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Brooklyn
scholastic sledgehammer
Reged: 07/24/08
Posts: 870
Loc: Central New Jersey
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I am sort of confused as to whats the best eyepiece to use for DSOs as of lately.
I used my plossls last night to view jupiter and it was nice. I was observing from 9pm-11pm, the only darkness time of the night (b/c of the moon).
I was doing a best of the day tour and was too lazy to get my baader hyperions for the DSOs, so i just used the plossls. At 160x (12.5mm) the open clusters, globular clusters, basically everything that gets washed away by a uhc filter, was visible brighter than it is in the hyperions. Of course the field of view was much smaller, but i could see far more tiny stars in the wild duck cluster, bufferfly cluster, M92, M22, M2, all those globular little fellers.
Basically, it seems that without filters, a plossl shows brighter objects than higher element designs. And, it also seems that the plossls have less field curvature at the ends, than a wide FOV eyepiece.
I wouldn't say that this eyepiece design is great for all DSO viewing, as when i tried to look at ring nebula, dumbell, or lagoon, they were hard to see, barely even visible. I would contend that for open clusters, the wide FOV eyepieces are better since you can magnify a large amount and still have the entire object in your FOV.
What do you think is the best eyepiece design for viewing galaxies, globular clusters, and any light emitting object?
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Meade 8.25"(209.55mm) LX-90 EMC (SCT)
Albert Einstein =>
“Intellectual growth should commence at birth and cease only at death.”
“If you can't explain it simply, you don't understand it well enough.”
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tigerroach
sage
Reged: 08/13/08
Posts: 292
Loc: Houston, TX
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I hear those Ethos eyepieces are nice... 
I like my Naglers and Panoptics a lot for dso's. (I haven't tried the Ethos yet). A big FOV really makes for a more interesting experience IMO. And as you say, if you can fit the entire object in the view and still have good magnification, contrast etc, so much the better.
I am an admitted TV fanboy, so figure that into your calculations.
Edited by tigerroach (08/20/08 07:55 PM)
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BillP
Carpal Tunnel
Reged: 11/26/06
Posts: 2188
Loc: Vienna, VA
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Hmmm. If I'm reading your post correctly you are saying that the Plossls you just used seem to show things brighter than you Hyperions. Is that correct?
If that's what you are saying then it could be several factors, all of which I would say are "perceptual" responses and not so much tightly tied to transmission.
a) Could be the impact of you not doing a direct compare this eveing and just working from memory. So perhaps this particular evening the seeing was very stable so more finer stars were evident or a host of other atmospheric factors.
b) Could be that the coating coloration of your Plossls were more neutral than the Hyperions which IME gives impression of brighter stars.
c) Could be the impact of the smaller AFOV. With a smaller AFOV and all that pure black space in your peripheral vision, things just look more impactful as far as brightness is concerned....at least it does for me perceptually.
My own opinion is that wide fields are more "fun" for star clusters or nebula "IF" there's lots of surrounding stars to make the fov more interesting. However, have never had any problem using Plossls for the Ring or any other nebula.
I think the answer will have more to do with you personal preferences for AFOV. I myself find that I prefer a 60deg afov for mid thru high magnifications. For low magnifications I usually prefer a larger afov. For very intensely on-axis interest on objects, like the Planets, really doesn't matter what the AFOV is for me...anything is just fine.
-Bill
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250mm f/4.7 Orion XT10i Dobsonian
102mm f/8.0 Tak TSA Super-APO
66mm f/5.9 WO ZenithStar SD APO
40mm f/10 Coronado P.S.T.
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MikeRatcliff
Pooh-Bah
Reged: 06/12/04
Posts: 1105
Loc: Redlands, CA
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I also tend to see a few more faint stars with Televue plossls compared to wide fields I've owned at similar magnifications. The effect is slight but definite. And this is in the central area only, in my faster f/5 telescope.
I guess it could be contrast rather than pure transmission. Slightly darker background.
One caution is you do need to be comparing similar magnifications. Higher magnification tends to show more faint stars. Due again to darker backgrounds and greater contrast?
As for what's best for DSO's, right now I'm leaning toward plossls etc that are a bit crisper in the center, versus the wide field experience. But both experiences are valid, and lots of people own both types. The low price of the plossls is a factor for me.
Mike
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16" f/4.9 dob
Tele Vue Plossls 32,25,20,15,11
13 Nagler T6
10.5 Pentax XL
Brandon 32, 16
12.5 UO ortho, 9 Circle T ortho
2x TV Barlow
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Brooklyn
scholastic sledgehammer
Reged: 07/24/08
Posts: 870
Loc: Central New Jersey
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Thanks for confirming guys, seems you had the same experience i had. Plossls showing more clarity and brightness, and revealing more faint stars, while extra FOV show more interesting things to look at. Exactly like BillP, i like to look through everything. I appreciate the views all the eyepiece designs give.
If an object is extremely faint, like a small nebula or star globular cluster, it's better to use a plossl on it. What would happen if you use an orthoscopic on a DSO, would it have an even greater effect on brightness?
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Meade 8.25"(209.55mm) LX-90 EMC (SCT)
Albert Einstein =>
“Intellectual growth should commence at birth and cease only at death.”
“If you can't explain it simply, you don't understand it well enough.”
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Lamb0
professor emeritus
Reged: 07/25/07
Posts: 668
Loc: Fairbury, Nebraska
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 Get thee to a star party, and compare with thine own Mark 1 eyeballs! 
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John "Have eyepiece - will travel!"
8" f/5 Dob w/2.14" sec in a 12" alum tube 'The Mortar' - w/PCorr 2° TFoV @ 36.5X ~70% illum *NICE*
Typical eyepieces: 32 Burg, 24 Pan, 20T5, 5-8 SW, Others ALL 2": Pcorr, 2X PwrMt, Ast H-b, Lum UHC + OIII
60mm $50 Walmart Special in training - aka "Backpack Observatory"
Minolta Activa 12x50 , Steiner 15X80
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coutleef
scholastic sledgehammer
Reged: 02/21/08
Posts: 806
Loc: Montreal and St-Donat, Québec,...
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A week ago, i compared the views of M13 using a 17T4, a TV plossl 15, a 12T4 and TV plossl 11.
I agree that the plossls gave a little higher magnification than the nagler counterparts BUT
more stars were seen with the plossls and the image was sharper!! With the 11mm it gave the impression that i was looking through a straw but still the image was clearer. But the view through a plossl is less pleasant that using a wide fields when it comes to looking at open star clusters or galaxies.
When i want to look at details, i use plossls. When i want immersive and pleasant views i use the wide fields.
This reassured me on one thing. There is some place for older designs in our EP case. Selling quality EPs to obtain the most recent EP line may not always be a good thing. I prefer using several EPs with different FL and different designs than having a minimal number of EPs.
But that is just me.
Plossls are there to stay in my EP case and the next EP i will purchase is likely the plossl 8mm rather than the Ethos!
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François
Nexstar 8 SE
50mm StellarVue finderscope, Astronomik UHC-E and Orion OIII filters
WO Swan 40mm; TV Pan 22mm; TV Nagler 9T6, 12T4, 17T4; TV Plossl 11mm and 15mm.
WO 2" dielectric diagonal retrofitted with Denk Power Switch (and now reach the zenith with the shorty adapter).
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BillP
Carpal Tunnel
Reged: 11/26/06
Posts: 2188
Loc: Vienna, VA
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Quote:
...When i want to look at details, i use plossls. When i want immersive and pleasant views i use the wide fields...
 Excellent tactic...no one eyepiece type does all things well!
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250mm f/4.7 Orion XT10i Dobsonian
102mm f/8.0 Tak TSA Super-APO
66mm f/5.9 WO ZenithStar SD APO
40mm f/10 Coronado P.S.T.
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Mr. Mike
scholastic sledgehammer
Reged: 11/08/05
Posts: 855
Loc: Churchville, NY
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Quote:
A week ago, i compared the views of M13 using a 17T4, a TV plossl 15, a 12T4 and TV plossl 11.
I agree that the plossls gave a little higher magnification than the nagler counterparts BUT
more stars were seen with the plossls and the image was sharper!! With the 11mm it gave the impression that i was looking through a straw but still the image was clearer. But the view through a plossl is less pleasant that using a wide fields when it comes to looking at open star clusters or galaxies.
When i want to look at details, i use plossls. When i want immersive and pleasant views i use the wide fields.
This reassured me on one thing. There is some place for older designs in our EP case. Selling quality EPs to obtain the most recent EP line may not always be a good thing. I prefer using several EPs with different FL and different designs than having a minimal number of EPs.
But that is just me.
Plossls are there to stay in my EP case and the next EP i will purchase is likely the plossl 8mm rather than the Ethos!
Good points and pretty much true. Wiht my smaller scope, I definitely need as many photons to get through as possible so simpler designs, like my Tak LEs are Da' Bomb for planetary use. 
Still though, I find myself reaching for my Vixen LVWs in medium to medium-low powers for DSO views. 
Good post though....
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Stellarvue NG 80mm ED
Meade 7x50 Binos
Pentax XW 5mm
Meade 5K UWA 8.8mm
Vixen LVW 13mm
Vixen LVW 22mm
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Stephen65
scholastic sledgehammer
Reged: 04/14/07
Posts: 934
Loc: Melbourne, Australia
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While I like XWs and Naglers for general widefield viewing my absolute best EP for detecting faint objects is my TMB/Zeiss 25mm ortho.
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Megrez 90
FLT 132
Mewlon 250
Lots of XWs, an Ethos, Supermonos and some other EPs
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Brooklyn
scholastic sledgehammer
Reged: 07/24/08
Posts: 870
Loc: Central New Jersey
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Think about nebulae that can only be seen well with special UHC filters.
These filters recommend only 1-9x per inch of aperture for magnification, but im sure people go far higher. For these objects, since the magnification wont be that high anyways, i think a plossls is best. No need for a wide view, if your target fits inside a plossl eyepiece 45 degree FOV. 
Anyone know what would happen if one tries to use orthoscopics on deep sky objects? I only have plossls as my lowest element eyepieces, the rest are wide fielders with 5-8 elements. No orthos in my eyepiece collection yet.
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Meade 8.25"(209.55mm) LX-90 EMC (SCT)
Albert Einstein =>
“Intellectual growth should commence at birth and cease only at death.”
“If you can't explain it simply, you don't understand it well enough.”
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nkoiza
sage
Reged: 12/17/04
Posts: 211
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Quote:
While I like XWs and Naglers for general widefield viewing my absolute best EP for detecting faint objects is my TMB/Zeiss 25mm ortho.
Exactly my feeling.
There are a couple of very faint planetary nebulae that I have just been able to detect with a TMB supermono and OIII filter - replacing with an equivalent focal length XW and OIII renders each of these objects totally invisible!
Nick
16-inch f/4.4 David Lukehurst Dobsonian on Brian Reed Tracking Platform
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BillP
Carpal Tunnel
Reged: 11/26/06
Posts: 2188
Loc: Vienna, VA
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Quote:
...Anyone know what would happen if one tries to use orthoscopics on deep sky objects? I only have plossls as my lowest element eyepieces, the rest are wide fielders with 5-8 elements. No orthos in my eyepiece collection yet.
IMO, I would not think you will see any transmission difference between a Plossl and an Ortho since they both have just 4 elelements. I think this would be true for the majority of Orthos out there. However, when you get to the very few which have a reputation for transmission performance (Zeiss, Pentax SMC Orthos) then you will get some gains here. I had the Pentax SMC Orthos and these units easily pulled in fainter stars that no other eyepiece I had would (including premium Plossls). When I eventually sold them they went to a guy who belonged to a group of avid galaxy hunters and this eyepiece was their preferred type for being able to pull in more extent and structure on faint galaxies than any other - plus somewhat reasonable at around $200+ each used when you can find them.
So if you don't mind using .965" EPs that have 40 deg afov and tight eye relief like all Orthos, then these (along with Zeiss Orthos and TMB Monocentrics) would probably be the best that could be had for this purpose.
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250mm f/4.7 Orion XT10i Dobsonian
102mm f/8.0 Tak TSA Super-APO
66mm f/5.9 WO ZenithStar SD APO
40mm f/10 Coronado P.S.T.
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