Sky watcher Evostar 120 & Celestron Omni xlt 120 - what is the difference

[casemonster]

Hi All,

I have been looking into this baby as my new scope upgrading from my old 4" 1960 scope which is very slow (f12or 16 can't remember) and am going to go for a larger Achromat. Budget being what it is, the 120mm refractor comes in to my price range and I am looking forward to the seeing more with this as it will pull more light than my 4", the optics will be better and it will be on a eq5 or cg4 mount when my present mount is an alt/azm mount. It also seems a lot more portable than a dob without the need to keep resetting it up.

All things now being considered, what is the difference between the two? does the special coating on the celestron optics which retails at £395 make the celestron a better buy than the £398 Skywatcher Evostar 120 on an EQ-5?

Any help anyone could give would be appreciated as this is my first real purchase of expensive (to me anyway) gear?

Many thanks,

Chris

[sologuitarist61]

I would suspect that there is not a lot of difference as both scopes are made by the same company, Synta. A awlful lot of people in the Lounge use SkyWatcher scopes, myself included, and are perfectly happy with their performance. The only difference between it and a Dob is that you will get more aperture from the Dob for the same outlay, but it depends on what you want to use it for. If just for general visual use then the Dob might be better, but if you anticipate AP through it, the the refractor and equatorial mount would be far better in my opinion.

[casemonster]

That would explain why they look so similar then. Does anyone know if the orion skywatcher 120 is also the same scope? read a review of this on cloudy nights and wondered if same thing?

Has anyone got one of these scopes?? if so what do they think as a general all round grab and go scope that doesn't do everything a mirror would in terms of DSO's but has a damn good go at it without the need to colminate (?sp) the thing every five minutes. BTW i am talking about the f8.3 scope not the ST f5

[casemonster]

also noticed that the sky watcher comes with 2 EPs and a 2x barlow the celesron has only a 25mm EP

[sologuitarist61]

Not sure about the Orion scope - is this the UK Orion or the US Orion which I believe are different companies? I don't think that the US orion company trade in the UK (but could be wrong!). I know that Cloudy Nights site seems to be predominantly US people contributing.

Another thing to consider is that many people on SGL all swear by the HEQ5 or EQ6 mount which are Skywatchers, but few seem to rave about the Celestron mounts so that tell me something about the quality of SkyWatcher gear.

[John]

Orion (USA) do, or used to do, a version of the 120mm F/8.3 as well. SCS Astro in Somerset stock their stuff but it seems to be a bit more costly than the Celestron / Skywatcher equivalents.

I've owned one for a while (the Skywatcher) and liked it although it's a bit undermounted on the EQ3-2 mount in my view.

For a first scope I'd go for an 8" F/6 dobsonian over the 120 achromat refractor though as the dob will noticably out perform the refractor on virtually all fronts. An F/6 newtonian is not much trouble to collimate and keep collimated either. Refractors need collimating as well, from time to time !.

[spaceboy]

Some will argue there is a difference in the coatings between the XLT120 & EVO120 but even if there was I doubt very much it would be obvious to the naked eye. I would not say the 120 is a big scope but neither is it small. What I mean is it is easily manageable in one hand but some may consider it a tad on the large size to be considered portable as you would need a fairly substantial mount for it (ideally EQ5). This would require a couple of trips to the house where as a 6" to 8" dob could probably be done in one. The larger and faster optics means CA will be more evident over your previous smaller slower scope. I had an EV120 and it performed reasonably well on DSO and the false colour really wasn't that bad on the moon. BUT given the choice between a 4.75" achromatic refractor and 6"-8" false colour free dob the dob would win hands down. BUT I am comfortable with collimating scopes where as some people consider this as an impossible task. I understand this is straying from the question at hand but given that you will only be gaining 3/4 of an inch and more pronounced CA you may want to consider other options. Another one being a Skymax 127 which will give similar diffraction free views to the frak but colour free views like the dob. A MAK is not the best on DSO's due to it's long FL but it is forgiving on eyepieces and gives some views of pinpoint stars and holds collimation superbly.

[beatlejuice]

Chris, The omni 120 works just fine on the cg4 mount. I am not sure how it would be for AP but for visual I have found the cg4 to be quite a nice working mount. I added an Orion (US) single axis drive which also works quite well.(FLO has the same item) The problem could be (wasn't for me because it was part of my plan) with upgrades you may want to make for the scope itself.

-2 inch diagonal

-9x50 finder (which I already had from another scope)

-Baader semi-apo filter which works great

-Orion(US) accufocus for smooth non-touch focusing.

The other 120 models may have a better diagonal and finder already with the package they sell, so consider that as well. As I said, I am quite happy with my setup but also ended up paying a fair amount on my upgrades.

Eric

[casemonster]

Some will argue there is a difference in the coatings between the XLT120 & EVO120 but even if there was I doubt very much it would be obvious to the naked eye. I would not say the 120 is a big scope but neither is it small. What I mean is it is easily manageable in one hand but some may consider it a tad on the large size to be considered portable as you would need a fairly substantial mount for it (ideally EQ5). This would require a couple of trips to the house where as a 6" to 8" dob could probably be done in one. The larger and faster optics means CA will be more evident over your previous smaller slower scope. I had an EV120 and it performed reasonably well on DSO and the false colour really wasn't that bad on the moon. BUT given the choice between a 4.75" achromatic refractor and 6"-8" false colour free dob the dob would win hands down. BUT I am comfortable with collimating scopes where as some people consider this as an impossible task. I understand this is straying from the question at hand but given that you will only be gaining 3/4 of an inch and more pronounced CA you may want to consider other options. Another one being a Skymax 127 which will give similar diffraction free views to the frak but colour free views like the dob. A MAK is not the best on DSO's due to it's long FL but it is forgiving on eyepieces and gives some views of pinpoint stars and holds collimation superbly.

Thanks Spaceboy,

I would not know where to start when comlimating a mirror which has deterred me from them. I understand that they can go out on a whim and when I want to go out to a dark sky site, I don't want to spend the first 30 minutes in light setting it up after the journey and then another 30 minutes waiting for my eyes to dark adapt. If I were to get one I would go for a 12" but really don't have the money for a 12 or 14" dob and I would lose portability. I am certian that the refractor will not be my only other scope and it time, I will get a large base scope when finances allow.

Not being blinkered so could you tell me who makes the skymax 127 and how much they go for?

Cheers Chris

[Nadeem Shah]

Even thought they are both manufactured under Synta, I have found the quality control a lot better on celestron scopes then skywatcher, even on the cheaper end of scopes.

[casemonster]

Chris, The omni 120 works just fine on the cg4 mount. I am not sure how it would be for AP but for visual I have found the cg4 to be quite a nice working mount. I added an Orion (US) single axis drive which also works quite well.(FLO has the same item) The problem could be (wasn't for me because it was part of my plan) with upgrades you may want to make for the scope itself.

-2 inch diagonal

-9x50 finder (which I already had from another scope)

-Baader semi-apo filter which works great

-Orion(US) accufocus for smooth non-touch focusing.

The other 120 models may have a better diagonal and finder already with the package they sell, so consider that as well. As I said, I am quite happy with my setup but also ended up paying a fair amount on my upgrades.

Eric

Thanks Eric,

I am pleased I can speak to someone who has one. Sorry if this sounds a bit daft but what are the differences between a 1.25" star diagonal and a 2" I assume I would need to upgrade my 1.25 EP's too but what are the advantages.

Did you find the original finder scope poor? Is it fully adjustable? i do have a another finder scope that is adjustable suspended in two rings but not sure how it would mount on the scope as it is screwed into the tube of my old 4" refrac.

what does the filter do (assume it helps the CA) and how much was that mod?

I will leave the AF alone for the moment as that sounds expensive?

may go for a drive but agian that would have to wait until finances allow.

Thanks

Chris

[newman]

I own an Evostar 120 and am pretty happy with it. Like John said, on an EQ-3 class mount it is a bit undermounted, but on the EQ-5 which is what you seem to be aiming for it's perfectly fine. I'm using mine on EQ-5 having upgraded from the EQ-3, and it's been rock solid since. Optics wise, it surprised me at how well this thing handles DSOs. OK, it's no light bucket, but the views of objects it does see have been pleasing indeed - put a quality eyepiece in the focuser and you'll see that this underappreciated type of a telescope does have some mileage in it

Of course, being an achromat, it does show some CA on the Moon and planets. I found it more than tolerable on the moon, especially since I only really see it on the edges, so when I get lost in high mags on crater hopping it's a non-issue. The CA does get a bit more obtrusive on higher mags with planets, so I've prefered to stay well below 200x for targets like Jupiter; I prefer a sharp smaller image over a blurry larger one.

As far as I know, optically it's the same as the Celestron XLT, main lenses being manufactured in the same factory. Some people expressed dissatisfaction with it's focuser, but I may have lucked out and got a decent one because I honestly never even had a need to re-grease it; it's no feathertouch, but it does work good enough for visual for me. The only real drawback I've found was the lack of a compression ring in the focuser; the retaining screw bores directly into your eyepiece/diagonal barrel, potentially scratching it. Optically it doesn't matter, but I have yet to meet an amateur astronomer who doesn't care whether his gear gets scratched or not. Focusers without compression rings ought to be against some law - they really need to disappear from the market, nobody's going to miss them.

[beatlejuice]

Chris, The 2 inch diagonal allows you to use 2 inch eyepieces as well as 1 1/4. Most 2 inch diagonals come with an adapter that allows this.

The original 6x30 finder is fine and fully adjustable but since I already had a 9x50 right angle correct image (RACI) finder on my XT10 it was a no brainer to just use it. Used in conjunction with a Telrad it is so much easier on my back.

The Semi-Apo filter helps with CA and is also useful as a general purpose planetary filter. I have the 2 inch model and it screws into the diagonal so switching eyepieces is not a hassle. (about $150)

The Accufocus and RA drive are about $80-$90 each

Eric

[casemonster]

I own an Evostar 120 and am pretty happy with it. Like John said, on an EQ-3 class mount it is a bit undermounted, but on the EQ-5 which is what you seem to be aiming for it's perfectly fine. I'm using mine on EQ-5 having upgraded from the EQ-3, and it's been rock solid since. Optics wise, it surprised me at how well this thing handles DSOs. OK, it's no light bucket, but the views of objects it does see have been pleasing indeed - put a quality eyepiece in the focuser and you'll see that this underappreciated type of a telescope does have some mileage in it

Of course, being an achromat, it does show some CA on the Moon and planets. I found it more than tolerable on the moon, especially since I only really see it on the edges, so when I get lost in high mags on crater hopping it's a non-issue. The CA does get a bit more obtrusive on higher mags with planets, so I've prefered to stay well below 200x for targets like Jupiter; I prefer a sharp smaller image over a blurry larger one.

As far as I know, optically it's the same as the Celestron XLT, main lenses being manufactured in the same factory. Some people expressed dissatisfaction with it's focuser, but I may have lucked out and got a decent one because I honestly never even had a need to re-grease it; it's no feathertouch, but it does work good enough for visual for me. The only real drawback I've found was the lack of a compression ring in the focuser; the retaining screw bores directly into your eyepiece/diagonal barrel, potentially scratching it. Optically it doesn't matter, but I have yet to meet an amateur astronomer who doesn't care whether his gear gets scratched or not. Focusers without compression rings ought to be against some law - they really need to disappear from the market, nobody's going to miss them.

Hi Newman,

Super job on the review, always good to hear that others like this scope. I am a big fan of the refractor despite the CA. I was a little worried that I would not be able to do much DSO observing but noting that it isn't a light bucket will not put me off, so long as I can see the things, which from your mini review indicates I will. The extra size over my 4" will bring in more light. I am planning on joining our local Astronomy Society so it seems I would have access to 12" mirrors some other scopes and a 10" Refrac! So I would not really be missing out with my home scope.

Eric,

Thanks for the advice on the filters, diagonal and drives. I may be tempted to upgrade with these mods and they will all work if in a few years I go for a 150mm!!!

Many thanks

Chris

[ollypenrice]

I've had one of these and also still have an old 6 inch version. They are not bad at all but the EQ5 would be the minimum for me. I had it on a 3 and found it marginal. These achromats are useless for DS imaging, however, because they are not colour corrected into the short blue wavelengths.

However, I think you are mistaken in thinking it would take less setting up than a Dob. I think it would take more. By the time you have set up the tripod, fitted the counterweights, balanced and then polar aligned the EQ the Dob would have been collimated and running for ten minutes or more. You don't collimate Newtonians every five minutes! I usually laser collimate our 20 inch every night. It takes about two minutes. However, if it's a quickie night and I don't bother it isn't the end of the world.

Olly

[newman]

Regarding DSOs, a few experiences with this scope;

- Star Clusters tend to make very pleasing targets. Things like the double cluster, M13, or my favorite, the M11 Wild Duck cluster all make for stunning views.

- Galaxies tend to be faint smudges in most cases. M31 does show some nice detail under dark skies, otherwise it's your standard faint but large blob. I was able to just make out the two main shapes of the whirlpool galaxy under dark skies.

- Nebulas.. depends on which. Certain planetaries look great; the ring nebula shows a clearly defined ring, M42 looks incredibly good as always. Dumbbell nebula resembles a small puff of smoke, it would seem this one is kind of fiddly on sky conditions; I could swear I was able to clearly resolve it's edges the first time I saw it, under very dark skies and with excellent seeing. Things like the Crab Nebula I was barely able to see, but M1 was definitely there if very, very faint. Note that these are all unfiltered views, I need to retry some of these with a UHC filter.

[spaceboy]

Not being blinkered so could you tell me who makes the skymax 127 and how much they go for?

Cheers Chris

Sorry for the delay First Light Optics - Maksutov TELESCOPE SUPPLIERS - SKY-WATCHER TELESCOPE

Cool down time can be a little long on them and you will need an optional dewshield or dew heater but for there size MAK's pack a hefty punch and give some superb planetary images as proven by one of SGL's members Stargazers Lounge - bigal1's Album: Astro pics

They almost never require collimation and stars are some of the sharpest you will ever experience. No issues with false colour and they are very compact making them a perfect grab and go. On the down side they are very slow scopes so no wide field DSO viewing. They for there small aperture work well on a lot of the smaller brighter DSO's but they are more suited to planetary observing/ imaging. As with any scope the mount plays a big part so choose wisely. Most budget EP's work well in the Skymax and as it is such a high focal ratio you often only need use longer focal length EP's meaning the eye relief is as a rule more comfortable.

Just for the record.....If your budget had been larger I would have no hesitation recommending an ED refractor. The EVO120 achromatic is a very nice scope but you may find CA will rob you of some detail on brighter planets and it will almost certainly make imaging more difficult.

HTH

[casemonster]

I've had one of these and also still have an old 6 inch version. They are not bad at all but the EQ5 would be the minimum for me. I had it on a 3 and found it marginal. These achromats are useless for DS imaging, however, because they are not colour corrected into the short blue wavelengths.

However, I think you are mistaken in thinking it would take less setting up than a Dob. I think it would take more. By the time you have set up the tripod, fitted the counterweights, balanced and then polar aligned the EQ the Dob would have been collimated and running for ten minutes or more. You don't collimate Newtonians every five minutes! I usually laser collimate our 20 inch every night. It takes about two minutes. However, if it's a quickie night and I don't bother it isn't the end of the world.

Olly

Hello Olly, was going for the eq5 or cg4 mount. reviews tend to suggest that the eq3 is too wobbly!

Ok, understood re the dob. This was just my impression and I am sure that I will learn to collimate one in a few years time but for now want the ease of a constructed point and look scope. I have enough to learn without worrying about faffing around with a laser at this stage but thanks for putting me straight.

regards

Chris

[casemonster]

Regarding DSOs, a few experiences with this scope;

- Star Clusters tend to make very pleasing targets. Things like the double cluster, M13, or my favorite, the M11 Wild Duck cluster all make for stunning views.

- Galaxies tend to be faint smudges in most cases. M31 does show some nice detail under dark skies, otherwise it's your standard faint but large blob. I was able to just make out the two main shapes of the whirlpool galaxy under dark skies.

- Nebulas.. depends on which. Certain planetaries look great; the ring nebula shows a clearly defined ring, M42 looks incredibly good as always. Dumbbell nebula resembles a small puff of smoke, it would seem this one is kind of fiddly on sky conditions; I could swear I was able to clearly resolve it's edges the first time I saw it, under very dark skies and with excellent seeing. Things like the Crab Nebula I was barely able to see, but M1 was definitely there if very, very faint. Note that these are all unfiltered views, I need to retry some of these with a UHC filter.

I still have a month or to go before I buy the scope for myself as a birthday present, hopefully before the BBC do thier Stargazing live program and they all sell out!!

Would like to know what difference the UHC filter makes to the images. BTW what EP's do you have. What do you use for planets, clusters, galaxies and nebulae?

[casemonster]

Hi Spaceboy Thanks for the info. Just had at look at the photo's and the prices but with an eq5 may be outside of my price range.

Imaging is not really a big concern but may be in a few years time when I know my way around the sky. No denying it though I was impressed. quite a long focal length though and possibly too slow for the moment. I think my current beast is something like f12-16 with a 1600 focal length and I do find the very faint view irratating. I guess I would like to to pulling in as much light as my 12x50 bins but assume this isn't possible.

In the ideal world I would have three scopes (Will keep my old dinosaur 4" refractor) the 120 evo star/Omni xlt, a 12 dob and one of these Maks. All i need to do is win the lottery. Like I said I hope to have the opportunity to use other scopes, the club own a few and I dare say there would be a few member owned pieces of kit to look through so I would not be restricted to one scope only.

Thanks for all the advice and the time taken to post it up.

Cheers

Chris

[newman]

Would like to know what difference the UHC filter makes to the images. BTW what EP's do you have. What do you use for planets, clusters, galaxies and nebulae?

I have yet to try an UHC with this scope, I'm still in the process of building up my eyepiece collection. I started off with the standard 25 & 10mm and used them for a while. Then I got a Kasai Ortho 12.5mm (80x mag in that scope) and used it with a 2.5x GSO apo barlow to get 200x. The unbarlowed kasai gave excellent views and blew both standard eyepieces that came with the scope right out of the water. I found that I need really, really great seeing to get satisfactory views through the barlow at 200x. So much so I'm now considering just selling the barlow and the ortho, I probably made a mistake when I got the 2.5x and not a 2x.

Be that as it may, soon afterwards I lucked out and actually landed a job with a decent paycheck at the end of each month, so I figured - this won't be the last scope I ever get, but I would kind of like to buy my eyepieces once, and so I decided to build a minimalistic but premium quality collection. I started with a 17mm Ethos, any comment on it's performance is probably not necessary. I had a chance to use it for a few months now and the views it gives me are second to none. Since I am contemplating on getting a 10" or 12" flextube fast dob to keep at an observing site I spend my vacations at, this ep will be useful in more ways than one. It gives me a beautiful 1.7 degrees of true field / 2 mm exit pupil at roughly 59x magnification with my current scope, which is enough to frame most of the Pleiades, for instance. It works great both as a finder and a low power DSO eyepiece. That plus the Telrad means I no longer even mount my 9x50 finderscope as I tend not to use it.

Then I followed that up by ordering a 10mm Ethos which actually arrived yesterday. Weather's pretty horrible over here right now - which is to be expected and is really my fault; ordering the Ethos has that effect. Future plans involve buying a 6mm Delos for my safe bet high mag eyepiece. I might get a 5mm Pentax XW when I get that dob or replace this scope with an apo some time in the future. But for now, there's still mileage left in the good old achromat. Not sure what to tell you about eyepiece recommendations, because I've found myself spoiled by the Ethos experience, and I fully realize they're way too expensive for most folks to consider. I kind of lucked out financially over the past year, plus if I was married with children I'd probably never buy one, let alone two

[FLO]

I used to own an Evostar-120 and liked it very much. It is an achromat, of course, so there will be some colour fringing around brighter objects. I never used to find it obtrusive but then I used it only for visual. There is something special about a longish 5-inch refractor, it works well for so many targets. Coincidentally I have the Celestron version in the back of my car, I wanted something for my eldest Son and thought it'd be perfect. Quick to set up, low maintenance and nice views.

As for the difference between Celestron and Skywatcher, one of the Celestron's lens elements has an aspheric surface. An aspheric lens surface in a refactor is similar to a hyperbolic surface on a Newtonian mirror. They both reduce aberrations. I don't know whether it makes a big difference as I haven't put them side-by-side. I doubt the difference would be significant. My main reason for choosing the Celestron is it looks more 'cool', which for an eight-year-old is important, and the Celestron CG-4 mount is higher specified than the Skywatcher EQ3 (Ball bearings in both axis and larger diameter tripod legs).

HTH,

Steve

[spaceboy]

If I am honest Chris I think you are letting the idea of collimation get the best of you. Reading through the thread again I can't help but think your interest is in DSO and if this is the case there is no real substitute for aperture. Due to the cost of larger refractors and increase in CA this often means a newt is the most obvious choice. Also if you are getting better views through the bins than the frak there is a problem some where.

[casemonster]

I used to own an Evostar-120 and liked it very much. It is an achromat, of course, so there will be some colour fringing around brighter objects. I never used to find it obtrusive but then I used it only for visual. There is something special about a longish 5-inch refractor, it works well for so many targets. Coincidentally I have the Celestron version in the back of my car, I wanted something for my eldest Son and thought it'd be perfect. Quick to set up, low maintenance and nice views.

As for the difference between Celestron and Skywatcher, one of the Celestron's lens elements has an aspheric surface. An aspheric lens surface in a refactor is similar to a hyperbolic surface on a Newtonian mirror. They both reduce aberrations. I don't know whether it makes a big difference as I haven't put them side-by-side. I doubt the difference would be significant. My main reason for choosing the Celestron is it looks more 'cool', which for an eight-year-old is important, and the Celestron CG-4 mount is higher specified than the Skywatcher EQ3 (Ball bearings in both axis and larger diameter tripod legs).

HTH,

Steve

Hi Steve,

Thank you for the information Steve, Thought as much. Will be buying the celestron then

[casemonster]

Hi all,

Newman,

Thanks for the info on the Ep's I will probably go for a 2xBarlow as well and I could do with a decent 20 or 24mm EP and a better 12mm but I have to say, that I really don't know how much you spent on yours but it does sound like a lot!! As you say, your scope may change but you will keep your EPs for life.

I am a keen photographer and know that a camera is only as good as the glass you attach to it and I guess this is the same with EP's too. BTW I have no intention of doing imaging at this moment in time, I want to spend a while getting used to the sky which will take a good few years, there really is so much out there to look at. There is so much background information to digest on each constellation, planets and moons and DSO's I am guessing I will want to upgrade in the next three to five years. I have to be honest and say I like the idea of having a good all round scope and like using fracs.

I have the Wife & two kids who seem to get more expensive as they get older so I'm into moderately priced ep's that work well but these may be upgraded in time. I have the balance of my lifetime to enjoy this hobby so there is no rush.

Spaceboy,

Ok I admit it, I have no idea how to collimate and yes I am probably worrying about it too much

If I am honest I have an interest in everything, but I don't think anyone can look outside of our galaxy without being blown away by what you are seeing. I found M81 last night which was a reasonable view in the scope when used at 20mm but higher magnification didn't help. It still remained a fuzzy blob in black and white and it would, I guess, still be a fuzzy blob in a newt as well. it doesn't take away the wow factor.

As I said the frac I have is old and with the longer focal length it is very slow and although it is quite good with the brighter objects, the quality isn't good at higher Magnification, stars show as small lines but Jupiter is a nice sight as is Saturn. So for bright objects and low mag it does well but being so slow, the light coming in isn't good.....don't forget, I did only pay £30 at a boot fair for this enormously long but limited aperture scope. I can't complain really!!

I really think the idea should be for me to Join our local astronomical society and have alook through thier scopes and see if my choice of the 5" frac as my next scope is correct. I still have a few months!

Kind regards to all

Chris