celestron omni xlt 150

[LuisOValadez]

Can anyone give me their opinion on the celestron omni xlt 150? I'm looking to upgrade from my 70mm refractor and I'm leaning towards the omni xlt.
Your opinion is greatly appreciated.

Luis Valadez

[redshifter]

First we need more info:

What is your knowledge and experience level? Do you use your current scope a lot? Only once? Owned it for a month? A year?
What types of objects do you tend to view? Planets, double stars, deep sky, a little bit of everything, etc.
What other types of scopes have you used?
What do you like about your current scope?
What don't you like?
Is portablity an issue?

I can give you my personal opinion, but you may have a different use and user scenario than I do; what wouldn't work for me might be perfect for you.

[RickJ]

A 6" f/8 or 8" f/6 Dob is a far better scope in all respects and costs less.

I'd not consider any equatorially mounted scope in this price range. I've never seen one worth the money and as a supervisor of a public observatory for 27 years I saw a heck of a lot of them.

Rick

[LuisOValadez]

I currently own a 70mm meade refractor and I've had it for about a year. I use it a lot but most of it its made out of plastic and its starting to fall apart so I'm looking to upgrade. As far as what I like to look at, I like to look at everything. The more I use my telescope the more I love it, but I want an equatorial mount and this telescope seems very well built. I would say my experience level would beginner to intermediate. Thank you all for your time.

Luis V

[LuisOValadez]

Redshifter
Yes I do use my telescope a lot and I've had it for a year now. The telescope is made mostly of plastic and its starting to fall apart little by little. I would say my experience level is beginner to intermediate. I like to look at everything but I'm limited by my telescope, the altazimuth mount it came with is very light al shacky. Its very nice to look at planets and the moon but thats about it. The Orion nebula looks like a very very faint cloud with a few stars here and there. I would like to see some deep sky objects with more clarity and take a few pictures. Portability is not a problem.

RickJ
I have been looking at some dobsonian telescopes as well but honestly they just seem kind of big. I want something I can disassemble and keep away safe and I know I should not make my decision based on this but I just love the way and equatorial mount look like. I also feel that an equatorial mount will give me more experience just because its so different from what I have now. Tell me some of the advantages of a Dob over the equatorial mount.

Thank you all for your time

[RickJ]

I just love the way and equatorial mount look like. I also feel that an equatorial mount will give me more experience just because its so different from what I have now. Tell me some of the advantages of a Dob over the equatorial mount.

Thank you all for your time

Exactly why poor ones like this are sold. They play on your attitude toward equatorial mounts. I consider them sucker telescopes for this very reason. Spend $30 for a home made Dob mount and it will be more solid giving far more steady views than any $800 commercial equatorial mount, for the same scope, I've ever seen. I'd say saving $730 is a good advantage. Others would be speed of setup. An equatorial takes some time to align each time you set it up. A dob mount you drop the rocker box, drop the tube in and in seconds you are ready to observe. 15 minutes later your equatorial buddy is still assembling pieces and aligning his scope. I know, I did it for years before such mounts were invented by Charles Dobson. It revolutionized amateur astronomy. You go backwards with the equatorial mount not forward. No major observatory built in the last few decades use them. All are of the far superior alt-azimuth design. Big scopes wouldn't be affordable on an equatorial mount in fact.

Attend a star party before buying and get some hands on experience with good scopes before buying anything. You'll start to learn the compromises in all of them. Some you can live with, some you can't. There you will see -- and use -- many different ones. Each owner decides these compromises somewhat differently. But if made understanding full well what they are then you will be able to determine what is a good scope for you.

I've never met someone happy with those on shaky equatorial mounts like this one however, as I mentioned before. Due to the difficulty of making a solid equatorial mount at a reasonable cost most good scopes today, even those that are driven, use alt-azmuth mounts. The gearing needed, the motors needed, the computer power needed are all far cheaper than the mechanics of a usable equatorial mount. Just an economic fact of life.

Tip an alt-azimuth mount until the vertical axis points at Polaris and it is now an equatorial mount. Nothing fancy about it. Just the same mount tipped, unless you're at a pole then it is an equatorial mount without tipping it. Of course, tip it at an angle and it is out of balance because it is no longer supported over its center of gravity. That alone should give you pause. Expensive, highly machined, heavy duty axes and bearings are needed to support something at this angle. The pivot is a weak point as all that weight, far from the center of g is supported by one pivot bolt which has to support that weight out on a pivot arm. Suddenly you have a pendulum. Putting a scope on a pendulum isn't a great idea but that's what a mount of this type does.

It might look sexy but shaky is its true nature. Yes it can be fixed but the cost is high. Serious astrophotographers pay the price. My equatorial mount cost $9500! It's solid but no more so than a $30 home built rocker box for my 6" f/12.

A 5 or 6" Dob is just as easy to store and keep safe as the one you are looking at.

I made my first telescope, completing it in 1954. It was a 6" f/12, far larger than a good 6" dob. It is still in good working order today, 58 years later. Dob's didn't exist then so it was on a shaky equatorial mount. Now it is on a solid dob type mount and rock solid. Gives great views about equal to a good 5" apo refractor costing many thousand dollars.

Rick

[Siguy]

To me it seems as though different astronomy forums seem to have a differing consensus on what makes a suitable beginners' scope. Here, dobs seem to be the only thing anyone will recommend to a beginner. However, those off at Cloudy Nights seem to quite like the Celestron Omni XLT series, as well as many other scopes that beginners are taught to avoid.

I don't own one myself, but from what I've seen, the CG4 isn't a bad mount. It's definitely more than a level above 'department-store'-grade. It's not rock-steady, but neither is my own LXD75, which cost more than twice the price. But overall I would say it's a decent low-end equatorial mount. Hell, some people even use it for imaging. That being said, RickJ is right in that equatorial mounts aren't exactly beginner-friendly. If it's really necessary, with most of them you can tilt the head 90-degrees and use it as an altazimuth mount, though it kind of defeats the purpose. Equatorial mounts take longer to set up, but being able to track on one axis is really quite convenient, IMO.

I think the Omni XLT series is more geared toward intermediate users on a budget, rather than beginners. A 4-inch ED refractor used to be among the lineup, for example.

6-inch Newtonians I've always felt were good beginners' scopes. They're preferable as dobsonians, but it seems to me as though people made due with equatorials before dobs became widespread.

I will also admit that it's really quite hard to beat the aesthetic appeal of a gleaming-white equatorially-mounted scope. But aesthetics should really mean little in deciding what scope to buy.

[redshifter]

Good points by RickJ and Siguy. There are things an equatorial mount can do that a dob mount (without fairly extensive modification) cannot; such as auto-tracking objects. With a manual dob mount, you track objects manually. In practice, this is not difficult to do. I own a 10" Orion XT 10 dob and have no issues tracking at up to 250X. At lower powers, objects stay in the feild of view for sufficienly long that tracking really isn't an issue, at least for me.

Stability is everything as far as what I would call a 'good' telescope feature. All the wiz-bang optics in the world don't mean squat if they're attached to a flimsy mount that won't stay still. With a dob, the design is not only cheap but inherently very stable. Sure, you can get close to 'dob-level' stability with an equatorial, but it'll cost $$$.

Here's more food for thought: I found the xlt 150 here for $520: http://www.telescopes.com/telescopes...0reflector.cfm

For only $350, you can get an 8" dob, that's 2" more aperature for $170 less and a more stable mount to boot: http://www.telescope.com/Telescopes/...CategoryId=398

For $550 ($30 more than the xlt 150), you can get a full 10" of aperature: http://www.telescope.com/Telescopes/...yCategoryId=13

I didn't look to see what accessories came with each scope, but you get the general idea: you get more aperature for the $ with a dob.

Aperature is only one aspect of what makes a telescope 'good' for a given user, and that's dependent on what type of objects you like to view. However, you mention you 'like to look at everything', and the 10" of aperature will show you a lot more detail in deep sky objects than 6" will. I started with the 8" Orion dob and upgraded to the 10" and noticed a bigger difference in what I could see than I thought. For example, with 6" of aperature, you might pick up some galaxies in Virgo on a good night, with 10" on a good night, you'll pick out dozens, and be able to tease out some detail in a few. M27 in a 6" will look like a blob, with 10" you can see the trademark apple core structure inside dimmer nebulousity.

IMO the best option for you would be to check out a star party and try out everything. You sound like you've moved beyond the beginner stage, or at least 'advanced beginner' and a star party would really help you figure out what works for you and what doesn't. Maybe a dob is for you, maybe it isn't. Only one way to find out...

[RickJ]

For 27 years I watched a parade of beginners bring their scopes to our observatory for help. Those with solid mounts, not just a dob but always alt azimuth or fork that could be tilted on a solid base were very happy. Those with equatorial mounts were virtually all very unhappy. Club members using pipe fittings made very solid equatorial mounts for no more cost than a dob mounting that were great. So I'm far from against them. About half my scopes are so mounted. Half are on alt-azimuth style mounts. The XLT scopes we saw at the observatory were not well received by their owners. Optics were so so, not crisp but usable. Mount pretty shaky making focusing difficult for beginners. Watching them try to use the mount would have made a "I Love Lucy" episode. I watched several give up on the meridian flip and pick the scope up and turn it around to reach an object on the other side of the meridian. I'd show them how and they'd be back the next week asking for another demonstration. Many returned 5 and 6 times before they figured it out. Or did they just stop coming out of embarrassment? I never knew. I have to recommend what I saw made those visiting us happy and this scope wasn't one of them. Virtually none who bought dobs or something similar were unhappy with their choice. Hence I tend to go with them first unless there's an obvious reason for something different (has to fit in a backpack for example).

I wonder how many happy with poor scopes haven't used anything else? I remember one fellow who brought out a scope similar to the one we're talking about and was very happy with it but wanted to know what other eyepieces he could get for it. As our club had a star party in a few days I invited him out where he could try many different ones in the scope and see which he liked best. He came out all gung ho. He left trashing his scope after seeing many there that were cheaper and better for him. Suddenly his great scope he'd be recommending to all his friends was far from great. I've seen it so many times I call it the V-8 moment. "I could have had..."

I prefer folks to attend star parties and try many different scopes of many different designs and capabilities as well as cost before even considering which scope to buy. What is right for one isn't right for others. Anecdotal information is a poor way to choose anything. Get out and test drive what's out there and ignore the comments, mine included, is the best advice I can give.

I expect the classic equatorial mount to soon vanish. It's no longer necessary to put up with its inherent design limitations at any price range or use. Today an alt azimuth mounted scope with field rotator can track better than equatorial mounts and carry heavier loads for a fraction the cost. Inertia will keep the equatorial around a while longer. New models will continue to be introduced but for most uses its days are likely numbered Manufacturers will be slow to retool but that day is coming sooner than most think. Users, especially old timers will be slow to accept the change. Heck we still can't make the change to the vastly superior metric system! After 59 years in the hobby that's my feeling for the way it is going. What the big boys are doing works down to our level. Its happening faster than ever today.

Ever used a Dob on a Poncet type platform? Gives a highly accurate driven telescope with the stability and low cost of a dob. Best of both worlds. We have several in our club. One poor sucker who I won't name went out and replaced his $100 Poncet platform with a highly vaunted equatorial mount costing $1800. He quickly regretted selling the platform and had to buy a new one and sold the equatorial mount. While it was as stable as the best in its price range it didn't compare to his dob rocker box on a Poncet platform, both for stability and for ease of use.

Rick

[LuisOValadez]

Unfortunately I don't think there are any astronomy clubs here in El Paso, I have tried searching for some but not luck so it will be hard for me to attend a star party and check out some of the telescopes. Your comments have made me reconsider Dob telescopes but honestly I'm still leaning more towards the equatorial. I don't know there is just something about that scope that appeals to me. Lets say that for some reason I don't like the EQ mount, would it still be possible to mount the Optical tube into a Dob mount?

[redshifter]

El Paso Astronomy Club
Listed information for this organization. Please contact this astronomy club for information on their astronomy viewing schedules, telescope availability, membership, and public programs.


Name: El Paso Astronomy Club
Address: 6531 Boeing Drive
City: El Paso
State: TX
Country: USA
Contact: Cory Stone
Phone: 915-779-4317
Email: President@elpasoastronomy.org
Website: http://www.elpasoastronomy.org


I'd think there would be several astronomy clubs in the El Paso area. The sky conditions down there must be pretty good: Dry, higher altitude, and the ability to get to a very dark sky once you get out of the light pollution of El Paso. Consider yourself lucky! I've been dreaming of taking my scope to Big Bend National Park, not too far from your neck of the woods.

[LuisOValadez]

oh nice! thanks a lot redshifter. I will give them a call, again thanks to you all for your time

[RickJ]

Unfortunately I don't think there are any astronomy clubs here in El Paso, I have tried searching for some but not luck so it will be hard for me to attend a star party and check out some of the telescopes. Your comments have made me reconsider Dob telescopes but honestly I'm still leaning more towards the equatorial. I don't know there is just something about that scope that appeals to me. Lets say that for some reason I don't like the EQ mount, would it still be possible to mount the Optical tube into a Dob mount?

Redshifter already pointed you to your local club. Call them for their opinion and next star party. I doubt very much you'll see any scope like the one you mention at their star parties. There's a second club in your town that appears to be run through the The Gene Roddenberry Planetarium. They have a Yahoo discussion page but not much else. For info contact Cory Stone at the planetarium. -- 915-881-2498. I found both simply putting El Paso Astronomy Club into google. Clubs don't ordinarily have listed phone numbers. Before internet I always recommended going to your local planetarium or if none museum or library for that type of information.

Yes you could put the tube on a dob mount but I sure wouldn't recommend it. This is a scope that makes some optical trade offs to be short enough that the light mount can have any chance of handling it in calm weather. This is why I said its optics are not all that fantastic. Least the ones I saw were just barely adequate. OK for low power but struggled above 125x. Dob mounts can handle longer tubes with far better stability. This also puts the eyepiece at a more convenient height. That short tube on a dob style mount would have you on your knees most of the time. Most commercial dobs have pretty good optics due, in part, to their longer tube (Parabolizing an f/8 mirror is easier and thus cheaper than parabolizing an f/5 mirror to the same accuracy -- this from actual experience making optics. Some of the more expensive ones have very excellent optics. All I've seen beat every XLT and other short tube scopes for optical quality that came into our observatory for help or to our star parties. I'm sure exceptions exist, we never saw any however.

Living where you do with your dark skies nearby aperture will benefit you far more than an equatorial mount. Both cost extra. Spend for that not for an inadequate equatorial mount. Once you've used some scopes at their star party you'll understand what I'm saying.

I should say the XLT will be a better scope than your plastic monstrosity of a 70mm scope did when new. But why pay that steep price when for significantly less you get more aperture (brighter view of dim things), better optics (sharper view of small things) and a better mount (steadier view of everything)? Seems a no brainer to me to look elsewhere. Of course if your bank account is healthier than mine it may not matter to you to get more for less.

Rick