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Optics Problem with new scope?

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#1 SAL

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Posted 19 October 2003 - 10:50 AM

After spending about 30 days with my Orion AstroView 120 refractor, I became weary of the amount of slop in the mount and vibration in the tripod system. I think it is just a bit too much OTA weight for this mount and tripod combination. Also my sample had a broken plastic leg tensioner bracket, and some other mechanical problems with the system. Orion was good about sending replacement parts. However, based on my concerns, and the fact I was still just inside my 30-day purchase window, Orion allowed me to upgrade my order to the SkyView Pro 120 system. (Same Chinese Synta 120mm f8.3 scope, but far more massive and stable mount). I have only had 1 night (last night) without heavy clouds since the scope arrived earlier this week.

My initial impressions regarding the heavier mount and tripod are that there is simply no comparison. I would say it is 50% - 75% more stable than the AstroView system with this particular OTA. I was able to focus at magnifications up to 200x with very little vibration and able to remain “on target” during focusing at all times (something that at least my sample of the AstroView would not allow me to do). The OTA is the same scope, but rather than being painted white, it is finished in gunmetal gray to match the tripod and mount. One would think the optics quality would be very similar if not identical, right? I’m not so sure…

The first OTA had (in my newbie eyes) excellent optics. Very bright, stable images with surprisingly little false color evident even on very bright images. I was able to move my eye around the perimeter of the eyepieces and still maintain stable views. Star tests showed no evidence of astigmatism in the optics. Collimation was off significantly, but was quickly corrected with the adjustable lens cell. Fellow observers commented on the surprisingly good views it offered for the price. I would rate this OTA as 9 out of 10 for this achromatic price range. Unfortunately, these are "package deals" (with different color graphics) so Orion requires you to return the entire AstroView system to upgrade to a SkyView Pro system. Basically I had to return this excellent OTA for the system upgrade.

The new OTA appears to have some behaviors I can’t explain. (Collimation was also off on this OTA, but was quickly corrected with the lens cell adjustments. This OTA does not show signs of astigmatism either). Please remember, I have only had about 90 minutes with it in the field under far less than perfect conditions so far. There appears to be significantly more false color in this OTA (purple halo around bright objects). I would say it is perhaps 50% more noticeable than the previous sample. Secondly, there is some kind of strange optics effect occurring. My eye must be perfectly centered over the Plössl eyepieces (the same EP’s I used with the first scope BTW), or the image appears blurry. In addition if I move my eye toward the edge of the EP part of the image simply disappears as if it is being “cutoff” from the field of view. If I keep my eye position nearly centered, the image is quite good (similar to my first OTA sample), other than the increase in false color. Using the 2x Shorty Plus Barlow actually appears to reduce the image cutoff effect. I can position my eye less centrally when using the Barlow and not loose the part of the FOV image. I am hoping perhaps there is something that can be done to correct this behavior, as each time I ship something to Orion it takes a week to get there, a day or two for them to process the order, then a week back to me. Between waiting for tripod replacement parts and upgrading my order, I have been out of a telescope for nearly 4 weeks already. Do the OTA’s vary this much in CA, or is this an OTA with more serious optics problems? Any insight would be greatly appreciated…


#2 SAL

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Posted 19 October 2003 - 10:55 AM

One additional question: Could a faulty diagonal cause all of this? I received a different diagonal with the system as well…

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Posted 19 October 2003 - 12:11 PM

Yes a bad dia will affect views. Do all testing using the eyepiece straight thru the refractor. Also, did you chk to see that the focuser was perfectly collimated before adjusting the mainlens? If not adjusting the mainlens wont remove all that chromatic abberation just went thru that issue with my Meade 5" achro after recollimating the focuser alone it now has almost no color at all on bright objects verses before it had just terrible spiking and purple halos even at low mags. You can easly chk the focuser by shining a flashlight thru the mainlens while eyeballing the baffles, focuser, and mainlens to see if they all are concentric to ea. other if not then the focuser will need to be loosened and slightly racked then add some small washers under the screws to hold it in place on the tube otherwise when you screw them back in the focuser will just move back out of collimation, hope I have helped solve your prob, PS- I have yet to encounter a non-APO focuser that didnt need some adjusting yet....Dave

#4 SAL

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Posted 19 October 2003 - 12:23 PM

Dave: Thanks for the tip! I'll check the focuser right away, and let you know what I find. Hope this is all that's needed to put the OTA into proper working order...

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Posted 19 October 2003 - 01:31 PM

Sal,
I just placed an explaination about focuser adjustments under telescope equipment if you want to see how I do it myself, best part is you cant harm the scope and can always go back to the stock adjustments tho I doubt you would want to, Dave

#6 SAL

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Posted 19 October 2003 - 01:46 PM

Thanks again Dave. I'll check out your post right now...

#7 Jacques

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Posted 19 October 2003 - 03:36 PM

Hey Dave,

Now that you mention focusser collimation as an important part of the optical train, it reminds me of 'the pinpoint stars across the field of view' that we talked about in another topic. I'm convinced of the necessity of perfect alignment for sharp views. I bought my 6" achro used, but it had a ronchi test (which showed very slight undercorrection) and the focusser was perfectly collimated by the shop. So I think it is a good thing that you brought this to attention as it is overlooked many times.

And Sal, I really hope you manage to bring the optical performance of your new tube back up to the level of the traded one. And yes, diagonals do vary in quality (and alignment), so there's hope.

Good luck!

Jacques

Sky Watcher achromat 102F10
Celestron CR150

#8 SAL

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Posted 19 October 2003 - 04:02 PM

Dave: My focuser appears to be properly centered with the rest of the OTA baffles, so I don't think this is the problem. However, I did put my collimation EP back in and watch the image while moving through the full travel of the focuser's range. Correct collimation at one extreme of focus is out of collimation at the other extreme. I am going to place the focuser in the range I normally use it to observe with and collimate the main objective in this area for the most accuracy. I tried viewing bright silver objects (roof vent pipes) at ¼ to ½ mile range (in daytime) and got the same purple halo effect both through the diagonal and when using the EP directly into the OTA, so I don’t think the diagonal is the problem either. I’m still hoping this is a collimation issue, not a bad set of optics in this scope...

#9 Mike Sandy

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Posted 19 October 2003 - 05:02 PM

Hi Sal.....I sent you a response to your email - but hadn't read this latest post. I'd get the collimation issues fixed as best you can and give it all another night under better conditions. If the problems persist......get ahold of Orion. The week or so you have to wait to get it turned around by Orion is a small investment - if the optics are not right.

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Posted 19 October 2003 - 07:20 PM

I agree,
the optics shouldnt really exhibit bad blue/violet except at hi mags period especially being a f8 refractor. Might be a bad mainlens it happens. I had a Meade 90mm f11 that no matter what I couldnt get stars across the FOV without comas everywhere but at the center, I finally bought a new mainlens and sure enough it was suddenly ok, lucky for me as that cell was un-collimatable by me anyway. The focuser was really off on that one too must be a focuser trait of the low end Meades.

#11 SAL

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Posted 19 October 2003 - 11:02 PM

Well, I spent three and one half hours with the scope this evening. Conditions were finally really good. I carefully recollimated the scope with the focus tube extended to the length I normally observe with. This did reduce the false color by about an additional 25% - 30% I would say. Definitely an improvement not only in false color but it also greatly reduced spiking on bright stars as well. So Dave, you are certainly on to something here. However the scope still has more false color than my previous 120mm had. I think I could live with the false color issue at current levels, but the crazy optical distortions continue. I again checked the scope with the diagonal and without the diagonal. Same results.

My eye must be centered over the Plössl EP almost exactly to see a good image. If I move my eye even the smallest amount off center, the outer edges of the image become “wavy” almost like poor seeing conditions, or like I am looking through a very thin layer of moisture. Stars near the edges of the FOV “smear”. I have never seen anything quite like it, so it’s hard to describe properly. However, if I reposition my eye carefully, the image snaps back into proper focus. I did not ever notice this type of behavior out of my previous 120mm. Again these are the same EP’s I used with the previous scope without problems.

I sure appreciate all the suggestions to alleviate the problem. They definitely helped reduce false color and spiking by getting the OTA collimated for the exact range I use the focuser in. Unfortunately, I am beginning to think I have gotten a bad sample in this OTA. I just can’t make any improvements in the optical distortions. So, once again, I will contact Orion to see what course of action they suggest…


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Posted 19 October 2003 - 11:44 PM

Keep us informed, id like to hear what the next one is like. Ive never owned an Orion refractor before so im curious as always. Sounds like you have walked the dog far enough, id send it back myself at this point. Dave

#13 Mike Sandy

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Posted 20 October 2003 - 02:05 AM

I agree` Sal.....let us know how Orion deals with the situation.

#14 SAL

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Posted 21 October 2003 - 08:46 AM

I spoke with Orion late yesterday afternoon. At first I was a bit concerned, because they indicated false color is normal in larger achromatic refractors, suggested a filter, and acted as though this would probably solve the issue. But after explaining the large difference in coloration between this scope and my previous sample, plus the optical distortions, they have agreed to take a look at the scope and either fix the OTA or replace it. I told them that if they cannot be absolutely certain the scope is properly fixed, I would prefer a replacement OTA. I will be shipping it back to them today. And thus begins another couple of weeks of waiting … (sigh). To their credit, Orion’s customer support had been very helpful and willing to try to make my order right. I told them I know these Chinese scopes can vary a lot in quality, and just want to make sure I get a sample like my last one that I view as an excellent value for the money…

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Posted 21 October 2003 - 08:58 AM

I know what you're going through, except my problem is electronic rather than optical.

Good luck with Orion, I hope they take care of you.

#16 SAL

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Posted 21 October 2003 - 09:02 AM

Thanks Schultze. It's frustrating, but as long as it gets resolved in the long run, everyone will be happy...

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Posted 21 October 2003 - 09:38 AM

Ive often thought that if they ( Meade, Celestron, Orion) and a few others would hire someone to just peek thru ea. scope for 10 sec ea. before shipping that an awful lot of probs would be found/solved way before it ever reached the publics hands, thats what Televue and a few other manufacturers do, and you of course notice NO ONE ever complains about their quality....... ever. Some manufactures dont have that kind of concerns and never will thats why this prob will never get better. been there myself too so I fully understand how frustrating it is.Of course we arent talking about $1000-$4000 Televue scopes either here, so mass production with little if any testing isnt going to happen, just replacements. Being abe to recollimate the focusers and mainlenses ourselves is the best weapon we have to repair the Chinese refractors other than replacement. Dave

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Posted 21 October 2003 - 12:21 PM

No most manufacturer's don't do that. Rather than getting the product right the first time, they'd rather do it two or three times before it's right.

It amounts to lost productivity, unhappy customers, and higher costs in the long run, as well as a very busy repair center.

#19 Stacy

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Posted 21 October 2003 - 01:31 PM

While most mfgs. do not test their scopes, some retailers do. Company 7 for one charges about the same price as others and tests every scope they sell. From talking to them directly, I understand they do reject quite a few. (However, mfgs. know this and try to send good samples).

But then there is the shipping issue. UPS/FEDEX/USPS can turn a perfectly collimated OTA into a misalignment mess. Some fixable, some not. Maybe Orion and others gamble that by accident shippers will knock a Chinese scope INTO alignment occasionally. :o

Regards,
Stacy

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Posted 21 October 2003 - 03:22 PM

HA,HA,HA! I think you have stumbled onto something there Stacy..........knocked INTO alignment? I can almost believe it sometimes. Dave

#21 Mike Sandy

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Posted 21 October 2003 - 05:43 PM

As competitive as the pricing gets for these scopes I understand why they aren't tested by the distributor. Think about the cost to unbox, test, and repackage each scope - plus the cost to deal with all the rejects. That's the kind of testing that should be done by the manufacturer - but these folks are driven everyone to cut costs to the bone. :tonofbricks:

It is "easier" for everyone to just let the end user do the testing - sort out the good pieces from the bad. Some retailers like Company 7 (as I understand it) take the time to test each piece and work through any problems before they ship, and TEC, AP, TMB (among others) perform a lot of testing as the manufacturer. Their customers might pay a bit more, and may have to wait a little longer to receive their purchase, but they have better assurance of a good product first time.

I don't mean to sound like the only answer is to pay big bucks for every piece of equipment - that is just not the right answer. There are lots of companies that offer reasonably low prices, and good customer support when something goes wrong. Orion seems to be doing just that in Scott's case. My only point in this trip to the soapbox, is to say that we, the consumer, can help encourage the appropriate level of quality and support in this market. When we shop based only on price or delivery - rather than looking for the best value - we place the folks doing all the testing at a big disadvantage. We can also let others know when a company works us over, or leaves us hanging. :mad:

Next time you look at a purchase, do your homework, support the companies that you know are working to do it right. Vote with your dollars and your feet - and run away from the low quality companies with customer dis-service departments.

#22 Guest_**DONOTDELETE**_*

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Posted 21 October 2003 - 06:23 PM

Meade has also been great at helping me with my scope's problems. However, the current problem has yet to be resolved.

It is unfortunate that is has come to having to send two mounts back. The second, withing 72 hours of delivery. I wouldn't mind paying a few extra dollars to have one work correctly out of the box.

#23 SAL

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Posted 21 October 2003 - 07:37 PM

Well here is an update. After I touched base with Orion, I called back to confirm the details and they agreed to OVERNIGHT the scope from Indiana to California. The cost to do this is nearly 60% of purchasing another OTA from them retail! Orion indicated they know I have had several problems with my orders and they were willing to rectify the situation as quickly as possible. I don't know what more I could ask of them (other than making sure the next Chinese refractor is a good one...LOL). Bravo Orion, that's really taking your customer's satisfaction seriously, and “putting your money where your mouth is” as the saying goes.

Well-said Mike. It is true that products are sold at a targeted price points, and checking every scope would significantly increase labor costs, and therefore equipment costs to the consumer. I’ve been surprised that most of the Chinese scopes I have read about have been of at least descent quality as is. If you get a really good one, they are rated even higher in quality. The first Chinese OTA I used I would have rated as surprisingly good. The OTA I just returned is unfortunately at the opposite end of the spectrum. There is a reason the best companies are more expensive. They would have caught that OTA before it ever made it out the door. Like you said, it’s their attention to detail (read labor costs) that promises better consistency in quality.

With my astronomy budget (read entry level…LOL), I’m always looking for products that provide surprisingly good value for the money, and companies that provide exceptional customer support for the price of their products. (I now consider Orion to be one such company). I fully understand these products will never provide the type of rock-solid quality control the true “giants” offer. But it’s amazing that within each price point there are always a few manufacturers that “raise the bar” in terms of performance/price/value ratios. Some day I hope to own top of the line equipment, but I will be actively searching for just such companies as I work my way toward that lofty goal. In a way, that’s part of the charm this hobby provides. And this excellent forum has done more to educate me over the past few weeks than I could ever have imagined…


#24 Mike Sandy

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Posted 22 October 2003 - 01:13 AM

Glad to hear that Orion is doing the right thing! They have always been on my list of good companies - because of the values they offer, and their customer support.

Hope you end up with a "pick of the litter" scope when this is all done.

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Posted 22 October 2003 - 08:26 AM

I dunno Mike about finding any happy medium here. From what ive seen there isnt much gray area when it comes to refractors, especially the larger ones over 90mm. They either are almost junk with regards to their focusers and EQs OR they are first class with awsome focusers and great EQs as well as multi baffling and first class lenses. Between these two is nothing.............in the 90mm-8" sizes. Ive only seen a middle rd. on the 60mm-80mm refractors. Im fairly happy with Meades mainlenses but I WISH I could buy an upgrade focuser like the TMB or AP units have for them when buying one, thats their greatest failing, REALLY crappy focusers! A Feathertouch focuser would be worth every bit of $300 more to me, and make a so-so Meade a pretty darn sweet refractor! Im just sick and tired of these crappy Chinese focusers there has to be a better way here. They wont support anything of substantial weight on them. Dave


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