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Something for nothing: Celestron C90

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#1 jrbarnett

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Posted 12 January 2012 - 11:15 AM

Well it's here. I've been on a catadioptric binge lately. Within the last 6 months I've picked up a C6, C5, MN68 and most recently (opened it this morning here in the office) C90. This is odd behavior for a guy whose least favorite telescope designs are catadioptrics.

My recent C6 and C5 purchases didn't prepare me for what to expect with the little C90 spotter. I'll explain. One of the factors underlying my recent catadioptric buying spree is the fact that each and every one of them has been deeply discounted, well below the price range where I could pick up a comparable aperture EQ mountable scope of *any* other design. I paid $390 for the C6, $380 for the C5 bundle which includes a nice padded case, $1000 for the MN68 which is approximately half of the MSRP and for the C90 I paid a shockingly low $160 for the scope, padded backpack, two eyepieces, 8x21 finder, 45-degree diagonal...and a small Celestron photo tripod.

Separately the C90 backpack bundle without the tripod retails for $209. The included tripod, Celestron's model 93606, typically goes for $40. On paper, the bundle looked to be a great offer. In reality?

The C90 is solid! It's a tough little all-metal (save for the finder bracket arm) scope that is remarkably well-made. The paint quality, for example, is higher than that used on my CPC-1100 or C6. It uses the sparkle, metal-flake black used on the C5 (also pitched as a spotter) rather than the gloss black of the larger SCTs. I think the sparkle black is a much nicer looking paint than the gloss.

The optics are clean and sleek-free (unlike my CPC-1100 which arrived with a coating flaw on the corrector). Unlike the C5, this scope does not use Starbright XLT coatings. Instead it uses multi-coatings on all surfaces. This leads me to suspect that the optics and coatings are the same as those used in Synta MCTs made for Orion.

The proof is in the pudding, of course, and I won't really know how good of a deal I got until I get the little OTA out under the stars, but at this point my perception is that I received much more than I ought for a modest $160 investment. The only "negative" comment I have right now is that the focuser is on the stiff side, but as I do this morning's conference calls, I'll run the mirror back and forth along the baffle a few times to see if redistribution of lubrication smooths it out any.

If the optics turn out to be decent, I may elect to use this scope (together with the C6) for an article I'm writing on the "trickle down" of decent astronomy gear to us masses at shockingly good (from a historical perspective) prices.

I'm going to use the OTA tonight for a brief first light on my Lapides Teegul and may also get a chance to snap a few pictures. I'll update this thread once I have some user impressions from the field.

Regards,

Jim

#2 MrJones

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Posted 12 January 2012 - 12:58 PM

Geez another one? I've been blown away by planetary images done with C90s and look forward to your report. Jupiter with c90 -another. And how about a C6/MN68 comparison!

#3 orion61

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Posted 12 January 2012 - 01:11 PM

I have heard very good things about the new C90's

#4 gnowellsct

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Posted 12 January 2012 - 02:15 PM

I had an orange c90 and was glad to re-sell it.
G

#5 orion61

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Posted 12 January 2012 - 02:31 PM

there is a shoot out with the new C90, an ETX, and Questar.. the C90 really held its own I found it by a Google search. It was signicantly brighter than the Questar and ETX..

#6 jrbarnett

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Posted 12 January 2012 - 04:47 PM

Ed Ting's review:

http://www.scoperevi.../page1ac.html#1

Ed's 3-scope comparo:

http://www.scoperevi...0mmComparo.html

These are what prompted me to try the C90 in the first place. I was looking at the Orion 90mm Apex MCT, but at $229 it's not quite as much of a value as the C90 for $169 given that they likely use the same optics (Synta).

Regards,

Jim

#7 Icarus

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Posted 12 January 2012 - 05:12 PM

Hey Jim, congratulations on your new purchase. Can't wait to see the pictures and your opinion of the optics.

After the refractor conversations we've exchanged before, I am also surprised you've dove into the SCT pool. :grin: I too would like a C9.25 or C8 but can't seem to pull the trigger, as I just don't know what type of optics I will get. :question:

Clear Skies,

Scott

#8 jrbarnett

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Posted 12 January 2012 - 06:32 PM

Hi Scott.

Let's just say I'm on the first step of the ladder into the SCT pool. It's not the first time I've swum there. In fact, I've had over the years and currently do have several SCTs and other catadioptrics. Problem is, about half of them have been mediocre in optical quality, which is why they aren't my faves. Basically if, every other time you pet a strange dog, you get bit, you tend to hesitate to pet strange dogs. :grin:

You'll notice that all of my recent commercial SCT/MCT purchases have been at the small, cheap end of the range. That way, if the dog bites me, it hasn't bit that hard. Of the recent Celestron purchases, the C6 is great optically. The C5 is more mediocre or average. The C90? Who knows. I'll do my $159 dice roll tonight. :lol:

I think the non EdgeHD 8" and 9.25" OTAs, and the EdgeHD 8" OTA, are well priced, though not cheap, such that they may be worth a roll of the dice. If I could be guaranteed to receive an SCT comparable in quality to the C6 every time I bought one, I'd have many more larger SCTs.

If you buy from a reputable dealer, you typically have a no-fault 30-day return policy. So long as you buy in a season where you'll get a couple of opportunities to test the scope during that period, and save all of your original packing material, it's fairly low risk. You may have to eat the shipping costs (OPT makes you pay shipping, for example), but at least you're not stuck with a dud; they are.

On the other hand, it was an affordable catadioptric that sustained my interest in astronomy during college and graduate school. My astronomy gear, and interest, stayed at mom & dad's house when I left home. I was too busy both socially and academically to think about astronomy, until one summer between my junior and senior years of college (third and fourth years, in those days; undergraduate degrees really were 4-years back in the day :grin:). I was working for a photo-processing lab that summer and being surrounded by cameras and optics on the retail side of the store made me think: "Y'know, I really should have a telescope to unwind with some evenings."

I shopped around and picked up a Bausch & Lomb MCT (3.1") bundle with a diagonal, couple of eyepieces and a soft case, and a Velbon photo tripod, and spent most clear non-social evenings out in one or another local school's fields sitting cross-legged looking at stuff above. The optics were pretty bad. The mechanicals were worse. The eyepieces were garbage. But the scope did its job - kept me interested in observing. In fact, I probably logged more objects with that little MCT than I have in all of the dozen plus scopes I have today.

So my cats & casses outlook is something of a love/hate relationship. :grin:

Regards,

Jim

#9 jrbarnett

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Posted 12 January 2012 - 06:37 PM

Y'know, there's one thing I should add. Celestron spotting scopes feature lifetime limited warranties. Their astronomical scopes do not. The current C5 and C90 are spotting scopes and have the perpetual warranty as a result.

Oddly enough, if your focuser mechanism on a C5 craps-out after 3 years, you can still make Celestron fix it. If the focuser mechanism on your C14 craps-out after 3 years, it's your problem on your nickel. Crazy, huh?

Regards,

Jim

#10 michalh

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Posted 12 January 2012 - 09:29 PM

I, too, ordered a C90 after reading Ed Ting's review. Still waiting for mine to arrive. I'd been thinking about a small refractor, but the performance and price got me to change direction. For less the $200 delivered I got the C90 and a C90 camera adapter. Can't wait to get it outside and do a star test to check the optics, then look forward to a true grab'n go scope. - Michal

#11 oldstargazer

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Posted 12 January 2012 - 10:29 PM

I managed to get a used C8 from this sites sale section and I have really enjoyed it views. Until I got my used 10 inch dob it was the biggest scope I had owned. Now I have a savings account setup for the purchase of a C14 next year, or I guess now that might be later this year. My only problem with my C8 is my dovetail is too short to get a good balance, very tail heavy. Just got a new dovetail for the 10 inch so now I hope the one that was on it will work for making the C8 a better fit in the balance department.

#12 jrbarnett

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Posted 12 January 2012 - 11:23 PM

Howdy fellers.

First light is done. Well, underway really. I've learned a few things. The optics aren't bad. Not fantabulously good, but not bad. A hair better than the optics on my C5 and a longish shot from the optics on the C6. That said, I still have some cooling to do and will re-assess once the heat-plume is gone.

Heat plume. Ugh. I'd hoped the little guy would cool quickly. Not a chance. It's like a brick. Seriously. It has big thick cast aluminum rear cells and a large casting around the corrector end of the tube. The corrector is moderately thick and the primary is way down in there in the well. Mine sat outside for an hour and a half before I uncapped it. Nonetheless it still shows a bit of a heat plume. Should be gone in another half hour or so I estimate.

In its present state, it's a little mushy at 35x per inch (10mm CZJ Ortho). Backing it off a bit to 22x per inch (16mm UO Konig II) and things tighten up nicely. Jupiter looks pretty. NEB and SEB and a couple of other belts hinted at 78x. I'll check it again at >100x once we're cooled down completely. I'm on my way back out to catch M42 when it clears the tree.

The scope is *very* prone to glare from local light sources. A distant neighbor's house lights cause visible glare in the eyepiece when the scope is aimed in the general direction of the house. Figure this little guy demands a dew shade unless you're under seriously dark skies.

The focusing has smoothed out a lot after I ran the mirror fore and aft twice. Too dark for pictures tonight, but Saturday morning I should have a good chance to post a few. More to come.

Regards,

Jim

#13 jrbarnett

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Posted 13 January 2012 - 12:26 AM

First light part 2: The scope cooled down nicely and after cooled put up some very decent images. I'll up my original rating and nudge it a bit further ahead of the C5 but still shy of the C6. Definitely in the zone of "satisfying" in terms of optical quality; especially if you factor in the price - $159 with a $30 tripod included; $130 for the OTA and accessories. It's unreal, really. Jupiter was splendid at 125x after cool-down. Very, very nice.

Now, here's some good and bad. Good: Reasonably small CO (32%) courtesy of a nice long focal ration (f/13.9). Bad: monster 1250mm focal length for its modest 90mm aperture. This is a fairly narrow field rig; it begs for a driven mount as a result. Mating the 5# OTA to a driven mount, however, compromises its role as a grab & go scope; motorized mounts tend to be fairly hefty. Good: After reading horror stories about how useless the little 8x21 finder is, I was pleasantly surprised that it worked reasonably well. It has a wide enough FOV to capture all of Orion's belt stars with context around them in a single FOV. Bad: Erm...mmmm...hmmm...I'm thinking...Oh, okay here's one. It has a kludgy visual back. Rather than an SCT visual back, it has a two-piece visual back with dual set screws. The problem is, when the visual back is fully tightened, one of the two set screws almost interferes with the focuser knob. Yeah, I'm digging for bad here and not coming up with major wrongdoing on the C90's part.

So far, so good.

Regards,

Jim

#14 Binojunky

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Posted 13 January 2012 - 09:51 AM

Glad you like it Jim, I love mine, by the sound of it you got the earlier stock run of this latest version, Celestron have since dropped the tripod and one of the eyepieces, now it comes with the backpack and 32mm , pays to shop around price wise as well, enjoy Dave.

#15 jrbarnett

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Posted 13 January 2012 - 10:20 AM

Thanks Dave.

For folks who may be interested in giving the C90 a whirl, Optic Planet still lists the old bundle that includes the tripod for the sale price of $159. They sell the new bundle (less one eyepiece and the tripod) for $209. If you think about it, the bundle at the discounted price is actually incredible. If you already have eyepieces and a diagonal (such as if you were after the OTA as a G&G alternative to a larger scope), you could sell the tripod, eyepieces and diagonal and likely get back $40-50. That drops the price for the OTA, finder and backpack to $109. Pretty 'mazing.

I wish I'd known about the bundle at Christmas time. I would have let my co-workers know about it. many of them were shopping for first telescopes for for children or for themselves (mostly driven by the iPad, believe it or not - folks get an iPad, purchase one of many locationally aware planetarium apps, look up at night for the first time in a serious manner, and then want to see more).

Regards,

Jim

#16 Torgyg

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Posted 13 January 2012 - 02:57 PM

It's realy nice to beable to read about the C90 as i have one my self sitting in my living room. I managed to get mine back in Oct, 2011 for $118 delivered new to my door. I used it for a few weeks on my AM 114 gem and found the viewing to be much better then i was getting from the 114 OTA. In December I decided I wanted to try a goto mount so the C90 is now hanging on a CubePro. Now all i need is better weather so i can get more than only an hour or so of looking at one time. It's a great scope from what I have tried so far, i'm even thinking about trying a little AP with a Sammy on it.

#17 esldude

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Posted 13 January 2012 - 03:28 PM

I agree about the tracking. I found it troublesome at much power on an Alt/Az arrangement (though it was a sticky not very good Alt/Az). I had a lightweight totally manual GEM that went with an older refractor. Adapted a mount for it using a 2x4 and used it on that. Line the GEM up with north, and go. Not quite as totally grab and go as Alt/Ax, but pretty close.

Once you get onto an object twirling the slow motion control to track is very little bother with such a nice small scope. Seemed more in line with the cost of the scope to do such thing rather than get a full goto mount.

#18 Icarus

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Posted 13 January 2012 - 06:31 PM

Hi Scott.

Let's just say I'm on the first step of the ladder into the SCT pool. It's not the first time I've swum there. In fact, I've had over the years and currently do have several SCTs and other catadioptrics. Problem is, about half of them have been mediocre in optical quality, which is why they aren't my faves. Basically if, every other time you pet a strange dog, you get bit, you tend to hesitate to pet strange dogs. :grin:


:funny: Makes me wish the TEC still made their MCT. :jump:

Jim, great post. It took me back to my first telescope. When I was 10. I purchased a 60mm Tasco from a guy on my paper route when working for the Mpls Star & Tribune. It was not very good or well cared for before I bought it, but it looked cool and I wanted to get into astronomy. As it was when NASA was going out to look at the Gas Giants for the first time.

When I know that I will have a good viewing period. I will have to pull the trigger and evaluate, as you suggest, one of the SCTs. I've looked through a C9.25 before and was impressed. Very sharp optics. Good to read that your C6 has very good optics as well. :grin:

Glad to see that your impression of the little C90 is favorable. :grin: Your evaluations IMHO are spot on. Keep us posted on further observing efforts that you make with it. So far, it seems that cooling is the only real issue. :cool:

Clear Skies,

Scott

#19 MrJones

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Posted 13 January 2012 - 06:39 PM

There is a version with tracking you can still find around. link

There are also some Orion versions.

#20 n1toga

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Posted 17 January 2012 - 07:21 AM

Jumping in a bit late,
Are the celestron C90, Orion apex 90 and the skywatcher 90mm mak the same scope?
Rahul

#21 jrbarnett

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Posted 17 January 2012 - 11:48 AM

They should have identical optics; all from Synta and none using Celestron's proprietary XLT coatings. The castings on the OTAs and the accessories bundled with each differ though, as does the pricing.

Regards,

Jim

#22 mattyfatz

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Posted 17 January 2012 - 03:28 PM

I had the old school orange C90, where you rotated the tube like a camera lense to focus it. I sold it when I got an ETX 90 UHTC type. Even though I got rid of the GoTo mount, I still use the OTA. 90mm MAKS are awesome. I think they're a sweet spot for that design. Great planetary views, great double star performance, and great portability.
.... BTW... I think the C6 is a perfect SCT for the same reasons. All the portability of the C5... Less cooling issues than the C8. Great views all over.

#23 FeynmanFan

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Posted 18 January 2012 - 12:45 AM

Gotta agree, Matty. I had an ETX90RA that I deforked after getting tired of the junk mount it came on. Put it on my Minitower as a grab n' go, and used it extensively until my C6 arrived. Well, the C6 quickly won out, only a few pounds heavier, short cool down, and much better views. The ETX is now in my shooting accessory box as a spotting scope for when I'm too lazy to actually walk downrange, and I'm betting it will stay there unless one of my grandkids gets the astro bug. :watching:

#24 mattyfatz

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Posted 18 January 2012 - 12:04 PM

I don't know what kind of tripod/ mount this package came with, but I'd like to make a suggestion. The Dwarf Star Mount from UA is a great companion to the small MAK. It's solid and portable, and you can really step up he power on the scope with confidence. You can also mount your C6 on it with ease.

#25 n1toga

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Posted 18 January 2012 - 12:51 PM

Thanks jim,
Just pulled the trigger on the SkyWatcher 90mm available on Amazon with a Table Top TeleTrack type of mount.
Rahul






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