Bart
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Reged: 05/28/06
Loc: Somewhere near Charlottesville...
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Re: EdgeHD or no?
[Re: bilgebay]
#5282090 - 06/21/12 10:51 AM
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Is the following a fair statement? With a focal reducer, such as the one provided by Celestron, the standard C11 is essentially the same as the C11 Edge HD in terms of optics.
Thanks Bart
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dscarpa
Carpal Tunnel
Reged: 03/15/08
Loc: San Diego Ca.
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Re: EdgeHD or no?
[Re: Dan F.]
#5282117 - 06/21/12 11:12 AM
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A standard C11 wouldn't be the same as a C11 Edge. As far as a 8" Edge out performing a high quality 7" mak it wouldn't surprize me at all. It might be more seeing sensitive than a F 15 mak what with the SCT's bigger CO. I've been told the bigger the CO the more seeing sensitive the scope. As far as a 8" edge vs a top line 8" mak my money would not be on the SCT. I have what a suspect is a very good regular C9.25, one of the last to me made in the USA. With very good seeing it equals my 1/8 wave IM715D for lunar-planetary. When I have excellent seeing and can use 45X-50X per inch in the C9.25 it smokes the mak. The SCT is a lot more seeing sensitive, with good and below seeing I usually prefer the mak for lunar-planetary. As to your question I think it's worth getting a Edge over a regular SCT. David
Edited by dscarpa (06/21/12 11:48 AM)
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Bart
Carpal Tunnel
   
Reged: 05/28/06
Loc: Somewhere near Charlottesville...
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Re: EdgeHD or no?
[Re: dscarpa]
#5282161 - 06/21/12 11:53 AM
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I currently have the C11. As others have expressed, the difference in cost was a deterrent for me when considering the Edge 11. Maybe someday I'll get one...
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skyjim
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Reged: 01/13/07
Loc: Long Island, NY
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Re: EdgeHD or no?
[Re: Bart]
#5282328 - 06/21/12 01:53 PM
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THe focal reducer on a stock C11 does more harm than good, you still end up with coma and feild curvature, the FR was designed more for the folks that do ap and just want a faster speed but from what I have seen ot just makes the starts more bloated not sharp at all. On the standard C8 and C9.25 that I had the FR made things worse IMO, eveything looked much better at F10. As far as USA built scopes over the ones that are now coming from Synta in china that add little to its optical quality, in 2003-4 I bought a new C9.25, USA made gray tube, that scope wasn't even 1/4 wave and had focus shift that was horible even at 120X a planet would jumphalf way across the FOV, I sent it back to the big C and when it returned the optics maybe just made 1/2 wave and the FS was less but still IMO poor. THe last C9.25 I had back two years ago that was built by Synta was very good as far as mass produced optics at least 1/6th wave and would give my M703 a run for the money but the 703 was always slighly sharper no matter waht the seeing was but the C9 was brighter. I think the one thing that the EDge HD scope does which the standard models dont is the amount of SA for a SCT design which is always gonna be there, less so in the better MCT's but on the Edge HD's the level of SA is way low so when you do a star test and have the seeing to do it well the way it focuses exactly is much sharper than a standard sct, its snaps were you are always trying to find focus on regular sct's plus the definition on the diffraction rings is perfect on both sides of focus like it should be. What all this means is the detal that your looking for at focus is gonna look better time after time. I didn't think that this corrector in the HD scopes was all that big of a deal but they did design it into the optical system not just for the AP group but for everyone and now that I have tried one well I could never go back to a standard SCT, been there done that. As far as an 8" MCT well until there made here I dont wanna mess with trying to get parts for the russian scopes anymore, you have to either have a machine shop or go to one if something snaps and they take forever to cool down. As far as the optics after having owned 1/6th.1/8th and 1/9th wave IM MCT's the 8HD smokes them all, I ahve owned enough Intes Micro scopes over the past 15 years since they been imported here to tell how they perform, they are great scopes and when compared to standard sct's they do come out on top but not anymore, these Edge HD's are better and they dont cost a ton and you have to waite. A M809 is around $4500 plus import dutes and shipping a C8HD is $1300, hell a C9.25HD is $2300. For what the 8" mac cost you could almost buy a C14HD. ITs not 10 years ago its 10 years after and the old designs that are good have been improved this ait your daddys sct anymore, you can justify what makes you wanna keep the old design but when it comes down to it these Edge scopes are a different animal, there optics are much better. Jim
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edl
professor emeritus
Reged: 06/24/04
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Re: EdgeHD or no?
[Re: skyjim]
#5282416 - 06/21/12 03:00 PM
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Hi skyjim,
You make a great point regarding focus "snap" in the Edge. No mush at all, especially compared to any other CAT I've had.
Best, Ed L.
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giulianb
member
Reged: 05/21/08
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Re: EdgeHD or no?
[Re: edl]
#5282431 - 06/21/12 03:15 PM
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I tried a snap test on my c8 edge at 1200x (public lamp at 1 km distance) and focus was still critical and sharp. I could not believe my eyes!
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dscarpa
Carpal Tunnel
Reged: 03/15/08
Loc: San Diego Ca.
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Re: EdgeHD or no?
[Re: Dan F.]
#5282522 - 06/21/12 04:17 PM
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As far as my PCA-Primitive Coma Afflicted-C9.25 goes it's a keeper. Saturn at 500X was very sharp with good contrast on one first rate night. I've had many excellent lunar-planetary sessions with it. I've got a WO Crayford on the back so focusing and image shift aren't issues. If I drop my SCT-I've come pretty close a few times-I'll go with an Edge. David
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herrointment
Carpal Tunnel
   
Reged: 03/12/11
Loc: North of Hwy. 64
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Re: EdgeHD or no?
[Re: dscarpa]
#5282601 - 06/21/12 05:24 PM
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When I had the chance to purchase the 11 or the 11HD I thought there was no question that the HD was the correct model for me.
The price difference I simply chose to ignore. I hate to second-guess a decision like that.
It was delivered a week ago and if it ever clears I might get to use it.
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vct123
sage
   
Reged: 11/17/09
Loc: Staten Island, N.Y.
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Re: EdgeHD or no?
[Re: herrointment]
#5282730 - 06/21/12 06:32 PM
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I am not sure how anyone can think adding a $139 focal reducer to a standard sct can turn it into the optical quality of an edge scope. I had an 8hd but ended up trading a friend for an xlt c9.25. For me its mostly planetary viewing and I preferred the slighlty larger aperture of the c9 which happens to be an excellent sample, I have owned (4). The 8hd was super sharp to the edge with no coma or field curvature that I could detect.
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skyjim
Carpal Tunnel
   
Reged: 01/13/07
Loc: Long Island, NY
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Re: EdgeHD or no?
[Re: vct123]
#5282896 - 06/21/12 09:01 PM
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Yes it is and I know its a good sample cause that C9 was mine for two years, at least 1/6th wave optics and the box said China on it so the naysayers that say you gotta find a USA built SCT are wrong, thats one really good C9.25! Jim
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teskridg
Pooh-Bah
Reged: 01/15/08
Loc: PA
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Re: EdgeHD or no?
[Re: skyjim]
#5292244 - 06/27/12 09:19 PM
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Maybe I read some of Rod Mollise's posts wrong on this site, but I believe he suggested that the .63 focal reducer accomplished the same thing visually and photographically as the Edge system of correctors. I'd love him to chime in on this. Tim
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skyjim
Carpal Tunnel
   
Reged: 01/13/07
Loc: Long Island, NY
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Re: EdgeHD or no?
[Re: teskridg]
#5292601 - 06/28/12 01:24 AM
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"I believe he suggested that the .63 focal reducer accomplished the same thing visually and photographically as the Edge system of correctors."  Really, maybe if your smokin crack, the .63 FR is exactly what it is a focal reducer, thats it, you still have feild curvature, you still have coma and you still have a higher level of SA compared to the same size scope in the HD line. I love those who post something on the internet, have never spent any time with the scopes they are nay saying about or have never looked threw one and come out with a half baked coment like that. The Edge scopes have a correcting lens, its not a focal reducer, its designed to reduce feild curvature and coma not just for the AP guys but for visual as well. Thats like someone made a coment on the optics bein the same as the standard scope, sorry the secondary is made to a different spec cause of the correcting lens and were its placed in the focal plane, also the secondary, corrector and the primary haave to be matched as well as the secondary has to alligned perfectly up with the corrector so the HD scopes go threw another step in there final assembly to insure best results. Jim
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frozen.kryo
member
Reged: 01/28/11
Loc: East of the Sun, West of the M...
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Re: EdgeHD or no?
[Re: skyjim]
#5292754 - 06/28/12 06:33 AM
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Standard C8, C8 w/ .63 FR/FF and C8 EdgeHD annotated comparo:
Standard C8, no .63 FR/FF: http://www.flickr.com/photos/26671216@N02/3570358283/sizes/l/in/photostream/
Standard C8, with .63 FR/FF: http://www.flickr.com/photos/26671216@N02/3570358231/sizes/l/in/photostream/
C8 EdgeHD, no reducer: http://www.flickr.com/photos/26671216@N02/3570358333/sizes/l/in/photostream/
No contest, IMO. EdgeHD all the way.
I own a standard C8. For visual observation with an ES 14mm 100Deg, it is quite usable at f/10 or f/6.3. Nothing to complain about really.
But if I could do it all over again, I'd definitely get the Edge. Currently saving up for a C11 Edge.
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RAKing
Postmaster
   
Reged: 12/28/07
Loc: West of the D.C. Nebula
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Re: EdgeHD or no?
[Re: skyjim]
#5292809 - 06/28/12 07:57 AM
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Quote:
"I believe he suggested that the .63 focal reducer accomplished the same thing visually and photographically as the Edge system of correctors."  Really, maybe if your smokin crack, the .63 FR is exactly what it is a focal reducer, thats it, you still have feild curvature, you still have coma and you still have a higher level of SA compared to the same size scope in the HD line. I love those who post something on the internet, have never spent any time with the scopes they are nay saying about or have never looked threw one and come out with a half baked coment like that. The Edge scopes have a correcting lens, its not a focal reducer, its designed to reduce feild curvature and coma not just for the AP guys but for visual as well. Thats like someone made a coment on the optics bein the same as the standard scope, sorry the secondary is made to a different spec cause of the correcting lens and were its placed in the focal plane, also the secondary, corrector and the primary haave to be matched as well as the secondary has to alligned perfectly up with the corrector so the HD scopes go threw another step in there final assembly to insure best results. Jim
Jim,
I don't know what unit you had, but it sounds like it was defective or something.
My Celestron f/6.3 Focal Reducer/Field Corrector worked very well. It not only reduced the focal length - it flattened the field and eliminated coma in my C8. In fact, I couldn't stand that scope until I added the FR/FC. I only have about 75 observing sessions with my old C8 to back me up on this, BTW.
The f/6.3 FR/FC was designed for imaging with the C8, but many of us have seen decent results visually in the C6, C8, C925, and C11 regular SCTs. I have owned each of these sizes and used the FR/FC on all of them.
The one negative about the FR/FC is it chews up a lot of focus travel, so some of your eyepieces might not work with this combination. I used a Televue "Shorty" visual back and diagonal to get back some of that lost focus travel.
I will agree that the Edge series is definitely nicer than the regular SCT at the native focal length. I had an 8 inch Edge a couple of years ago and now I have a C925-HD Edge. I hate the corrector lenses stuffed into the baffle, but I am learning to grit my teeth and ignore them while I enjoy the view. 
Cheers,
Ron
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edl
professor emeritus
Reged: 06/24/04
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Re: EdgeHD or no?
[Re: RAKing]
#5292894 - 06/28/12 09:20 AM
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I've had a couple f6.3 reducers and used them with my older c8's and CPC925. In all cases I felt they were adequate for low power use (what they were designed for), but the amount of CA visible and added astigmatism was unacceptable to me above 125x or so. I personally wouldn't refer to them as general purpose pieces of hardware as they diminish the performance of the scope at higher powers. Not so with the Edge.
Ed L.
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rmollise
Postmaster
   
Reged: 07/06/07
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Re: EdgeHD or no?
[Re: skyjim]
#5292943 - 06/28/12 10:05 AM
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Really, maybe if your smokin crack, the .63 FR is exactly what it is a focal reducer, thats it,
Well yeah...except it's not. 
Not if you mean the Celestron (or Meade) f/6.3 reducer/corrector.
The Jim Riffle designed f/6.3 reducer/corrector also corrects field curvature. That's the "corrector" part.
The coma will still be there, but field curvature reduction improves the edge of the field quite a bit. Next time you use one...well...take a closer look.
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George Methvin
Pooh-Bah
Reged: 01/30/06
Loc: Central Texas
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Re: EdgeHD or no?
[Re: rmollise]
#5293067 - 06/28/12 11:47 AM
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So let me get this stright you all are saying that the HD scopes are a lot sharper in the center view then the non HD scopes. That the HD scopes are better in every way over the non HD scopes and you all could never go back to the old style SCT. So a person not owning a HD scope is really missing something by not owning a HD scope ? Has anyone done a side by side study on just how much better the HD scope are over the old non HD scopes? Is the diffrance like going form the old style TV to HD TV viewing, is it that big a change? Wish someone in my area had one so I could see for my self.
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brianb11213
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Reged: 02/25/09
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Re: EdgeHD or no?
[Re: George Methvin]
#5293103 - 06/28/12 12:06 PM
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So let me get this stright you all are saying that the HD scopes are a lot sharper in the center view then the non HD scopes.
Some people are saying that, but in the opinion of some of us this statement is pure unadulterated hogwash. The HD has a flatter field of view, with less obvious coma when incorrectly collimated, that's all. The standard SCT has a flat enough field of view for visual purposes and the lack of the baffle tube mounted corrector group should give a contrast advantage to the standard SCT.
HOWEVER a standard SCT with a field flattener/corrector fitted is not really suitable for visual observing.
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jrbarnett
Eyepiece Hooligan
   
Reged: 02/28/06
Loc: Petaluma, CA
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Re: EdgeHD or no?
[Re: rmollise]
#5293144 - 06/28/12 12:30 PM
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So here's the rub for the FF/FR versus the Edge's FF/Coma Correction. By reducing the focal ratio to f/6.3, the FF/FR brings out eyepiece astigmatism in simple eyepieces that is largely invisible at f/10. The Edge system, by leaving speed alone and tackling coma, does produce a cleaner field with simple eyepieces. The flip side, however, is that if you have well-corrected eyepieces, you don't worry about astigmatism at f/6.3 any more than you do at f/10.
- Jim
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skyjim
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Loc: Long Island, NY
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Re: EdgeHD or no?
[Re: RAKing]
#5293162 - 06/28/12 12:38 PM
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I have had the celestron and meade FR's on both C8's and C9.25's I owned and belive me there feild was not any flater and they still had coma. Back when I had those scopes I also owned some Intes/Intes Micro rumak desined MCT's, now they had no coma and no FC. I also felt that no matter how you sliced it the stars always had that bloated look, yes it gave you a wider feild of veiw but the omage was not as crisp as it was at F10. I think its all what you are willing to accept and if you own a scope with no FC orno coma you just cant get used to one that does, thats also why I dont like fast dobs maybe as well. The Edge scopes are the first production SCT's that equal the russian mct's in image and total edge to edge performance, the SA is far less than standard sct's, even there star test is much better than any compound scope I have owned and I've owned more than a few. If Ron made that statement he must be drinking way too much of that ole JD when he observes, I wonder if he even has really tried an Edge HD scope as of yet. The internet has lots of "IMO" but were the rubber meets the road is to my own eye's and I didnt just get into this hobby yesterday, the Edge HD's are better optically and to the visual observer as well not just the ap guys. Well the correcting lens is need and doesn't allow a cat cooler but they have those vents along side were the primary sits and also there are aftermarket companies that have fan kits for the vents as well. BTE when I tried the FR on the std sct I did have and still do use the TV shorty VB also tried an SCT diagonal, never had a problem with focusing ep's, I just didnt like the veiw, it was wider but not as sharp or crisp. Hey is a $140 dollar focal reducer, its not really sold as a feild flatener, there add copy will lead you to belive it might and thats creative marketing but from what I have seen it doesnt. There are RF/FF out but there no $140 dollars, more like $300 to $500 dollars. I also tried both the Meade FR as well, same results. Jim
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