Celestron 102mm f5 WA - Initial thoughts
Posted 11 October 2003 - 10:22 PM
In the package comes two of the *new* celestron chinese silvertop plossls (NOT to be confused with the old japanese silvertops from Vixen) that Celestron is now calling their *premium* plossls <cough, cough - ahem, yah ok> a 45 deg erect image diagonal (better than I thought, but still not that hot), a manual written for a person who's never seen a picture of a telescope, an 8x20 erect image finderscope and the obligatory copy of TheSky level 1.
The scope has a 1/2 - 20 mounting block affixed to the bottom of the OTA, for easy mounting on a photo tripod or othe mount.
I also immediately ordered the 2" alum focus knobs from focusknobs.com ($25 + $5SH) and a $45 softcase (c5) that I *hope* will fit from Stellarvue (I suspect it will, as the Celestron is even shorter than they list it - mine measures slightly over 20"). I also ordered a WO diagonal from anacortes, but alas - Anacortes is out of stock, and it will be a couple of weeks before it shows.
The focus knobs showed today (well worth the $30 - get the 2" ones if you do it, they look great and make a huge difference as per focusing), and the case will be here on monday.
The first thing I did (and perhaps a bit unjustly - as further examination shows it's really not that bad) was toss the included 45" erect image diagonal in favor of the everbright that usually resides in my TV102.
I have the scope mounted on my telepod head / bogen 3036 tripod which holds my TV102 decently. (this mount aslo has w/ encoders and the sky commander - although I didn't bother to hook it up).
Standing back and looking at the setup, I had to supress a laugh. Including the everbright and nagler zoom, I found it funny that I was using ~$750 - ~$800 in accessories on a ~$200 scope. And this didn't even include the tripod. Not too many people can say the telescope is the cheapest thing in their setup. Ahhh my, the things we do for aperture. (The whole reason I wound up with this scope was because I had to sell my Pronto to fund purchase of my 15" StarSplitter.)
First light was last night, and I was pleasently surprised. The startest showed a misalignement *somewhere* in the optical train (I was to eventually find it was in the focuser which I'll need to shim - the adjustment screws don't *quite* do it) but even so, the images were pretty decent and it took magnification surprisingly well. Certainly better than I had expected. There were no signs of pinched optics, astigmatism or any of the other real nasties.
Even with the slight resident funkieness in the startest, I was able to easily and cleanly split the double double with the 6mm (83x) setting on the nagler zoom, and I suspect I could have done it with my 7mm ortho if I'd have been inclined to dig it out - alas, I was feeling a bit lazy.
The moon and mars gave amazingly good images at 166x (3-6 zoom at 3mm) with the polar cap and other surface detail clearly showing. Yes, there is false color, and yes on the moon, it's a little irritating, but hey - it's a sub $200 scope. Can't have everything.
Today / tonight I stripped the scope to it's component parts, blackened a few shiny internal surfaces, cleaned the threads, blew shavings out of the ota, removed most of the glue - errr, I mean the grease - the chinese put in (anyone know what that gunk is anyway??) and reassembled everything installing the focus knobs in the process.
I then did a makeshift fix/shim and took the scope out for a quick evaluation - as decent as the images were yesterday, they were noticably better tonight. The most surprising thing (and I'm not sure why it surprised me, if I'd have thought about it I would have realized it should be that way, but I'm not really used to ATM refractor stuff) was that with the eyepiece *correctly* aligned in the light cone, secondary color was knocked down quite a bit, making the moon in particular *much* more attractive. Even with a nearly full moon, M13 showed a fair amount of resolution with averted vision, m57 was an obvious smoke ring, and mars showed better detail than the previous night(The polar cap is getting small!) Surprisingly, it was in this scope tonight that I was actually able to see a feature with the 5mm TMB supermono, but not with the nagler zoom (at 5mm).... In the central peak in Langrenus(?), I was able to make out that it was in fact several peaks, and clearly see what looked like a central divot. The "divot" was invisible in the nagler zoom. The double cluster was quite pleasing in the 13mm nagler t6, and the star colors showed crisp and clean.
Well, it's not a scope that will replace my TV102 by any means, but given the price and the size, I think it will make a heck of a travel/quick look scope - and it's one I won't be the slightest bit worried about.
And lastly, a thank you to everyone who had suggestions or input on this purchase.
Posted 11 October 2003 - 10:52 PM
It's interesting to hear the varied impressions folks have about false color in an Achromat.
Very detailed report. Thanks again.
Posted 11 October 2003 - 11:43 PM
Thanks for the report. I recently purchased the Hardin DSH 8inch dob but I'm thinking about buying a cheap refractor as a secondary scope. This is a very encouraging news. What's your thought on the Chinese made plossls? Are they decent enough or need to be replaced? I'm a newbie who is very happy with the Astrol 25mm and 9mm that come with the DSH-8 as well as the 6mm Orion Expanse I purchased recently, if that can give you any indication. Thanks.
Posted 12 October 2003 - 12:32 AM
I just wanted to congratulate you on your new scope, and to "thank you". I'm thanking you because, your initial search for a travel scope led me to finding the 102mm @ Adorama, but when I found it, it was $199, then you discovered that it was on sale for $179, and I unfortunately found that deal to be irresistable, and ended up getting one myself. I don't know how they have such a low price on them? The lowest price I've been able to find, anywhere but Adorama, was $249, and everyplace else, it's usually anywhere from $279 to $349, and I've seen it at a few places for as much as $649 and up!!!
Anyway, good luck with it, I feel it's a great buy, and a great worry-free travel scope, someday I'll be able to afford a nice, big, better-quality scope(If I stop falling for all these "deals").
Posted 12 October 2003 - 10:03 AM
As per my thoughts on the chinese made plossls - well they are decent enough that they won't need immediate replacement - especially if you are happy with the astrola and the expanse. If you are looking to fill anything out FL wise, you might want to check out the apogee wide-scans. For $40, I like em a bit better on DSO's than the Expanse / Synta Ultrawides.
IMO, a ST80 or ST102 (such as this one) is a perfect compliment to your 8" dob, and the price (as others have attested) is pretty dang good.
Posted 12 October 2003 - 10:07 AM
Thanks for the news on the diagonal. After taking another look at the scope last night, I suspect I can just shim the diagonal instead of the focuser (that would probably be a lot easier, although it would mean that that particular diagonal should only be used in that particular scope - no big deal really).
As per false color, this is my first *real* achromat. My other refractors have been all been semi-apos or true apos. For the low power wide field views for which this scope is designed, the false color is not that big of a deal IMO. YMMV of course.
I did see one report on this scope where the individual doing the write up stated "there was no false color" - no kidding. Well, I'm not exactly sure how he got THAT impression, (There's a lot of false color) but it's not as bad as I feared.
Posted 12 October 2003 - 10:30 AM
As a travel scope, I often thought (though have no experience) that one probably won't spend a whole lot of time on the Moon or planets while away from home. So DSO will likely to be the travel objective ?
One question: how does the focusknob make focusing better?
I never did like the Celestron plastic knob either; so is the focusknob larger in diameter? BTW, oh how's the weight compared to your old Prodigeous Pronto?
Posted 12 October 2003 - 10:51 AM
Thanks for the follow up. What's the eye relief for the Apogee widescans? I wear glasses so I need long eye relief EPs. Thanks.
Posted 12 October 2003 - 01:01 PM
Posted 12 October 2003 - 03:20 PM
Value is the operative word. For the money it's an exceptional deal, but if I could find a Pronto, Borg, or Megrez for $200 I'd swap in an instant.
As per the focusing knobs: Well I ordered the 2" knobs, and they are *quite* a bit bigger than the ones they replaced thus allow for easier fine focus. Plus they look and feel WAY better than the plastic things. This is such a small upgrade for the chinese scopes and it makes a very large (if somewhat subjective) difference - I wonder why this just isn't standard. Although I do see Orion is selling their TV clone knobs in their latest catalog. FWIW, I had a chance to use the 80ED with those knobs, and I like the ones from focusknobs.com much better.
If memory serves the pronto was right around 5 lbs (and built like a Abrams Tank). The specs for the celstron list it at 5 lbs as well (and built more like a Hyundai).
This thing will probably wind up pointed at whatever is in the sky.
Posted 12 October 2003 - 03:26 PM
I'm pretty sure it's slightly less than the FL of the eyepeice. So alas, I don't think they would work for you (except possibly the 20 and 32).