Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Refractors

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | (show all)
B. Cook
professor emeritus
*****

Reged: 10/18/10

Loc: No. California
Istar refractors Pros and Cons? new
      #5774396 - 04/02/13 11:10 PM

Are these refractors worth the money they cost and is the build quality there? They seem to have a good selection of different scopes. From what I can find they are made overseas in Europe if I am correct. Are they a new company or have they been around in Europe long? I wonder if they have a warranty service here in the USA? I see OPT has them for sale. Availability on some of them you have to call them for that information its not online by phone only. I am going to get a refractor this fall be interesting to see if they are worth there cost and if they become popular on this side of the pond. Thanks

Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Istar refractors Pros and Cons? [Re: B. Cook]
      #5774435 - 04/02/13 11:29 PM

The optics are made in China. The tubes? Dunno. Europe, maybe. Or the US. Their HQ is in Page, AZ, USA, these days. They haven't been in business all that long. They do have an interesting selection. I'd love to see some independent interferometer reports for their larger optics done with meaningful parameters. If the optical quality is there, then they are a good value. If not, then I'd say there's not as much to be excited about.

Regards,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
mikey cee
Postmaster
*****

Reged: 01/18/07

Loc: bellevue ne.
Re: Istar refractors Pros and Cons? [Re: jrbarnett]
      #5774586 - 04/03/13 01:15 AM Attachment (180 downloads)

Well I for one am an extremely satisfied customer. After a year's plus usage I find this lens is truely top notch. I can honestly say I can see no room for improvement. Double stars of .5 arc seconds are easily split and Mars and Jupiter are phenominal to say the least. Seeing conditions obviously need to be cooperative and those times are far and few between but this lens still amazes. Ales K. Istar's owner is a straight shooter and will personally see to it that you will become a satisfied customer. I exchanged approximately two dozen e-mails with him. Go ahead take the leap. Mike

Edited by mikey cee (04/03/13 11:22 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
RGM
scholastic sledgehammer
*****

Reged: 09/15/03

Loc: Burks Falls, Ontario, Canada
Re: Istar refractors Pros and Cons? [Re: mikey cee]
      #5774742 - 04/03/13 06:29 AM

I am also a happy owner. I believe they have a 5 year warranty period. I needed some work done on my focuser recently. Instead of repairing my existing focuser, they exchanged mine with a new/latest model focuser. Scope is built like a tank, and therefore heavier than other scopes. I rate it as high quality. They do have options to reduce weight on their website.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Jim Curry
Pooh-Bah
*****

Reged: 10/29/07

Loc: STL
Re: Istar refractors Pros and Cons? [Re: RGM]
      #5774773 - 04/03/13 07:07 AM

Mr. Cook:

I purchased both the 4" & 6" f/12 regular achro lenses and built OTA's. The 4" star tests perfectly at 200x, the 6" perfect @ 300x.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Darren Drake
Carpal Tunnel
*****

Reged: 10/09/02

Loc: Chicagoland
Re: Istar refractors Pros and Cons? [Re: mikey cee]
      #5774880 - 04/03/13 08:42 AM

Quote:

Double stars of .05 arc seconds are easily split and Mars and Jupiter are phenominal to say the least.




Wow that's some really good glass there lol.


Post Extras: Print Post   Remind Me!   Notify Moderator  
CounterWeight
Postmaster
*****

Reged: 10/05/08

Loc: Palo alto, CA.
Re: Istar refractors Pros and Cons? [Re: Darren Drake]
      #5774912 - 04/03/13 08:57 AM

Folks that own them seem happy, at least those in the Istar user group and here - but I think in the end 'value' and etc are a personal call. I think you need to be aware of mount requirements if you goi with one of the long focal length and larger apeture.

Post Extras: Print Post   Remind Me!   Notify Moderator  
mikey cee
Postmaster
*****

Reged: 01/18/07

Loc: bellevue ne.
Re: Istar refractors Pros and Cons? [Re: Darren Drake]
      #5775328 - 04/03/13 11:24 AM

Quote:

Quote:

Double stars of .05 arc seconds are easily split and Mars and Jupiter are phenominal to say the least.




Wow that's some really good glass there lol.


Ah c'mon man lay off me. I meant to put down .5 arc seconds! Mike

Edited by mikey cee (04/03/13 11:25 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Istar refractors Pros and Cons? [Re: CounterWeight]
      #5775405 - 04/03/13 11:57 AM

Also, there are lots of "happy users" in users groups for every brand of scope. Heck, there are even Meade fans if you can believe it. The cold harsh light of some objective interferometric test data using methods and metrics identical to those used to test other optics would go a very long way to establishing or undermining the value proposition represented by Istar optics. Large optics are hard to fabricate well no matter where in the world you figure them.

It would be great if Rohr on astro-foren were to test a handful of non-cherry-picked Istar lenses. For me, that would establish quickly whether the goodwill is earned or just derived from "clubiness" that follows every brand, good or bad. It would also give an idea how these lenses stack up to other brands whose lenses have already been tested.

The large (6" and larger) Chinese achormatic optics tested thus far on astro-foren haven't been very good. This is why I think the absence of similarly derived data for these optics gives reason to pause. It would be a huge "win" for Istar if scopes already in users hands (not hand picked examples) were tested in that neutral context and shown to be exceptionally high in figure quality. Conversely, if the test results looked a lot like the other big Chinese achromats tested on the site, it could be problematic for the business. I'll put it another way: if there were one or two actual-customer-owned Istar scopes tested on astro-foren and they were shown to be in the neighborhood of 1/6 wave or better, I would buy an Istar tomorrow. If instead they look more like the DKD and other large China acromatic optics tested on the site (a little over 1/3 wave) I'd have zero interest in owning one at any price.

"Do you/we feel lucky?"

Regards,

Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
jhfenimore
member


Reged: 11/30/08

Loc: Upstate New York
Re: Istar refractors Pros and Cons? [Re: jrbarnett]
      #5775446 - 04/03/13 12:24 PM

I purchased an Istar 6" F15 achro lens a few weeks ago to use in a folded refractor on a dob mount I plan to build this spring and summer. Chose the Istar based on availability (at age 72, you don't want to be on a multi-year wait list), and to a lesser extent, on price. Have only built Newtonian dobs, so this will be an interesting experiment. When I am able to test it on the night sky, I'll be happy to pass along the results, if anyone is interested.

Jack


Post Extras: Print Post   Remind Me!   Notify Moderator  
telescopemullet
professor emeritus
****

Reged: 11/16/09

Re: Istar refractors Pros and Cons? [Re: jhfenimore]
      #5775502 - 04/03/13 12:52 PM

You can add me to those who can attest to the great quality of the optics and OTAs of these scopes. I owned a D&G scope and the ISTAR was of better build quality and had optics that were just as good.

Edited by Scott in NC (04/17/13 05:32 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Sean Cunneen
Let Me Think
*****

Reged: 08/01/07

Loc: Blue Island Illinois
Re: Istar refractors Pros and Cons? [Re: telescopemullet]
      #5775564 - 04/03/13 01:25 PM

I purchased and built a scope around an Istar 6" f15 objective. Over a couple of years maybe a hundred people looked through it and I received lots of compliments. I sold it when I came across my current Jaeger's lens which I find to be sharper but dimmer(the Jaegers is uncoated). My reports are that I had a large objective with no major errors (astigmatism, SA). The lens was not perfect, but I thought the performance outstanding for the value and there were few times my scope did not have the best planetary images around. I have not dealt with Istar complete scopes, though I did check one out at a star party. I felt the tube was very heavy and I did not like where the scope balanced aesthetically. Istar builds their OTAs in a premium way, with machined baffles and a thick tube. I felt you'd have to add perhaps 15# on the focuser end to make the OTA sit properly on a mount. That additional weight would make an already heavy tube just about at the limit for one person to move around. You will need a very robust (HUGE!) mount as well.

Pay no attention to where this or that is made, we live in a world of stuff being made everywhere. Istar has their own factory making their own stuff. Istar service and communication is first rate, except when they post anything


Post Extras: Print Post   Remind Me!   Notify Moderator  
cliffy54
professor emeritus
*****

Reged: 03/14/10

Loc: ma
Re: Istar refractors Pros and Cons? [Re: telescopemullet]
      #5775607 - 04/03/13 01:41 PM

Moderators should not get involved. Look at the title of the post. Pros and Cons. Mr Barnett is stating his opinon of Cons.

I to would like to see some testing numbers also.


Post Extras: Print Post   Remind Me!   Notify Moderator  
telescopemullet
professor emeritus
****

Reged: 11/16/09

Re: Istar refractors Pros and Cons? [Re: cliffy54]
      #5775629 - 04/03/13 01:48 PM

Quote:

Moderators should not get involved. Look at the title of the post. Pros and Cons. Mr Barnett is stating his opinon of Cons.

I to would like to see some testing numbers also.




They are not his opinions as he has never used one. He is using conjecture to cast doubt upon a fine product, big difference.


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Istar refractors Pros and Cons? new [Re: telescopemullet]
      #5775686 - 04/03/13 02:12 PM

It is not an opinion that there are no published, neutral, interferometric test reports for Istar optics. I suggest that astro-foren is the best we have since we have test reports constructed using identical methodologies and criteria for many, many lenses from many, many sources. That is FACT.

It is not opinion that the large Chinese-made achromatic lenses tested on astro-foren using these standardized methods have been relatively poor in quality; below that which I would accept as a good quality optic. That, too, is FACT.

Here is the menu of astro-foren.de test reports:

http://www.astro-foren.de/showthread.php?6084-Verzeichnis-optischer-Berichte

Here are examples of poor quality large Chinese achromatic optics:

http://www.astro-foren.de/showthread.php?12046-DKD-Doublet-FH-Achromat-154-22...

http://www.astro-foren.de/showthread.php?11121-China-FH-ein-brauchbarer-Achro...

http://www.astro-foren.de/showthread.php?12046-DKD-Doublet-FH-Achromat-154-22...

Here is the DKD website:

http://dkdoptics.com/

Here is Istar's webpage for optical groups:

http://www.istar-optical.com/istar_031.htm

Here's a DKD lens with the accompanying "test report" (scroll down):

http://dkdoptics.com/productus.asp?id=108

Here is an Istar "test report":

http://www.istar-optical.com/istar_083.htm

It is not opinion that they look to be quite similar in parameters and presentation. That is a FACT, too.

Now every DKD optic that shipped with telescopes tested on astro-foren.de was accompanied by a similar test report, yet the actual figure quality of the optic when tested more rigorously wasn't consistent with that comforting report.

Therefore because we have no non-anecdotal evidence of high quality large Chinese achromatic optics, and do have some neutral, non-anecdotal evidence of large Chinese achromatic optics (shipped with glowing "test reports" no less) with poor optics, it is reasonable to proceed with caution and not be too hasty to accept anecdotal opinions from those who have drunk the kool-aid...er...I mean offered only pride of ownership endorsements rather than real data.

But hey, it's your money. I do have a question for the Istar owners. That ring on the front of the objective on which the focal length, aperture and company name are painted - can that be threaded off the front of the cell or is it glued on? I'd like to see the cell with the nameplate removed. Thanks!

Lastly, Istar hasn't helped itself among more skeptical and careful potential customers. It was Istar's principal to played "hide the banana" with the FACT of Chinese origin for Istar's lenses very early in the game. You see, I just want the FACTS, not the fanboism. A couple of 1/6 wave Istar objectives on good 'ol astro-foren, and I'd not only lose my skepticism but also become a customer. But as thing stand, a bunch of club members pumping glass they already bought, who display a severe case of "need to believe" doesn't cut it in my book.

What's the harm in wanting some FACTS? Heck, I'll pay to have telescopemullet's objective shipped to Rohr for testing and then back to him.



- Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
Gord
Carpal Tunnel
*****

Reged: 01/06/04

Loc: Toronto, ON, Canada
Re: Istar refractors Pros and Cons? [Re: telescopemullet]
      #5775727 - 04/03/13 02:41 PM

Quote:

Quote:

Moderators should not get involved. Look at the title of the post. Pros and Cons. Mr Barnett is stating his opinon of Cons.

I to would like to see some testing numbers also.




They are not his opinions as he has never used one. He is using conjecture to cast doubt upon a fine product, big difference.




You know, this is one comment/attitude that I have seen presented here quite a few times (and not just related to a single vendor/thing...) that I just can't agree with; the whole "this person doesn't own/hasn't used so is in no position to say anything". *Everyone* is in a position to share things here, be it personal experience first hand, or observations from afar.

Of course, I *AM* an IStar owner and so by your own position on this, you shouldn't have any problems with me sharing my experience!

I'll start with saying that Jim has hit on a lot of it already (and has things pretty clearly laid out). I'll add my own experiences and other information separately.

Clear skies,


Post Extras: Print Post   Remind Me!   Notify Moderator  
Gord
Carpal Tunnel
*****

Reged: 01/06/04

Loc: Toronto, ON, Canada
Re: Istar refractors Pros and Cons? [Re: jrbarnett]
      #5775743 - 04/03/13 02:52 PM

Quote:


But hey, it's your money. I do have a question for the Istar owners. That ring on the front of the objective on which the focal length, aperture and company name are painted - can that be threaded off the front of the cell or is it glued on? I'd like to see the cell with the nameplate removed. Thanks!





Jim, I'm pretty sure it threads on, although I've never completely removed it. I'll have a look the next time I get a chance.

Clear skies,


Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Istar refractors Pros and Cons? [Re: Gord]
      #5775755 - 04/03/13 02:56 PM

CNer Sasa also had an Istar - briefly. I'd love to hear him share his own "hands on" experiences with the instrument.

- Jim


Post Extras: Print Post   Remind Me!   Notify Moderator  
stanislas-jean
Carpal Tunnel


Reged: 10/22/08

Re: Istar refractors Pros and Cons? [Re: jrbarnett]
      #5775893 - 04/03/13 04:07 PM

When buying an Istar 150F10 doublet I was pretty sure that this was a chineese one.
China is a strange company of several sources.
When visiting some I was surprised to see the catalog of OTA in a room and some special orders at the corner, 8, 9, 10" and more.
You know that this is mass production and into the lots there are good ones.
Having got a problem with the 1st 150 showing spikes at high power the second one was without spikes and a little better in acuracy.
The bulletin is what it is, it is always possible to perfom a roddier on by yourself in order to be confortable. I did.
This is not the initial bulletin but the acuracy remains above the minimum required.
A L/4 PTV for the refractor equals a L/8 reflector on glass surface. The strehl given on the website is what can be expected and there is it seems at the receipt a polarimetric light test to see internal stressing of the glasses.
This is not may be a DGO but this works. The 150mm tool gave me images of Mars and Venus that didn't get mostly.
Jim reported the importance of the optic elevation to keep less seeing locally from ground. Absolutly right.
With the one way light into tube there is a gain with internal air currents.
Products are not the more exceptionnal optics to find but this works more than honestly. Better than the synta line.
Doublets are engraved on the front, not a stick glued on the front.
I dismounted the doublet from the cell to see how it is installed/ very well, not pinched, well spaced, diametrally spaced, all surfaces FMC. Easy to maintain and to collimate.
I improved the assembly with the installation of 6 screw helping to collimate the lenses together for avoiding any shift.
People using these doublets on the sun found them very correct in Halpha, me on Mars and Venus.
Stanislas-Jean


Post Extras: Print Post   Remind Me!   Notify Moderator  
careysub
Carpal Tunnel
*****

Reged: 02/18/11

Loc: Rancho Cucamonga, CA
Re: Istar refractors Pros and Cons? [Re: jrbarnett]
      #5775923 - 04/03/13 04:21 PM

What we need is a Consumer's Union for telescope owners.

It would be a membership organization in which, upon joining, members submit a list of their optics that they own and information about acquisition for compilation into a confidential database.

The organization would then select and contact members to provide free testing of their optics so as to get a random or representative sample of vendors without having to front the money for purchases.

Members would have log-ins for access to the complete test database.

Additionally the organization could purchase optics anonymously for testing and then offer them for auction to members after testing to recoup the purchase money.

A suitable incentive structure to get members to pay sufficient membership fees to support this would be necessary.

Sort of a pipe dream, I know. But such a thing might be workable.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | (show all)


Extra information
12 registered and 28 anonymous users are browsing this forum.

Moderator:  FirstSight, panhard, star drop, dr.who 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 11944

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics