs being better, but I have to say that I have gotten more double star observing done with my 9.25 inch SCT than with any other scope, simply because I decided to use it as much as possible, especially on nights when the moon was out. The scope's go-to capability made finding even some of the more obscure doubles easy, as well as allowing me to cover more doubles in a single observing session. Optically, it performs pretty well (I have used it at 297x to 480x and up to 1199x on a few really tight doubles), so I have few complaints (other than cloudy skies and not enough time to devote to observing). Clear skies to you.
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David W. Knisely
Hyde Memorial Observatory
http://www.hydeobservatory.info
Prairie Astronomy Club
http://www.prairieastronomyclub.org
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PJ Anway
Pooh-Bah
Reged: 06/04/03
Posts: 1136
Loc: Michigan's U.P.
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Quote:
Neither; the best scope for viewing and splitting doubles is the one you use.
I would agree. I use a 100mm refractor and 160mm & 203mm newtonian reflectors. However, I do find that I prefer
1) the aesthetics of the refractor view and
2) a long focal length scope
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PJ
_________________
Lookum Observatory
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1055
Loc: Suburban Maryland
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I tend to prefer the way doubles look in refractors and Maks, at least the brighter stars: no diffraction spikes. The additional advantage to Maks is that they show the true colors, like a Newt. (Forget about APOs: I still can't wrap my mind around - or open my wallet to - 80mm OTAs for $700+.) But I don't like the reversed image view in those scopes. It makes it much more difficult to get your bearings when using an atlas, at least for me, since I am accustomed to observing mostly through Newts. With Newts, all I need to do is turn the atlas upside down. It's easier to read upside down than to flip the image right to left in your mind while sitting outside in the dark. And I don't have goto or DSCs, so I need to star hop to locate the fainter doubles. Mounting a RACI finder and QuikFinder or Telrad on the refractor or Mak does help, though. Other than actually getting the doubles to my eyepiece field to look at them, I still like them better in a refractor or Mak.
Clear Skies,
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1055
Loc: Suburban Maryland
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I see the original post specifically asked, "What is the best scope for viewing and splitting doubles? A Refractor or a SCT?" I have never owned an SCT, and have very little experience with them, in fact, only one, a 10". The images were not as sharp and contrasty as in my 10" Newt, but then again, one specimen is the smallest possible sample, so I don't know how significant that observation really is. I have heard, though, that SCTs do tend to have softer images. Many who have top notch, well-collimated SCTs might deny that, of course. On the other hand, it would make sense that a larger aperture SCT would be better for viewing and splitting close or faint doubles - and for most everything else - than a smaller aperture refractor.
Clear Skies,
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Rick Woods
Postmaster
Reged: 01/27/05
Posts: 5665
Loc: Inner Solar System
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I think it depends on what you're looking for.
I like my little 120mm achro for the bright colorful doubles like Alberio, Almach, Izar, Alpha Herc, Xi Boo, etc. It shades them just a bit, adding a beautiful tone to them. I compared one night on Almach: my SCT showed it yellow and blue, nice and bright; but the refractor made it look like burnt gold and sapphire, which was so beautiful I couldn't take my eye away.
So, the answer is different I guess depending on the experience you want.
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- Rick
14" LX200GPS
Dyslexics Untie!
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blb
sage
Reged: 11/25/05
Posts: 214
Loc: Piedmont NC
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Of all the scopes that I own, when I was doing the Astronomical League's Double Star Club, I used my TV102 and ETX125PE. I really like my 10" dob and C11 but it seams like I have to use so much more magnification with these to get the same separation. The scope that I used the most,because I liked it's views best, was the TV102. So I guess the refractor won.
Buddy
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C-11, C-6, XT10i Dob, ETX125PE, TV102, & AT66
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kevin M13
member
Reged: 03/07/09
Posts: 88
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I think it depends on your seeing quite a bit, but up in the northeast, I have found my 5.5" refractor to be the best absolutely hands down. This is after owning, cooling, critically collimating many SCTs. I think it is the average smoothness of the optics and a "compound" effect on seeing from the CO. The only scope that ever came close was my 15" obsession that had an equisite mirror. That would very often equal the refractor, but hard to split the brighter doubles. On a couple nites it blew the refractor away on real tight doubles.
I recently found a small refractor can be a blast. And if you use it a TON which I have, perhaps it's the "best scope" as somebody mentioned.
Just my opinion and my preference.
Kevin
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gtown1
member
Reged: 11/07/08
Posts: 65
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Any telescope that has good optics will work fine on doubles. Follow the usual common sense rules such as letting your optics reach the outdoor temperature and so on. The larger your mirror or lens, the better doubles will be split and look at the eyepiece. Of course, extremely wide doubles most probably would look better in smaller lenses.
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Happy owner of an Obsession, 18 inch Ultra Compact and a Mag 1, 12.5 inch Porta Ball.
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astroneil
member
Reged: 07/28/09
Posts: 21
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A good long focus refractor: F9-F15. Achromat or Apo, it matters not.
Reasons: excellent contrast, lower Seidel aberrations, eyepiece astigmatism and greater depth of focus.
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chuckscap
sage
Reged: 07/18/09
Posts: 217
Loc: Colorado Springs, CO USA
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What's your opinion of a Mewlon 250 for splitting doubles? I recently bought a used one and just have started really using it.
Thanks,
Chuck
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1055
Loc: Suburban Maryland
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astroneil,
Quote:
A good long focus refractor: F9-F15. Achromat or Apo, it matters not.
Reasons: excellent contrast, lower Seidel aberrations, eyepiece astigmatism and greater depth of focus.
Hmmm ... Maybe I should start taking my C4-R f9.8 out more often for observing doubles. It's taken a back seat - or back of the closet - since I've gotten my bigger scopes and my grab-n-goes. But I don't like the reversed image - makes it difficult to star hop to the double stars. I guess I could put in my 1.25" prism diagonal. Sounds like a plan. What do you think?
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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astroneil
member
Reged: 07/28/09
Posts: 21
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Hello Chuckscap and Sarkikos,
A 4-inch F/10 will be a fine double star instrument based on my own experiences with a few other instruments in the same genre. So your Celestron refractor will be a fine choice.
Never looked through a Mewlon but give it a go. Start with easy doubles first then gradually close in on the more difficult pairs.
Have fun,
Neil.
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John Kocijanski
Carpal Tunnel
Reged: 08/22/03
Posts: 1663
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My C102 f/10 splits doubles nicely. How about a reflector? The XT4.5 I have does a great job with doubles too.
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Deep Space Observer 10 * SPC-8 * C102 HD f/10 * XT 4.5 * Orion/Moonlite 80ED * PST *
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Sarkikos
Pooh-Bah
Reged: 12/18/07
Posts: 1055
Loc: Suburban Maryland
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John,
My 5.1 inch Newt on a driven CG4 might not be bad for doubles, either. It would have the advantage of true-to-nature colors, a little more aperture than my C4-R, merely upside down rather than reversed orientation (better for star hopping), and would be more nearly grab-n-go. But then there are the diffraction spikes. And the uncomfortable positions a Newt's eyepiece can get itself into on a GEM. I really need to make some Wilcox Rotating Rings for it! Well, NO scope is perfect for all purposes.
Clear Skies,
Mike
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Celestron 10" f5 Newt on 1stBase (DSO)
Zhumell 8" f6 Newt, Bosma 6" f12 MCT (NSO)
6" f5 Newt, 130ST, 4.5" f4.4 Ball w/GLP, ST80 w/Crayford (RFTs)
C4-R (NSO/DS)
90mm f13 MCT (Luna/DS)
SkyMaster 25x100, 15x70
Zhumell 20x80
Barska XWA 10x50, 8x40
OptiView LPR 10x50
Const View 2.3x40
BV-125C
CG5, 2 drv / CG4, 2 drv, wood legs, ScopeStuff saddle / CG3, 1 drv
SV AZ / 501HDV on Bogen 055XB / P+ on Oberwerk
QuikFinder, Telrad
Orion Dynamo Pro 12, Dew-Not
Have GLP and not afraid to use it!
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Gord
professor emeritus
Reged: 01/06/04
Posts: 694
Loc: Toronto, ON, Canada
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I'm curious if anyone has any experience with un-obstructed reflector designs (ex. Chief). Seems to me that these would be the ideal choice. Cheap, large aperature, ability to get very high quality (again, cheaply), generally longer FL, and no obstruction. Also, since with doubles we are really only talking about on-axis, none of the off-axis issues should be a factor.
Has anyone tried these?
Thanks,
-Gord
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* Celestron C10/Normand Fullum primary
* Tasco 11TR/Normand Fullum primary
* Orion StarBlast
* Orion Apex 102
* SkyWatcher 80ED
* Celestron CG5a mount
* MallinCam Pro & Color II
* Lots of other astro toys
...and the best wife I could ever dream of for letting it all happen! 
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