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Charlie HeinAdministrator
Postmaster
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Reged: 11/02/03

Loc: 26.06.08N, +80.23.08W
Istar Phoenix WFT 204 “Comet HUNTER “…
      #6379335 - 02/16/14 12:17 PM

The Istar Phoenix WFT 204 “Comet HUNTER “…

By James Edwards


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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Charlie Hein]
      #6379677 - 02/16/14 04:12 PM

47 telescopes since 2001 ?
Wow..
I hope you have finally found what you were looking for.


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galaxyman
Vendor - Have a Stellar Birthday
*****

Reged: 04/04/05

Loc: Limerick, Pa
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Charlie Hein]
      #6380707 - 02/17/14 09:20 AM

Amen brother of an 8" refractor

Congrats

Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5" f/5 reflector (new)
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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RGM
scholastic sledgehammer
*****

Reged: 09/15/03

Loc: Burks Falls, Ontario, Canada
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6380725 - 02/17/14 09:30 AM

I have the 127mm f12 R30 Istar. I am looking at the 204 as my next scope. I really enjoy refractor views. In fact, my 10" Dob has not seen starlight in 2 years. The Dob can not put up the quality of views that my refractors can.

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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Charlie Hein]
      #6381114 - 02/17/14 01:44 PM

Seriously, an 8" f/5.9 achromat?
That makes the chromatic aberration of this scope worse than a 6" f/5 refractor, which has some of the worst CA I've ever seen in a scope.
The 6" f/5, at least, is a short focal length, low power, wide field scope for comet hunting and wide views.

So do tell: how did you tame the CA in the scope? Which minus violet filter did you use? That might be an excellent one to use in the 6" f/5.


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galaxyman
Vendor - Have a Stellar Birthday
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Reged: 04/04/05

Loc: Limerick, Pa
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6381230 - 02/17/14 02:44 PM

What's interesting Don, is his review seems to be in line what a CAS member's APM 7.1" F/6 does, particularly with DSO's and using up to 300x.


Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5" f/5 reflector (new)
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6381244 - 02/17/14 02:56 PM

Quote:

What's interesting Don, is his review seems to be in line what a CAS member's APM 7.1" F/6 does, particularly with DSO's and using up to 300x.


Karl
E.O.H.





Karl,
Yeah, a good lens is a good lens. My question was about taming the CA. I wouldn't believe a claim that there was none, but sometimes having a little (i.e. using a gentle filter) is just fine.
What does the CAS 7.1" owner use?


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galaxyman
Vendor - Have a Stellar Birthday
*****

Reged: 04/04/05

Loc: Limerick, Pa
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6381275 - 02/17/14 03:12 PM

Here's a short review he did.

FYI he owns some other very serious scopes like a 22" f/3.6 dob and a AP 5" APO to name a few. Also as with most of CAS (yes thanks to me), he's more of a dedicated DSO observer, and most of the time the large refractor is used for that.

APM 180 mm F/6 Achromat Deluxe :


I couldn't stand it any longer finally broke down and set up the 180 on
my deck last night on the G11 in manual mode. Using the scope's rings as a
1x reflex finder I went hunting! It was like pointing a cannon at the sky!

Without a minus violet/Fringe Killer, the Moon was awesome (36 ortho, 24
Pan, 0-18 SMC ortho, 0-12 SMC ortho and the 3-6 TV Zoom set at 3mm (360x)!)
Obvious chromatic aberration at the bright limbs either side, but tolerable.

With the Fringe Killer, it's APO like!!
I have never seen so much surface texture and detail on the Mare, subtle
contrast was amazingly detailed.

Bands of clouds kept me away from the DC and UMa galaxies and Orion was
obscured by the house (I was set up on my deck blocking the southern
horizon)! But, over head, I got M37 and M36 in Aur and M35 in Gem. Pinpoint
stars, just like diamonds on black velvet! And the COLOR of the different
stars was extremely obvious, reds and blues and orange tints.

And then my heart stopped and I had a religious experience: Saturn!

Only about 1.25 degrees below the Moon, high clouds and lousy seeing, but at
180-360X with the TV zoom, planetary banding obvious and the Cassini
division winked in and out with the seeing. Five moons easy even in the
moonglow and skyglow!




Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5" f/5 reflector (new)
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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B. Cook
professor emeritus
*****

Reged: 10/18/10

Loc: No. California
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6381591 - 02/17/14 06:59 PM

In his review at the bottom he stated the weight was at 24 lbs. In Sept 2013 I E-Mailed Mike at Istar on how much the scope weighs he said the scope weighs 34 lbs not including the tube rings. This is an error and a pretty big one if someone is serious about this scope and to make sure they can handle that weight especially when mounting it on a tripod or any other support with a pier extension. I am possibly looking at one next year but have help available to mount it with out damaging it or myself. Thanks

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stevew
Now I've done it


Reged: 03/03/06

Loc: British Columbia Canada
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6381911 - 02/17/14 10:34 PM

Quote:

Seriously, an 8" f/5.9 achromat?
That makes the chromatic aberration of this scope worse than a 6" f/5 refractor, which has some of the worst CA I've ever seen in a scope.
The 6" f/5, at least, is a short focal length, low power, wide field scope for comet hunting and wide views.

So do tell: how did you tame the CA in the scope? Which minus violet filter did you use? That might be an excellent one to use in the 6" f/5.




Don, you must have missed this part of the "review"...

"The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense"


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Darren Bly
sage
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Reged: 07/24/06

Loc: Bakersfield, Ca
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: stevew]
      #6381985 - 02/17/14 11:26 PM

Quote:

"The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense"




This could be a very nice deep sky telescope but it would be a niche telescope. ANYTHING bright would have horrendous false color.


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: stevew]
      #6382107 - 02/18/14 01:56 AM

Quote:

Quote:

Seriously, an 8" f/5.9 achromat?
That makes the chromatic aberration of this scope worse than a 6" f/5 refractor, which has some of the worst CA I've ever seen in a scope.
The 6" f/5, at least, is a short focal length, low power, wide field scope for comet hunting and wide views.

So do tell: how did you tame the CA in the scope? Which minus violet filter did you use? That might be an excellent one to use in the 6" f/5.




Don, you must have missed this part of the "review"...

"The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense"



Having owned a 6" f/5 and a 4" f/15, and, now, a 4" f/5.4 apo, I can only say, "to each his own". Chromatic aberration definitely spoils the view of Moon, planets, and bright double stars. Deep sky? You're right.
Anything brighter than about 3rd or 4th magnitude? Give me an apo or a reflector. The 6" f/5 even still had too much false purple for me with the "atom bomb" of minus violet filters, the Baader Contrast Booster. I eventually sold it.


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David Knisely
Postmaster
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Reged: 04/19/04

Loc: southeastern Nebraska
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Darren Bly]
      #6382141 - 02/18/14 03:02 AM

Quote:

Quote:

"The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense"




This could be a very nice deep sky telescope but it would be a niche telescope. ANYTHING bright would have horrendous false color.




Even some of the fainter doubles might have some haziness around them which some people might object to. Even my 100mm f/6 doublet has faint almost colorless halos around many doubles that really impacts the view at higher power, especially when trying for very faint companion stars that might get buried in that haze. Indeed, some tighter open clusters or globulars could get a little dose of extra "haze" in them with 8 inches of f/5.9 achromatic doublet to play with, although the aperture would certainly resolve them well. I suspect that my old 8 inch f/7 Newtonian or my friend's 8 inch f/5 RFT probably could probably do a little better planet-wise, although the 8 inch f/5.9 refractor could get true fields of view of up to 2.2 degrees or so with somewhat better edge illumination. Oh well, whatever trips your trigger (especially for around $3000). Clear skies to you.


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galaxyman
Vendor - Have a Stellar Birthday
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Reged: 04/04/05

Loc: Limerick, Pa
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: David Knisely]
      #6382379 - 02/18/14 09:17 AM

Interesting that we seemingly are trying to dimminish what the owner of this scope saw through the scope. He seems to be quite positive on the views and scope.

I do understand why he seems so positive on the scope, not so much because of my longer focal length 8", but what has been seen in the APM 7.1" f/6. Yes, globs at high power in that scope also "rocks" as being well resolved to crisp points.

I'm sure if you send a PM to Deep Sky moderator Mr Mitsky, who has seen through this 7.1"

I am anxious to read more observing notes down the road from the owner of this 8" refractor.



Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5" f/5 reflector (new)
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6383160 - 02/18/14 03:53 PM

galaxyman wrote:

Quote:

Interesting that we seemingly are trying to dimminish what the owner of this scope saw through the scope. He seems to be quite positive on the views and scope.

I do understand why he seems so positive on the scope, not so much because of my longer focal length 8", but what has been seen in the APM 7.1" f/6. Yes, globs at high power in that scope also "rocks" as being well resolved to crisp points.

I'm sure if you send a PM to Deep Sky moderator Mr Mitsky, who has seen through this 7.1"

I am anxious to read more observing notes down the road from the owner of this 8" refractor.




I don't think anyone is diminishing what the owner saw in the scope at all. From his almost gushing report, he seems quite happy with it (and more power to him if he likes what he got). However, as a true review, this article lacks some of the vital critical analysis which really needed to be there to make the article somewhat more useful. We need to know if this objective is some kind of "miracle" and tames chromatic aberration enough to work well, rather than being just another simple achromat (which I suspect the 8 inch f/5.9 actually is). The author hardly mentions how much false color there was in the views, and does not fully explore this in terms of the magnification when it became visible and how it varied between bright and fainter targets. Were there faint halos around double stars and how big were they? Did a minus-violet filter need to be employed at higher magnifications? How much scattered light appeared around brighter objects? Questions like this weren't really answered properly. All he says is the somewhat questionable response of:

"False color is prevalent on brighter objects (planetary, moon and larger stars) but guess what? The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense, "

For many observers, this latter statement is definitely not true. Without some really exotic (and expensive) optics, a two-element eight inch achromat at f/5.9 will show some really significant residual chromatic aberration, which those of us who have used such scopes of significant aperture know quite well. This color excess reduces the contrast of finer planetary detail and impacts the view notably at high magnifications much more than in reflectors or refractors of significantly longer f/ratios. It is nice to report on some of the good qualities that an instrument might have and how much fun one can have with it, but as a "review", this report left me with a few more questions than answers. Clear skies to you.


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Jim Curry
Pooh-Bah
*****

Reged: 10/29/07

Loc: STL
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: David Knisely]
      #6383549 - 02/18/14 07:47 PM

You guys are so mean. Do you just like to hear yourself type?

The reviewer "gushed" about the deep sky views. Planetary views getting a 3.5/5 rating (70/100) is not gushing. In fact, I would call that panning. “False color is prevalent on brighter objects”. Prevalent=dominant. It doesn’t sound like he was mincing his words or glossing over the deficiencies. “WHAT the 204 gives you is breath taking views that more than compensate for any color that shows”. That must be what set you guys off!! Way too much joy there.

The man is experienced, has owned some high(er) end refractors and was relating his joy of deep sky viewing with an 8" doublet. 8" is where deep sky views start to really get fun, noticeably brighter and more extensive. Some objects can start to take on a 3D look. He didn't write the review for you guys or perhaps you should have sent him your checklist so his review would have met your standard. What's with the straw man “We need to know if this objective is some kind of "miracle" and tames chromatic aberration enough to work well, rather than being just another simple achromat”. I could suggest you lower your proboscis enough to look over it and google the Istar website. But I won’t suggest that because I’ll bet a chocolate chip cookie you know darned well it is a simple achromat. And congratulations, you beat down two straw men in one paragraph, double stars (objects he didn’t even discuss).

Oh, I don’t want to neglect the red herring: “So do tell: how did you tame the CA in the scope?” Prevalent=dominant. There’s a lot of attitude in that sentence, Don. (Me too in this missive) :>)

"If you aren't having fun in this hobby, you aren't doing it right." But apparently the fun needs to be pre-approved.

Big tough guys here.
Give it a rest.
Oh, yeah. To keep it all pleasant:
Clear Skies


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galaxyman
Vendor - Have a Stellar Birthday
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Reged: 04/04/05

Loc: Limerick, Pa
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: David Knisely]
      #6383567 - 02/18/14 07:58 PM

Hi David

Certainly and I respect your comments, and one reason why I want to read a more detailed observing report.

What I find interesting is that James (the owner) seems to be experienced, and has written reviews of other quality scopes here on CN. So I may take it from his experience that the scope is quite good, for that’s all I can go on short of actually viewing through the scope.

The one thing that may need to be acknowledged, is though I’m sure it’s a standard doublet achro, the optical quality (including using high quality glass) may be far better (as mine is), then the standard mass-produced Celestron (Synta) achromats.

I can tell you with all honesty that his rave or shall we say positive review did not surprise me. Partly yes because what I’ve seen with my own 8” refractor albeit longer focal length, but again as I mention the APM 7.1” f/6, which of course is close to the instrument in this review as in aperture and focal ratio.

The owner here has pushed this scope, as you can read in the short review I posted above.

I’ve seen this scope many times in action, and the views even at 300x plus using high quality eyepieces are quite good. Whether it is a small planetary nebula or a tight glob.

We’ve seen 14th mag plus galaxies in this scope from good (not great dark sites).

Anyway, maybe the owner of this Istar 8” scope will post some more comments here or answer any questions, and hopefully a detailed observing report.




Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5.1" f/5 reflector
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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David Knisely
Postmaster
*****

Reged: 04/19/04

Loc: southeastern Nebraska
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Jim Curry]
      #6383864 - 02/18/14 11:50 PM

Jim Curry posted:

Quote:

You guys are so mean. Do you just like to hear yourself type?




No, I just wanted more information. My questions were not answered quite completely enough by this review for the reasons I stated earlier, that's all.

Quote:

The reviewer "gushed" about the deep sky views. Planetary views getting a 3.5/5 rating (70/100) is not gushing. In fact, I would call that panning. “False color is prevalent on brighter objects”. Prevalent=dominant. It doesn’t sound like he was mincing his words or glossing over the deficiencies. “WHAT the 204 gives you is breath taking views that more than compensate for any color that shows”. That must be what set you guys off!! Way too much joy there.




No, you have definitely overreacted to what I have said. When someone says "refractor", many observers think, PLANETS, as planetary viewing is what they tend to be most known for. I know some refractor "lovers" who put up with the fairly minor chromatic aberration in their D&G f/12 to f/15 large refractors in the six to eight inch aperture range and yet still complain about it (at least a little). They would very probably be a lot more critical of an f/5.9 8 inch doublet unless some more detailed information was presented about how it performed as far as color excess is concerned. Instead of just the quick "on a planetary scale the jury is still out, but Mars and Jupiter looked good (3.5 out of 5)" statement, it would have been nice if the author of the article had been somewhat more descriptive about what the scope exhibited in that residual color on the moon, planets, and double stars. That way, one could truly judge if the statement of "breath taking views that more than compensate for any color that shows", is fairly accurate. We just need a little more information and not blanket emotional statements like "The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense". Like the author, I enjoy what my simple f/6 doublet does at low to moderate power on deep-sky objects, but for the planets or double stars, well, it is functional but isn't exactly overwhelming. It would have been nice to put a little more in the description of the views at high power in that 8 inch f/5.9 refractor, and on objects other than the deep-sky ones which the author obviously feels are the forte of that instrument.

Quote:

What's with the straw man “We need to know if this objective is some kind of "miracle" and tames chromatic aberration enough to work well, rather than being just another simple achromat”




It is not a "straw man" argument. There are recent (and sometimes fairly frequent) changes in optical materials and design that have made a few 2-element achromats perform notably better than earlier designs (in some cases, almost as well as some of their more expensive 3-element bretheren). I would have been interested to see if this objective was better than what I have seen previously with 2-element objectives (especially those with f/ratios below f/10). In the past, I have been pleasantly surprised occasionally by something like the Vixen 103mm f/7.7 doublet which gave sharp almost color-free images of Jupiter one night at the Nebraska Star Party (wish I would have bought that one). I can't really effectively judge how good the eight inch performed based on a simple "3.5/5" rating. I needed just a little more. It's that simple.

Quote:

And congratulations, you beat down two straw men in one paragraph, double stars (objects he didn’t even discuss).




Again, not a straw man, but missing information in that the reviewer didn't discuss doubles at moderate to high powers. Refractors are a mainstay of many double star observers, so again, it would have been nice if the reviewer had included at least a few in his tests of the instrument. With a short f/ratio achromatic doublet, there would undoubtedly be at least some issues with the performance on some close brighter doubles, but it would have been nice to know exactly how good (or bad) the instrument performed on them.

Quote:

But apparently the fun needs to be pre-approved.




Nope, it doesn't have to have any "approval". I would have just liked the reviewer to have covered a little more of the bases when it comes to something I might want to someday purchase. I guess the only way to judge this instrument is to see it at a star party and get a look for myself. Clear skies to you.


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PGW Steve
Pooh-Bah


Reged: 10/03/06

Loc: Winnipeg, Canada
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: David Knisely]
      #6383918 - 02/19/14 12:28 AM

It's a golf club.


I have a 6" f5.9 and I know better than to point it at a planet or the Moon. I do love the crisp stars delivered to my eye in a huge FOV. Knowing the limitations of this optic, and its strengths, I employ it as a putter.

If I need to look at colourless views of the Moon or planets, I'll grab my 7" LX200 Mak, my driver.

Thank you for the review, been drooling over this OTA for a while, you confirmed my suspicions.

What I would like to know from the reviewer, it looks like you said the rings and dovetail were included. However, on the Istar site, it looks like the scope is a-la-carte. What was the total cost of the scope as reviewed, did the focuser come from Istar installed?


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Jim Curry]
      #6383997 - 02/19/14 02:16 AM

Quote:


The reviewer "gushed" about the deep sky views. Planetary views getting a 3.5/5 rating (70/100) is not gushing. In fact, I would call that panning. “False color is prevalent on brighter objects”. Prevalent=dominant.

Oh, I don’t want to neglect the red herring: “So do tell: how did you tame the CA in the scope?” Prevalent=dominant. There’s a lot of attitude in that sentence, Don. (Me too in this missive) :>)




Actually, you read into my words a meaning they didn't have. Since he had said what he did, I actually was curious about how he compensated for it.
I know a short achromat will work fine on deep sky--I enjoyed my 6" f/5--but there are a lot of objects up there where the false color would be obtrusive.
The reviewer of the 7.1" mentioned he used a Baader Fringe Killer filter, whose characteristics are well known. Had this reviewer mentioned his solution for violet fringing, it would speak volumes on just how tamable the violet was.
I used a Baader Contrast Booster on the 6" f/5, and it was barely strong enough. In one sentence, you know exactly how my scope was on bright objects.
Perhaps the author didn't buy the scope for any purpose requiring a minus violet filter, and if so, that's just fine. I was merely asking.

Edited by Starman1 (02/19/14 02:18 AM)


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Kevin Barker
super member


Reged: 04/22/09

Loc: Auckland, NZ
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6384495 - 02/19/14 11:13 AM Attachment (44 downloads)

I have been reading this thread with some interest. Mostly because I have recently constructed a 180 mm 7.1 inch f-8 achromat myself. It was sold as a R30 improved achromat etc and it does appear to control CA a fair bit better than i would expect for a standard achromat.

I am well aware of the limitations of this type of fast large aperture refractor(e.g the 204 f-6). A cruise at low to medium powers across star fields with a big fast achromat and modern well corrected wide field eyepieces is pretty darn good. As has been stated above they can illuminate a wide field well and provide very sharp pin point stars. Views of deep sky wonders are also quite impressive. They can also do surprisingly well on double stars.

In my own experience I have found the scope I have to be pretty darn impressive with respect to CA as seen at the eyepiece. Planetary performance is not up to a long focus achromat but heh I knew that. For example to some extent CA washes out some belt detail on Jupiter compared to a newtonian of slightly larger aperture. This is tightened up a bit using a fringe killer.

I have enjoyed reading Singaporean astronomer James Ling's reports using an Istar 8 inch f-8.8 achromat over recent years have been interesting. His scope has performed well in most respects. On You tune I found a video of a lunar view through this scope. It shows quite well the type of CA a big achromat produced on bright white objects. My 180 has a heck of a lot less CA than this.

CA is an issue but realistically I think it is often overstated as much as it is understated. For visual observing I tune it out and appreciate the sharp diffraction spike free views unobstructed apertures can deliver.

Still I'd love to spend a night under a dark sky with his big 204 f-6 refractor.


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galaxyman
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6384498 - 02/19/14 11:15 AM

I think we all agree that a bit more info would be good.

The owner of the APM 7.1" added it to his ever and still growing line-up of quality scopes after some observing sessions that I was using the APM 8".

His initial thought was that it would make a wonderful wide-field instrument (which it is of course), but soon realized that the scope could do much more. I believe James here in the review of the Istar 8" saw the same, hence his very positive review. Both of these scopes are of course more for DSO observing to those who enjoy refractors.

Each fine scope has it's strengths and yes some negatives, but I find it wonderful that with the owner of the 7.1" and this new 8" gives their respected owners a bit more than expected.



Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
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Telekit (Swayze optics) 22" F/4.5 Dob
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ES 6" f/6.5 achro. Good one
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Starman1
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6385149 - 02/19/14 05:31 PM

For those planning to build their own refractors using commercially-available doublet achromatic lenses, the standards for "no appreciable chromatic aberration" are:
Conrady's Standard (f/ratio = aperture in inches times 5)
Sidgwick's Standard (f/ratio = aperture in inches times 3).
Correctable chromatic aberration, using filters, normally considered to be:
f/ratio = aperture in inches times 2.

Special purpose scopes, of course, violate these rules all the time. And they don't apply to ED doublets, either, where FR = 2A is considered to be similar to Sidgwick's standard for normal achromats.

With a plethora of really good minus violet filters out there, though, it's tough to apply these old standards.

But, having owned a 4" f/15 instrument, I can tell you Conrady's Standard probably applies if you want to see NO chromatic aberration at all, ever.
With all the different glass types available today, though, I wonder if some of the modern lenses may bend the rules some.

And, they certainly don't apply to special uses for refractors, like comet hunting, deep sky viewing (how many of us have experienced that much aperture in a refractor, eh?). An 8" refractor sure sounds like a fun instrument to use.


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jrbarnett
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6385722 - 02/19/14 10:48 PM

Very simple, Don. Permanently install an OIII filter.

- Jim


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jrbarnett
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: PGW Steve]
      #6385740 - 02/19/14 11:04 PM

"I do love the crisp stars delivered to my eye in a huge FOV."

A scope with an 900mm focal length isn't capable of a particularly HUGE FOV. Any scope with a shorter focal length will produce a considerably larger maximum FOV. Case in point: 78mm f/8 fluorite doublet with a 630mm focal length will produce a larger TFOV with any eyepiece than the 6" f/5.9. A scope with a slower focal ratio will produce a flatter field as well, and a scope with less chromatic aberration will produce crisper stars if the stellar magnitudes are 3 or brighter. If a big TFOV and crispy stars is really what lights your rockets, for $900 a used Takahashi FS-78 would be a better scope than the 6" achromat.

I have one of the Kunming 6" f/5.9 achromats as well. What I like about it is moderate (rather than small, as is usual with refractors) unobstructed aperture with the inherently superior contrast that comes with a well-baffled, unobstructed optical system. While it's far from my favorite scope, the fact that I haven't dumped it tells me that id does some things I like that my alternatives don't do.

Still, fast achromats have plenty of faults. While I'm certainly not "against" them or being "mean", whether a reviewer likes or dislikes a scope is the least interesting and least useful part of a review. The meat of a good review is the description of what the scope does well and what it could do better.

Mi dos centavos.

- Jim


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Kevin Barker
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: jrbarnett]
      #6385998 - 02/20/14 02:56 AM

Jim
Whilst the used Tak 78 will deliver superb images and larger TFOV I bet the 6 inch f 5.9 will render deep sky objects (fainter planetary's, galaxies and nebulae) better. Better meaning more and brighter detail visible, more resolution etc

I have an AS80/840 Zeiss Jena lensed scope, It's optics are superb on tightish doubles around 1.5" seperation and brighter medium power planetary viewing etc. It will not however beat even an average 4 inch achromat on deeper sky.

I agree refractors are great for wider skies. My 8 inch Dobsonian for example has a limited fully illuminated field. This is to reduce CO and enhance contrast.

As you say "whatever lights your rocket". I think this is why many of us own an arsenal of scopes.

Kevin


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galaxyman
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6386540 - 02/20/14 11:10 AM

Quote:

An 8" refractor sure sounds like a fun instrument to use.




Oh yeah


Karl
E.O.H.

Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
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HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5" f/5 reflector (new)
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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PGW Steve
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6387077 - 02/20/14 03:46 PM

Jim,
I have a 14" LX200R, a 16" Hyperion and a 7" F15. Meade Mak.....Would you agree that the 6" f5.9 provides me with a huge FOV??


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Kevin Barker
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: PGW Steve]
      #6387820 - 02/20/14 10:42 PM

Steve
Focal length is the key here.
I wrote an article on focal length a few years ago(12 ??) for our local astronomical society for beginning astronomers. From memory I ignored the concept of barlows or focal reducers. I compared the actual field of view with three common eyepieces in four of my telesopes. At the time I think I had a 100/1000 refractor, 203/1200 newtonian, 80/840 refractor and a 152/1800 refractor.

Big fast refractors have quite short focal lengths as do some fast Newtonians. Refractors can often produce a very wide field fully illuminated field with modern wide field eyepieces.

Kevin


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Mark Costello
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: PGW Steve]
      #6388329 - 02/21/14 09:08 AM

Hi Steve. If I had a scope like that and something like a 30mm eyepiece with an apparent field of view of 80 degrees, I'd be able to frame almost everything and use it as its own finder. I work that way with my 5" achromatic refractor.

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Vondragonnoggin
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Mark Costello]
      #6388480 - 02/21/14 10:31 AM

I read the review. It seemed to cover enough material to get an idea how it performs. I don't see what all the extra questioning is about. Particularly from well experienced observers with no interest to begin with in a scope like this:


From Don:

Quote:


Having owned a 6" f/5 and a 4" f/15, and, now, a 4" f/5.4 apo, I can only say, "to each his own". Chromatic aberration definitely spoils the view of Moon, planets, and bright double stars. Deep sky? You're right.
Anything brighter than about 3rd or 4th magnitude? Give me an apo or a reflector. The 6" f/5 even still had too much false purple for me with the "atom bomb" of minus violet filters, the Baader Contrast Booster. I eventually sold it.




From David:

Quote:


Even some of the fainter doubles might have some haziness around them which some people might object to. Even my 100mm f/6 doublet has faint almost colorless halos around many doubles that really impacts the view at higher power, especially when trying for very faint companion stars that might get buried in that haze. Indeed, some tighter open clusters or globulars could get a little dose of extra "haze" in them with 8 inches of f/5.9 achromatic doublet to play with, although the aperture would certainly resolve them well. I suspect that my old 8 inch f/7 Newtonian or my friend's 8 inch f/5 RFT probably could probably do a little better planet-wise, although the 8 inch f/5.9 refractor could get true fields of view of up to 2.2 degrees or so with somewhat better edge illumination. Oh well, whatever trips your trigger (especially for around $3000). Clear skies to you.




To sum it up, statements like "to each his own" and "whatever trips your trigger" are indicative of a lack of interest in such an instrument.

What is the purpose of getting more info on something you would never purchase?

I do believe this to be a scope that would never get purchased by someone that knows about CA in a fast achro and finds it objectionable. Also, because of mounting requirements, mass, and cool down, plus expense, I don't believe some newbie unaware of CA is going to rush out to buy a scope like this, so what possible extra info should have been necessary to share that would satisfy whatever the real reasons for the extra questions?

Since there is obviously no interest in purchasing, what motive other than diminishing the review as previously mentioned, is there for extra questioning? Is it so people that don't know about how CA affects viewing high power planetary and brighter objects or a haven't experienced a "haze" as mentioned earlier?

Could do nothing but agree with Mr. Curry's post here. Bottom line - this is a niche scope that would be picked by those that already know their tolerance levels for CA and are ok with what it does good (definitely mentioned in the review) and what it does not so good (again, definitely mentioned in the review).

While Jim's (Barnett) line of questioning is similar, I don't believe that he would never consider a scope like this. Might not be first on list of wants, but I could see curiosity to at least give it a go with an open mind. That's just a guess though....

Pointing out the elephant in the room is all fine unless others see it as a miniature elephant that can be ignored mostly.

"See the big elephant!"

"Yeah, but it's not that big and so what, peanuts are cheap"


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terraclarke
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Jim Curry]
      #6388631 - 02/21/14 11:56 AM

Jim!

I have found that amateur astronomy is becoming a lot like wine-tasting! That's why I don't go to wine tasting events anymore.

They say an 8" F5 or F6 Newtonian reflector would be much better, but believe me, if the review was of that sort of instrument on here, you'd have scores of them coming out in droves to complain about coma instead of CA! Sadly, at least in many of these fora, it has become more about sounding erudite than having fun.

I have a 6inch F5 Omni XLT refractor on a heavy duty mount and it is sheer fun and cheep thrills at a dark site. But then, I'm a girl that can have fun at a carnival too.

For some people it's more about spending money than it is, having fun. For the rest of us, it's about spending the money you have, and having fun. To each his/her own.

Edited by terraclarke (02/21/14 12:36 PM)


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gdd
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6388758 - 02/21/14 01:14 PM

On nights when you feel more like viewing in true color than in bright high resolution, you can put on an aperture mask and still have a quite a bit of aperture. Or cut the aperture less aggressively and use a milder filter.

Gale

Edited by gdd (02/21/14 01:17 PM)


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Starman1
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: gdd]
      #6389332 - 02/21/14 06:52 PM

Each scope type has its issues, and each scope type can have its aberrations tamed: a reflector by using a coma corrector, and a refractor by using a minus-violet filter.
That's not a bad thing, merely an adaptation of the observer to the idiosyncrasies of the scope type.
I still think an 8" f/5.9 refractor would be a fun thing to use. Needs a TALL mount, of course.


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Rachal
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6389696 - 02/21/14 11:47 PM

Quote:

Each scope type has its issues, and each scope type can have its aberrations tamed: a reflector by using a coma corrector, and a refractor by using a minus-violet filter.
That's not a bad thing, merely an adaptation of the observer to the idiosyncrasies of the scope type.
I still think an 8" f/5.9 refractor would be a fun thing to use. Needs a TALL mount, of course.


I image Leslie Peltier would have really liked one to search for comets; I think he used a 6"F10(IIRC).

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cheapersleeper
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Rachal]
      #6389873 - 02/22/14 03:20 AM

Many here see these comments on reviews as a "peer review" process. Not a formal one obviously, but something like that. If that is how you feel, then the line of questioning is perfectly reasonable regardless of whether one has an interest in purchasing the sceope.

I can generally just leave it alone unless someone seems to be really putting false information out there.

B


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russell23
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: cheapersleeper]
      #6390109 - 02/22/14 09:27 AM

The statement that "The notion that “fringing” or “false” color hinders or hampers what you see in a “doublet” is phony baloney nonsense" is not supported by anything in the review. Unless it was compared with an 8" APO or a CA reducing filter was used on the scope to check for differences the statement is speculation.

I think what is meant is that the false color need not ruin enjoyment of the scope. That is a position that is clearly supported by the author's enthusiasm.

Dave


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Mr. Bill
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: russell23]
      #6419253 - 03/21/14 01:17 PM Attachment (26 downloads)

I've always toyed with the idea of a large RTF refractor (almost bought the APM 8 inch f/6) but good sense prevailed in the end.

Too heavy, too expensive for what you get in return.

My Orion 10 inch f/4.7 with Paracorr (f/5.4) would "blow the doors" off the Phoenix WFT 204 for a fraction of the cost.

PS...I own an Istar 6 inch f/5 lens set and made a binocular from a pair of Istar 5 inch f/5.5s so I've had some experience with Istar products, which are good value for the money.



Edited by Mr. Bill (03/21/14 01:57 PM)


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Mr. Bill
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Mr. Bill]
      #6420078 - 03/21/14 09:23 PM Attachment (25 downloads)

6 inch f/5 Istar box refractor with binoviewers...

Edited by Mr. Bill (03/21/14 09:25 PM)


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Mr. Bill
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Mr. Bill]
      #6420157 - 03/21/14 10:24 PM

Another 8 inch f/6 refractor reviewed in CN

http://telescopereviews.com/item.php?item_id=1219


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JKoelman
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6434029 - 03/28/14 10:11 AM

Quote:

So do tell: how did you tame the CA in the scope? Which minus violet filter did you use? That might be an excellent one to use in the 6" f/5.



Forget these filters. Just weld a 30 mm widefield eyepiece into this scope. The title says it all: we are talking a comet hunter!


Edited by JKoelman (03/28/14 01:46 PM)


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aa6ww
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Mr. Bill]
      #6441868 - 04/01/14 04:05 PM

You only need to look once through his 8" refractor at the Helix Nebula or the North America nebula or the Andromeda Galaxy to know how utterly ridiculous your comments sound.

Ralph


That's my C14 next to his big refractor in one of his photos.


Quote:

I've always toyed with the idea of a large RTF refractor (almost bought the APM 8 inch f/6) but good sense prevailed in the end.

Too heavy, too expensive for what you get in return.

My Orion 10 inch f/4.7 with Paracorr (f/5.4) would "blow the doors" off the Phoenix WFT 204 for a fraction of the cost.

PS...I own an Istar 6 inch f/5 lens set and made a binocular from a pair of Istar 5 inch f/5.5s so I've had some experience with Istar products, which are good value for the money.






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norcalastroguy
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: stevew]
      #6444165 - 04/02/14 08:08 PM

Yea, after "blowing" my dough I have finally settled down to a multiple "set-up" that meets my thirst for aperture AND a solid "super" sized refractor...

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norcalastroguy
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: terraclarke]
      #6444226 - 04/02/14 08:35 PM

Hey ya Terra...

Ya know, if I actually knew what I was doing some 13 years ago, I would have landed on a 300 Mewlon, snagged a FS152 and called it a day...Astronomy to me was never about the expense, I repeat, Astronomy to me has never been about the money/COST, I love everything this hobby affords, even though I pursued it like a drunken sailor ( once upon a time LOL)... That said, I have blown through many scope types, many mounts types, many eyepiece collections ( 3 total, + all the LE Takahashi's when I owned my last 2 Mewlons, 210 and another 250) PLUS all the "brick-brack" you need to view ( filters, adapters, tables and chairs and LETS not forget Software, YIKES)...But with all I have done, my quest for the sky is ever present, no matter what I own and use, to me it's all about viewing, NOT owning astro gear!!! I am now in my late fifties ( FYI, calculated in dog years LOL), so I am down to my last set of scope types which to me I HOPE will take me to the end of my journey, into my golden years as an amateur astronomer!! In conclusion, I wanted to share my experience about a wonderful piece of gear, NOT Boast OR act like a pompus *BLEEP* just because I own a Big refractor...If no one here has had the honor to view though a lens system of this size, don't LOSE your cookies and get all technical, IT'S a Blast, IT'S a Beast to look through and IT'S MORE fun looking through an 8" piece of glass than maybe a BIG Dob ( Alvin Hueys 31 was the BOMB!!!)..Thank YOU each and everyone for your comments and criticism ( I am laughing ), but do yourself a big huge favor, GET OFF the COUCH, turn the friggin TV set off, GET out of these forums and go outside and LOOK into Space, The Universe is calling, Can YOU Hear IT??? Clear and darker skies, James E. ( aka NorCal Tak GUY)

p.s. That XLT refractor is a Monster, 2 of my viewing buddies own the 6" and the 5", LOVE em!!


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norcalastroguy
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6491755 - 04/27/14 12:43 PM

I actually purchased a minus violet filter ( 2" Williams Optics) for that simple reason, to eliminate existing false color and to bring additional contrast to various objects ( nebula and clusters)...That said, unless you have looked through a refractor of this size, making remarks regarding it's optical quality and OR ability is simple non-sense, why? Because it's size simple takes over what it lacks in elements ( a third lens to correct )...I use a Bak 4 prism diagonal, which when used in a "doublet" helps compensate for it's lack of full correction ( that false color term again )...I use 2" explores, the 5.5, 9, 14, 19,( 100 degree ) and I top off my eyepiece collection with a 24 and 30 explore ( 82 degree), a 35 ( 78 field ) as well as a 41 TV Pan and a 56 Plossl Meade ( I enjoy the 56 over the 55 TV, although I TRULY miss my 50 Tak)...Again, I have only used the Istar in minimal skies( 3.5 to 4 transparency, in the outer suburbs of Elk Grove / Sacramento) so again the jury is still out regarding a complete viewing report until I can get this scope into some very dark skies and see what she will do...All in all I am not trying to convince anyone of anything, merely stating that it's general performance as a refractor surprised the heck out of me, 8" or NO 8", it's a very good scope!! p.s. Dear Mr. Curry, YOU are simply a good guy and one person I will personally thank...A "Complete" Viewing report is coming, be patient group!

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jrbarnett
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: norcalastroguy]
      #6492213 - 04/27/14 04:59 PM

Pretty much an 8-inch is an 8-inch is an 8-inch. Anyone who has familiarity with *any* 8" aperture (C8 SCT, 8"f/6 Dob/Newt, etc.) will understand something about what's visible with another 8-inch even if of different design. Sure there are differences - one has a shorter focal length and produces wider TFOVs with a given eyepiece than another, one has false color that other lacks, one can be easily carried in one go, mount included, etc., but there are similarities too, which IMO grossly outweigh the differences in performance terms.

Accordingly, the only real "non-sense[sic]" here is the suggestion that one has to look through a particular design of 8-inch scope in order to have anything pertinent to say about it. I've looked through a 36-inch achromatic refractor. I've never looked through a 36" reflector. Nonetheless I know that were either mine, I'd rather have the reflector to escape the loads of false color present in the big achromat (17,600mm focal length). While I've never looked through a 36" reflector, having used other smaller but still large reflectors, I know how much difference a lack of false color makes on many targets in big aperture scopes. That is, though I've never looked through the hypothetical 36" reflector, my experience with 20" and 25" reflectors has some relevance when it comes to picking between a 36" achromat I have used and a 36" reflector that I have not used.

- Jim


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galaxyman
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: aa6ww]
      #6495053 - 04/29/14 12:45 AM

Quote:

You only need to look once through his 8" refractor at the Helix Nebula or the North America nebula or the Andromeda Galaxy to know how utterly ridiculous your comments sound.

Ralph


That's my C14 next to his big refractor in one of his photos.


Quote:

I've always toyed with the idea of a large RTF refractor (almost bought the APM 8 inch f/6) but good sense prevailed in the end.

Too heavy, too expensive for what you get in return.

My Orion 10 inch f/4.7 with Paracorr (f/5.4) would "blow the doors" off the Phoenix WFT 204 for a fraction of the cost.

PS...I own an Istar 6 inch f/5 lens set and made a binocular from a pair of Istar 5 inch f/5.5s so I've had some experience with Istar products, which are good value for the money.









That's the problem Ralph is that negative comments come from those who never looked the particular scope of conversation. It's almost like they doubt the review or the owner.

In fact I think many who are negative, observe more here on Cloudy Nights then actually under the stars where it counts.



Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5.1" f/5 reflector
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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davidpitre
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Reged: 05/10/05

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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: jrbarnett]
      #6495293 - 04/29/14 08:14 AM

Quote:

Pretty much an 8-inch is an 8-inch is an 8-inch. Anyone who has familiarity with *any* 8" aperture (C8 SCT, 8"f/6 Dob/Newt, etc.) will understand something about what's visible with another 8-inch even if of different design. Sure there are differences ...



Agreed. While there are certainly differences, it is just silly to say one is vastly different than another. 8" of aperture is 8". While 1 has a wider field and another a bit more contrast, it is still 8". And when you compare 2 with 8" of aperture at the same focal length, there just ain't a lot to yell about.


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galaxyman
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Reged: 04/04/05

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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: davidpitre]
      #6495351 - 04/29/14 09:05 AM

Actually David I have, and the refractor goes a bit deeper (like galaxies). Just the other night hit 15.2 mag galaxy with the 8" refractor.

Owned one 8" SCT and two very good 8" reflectors, and none has shown the detail or went as deep in DSO's as the 8" refractor.


Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5.1" f/5 reflector
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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Starman1
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: galaxyman]
      #6496000 - 04/29/14 02:33 PM

Quote:

Actually David I have, and the refractor goes a bit deeper (like galaxies). Just the other night hit 15.2 mag galaxy with the 8" refractor.

Owned one 8" SCT and two very good 8" reflectors, and none has shown the detail or went as deep in DSO's as the 8" refractor.


Karl
E.O.H.




Makes sense. A reflector would have to have enhanced coatings to even come close to the refractor's transmission (if using a dielectric star diagonal), and the SCT's secondary is just too large to show the same detail as easily.


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davidpitre
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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Starman1]
      #6499270 - 04/30/14 10:40 PM

Quote:



Makes sense. A reflector would have to have enhanced coatings to even come close to the refractor's transmission (if using a dielectric star diagonal),



I certainly wouldn't argue with anyone's personal experience, and don't want to highjack the thread into a reflector/refractor war, but indeed a Newtonian with newer enhanced mirror coatings (97-98% on the primary and secondary) does come very close to a refractors transmission. I think the limiting magnitude difference with the reflector at best case scenario would be negligible and hard to distinguish. My point is that I believe the time has past from when a refractor could always take you "deeper" than a reflector of the same aperture


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galaxyman
Vendor - Have a Stellar Birthday
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Reged: 04/04/05

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Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: davidpitre]
      #6499512 - 05/01/14 02:07 AM

I agree David with the new coatings. I had an 8" f/5.3 with high quality optics plus coatings, and was able to pull in some real faint galaxies, though not quite as faint as the refractor. Still wish I had that scope though.

For the $$$ a newt (dob) is best by far, and my 12.5" and 22" dobs are a testament to that for me. Both are optimized with high-end optics, coatings, and small secondary mirrors.

Anyway, any recent reports from the owner of this 8" Istar? That's what I would like to read.


Karl
E.O.H.


Chesmont Astronomical Society - www.chesmontastro.org
Galaxy Log - http://www.youtube.com/user/GalaxyLog4565
Galaxy Log Blog - http://galaxylog.blogspot.com/
HASB - http://www.haveastellarbirthday.com
Telekit (Swayze optics) 22" F/4.5 Dob
Homemade (Parks Optics) 12.5" F/4.8 Dob
Vixen 5.1" f/5 reflector
TMB/APM 8" f/9 Refractor”The Beast”. One great DEEP SKY achro
ES 6" f/6.5 achro. Good one
Celestron Omni XLT 102 refractor.
Celestron 10x60mm Binos


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Jim Curry
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Reged: 10/29/07

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Re: Istar Phoenix WFT 204 “Comet HUNTER “… *DELETED* new [Re: jrbarnett]
      #6499660 - 05/01/14 07:06 AM

Post deleted by Jim Curry

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PhaedrusUpshaw
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Reged: 04/21/12

Loc: Southwestern Indiana
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: Jim Curry]
      #6500614 - 05/01/14 03:58 PM

One could discuss the merits of telescope design and characteristics till the cows come home, however when all is said and done weather Reflectors, SCTs or Refractors, we are ultimately discussing a matter of personal preference. Personally I prefer the amazing contrast and depth of focus achieved by long focal length refractors. Of course this is simply my opinion and we each have one of those. Having said that I find myself dividing my time at the eyepiece, pretty much equally, between my 5 inch long focal length refractor and my 10 inch Dob which of course has twice the objective size...
Remember what Jack said, "Keep looking up!"
Bill


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michiel
sage


Reged: 09/16/04

Loc: The hague Netherlands
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: PhaedrusUpshaw]
      #6501762 - 05/02/14 06:43 AM

Hi James,
nice review. I recognize your thrill just as I had when I had first light on my 8 inch f9 APM achromat, the same as Karl has. There is something magic in the view through a big refractor that is missing in other telescopes. having owned, and still owing various telescopes, the big refractor remains a favourite toy, albeing it less practical than my 14 inch DOB. Big refractor performance is most bashed down by people that did NOT look through them, must be something psychological. The CA in your 204mm destroys apparently all viewing pleasure, but you just do not realise this.(sarcasm)
Enjoy
Michiel from Holland


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norcalastroguy
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Reged: 06/07/12

Loc: CA USA
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: michiel]
      #6504226 - 05/03/14 02:08 PM Attachment (17 downloads)

Quote:

Hi James,
nice review. I recognize your thrill just as I had when I had first light on my 8 inch f9 APM achromat, the same as Karl has. There is something magic in the view through a big refractor that is missing in other telescopes. having owned, and still owing various telescopes, the big refractor remains a favourite toy, albeing it less practical than my 14 inch DOB. Big refractor performance is most bashed down by people that did NOT look through them, must be something psychological. The CA in your 204mm destroys apparently all viewing pleasure, but you just do not realise this.(sarcasm)
Enjoy
Michiel from Holland




Hello and good health from California Michael...

You can easily tell when someone "hasn't" looked through a 8" refractor, they can't come to any reasonable conclusion only "arm chair" their voices using whichever scope they have had the most experience with...I will agree totally that a big " Dob" rules the skies, but looking through 8 inches of glass is really a treat, it's just that simple...The sky conditions here totally "reek", not good enough to get my Istar out, but I did manage to try out my newest set up, I simple dub my Double Barrel set up ( Astro Telescopes 152 f/5.9 and my Astro Telescopes 102 f/11 planetary killer )


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michiel
sage


Reged: 09/16/04

Loc: The hague Netherlands
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: norcalastroguy]
      #6509439 - 05/06/14 08:43 AM

Nice rig you have

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norcalastroguy
member
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Reged: 06/07/12

Loc: CA USA
Re: Istar Phoenix WFT 204 “Comet HUNTER “… new [Re: michiel]
      #6522656 - 05/13/14 10:27 AM

Thanks Michiel...It actually meets both uses, deep sky and planetary...I had originally purchased the 102 back in 2009, but sold it wanting more aperture...after a good friend of mine ( Alvin Huey of faint fuzzies fame)told me how good it was ( I only used my twice), I had to have another one...Sad part is this scope type won't be offered in the near future...Word has it that it's production cost just went up, making it over priced in today's telescope market :-(

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