16 replies to this topic

[Z28500]

I'm posting this after coming back inside, slightly frustrated from looking through a cheap "grab and go" telescope.
A few years ago I bought a Meade 90mm F/8.8 Refractor (800mm focal length) from someone on EBay for $37.00 minus shipping. At the time I thought I was getting a great deal. But that was before I started getting more serious about astronomy, and getting hooked on the beauty of the night sky in real time. Since then, I've acquired larger, heavier scopes, but like most of us, I still like light, "grab and go" telescopes.
The best thing I can say about that telescope, is that it did work, but when star testing, as long as the star is kept more or less in the center of the lens, it's in sharp focus. But about 4/5'ths toward the edge clarity starts to suffer and astronomical enjoyment becomes a bummer! At least for me anyway. I have read reviews about how great the scope is for the money, but NEVER once read about a "Star Test" being performed on that scope. Correct me if I'm wrong, but a Star Test is probably the first thing done to a scope once it (if it) has been collimated. At least I've done it to all my scopes when testing them for the first time. Sure the moon may come in clear, but that can be done with a pair of cheap binoculars! Not a true test. Before I bought this scope, I actually bought a 90mm lens in a cell first (same scope) for about 10 bucks, and then never did anything with it. However, after testing this particular scope, and becoming disappointed, I switched the lens, hoping the 1st one may have been defective. Didn't help. I even unscrewed the 1-1/4" EP attachment and rigged up a temporary 2" attachment, collimated it, and put in one of my favorite 38mm 2" eyepieces! It was much better, but still had the same problem with the objective lens. Which by the way is cemented! Like some binocular lenses, not air or oil spaced.
All in all, if you want a telescope just to see if you are interested in astronomy, thinking you may get out of it and not invest much $, then get it - especially if you DO plan on getting out of it! I wish I would have never bought the scope because the money invested in scope & shipping would have bought a decent eyepiece at the very least. And the moral of the story is: you really DO get what you pay for! If money is a issue, then save, little by little instead of buying junk. I'd stay away from that scope except maybe having it in a child's room for a beginning scope you're not worried about breaking. For my small grab and go scope, I have a 60mm F/12 I've had for 30 years, which I've rebuilt, adding a new aluminum tube. It IS clear from edge to edge, of which soon, a 2" focuser will be on it. I've already had a 2" E.P. up to it and-WOW! Edge to edge clarity!
Here is a scope I built a little later on, adding to a small modest collection of some much nicer telescopes:

http://www.cloudynig...5140754/page...

Z

[Jon Isaacs]

The best thing I can say about that telescope, is that it did work, but when star testing, as long as the star is kept more or less in the center of the lens, it's in sharp focus. But about 4/5'ths toward the edge clarity starts to suffer and astronomical enjoyment becomes a bummer! At least for me anyway. I have read reviews about how great the scope is for the money, but NEVER once read about a "Star Test" being performed on that scope.

Hi:

Are you saying that the scope star tests reasonably well in the center of the field but near the edge, it's not so hot?

At what magnifications? What aberrations are you seeing?

Personally, it sounds OK for an 90mm scope that cost $40. I have some pretty nice scopes and some that are pretty basic. Reasonable expectations, a 70mm F/10 achromat that cost $40 at Walmart can be enjoyed, a 101mm F/5.4 apochromat that cost $4000 can be disappointing.. it's all about expectations.

Jon

[BigC]

You are expecting too much from an inexpensive scope. 90mm f8.8 is getting towards fast and showing unwanted false colors,especially off-center. I have that scope and there is much you can do with it.Would have been thrilled to have such a scope when younger.Don't expect a Chevette to be a Lamborghini.

[Stipe Vladova]

This scope is from eBay, from William Vorce, right? Silver tube, black lens cell and plastic black focuser I bought that lens from him for $21.95 and came with plastic cell, dewshield and dewcap. It is Meade DS2090 scope. Mine lens is cemented, with normal colorcorrection, very smooth and overall very well corrected with mild turned edge which do not interfere with the image. That lens gives magnifications up to 333x and I'm very satisfied with it. My friend bought same lens several months later and when it came I tested it. This one gave the same optical properties and I concluded that newer chinese mass product lenses are much better than ones 10 yrs ago. You should ask someone to help you with it, I don't think the lens is problem, maybe your eyepiece was bad or so. Some bad eyepieces work well on a small f15 scope, but not on bigger f8.8.


This is moon taken thru this 90mm lens and with barlow 2x.

Regards,

S.

[Mike Lynch]

Gotta agree! I have this little scope, too... Good star tests, nice view of the Double-double in Lyra, and better than decent planet views.



Hope the original poster can work with that lens and get better views!

[avarakin]

I agree with others that it is a pretty decent scope for the money. What I really like about it is that it has focuser which can be modified to be 2" using a $2 ring sold by the same seller on ebay.
With my Meade 34mm 68^ this scope has sharp stars edge to edge. Another great feature is that its tube is aluminum and thus very light so you can mount it on some photo tripod and get a real g&g. It does show a little of CA, but it makes views more interesting .

Alex

[Stipe Vladova]

It is decently color corrected with only dark blue fringing and no purple/reddish haze. I saw M13 globular not as a fuzzy ball, but stars to the center. Refractors are great, darkening the dark background and brightening celestial objects. Reflector must be at least 6" in diameter to show M13 like that.

[Z28500]

This scope is from eBay, from William Vorce, right? Silver tube, black lens cell and plastic black focuser I bought that lens from him for $21.95 and came with plastic cell, dewshield and dewcap. It is Meade DS2090 scope. Mine lens is cemented, with normal colorcorrection, very smooth and overall very well corrected with mild turned edge which do not interfere with the image. That lens gives magnifications up to 333x and I'm very satisfied with it. My friend bought same lens several months later and when it came I tested it. This one gave the same optical properties and I concluded that newer chinese mass product lenses are much better than ones 10 yrs ago. You should ask someone to help you with it, I don't think the lens is problem, maybe your eyepiece was bad or so. Some bad eyepieces work well on a small f15 scope, but not on bigger f8.8.

Regards,

S.

No, it wasn't William Vorce. Also, I don't have any small F/15 scopes that are smaller than that 90mm, although I wouldn't mind it!
That picture of the moon's ok, I've also seen good moon shots through expensive telescopes & cheap binoculars too.
When star testing the 90mm meade, the star did not "Snap" into focus, though it still achieved focus in the center, but NOT the edge. (When a star test can be achieved with a "Snap" if you will, instead of gradual fight or "ooze" into focus as one Expert describes it when testing optics, that's good) different scopes have individual characteristics.
I used the same Baader EP's (Orthoscopic 18mm, Hyperoin 21mm, Hyperion-Aspheric Eyepiece 36mm, Plossl 32mm, then a couple other brands, Erfle 20mm, and a Wollensak) in several other scopes from F/5 to f/15, & F's in between, the Only scope they didn't perform well in was the Meade, They even worked Perfect in an old inexpensive 60mm scope I've had for 30+ years, edge to edge of the objective lens too, perfect focus(some of those old Japanese objectives were really good). And like I said in the meade, center of the lens focus was fine, and towards the edge progressively worse (the star lost it's focus). Trying out several EP's just didn't change anything. Bad Eyepiece? No, Help with a cheap meade? Lens orientation certainly can't be changed. Collimation was right on with a laser, telescope acclimated to ambient temperature which means there's no atmospheric turbulence or tube currents, clean optics including the ocular.No pinched lenses (the objective rattles a little like it's supposed to). What type of "help" are you referring to that someone could change the results of a star test? All in all, with the scopes I have, some totaling thousands, and others, well, out of the cheap ones like that meade and an Orion 90mm, and the 60mm I mentioned, and the good scopes, the only one that doesn't have good edge to edge focus is the meade. I have to say I'm happy that some guys enjoy their 90mm meade's because they are claimed to have good images. I'd sure like to see a perfect focused star on the edge of a 90mm meade after moving from center! Perhaps it's the other way around, maybe I shouldn't have used the expensive EP's that worked so well in all the other scopes! But I just don't like those cheap EP's (my old ones are collecting dust in a drawer)
I wish my 90 had sharp stars at the edge like Advarakin says his does. Says something about quality control, I've heard that about meade before more than once, but that's a different topic.
I think Jon's correct when he said you can get enjoyment from cheap Walmart scopes, very true, I enjoy to heck out of my old 60mm I bought 30 years ago, and I think BigC probably put it best when he said "Don't expect a Chevette to be a Lamborghini"! He's right! That meade I bought is no Lamborghini! Just a Chevette with a flat tire.
Z

[labmand]

I Like the size & weight but I did replace the focuser
overall I'm in the like it camp.

[tubehead999]

Z:

Some days, you eat the bear..some days the bear eats you.....

No reflection on the product itself. I imagine some are good, some not so good....

What I normally do when I receive something like that is "give it away"..usually to a couple of teacher friends for their classes. or use the parts for other projects. You do have value in the scope as far as the tubing, the cell, etc...Lot of folks out there who could use the parts and will probably toss the glass....last 90MM F/5.6 I had, gave it to a friend...40 bucks down the drain..hopefully he got some use out of it....last 80MM f/5 I had....used the tubing, tossed the plastic focuser....gave the objective to the classroom ..I guess they are burning leaves with it ...

I can only waste so much time with a piece of gear, before the frustration factor overrides the financial investment I have in it and off it goes for donation. Sounds like you are there!

That 90MM will probably make a great terrestrial scope for someone....

Bob

[Stipe Vladova]

Can you post some images of that scope? I would like to see it because there are 2 versions of Meade 90mm f8.8.

[careysub]

I agree with others that it is a pretty decent scope for the money. What I really like about it is that it has focuser which can be modified to be 2" using a $2 ring sold by the same seller on ebay...

Can you provide an exact link or product description for this? I have a DS2090 and would like to use it with 2" EPs, but I cannot locate the item to which you refer.

[Z28500]

here it is guys, a link on the owners manual for the DS2090 D=90mm x F=800mm F-8.8, it's the scope on the left.
That's a pretty funny analogy about the hungry bear Bob! I guess sometimes it's true. Although I really don't feel like I was his last meal. 50 bucks isn't that big of a deal to me on purchasing a *BLEEP* scope, it's the time wasted messing with it that I don't care for. If you want to see money crash and burn, get into another hobby of mine, R/C Aircraft, when one of them crashes it's $600.00 minimum hitting the ground sometimes more than a thousand... so 50 bucks?! I'll just use the objective for skeet practice and have a blast! and maybe one day come across a good air spaced objective that can be used in that tube, which by the way meade sells separate for about $115.00 I think it was. I also didn't know there were 2 different versions of the 2090, just goes to show about learning something new...
I sure appreciate the responses from y'all, at least some people are satisfied with their same type scope! I think if I was on a budget and wanted a cheap scope, there are some great used ones on EBay for about the same price.
Z

http://www.meade.com...0_TS_manual.pdf

[Stipe Vladova]

Have you tried to reverse the cemented objective lens or check the position. The thinner element must face the sky and thicker the focuser. Note that if the objective is up side down the spherical aberration occures and in huge amount. On low power the image in the center seems sharp due to greater exit pupil and just turned side a little the flare appears and not uniform, but as a tail to the one side.

[Z28500]

Yeah, The objective is in correctly.
On a different note however, I noticed you have a 90mm F-8.8 that's homemade, is it the same meade lens in question with a homemade tube etc? I also noticed your 4" Jaegers F/15. That's a really nice lens, crystal clear edge to edge, I know because I have one. Soon it will be it Astronomy Technology Today, I've already been communicating with the Editor, he's actually a pretty cool guy and we've been talking about the preliminary's. The Cloudy Nights link with my Jaegers 103mm F/15 in it, is the one at the beginning (1st post) of this thread, or: "D=103mm F=1575mm Jaegers Homemade Refractor update" started in March of last year. I believe I bought the lens in 2011 around the end of the summer and it's been over a year & a half in the making after taking the objective out of it's "mock-up" tube. I built it for my 20 year old son, a kind of a "you'll have it for the rest of your life" type of scope.
I sure appreciate yours and everybody else's reply's on this 90mm meade thread, I had no idea there would be this many responses on that scope! You know, now that I think about it some more, it really is kinda nice to have a cheap scope to kind of knock around & not worry about whether it gets scratched & dented. I already took it off the Go-To mount it was on & put another scope on it. It'd be nice to make a decent scope out of that "sows ear", but I like what Bob said about it, giving it to the kids to burn leaves! Excellent idea! And I know that from having been one myself, (& maybe 56 years later I still am) just give the lens to some boys, and there's going to be some ants terrorized by it! And other unlucky bugs! With a lot of laughs! That right there's worth more than the money!

Z

[Stipe Vladova]

Yes, 4" f15 Jaegers is really superb lens and I will not sell it. Untill recently I thought that I'm the only one person in Croatia to have Jaegers, but there is also one guy that has 5" f5 and 6" f10! They are waiting some better days to turn into scopes. Few days ago Fred Lamothe confirmed that 5" f5 which I ordered has been shipped.

As I wrote, me and my friend ordered meade ds2090 90/800 lens and they both have the same quality, just some turned edge and nothing else. Can you take some photos of intra/extra focal images to see what it really looks like? And you wrote nothing about higher magnifications. Try 5-6mm eyepiece on star and figure out is there any flare around star.

[Z28500]

Yes, 4" f15 Jaegers is really superb lens and I will not sell it. Untill recently I thought that I'm the only one person in Croatia to have Jaegers, but there is also one guy that has 5" f5 and 6" f10! They are waiting some better days to turn into scopes. Few days ago Fred Lamothe confirmed that 5" f5 which I ordered has been shipped.

As I wrote, me and my friend ordered meade ds2090 90/800 lens and they both have the same quality, just some turned edge and nothing else. Can you take some photos of intra/extra focal images to see what it really looks like? And you wrote nothing about higher magnifications. Try 5-6mm eyepiece on star and figure out is there any flare around star.

I'm glad there are people happy with their meade 90's - the fun of diversity!
The Wollensak eyepiece I mentioned after the Erfle 20mm was a 4mm and at the edge of the 90mm objective it went out of focus after being "in" in the center, Period. As of now I don't have a camera attachment for the EP's on any of my scopes, some of my friends do, however I have been star testing for almost 30+ years and there isn't too much I don't know about it (not saying I can't learn anything from an professional astronomer, of course I could) I am putting together a 6" apo with a beamsplitter from which I plan to start taking pic's though, I already have the lenses and the 2" beamsplitter. Good optics are where the super sharp pic's start happening. Like the moon shot up a few posts, although it's fairly clear, and a nice shot, it's not sharp, could be the camera, or the scope and/or both, it's probably as good as it will get with that meade 90mm. Knowing about the quality of your 4" Jaegers, I'll bet you could take some really sharp pic's through it.
As for my 90mm meade, I've already done what Bob suggested when he runs across junk, it's already off the mount. And I'm done fooling with it, it's just not worth it. I like my other scopes better and they all have sharp focus. I also like the idea of giving the 2 - 90mm objectives to a kid to burn ants with! Already have one in mind. Like I said earlier, I've crashed R/C plans worth over 10 times more than that scope, just like everyone else in R/C Aircraft - to get good, everyone crashes! And us ATM'ers, we've all bought things we're not happy with, I started a thread with one of mine! Lemonade out of a lemon! This really is a fun forum.

Z

Taken through another scope, not the meade, obviously a little on the fast side, but no filter.

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