Mr. Bill
Post Laureate
Reged: 02/09/05
Posts: 3147
Loc: Just passing through.....
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Mark's thread "Your favorite combination" brought to mind a corollary question.....
What is your favorite scope, ep, and mount combination for DSO observing?
I guess mine would be the 10 inch on an alti azimuth mount and Paracorr and 13mm Ethos ep. That combo allows me to stand comfortably to view zenith, the ep gives me a 100x magnification with a 1 degree flat fov and comfortable eye relief with a 2.5mm exit pupil....somehow it all comes together and the equipment "gets out of the way" for observing.
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10x50 Fujinon binos + 16x70 Fujinon binos + UA UniMount
Oberwerk BT100 45 degree +24mm Pans + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
130mm TMB 130SS f/7 APO refractor
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/8 homemade achromat
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery "Galactic Cannon"
Member IDA
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galaxyman
Pooh-Bah
Reged: 04/04/05
Posts: 1471
Loc: Limerick, Pa
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Hmm 
I would say my 22" f/4.5 dob (Telekit) and a 14mm Denkmeier eyepiece (180x).
The views with that big scope and great mirror (Swayze with Spectrum MaxR coating), and perhaps one of the best eyepieces on the market, is pure heaven!
Then again the 8" f/9 refractor, CGE mount, with a 8mm Ethos (225x) is up there!
Karl
E.O.H.
Chesmont Astronomical Society
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB 8" F/9 Refractor”The Beast”. One great achro
Astrozap 6" f/8 Refractor. Another fine achro
Orion 4" f/6 Refractor. Also not bad for an achro
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So many galaxies, so little time!
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Mr. Bill
Post Laureate
Reged: 02/09/05
Posts: 3147
Loc: Just passing through.....
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Quote:
Hmm
I would say my 22" f/4.5 dob (Telekit) and a 14mm Denkmeier eyepiece (180x).
The views with that big scope and great mirror (Swayze with Spectrum MaxR coating), and perhaps one of the best eyepieces on the market, is pure heaven!
Then again the 8" f/9 refractor, CGE mount, with a 8mm Ethos (225x) is up there!
Karl
E.O.H.
Chesmont Astronomical Society
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
TMB 8" F/9 Refractor”The Beast”. One great achro
Astrozap 6" f/8 Refractor. Another fine achro
Orion 4" f/6 Refractor. Also not bad for an achro
That's interesting that you got the Spectrum MaxR coatings on your Swayze mirror....when I bought my 8 inch mirror from him, he told me to stay away from the Spectrum coatings because in his opinion the multicoating process introduced stresses on the figure....must have changed his mind in the last two years.
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10x50 Fujinon binos + 16x70 Fujinon binos + UA UniMount
Oberwerk BT100 45 degree +24mm Pans + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
130mm TMB 130SS f/7 APO refractor
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/8 homemade achromat
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery "Galactic Cannon"
Member IDA
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Jeff Young
Post Laureate
Reged: 08/04/05
Posts: 4115
Loc: Ireland
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I most easily lose myself when sketching, so it'll have to be a driven mount.
Aperture rules, so it'll have to be my 16". On most nights, the sweet spot between "still crisp" and "background dark enough" is my 17mm Nagler T4 (235X).
-- Jeff.
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Nikon 18x70s / UA Millennium Colorado:
Solarscope SF70 / TV Pronto / AP400QMD Coronado SolarMax40 DS / Bogen 055+3130
APM MC1610 / Tak FC-100 / AP1200GTO Tak Mewlon 250 / AP600EGTO
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Mr. Bill
Post Laureate
Reged: 02/09/05
Posts: 3147
Loc: Just passing through.....
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Hi Jeff....
I think "aperture rules" is an oversimplification; IMO exit pupil rules. Sometimes, the best view is through binoculars or a refractor for rich field.
If you spend your time viewing objects of very small angular size, you need aperture to make them big enough to resolve structural detail. So it is not aperture per se but the magnification provided by the focal length in conjunction with a large exit pupil provided by aperture to provide a bright image.
I usually observe with binoculars, a refractor and a reflector of approximately the same f ratio (f/5-f/6) which using the same eyepiece provides different magnifications to frame the object being observed but at a constant exit pupil that provides the best image contrast under present conditions, ie the "sweet spot."
So, instead of changing eps in the same scope which effects the image brightness, I change telescopes to maintain constant best contrast while changing image scale (magnification.)
Edited by Mr. Bill (11/20/08 10:26 AM)
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LumpyDarkness
sage
Reged: 08/06/07
Posts: 388
Loc: San Francisco bay area
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The sweet spot for me typically is with my 18" f/4.5 and the 12 Nagler. It usually provides a steady enough view, dark enough background, and enough magnification to pick out structure/detail in a wide range of targets. If I push it with the 7 Nagler, the image will degrade more often (I always try though).
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Mark Wagner
Deep Sky Observing Blog
SF Bay Area Observers - TAC
Adventures In Deep Space
NGC/IC Project
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 10475
Loc: PA, USA, Planet Earth
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With the ASH 17" f/15 classical Cassegrain that I still use fairly often, it's usually a 25mm University Optics MK-70 (1.7mm exit pupil, 259x). The true field of view isn't very large but works well enough for the majority of DSOs. The additional "contrast" provided is effective in ameloriating the local light pollution.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Jeff Young
Post Laureate
Reged: 08/04/05
Posts: 4115
Loc: Ireland
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Quote:
Hi Jeff....
I think "aperture rules" is an oversimplification; IMO exit pupil rules.
Bill --
Yeah, that's probably a good point. I need to keep my exit pupil under 4mm for my light-polluted skies (and under 3mm anywhere below 45° in altitude, or on more humid nights).
My favorite targets are galaxies, PNs and globulars, all of which benefit from aperture. For larger targets I tend to use binoculars, but my 18x70s are only a sweet spot on nights of good transparency, and on targets of decent altitude. Perhaps if I had the 22x60 Takahashi's, they might constitute another sweet spot on average nights.
(Don't get me wrong -- I love my 18x70s. But a true sweet spot needs to be sweet on most nights.)
Cheers,
-- Jeff.
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Nikon 18x70s / UA Millennium Colorado:
Solarscope SF70 / TV Pronto / AP400QMD Coronado SolarMax40 DS / Bogen 055+3130
APM MC1610 / Tak FC-100 / AP1200GTO Tak Mewlon 250 / AP600EGTO
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GlennLeDrew
Pooh-Bah
Reged: 06/18/08
Posts: 1267
Loc: Ottawa, Ontario, Canada
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Like Mr. Bill, for me exit pupil is of paramount importance. The range 2.5-5mm is what I go for most often, the larger end being reserved more for large and/or low contrast targets. Otherwise nearer to 3mm gives just about the best 'wow' factor with the fairly dark skies I regularly observe under. That's why I expect my 120mm f/5 binoscope will be fitted with a pair of 13mm Ethoi (2.6mm exit pupil) at least 80% of the time.
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Home-made 11X50 right angle bino, 8.1 deg. FOV
Modified 26X100 bino, 3.5 deg. FOV
Home-made Mk II RA bino, using interchangeable objectives and eyepieces
My Gallery
Mediocre minds discuss people. Good minds discuss events. Great minds discuss ideas.
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Dave Mitsky
Postmaster
Reged: 04/08/02
Posts: 10475
Loc: PA, USA, Planet Earth
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A 12mm Nagler T2 was the workhorse DSO eyepiece with my 12.5" f/4.8 Starsplitter Dob. I have yet to use the 13mm Ethos that superceded my 13mm T6 with this scope.
Dave Mitsky
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Chance favors the prepared mind.
De gustibus non est disputandum.
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Silicon Owl
scholastic sledgehammer
Reged: 11/25/05
Posts: 949
Loc: Waimea, Hawaii
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Quote:
The sweet spot for me typically is with my 18" f/4.5 and the 12 Nagler. It usually provides a steady enough view, dark enough background, and enough magnification to pick out structure/detail in a wide range of targets. If I push it with the 7 Nagler, the image will degrade more often (I always try though).
I agree totally, my 18" f/4.5 with the 12mm Nagler IV is just about perfect visual setup for that 'scope. 175x and a 28' field are just about ideal for so many DSO's. Looking through my H400 notes that eyepiece is recorded for just about all of the observations. When I am out with the big dob the 12mm N4 is the eyepiece you will find in it 80%+ of the time.
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Andrew Cooper
Personal Website and CN Gallery
Handmade 18" Dob / NS11GPS / 6" RFT / 90mm APO / TV-76 ...and a twin 10m
"I have loved the stars too fondly to be fearful of the night." --Sarah Williams
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Mr. Bill
Post Laureate
Reged: 02/09/05
Posts: 3147
Loc: Just passing through.....
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Looks like we are on the same page....
My constraints on exit pupil size (besides local sky conditions) are floaters in both eyes make exit pupils under 1.5mm distracting and my 62 year old eyes will only dilate to about 5.2mm.
I find the 4mm exit pupil provided by 24mm Pans eps in my BT100 binoculars to be just about perfect...I have a pair of 14mm Denkmeier eps which though optically excellent just don't have the same "punch." So I have found the "sweet spot" for the BTs.
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10x50 Fujinon binos + 16x70 Fujinon binos + UA UniMount
Oberwerk BT100 45 degree +24mm Pans + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
130mm TMB 130SS f/7 APO refractor
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/8 homemade achromat
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery "Galactic Cannon"
Member IDA
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droid
rocketman
Reged: 08/29/04
Posts: 4034
Loc: ohio
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Id have to say "currently" my C102HD , with a 28mm orthoscopic, on my Super polaris mount with home made 5'6" legs allow me to remain upright and at ease typically.
Id like to try my comet catcher on a dob type base , but dont have the ability to make things lol.
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102mm Celestron C102HD
Tasco 7TE5 60mm Classic
Tasco 9TE5 60mm Classic
Celestron Ultima 2000 SCT
Remains of an 8 inch dob
Celestron Comet catcher(orange tube)
1960 Edscorp Space Conquerer 6inch f/8
10x50 Bushnell Binoculars.
11T 4.5 inch Tasco reflector Lunograsso?
60mm Telescope Club
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desertrefugee
Pooh-Bah
Reged: 08/06/07
Posts: 1215
Loc: Arizona
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At dark sites for me, it's the 10" dob and 12T4 Nagler. I pretty much leave that EP in for the evening. Saves a lot of hassle fumbling for other EPs. I used to waste a lot of time that way.
But, in town (Phoenix metro area), it's the 10TE 76.2mm f15 with Meade 8-24 zoom. Planets, moon and doubles are easy prey with that combo. [Edit: Oops, well at least doubles are in deep space . . .}
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"Illimitable ocean, without bound, Without dimension, where length, breadth, and height, And time, and place are lost." - Milton
-Darrell
Reflectors - 76 to 305mm (f4.7 to f9.2)
Refractors - 50 to 120mm (f5 to f16.7)
Binoculars - 6x15 to 22x100
N. Phoenix, AZ
Edited by desertrefugee (11/22/08 12:13 PM)
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DeepSpaceTour
Post Laureate
Reged: 10/25/05
Posts: 3164
Loc: In the dark and"WAY"out there!
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...The 17.5" Discovery TD with the 13E in the focuser,for detailed DSO's.
For wide field viewing the 31T-5 in the 6" F/6.5 refractor,mounted on the HEQ-5 Pro, is magic.
Clear skies.
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Bill
-17.5"F/5 Discovery TD /Dob driver/ArgoNavis
Kendrick dew control/Obsession Alt bearings
-Antares 152-F/6.5 refractor on HEQ-5 Pro
-25x100 Binos
-15x70 Binos
-Collimating tools "LOTS"
- TV ep's *13-Ethos *31T-5*
- 2" Barlows
- Pelican1600
Edited by DeepSpaceTour (11/26/08 10:25 PM)
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j3ffr0
sage
Reged: 07/06/08
Posts: 422
Loc: Virginia
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My 10"/f 4.7 with the 13mm T6 gives about 92X with a 2.5mm exit pupil. This combo seems to be the best for me on most DSOs... galaxies and most nebula anyway... Sometimes I like more magnification on globs and planetary nebula.
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10" Dob, 127mm Mak, 120mm f5 achro, PST
35, 24 Panoptic; 16, 13, 9, 3-6 Nagler
15, 10, 7.5, 5, 3.8 Ultrascopic
20, 15, 9, 6 Expanse
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Patricko
Carpal Tunnel
Reged: 01/30/07
Posts: 1533
Loc: SE New Mexico USA
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Hi Bill, my favorite scope for DSOs is a Televue Pronto using a 19mm Erfle on a Alt-AZ mount. The 19mm gives me ~25x with a 2.6 degree FOV. Awesome!
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Clear skies,
Patrick
INTERNATIONAL DARK SKY ASSOCIATION
60MM TELESCOPE CLUB!
"You can always have better, but will you ever be happy with what you have?" - Me, myself, and I
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Nick Lloyd
He asked for it
Reged: 10/24/06
Posts: 2156
Loc: cincinnati
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9.25" SCT and the 19mm EF Smart Astronomy eyepiece.
105mm Zenithstar and 28mm RKE.
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"The best scope is the one you use." -rcg
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rmollise
Post Laureate
Reged: 07/06/07
Posts: 4567
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Quote:
Mark's thread "Your favorite combination" brought to mind a corollary question.....
What is your favorite scope, ep, and mount combination for DSO observing?
I guess mine would be the 10 inch on an alti azimuth mount and Paracorr and 13mm Ethos ep. That combo allows me to stand comfortably to view zenith, the ep gives me a 100x magnification with a 1 degree flat fov and comfortable eye relief with a 2.5mm exit pupil....somehow it all comes together and the equipment "gets out of the way" for observing.
Me? For jus' lookin'? Prob'ly my good, ol' 12.5-inch Dobbie, and the Ethoses. I sometimes think about goin' to 18 - 20 inches, but when I'm haulin' scope parts up the front steps at 4am, I change my mind. 
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Uncle Rod
Rod's New Book:
Choosing and Using a New CAT
Available now!
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Patricko
Carpal Tunnel
Reged: 01/30/07
Posts: 1533
Loc: SE New Mexico USA
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Hi Nick, I too find the 19mm EF SA eyepiece to be excellent!
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Clear skies,
Patrick
INTERNATIONAL DARK SKY ASSOCIATION
60MM TELESCOPE CLUB!
"You can always have better, but will you ever be happy with what you have?" - Me, myself, and I
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