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Orion AstroView 120ST - a beginner's review

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#1 cpuoverclocker64

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Posted 10 November 2014 - 11:53 PM

So, after a long hiatus when I was living abroad, I decided to recently get back into astronomy. Years ago, I had an f/5 150mm Orion Newtonian reflector on an EQ mount. There were many things I liked about that and wanted to start off with something similar again...

So I got to thinking - and mathing... and I wondered if the 150mm reflector was all that brighter than the 120mm refractor that is also now offered. After crunching several numbers, considering average reflectivity of mirrors, the fact that there are two of them, and the fact that fast reflectors have a considerable amount of blockage by their secondary... I came to the conclusion that the light gathering potential would be virtually identical.

So it would be easier to carry, more compact and robust, has a 2" focuser just begging for some astrophotography... the 120ST was sounding like a good idea. So I bought it.

 

And then it was cloudy for a week. Of course. Anyway, begin review by the beginner.

 

First I will start with the mount and tripod - it is a EQ mount with polar alignment scope. It's reasonably stable although one's opinion of it will greatly depend on where they are coming from. To someone who has only dealt with "toys", it's going to really introduce someone to a real mount. If I had a complaint, it's more with the tripod. The tripod feels a wee bit shaky and I would say its quality does not match the mount. Overall, for the price though, it isn't bad.

Moving on to the OTA

 

The tube itself has a feeling of quality to me, quite substantial. The cylindrical areas of the tube are a black enamal coated metal and the transitions are graphite wrinkle paint. Overall, I feel that it is a tasteful job and has a professional look to it. Between the short fat tube, respectable aperture, EQ mount, and dark paint, this refractor looks like it means business. High marks for appearance.
 

To the mechanicals – the focuser is a 2” rack and pinion. I am pleased they decided to go with this size, as will many people who want to use this scope for photography. There was no backlash or harshness on my focuser at all, but it was quite stiff which can make precise focusing tricky. One can easily overshoot because of the heft it takes. Upgrading the focuser would be a good idea for some, but, once again, considering the price I think it is a reasonable unit.

The dew shield is integrated into the OTA and cannot be removed. On the plus side, there is a mildly rough surface with a dark flat black coating on the inside of the dew shield. This should reward one with both better contrast and some improved dew protection.

The lens itself has some sort of multicoating that appears violet in some light and green at other angles. It is a doublet so there will be some chromatic aberration present… we will get into how much in a bit.

 

Let’s get to the views! With three hours of clear skies and average seeing conditions, I thought I’d see what this is all about. I will only be reviewing the telescope with equipment that ships with it, just to be fair.

 

First light – The Double Cluster in Perseus. Easy to find and beautiful even to guests that wouldn’t consider this their hobby, I’ve always thought this is a great one to show people… and the results are great through this scope! With the 25mm eyepiece, I can clearly see the majority of the blue-white stars, with a few orange spattered in as well. Each star is as sharp as I’ve ever seen through a telescope, although this is my first time ever using a “real” refractor. While the overall view as far as brightness and field of view go are more or less identical to my old Newtonian (as math would support), the refractor’s sharpness and, despite fairly light polluted skies in unfavorable conditions, contrast, absolutely trump the Newtonian. First view, and now I finally understand the hype.

No CA whatsoever, but we wouldn’t expect that on this type of object, nor at this magnification.

 

Next object was the Pleiades. Overall, I can report a similar experience. Brightness was more or less identical to the Newtonian, but each star was so much sharper. By this time, I’m feeling pretty hyped. My favorite things to observe before were DSOs and this scope was really showing some real potential there.

Just as before, I saw no false color whatsoever at either 25 or 10 mm. This shouldn’t be *too* surprising, although these stars may be bright enough to provoke CA in very low quality scopes.

 

By this time, clouds are starting to roll in and I feel it may be time to get on with a real test to determine the amount of CA. The moon has cleared the tree line so I adjust and look at that. With the 25mm, the view is as sharp as I could expect given the circumstances, but rapidly deteriorating seeing conditions are making this test challenging. Still, at 25mm I am not detecting any noticeable false color. I change over to the 10mm and take a look. The moon now covers most of the view. Out of focus, I can see violet and yellowish arcs offsetting each other, but they fade to reasonable levels when proper focus is achieved. While looking at the moon with the 10mm is showing a tiny fringe around the border, it is not even close to bad enough to obscure the view. To anyone familiar with photography, this would be easily rectified in Lightroom if one could be bothered.

 

Curious to how much of an effect it would make, I place the lens cap with the center cap removed to stop down the telescope. The results are, from my point of view, probably around a 70% reduction in CA (that wasn’t that bad in the first place). While I cannot see any ill effects at this magnification, it bears mentioning that under greater magnification, stopping down a telescope this much will lower its resolution. Try it out, see what works.

 

Cloud cover now is moving over the moon and the seeing conditions have deteriorated from not so good to absolute crap. I pack it up and head in.

 

So, what is my conclusion? Well, I’ve heard people all over the board about the CA with these scopes and decided to take a gamble and buy it. I am completely pleased. It has exceeded my expectations quite a bit. If I were doing high magnification planetary viewing, I may have stuck with the Newtonian or gone with the similar package deal with the cat, but for what I mostly use it for, this cannot be beat.

This is my first impression with a moderately sized refractor (as opposed to the crap kids have) and I'm absolutely loving this so far. Just to pick hairs, what would I change?

The tripod could be more secure, the focuser isn't really a pleasure to use, the polar alignment scope isn't as high quality as the one my Newtonian had, and a removable dew shield might have been nice.|

My first upgrade will certainly be a motor drive though so I can get into astrophotography.

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#2 Mark Harry

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Posted 11 November 2014 - 05:56 AM

Nice review. I bought an OTA of this scope, and your experiences are on par with mine. The homemade mount I have is a boat anchor, and needs to be totally reworked.

I can add, with a 2" correct image diagonal using a 40mm  eyepiece at around 15x, I can see the 4 Trap stars sharp as a tack. Spectacular wide field view. As you said, it was easy on the wallet!

  Glad the clouds cleared out for you.
Enjoy,
M.



#3 BarrySimon615

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Posted 11 November 2014 - 09:16 AM

I am curious about something you said in your first post - "The dew shield is integrated into the OTA and cannot be removed.".  

 

I have the same optical tube assembly, I have actually had it twice.  The first one dated from approximately 12 to 14 years ago and was gloss black in color and the current one is a more recent version being approximately 5 years old.  This one has a very dark gray metal flake gloss color.  On both the objective cell will unscrew from the main tube and the dewshield, itself, is a tight friction fit on the objective cell.  I think this is done as it is likely that the "Orion" wording on the dewshield can be properly lined up with the tube.  Also makes it easier to shorten the tube for transport if space is a consideration.

 

One suggestion - in your photo the way you have your camera and telephoto lens mounted invites flexure and rotation of the whole camera/telephoto lens (as the connecting 1/4-20 screw will have pressure put on it to either tighten further or loosen.  I would make a connecting bar between the two rings as a platform for cameras.  This will also serve as a nice carrying handle for the scope and it will greatly (and safely) help you in connecting the scope to the mount. The photo I have attached will help to illustrate what I am talking about.  It shows a heavy Pentax67 camera and telephoto lens mounted on a bar with the front end of the telephoto lens stabilized by a ring.  Attaching a similar setup (bottom bar) to either another bar that already bridges between your two tube rings or direct connected to your tube rings is far more stable than the setup that your picture shows.  The front ring around the telephoto lens will stop tightening or derotation of the camera and will also stop up and down sway.

 

Overall the Orion ST120 is a popular and reasonably priced scope with good aperture and an easily transported rich field performer.  I think it just may now hold the record for being in the Orion catalog longer than any other scope, at least among refractors.

 

Barry Simon

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#4 cpuoverclocker64

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Posted 11 November 2014 - 09:44 AM

Thank you for the advice. I actually was using my 50mm prime because of the issues you talked about. Even the shutter raising and lowering was enough to cause blur and vibration with that unstable mounting.

I've seen two different versions of this scope on Orion's website - the black one including the mount and tripod, and the metallic dark gray one sold as an OTA. Perhaps there are some slight manufacturing differences, but I will examine it in further detail when I get home from work.

I initially thought my first purchase would be a fringe-killer or semi-apo filter, but based on my usual observing and the fact that this scope is performing far better than I initially expected it to, I feel I can go ahead and move on to other things - a kit of eyepieces and perhaps a 2" wide field if I can find one inexpensively. I've already found a compatible micro four thirds 2" T-ring so whenever that comes in, I'll see if it threads in nicely.

Most importantly will be the motor drive and mounting hardware for my camera and lenses when I piggyback. I'm just now getting into this so some flexibility will pay off I think.

I'm always up for advice on how to properly set up the drive for better photography. Any advice about setups using the mount I have that work would be appreciated.



#5 seasparky89

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Posted 11 November 2014 - 09:46 AM

Nice review.  I have had my ST-120 (OTA) for about 4 years now, and still enjoy it for the wide field and bright views it provides.  Immediately after I purchased the scope, I installed a ScopeStuff two-speed Crayford focuser.  It literally transformed the scope in a very positive sense.  IMHO, it's the single best thing you can do for the ST-120.  Other improvements include occasional use of a Sirus MV-20 CA filter for those times I want to use higher powers.  I normally mount the scope on either a Gibraltar for quick peeks or a SkyView Pro for longer sessions.  There are improvements you can make to your tripod - even hanging a 10 lb weight from the center of the mount hub will help to stabilize the system!  Good luck with your scope.

 

Stan



#6 Vondragonnoggin

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Posted 11 November 2014 - 10:06 AM

Nice review. Glad to read when someone gets a pleasant surprise using these and does not drone on and on about CA.

 

I have the Skywatcher version. The dew shield is removable on that one, but I never take it off. 

 

Two things you mentioned - focuser action and wobbly tripod.

 

I replaced my focuser because I had a need for a heavy duty one that would support 3+ lbs of gear hanging off it, but there are a lot of threads on how to rework the stock focuser. PM Jon Isaacs on it if you can't find a thread with info. They appear to be very usable after a simple rework (using better grease and adjusting a few things I think). I never even tried mine. I had Markus from APM throw the heavy duty linear bearing focuser on at purchase before they shipped it.

 

I also just bought an OTA and use mine on a 40 lb capacity geared center column photo tripod with a 25lb capacity fluid head equipped with a Berlebach Vixen style clamp. No shakiness in the mounting on mine.

 

Just listed it in the thread on Equipment forum for top 5 astronomy purchases. It is Goldilocks size and weight. Just right for grab n go.

 

I hope you get years of enjoyment out of it. I like the one you have the best out of all the ST120's because of the solid black finish with Orion logo. Very nice looking scope too. 



#7 LDW47

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Posted 11 November 2014 - 10:33 AM

So, after a long hiatus when I was living abroad, I decided to recently get back into astronomy. Years ago, I had an f/5 150mm Orion Newtonian reflector on an EQ mount. There were many things I liked about that and wanted to start off with something similar again...

So I got to thinking - and mathing... and I wondered if the 150mm reflector was all that brighter than the 120mm refractor that is also now offered. After crunching several numbers, considering average reflectivity of mirrors, the fact that there are two of them, and the fact that fast reflectors have a considerable amount of blockage by their secondary... I came to the conclusion that the light gathering potential would be virtually identical.

So it would be easier to carry, more compact and robust, has a 2" focuser just begging for some astrophotography... the 120ST was sounding like a good idea. So I bought it.

 

And then it was cloudy for a week. Of course. Anyway, begin review by the beginner.

 

First I will start with the mount and tripod - it is a EQ mount with polar alignment scope. It's reasonably stable although one's opinion of it will greatly depend on where they are coming from. To someone who has only dealt with "toys", it's going to really introduce someone to a real mount. If I had a complaint, it's more with the tripod. The tripod feels a wee bit shaky and I would say its quality does not match the mount. Overall, for the price though, it isn't bad.

Moving on to the OTA

 

The tube itself has a feeling of quality to me, quite substantial. The cylindrical areas of the tube are a black enamal coated metal and the transitions are graphite wrinkle paint. Overall, I feel that it is a tasteful job and has a professional look to it. Between the short fat tube, respectable aperture, EQ mount, and dark paint, this refractor looks like it means business. High marks for appearance.
 

To the mechanicals – the focuser is a 2” rack and pinion. I am pleased they decided to go with this size, as will many people who want to use this scope for photography. There was no backlash or harshness on my focuser at all, but it was quite stiff which can make precise focusing tricky. One can easily overshoot because of the heft it takes. Upgrading the focuser would be a good idea for some, but, once again, considering the price I think it is a reasonable unit.

The dew shield is integrated into the OTA and cannot be removed. On the plus side, there is a mildly rough surface with a dark flat black coating on the inside of the dew shield. This should reward one with both better contrast and some improved dew protection.

The lens itself has some sort of multicoating that appears violet in some light and green at other angles. It is a doublet so there will be some chromatic aberration present… we will get into how much in a bit.

 

Let’s get to the views! With three hours of clear skies and average seeing conditions, I thought I’d see what this is all about. I will only be reviewing the telescope with equipment that ships with it, just to be fair.

 

First light – The Double Cluster in Perseus. Easy to find and beautiful even to guests that wouldn’t consider this their hobby, I’ve always thought this is a great one to show people… and the results are great through this scope! With the 25mm eyepiece, I can clearly see the majority of the blue-white stars, with a few orange spattered in as well. Each star is as sharp as I’ve ever seen through a telescope, although this is my first time ever using a “real” refractor. While the overall view as far as brightness and field of view go are more or less identical to my old Newtonian (as math would support), the refractor’s sharpness and, despite fairly light polluted skies in unfavorable conditions, contrast, absolutely trump the Newtonian. First view, and now I finally understand the hype.

No CA whatsoever, but we wouldn’t expect that on this type of object, nor at this magnification.

 

Next object was the Pleiades. Overall, I can report a similar experience. Brightness was more or less identical to the Newtonian, but each star was so much sharper. By this time, I’m feeling pretty hyped. My favorite things to observe before were DSOs and this scope was really showing some real potential there.

Just as before, I saw no false color whatsoever at either 25 or 10 mm. This shouldn’t be *too* surprising, although these stars may be bright enough to provoke CA in very low quality scopes.

 

By this time, clouds are starting to roll in and I feel it may be time to get on with a real test to determine the amount of CA. The moon has cleared the tree line so I adjust and look at that. With the 25mm, the view is as sharp as I could expect given the circumstances, but rapidly deteriorating seeing conditions are making this test challenging. Still, at 25mm I am not detecting any noticeable false color. I change over to the 10mm and take a look. The moon now covers most of the view. Out of focus, I can see violet and yellowish arcs offsetting each other, but they fade to reasonable levels when proper focus is achieved. While looking at the moon with the 10mm is showing a tiny fringe around the border, it is not even close to bad enough to obscure the view. To anyone familiar with photography, this would be easily rectified in Lightroom if one could be bothered.

 

Curious to how much of an effect it would make, I place the lens cap with the center cap removed to stop down the telescope. The results are, from my point of view, probably around a 70% reduction in CA (that wasn’t that bad in the first place). While I cannot see any ill effects at this magnification, it bears mentioning that under greater magnification, stopping down a telescope this much will lower its resolution. Try it out, see what works.

 

Cloud cover now is moving over the moon and the seeing conditions have deteriorated from not so good to absolute ****. I pack it up and head in.

 

So, what is my conclusion? Well, I’ve heard people all over the board about the CA with these scopes and decided to take a gamble and buy it. I am completely pleased. It has exceeded my expectations quite a bit. If I were doing high magnification planetary viewing, I may have stuck with the Newtonian or gone with the similar package deal with the cat, but for what I mostly use it for, this cannot be beat.

This is my first impression with a moderately sized refractor (as opposed to the **** kids have) and I'm absolutely loving this so far. Just to pick hairs, what would I change?

The tripod could be more secure, the focuser isn't really a pleasure to use, the polar alignment scope isn't as high quality as the one my Newtonian had, and a removable dew shield might have been nice.|

My first upgrade will certainly be a motor drive though so I can get into astrophotography.

I have three ST refrac incl the Sky Watcher version of your scope and the CA is almost unnoticeable in all of them, a heck of a lot less than many profess. One big change I made with mine is that I replaced the R&P with a GSO two speed Crayford from Agena Astro for about $150 and it performs great, an excellent upgrade. I also purchased three 2", low power, wide field 70° ep's a great addition to what will be a large stable of ep's you will acquire if you are anything like most of us. Just a few comments as many others will feed you their thoughts / recs before it is all over. An excellent first report and you will enjoy that scope for what it is meant, low power, wide field viewing as to quality AP other experienced photogs will have to give you their thoughts !  Clear Skies to you !


Edited by LDW47, 11 November 2014 - 10:35 AM.


#8 BarrySimon615

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Posted 11 November 2014 - 10:49 AM

Here is mine at the 2013 Deep South Regional Star Gaze.  The Celestron CG4 is a very compatible and affordable mount for this scope.

 

Barry Simon

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#9 cpuoverclocker64

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Posted 11 November 2014 - 10:50 AM

Yes, I noticed that the grease used in the rack is more of some sort of sticky goop than something with actual lubercating properties. While I'm sure that the very high viscosity does help reduce backlash, it doesn't have a very delicate actuation. I was considering tearing it apart, cleaning it up, and using moly engine assembly lube in there, but if others have already played with this, I'm totally willing to learn! Time to scour the forums.

I also noticed the declination had quite a bit of play in it and it was frusterating me... not that I would expect otherwise at this price point, but if it can be improved, I'd take a stab at it... and I came up with sort of a fix. Of course try this at your own risk, I'm not responsible if you break it.

There is a pair of bolts that hold the top of the mount together, one under the scope and one in the cavity where the polar alignment scope hides. I found the top bolt secures the whole thing together and the ring/dovetail mount (depending on which scope you have) to the rod, and the bottom bolt puts pressure on the bearing... so the bottom bolt determines the bearing pre-load.

I concluded that the top bolt can be tightened as much as reasonable, not breaking anything, but the bottom bolt is a balancing act. When I first got at it, I found it unreasonably loose, providing no friction whatsoever and allowing the scope to torque back and forth even with the clutch locked hard. Not thinking, I went ahead and tightened it quite a bit and was pleased with myself when the head felt rock solid when I was done... until I noticed the slow motion controls were too tight to turn! That's when I determined it is a bit of a balancing act - securing the bolt tight enough to remove the unwanted play but loose enough where the bearing can slide around fairly easily. When I have more time, I will probably remove the bearing entirely and change the lube (it seems pretty dry to me) to allow more pressure while still sliding easily.

Then I tightened all the bolts and screws that hold the tripod together. It did improve the stability a considerable amount but I will still probably replace the tripod in the near future.

I appreciate all the help and advice you guys are providing me.

Upper bolt.jpg

Lower bolt.jpg



#10 cpuoverclocker64

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Posted 11 November 2014 - 10:56 AM

BarrySimon615, I'm loving that tripod. I heard that the tubular stainless legs on that mount are more stable than the three-way aluminum ones on the Orion version. If I can find that whole mount for a reasonable price, I'd be very tempted. At the very least, I'd swap out the tripod.

If I get more scopes (you all know I will, that's how it goes hahaha), I'd also be interested in chainging the rings attached to the mount to the setup you have, with the rings attached to the dovetail and that sliding into a plate. That way, if I wanted to change over to planetary or lunar observation, I can change out quickly to a longer focal length OTA, perhaps some sort of Cassegrain.

All your ideas and pictures are going to damage my bank account lol.



#11 cpuoverclocker64

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Posted 11 November 2014 - 01:55 PM

I was thinking some people, perhaps newbies like myself, would be interested in the image quality they *might* be able to expect from this tube so I wanted to get some shots through it. It's daytime... and raining... so of course it won't be anything astronomical (pun totally intended)... Anyway, here's a shot I took of my backyard.

Now, I don't have a t-ring so first I tried to do it by taking a picture of the eyepiece (afocal projection?) but that turned out like crap... so I took a risk, took off my lens, stuffed the camera down the focuser while clamping onto my m43 to MD adapter and got a prime focus shot. Ignore the left side vignetting, the camera was a bit crooked. This is far from ideal, after all.

As you can see, there is some purple under semi-bright daytime lighting, but seriously, it doesn't appear that bad at prime focus. I assume it would get far worse if I used a teleconverter or something, but *personally* consider this to be completely acceptable.

As the camera position changes and the focus is adjusted, you can see the CA vary from more violet to more green. In either case, it isn't terrible.

Original_zpsb0159f73.jpg

P1080175_zpsef005a97.jpg

After this, I was curious to how much improvement could possibly be made if I fiddled around so I got out to playing in some software. In my opinion, the results look promising. Granted, since virtually all the CA is from out of focus, it might be totally irrelevant during prime focus astrophotography, but it seems that, with the help of a computer, it's not hard to clean it up.

P1080173_zpsa22c574f.jpg

Bear in mind, the camera is crooked, I'm shooting a picture through a window, and a million other non-ideal situations are going on. Sharpness through an eyepiece is considerably better, this is for color correction purposes only.

 



#12 cpuoverclocker64

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Posted 11 November 2014 - 01:57 PM

Haha the forum censorship makes it look like I've said worse things than I have. Each time I said a word that starts with c and ends with "rap". Go figure.



#13 LDW47

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Posted 11 November 2014 - 02:04 PM

Haha the forum censorship makes it look like I've said worse things than I have. Each time I said a word that starts with c and ends with "rap". Go figure.

Go figure is right, 99.9% of us on here are mature adults and our mothers / fathers have used that word for years ! It may even be in the dictionary ?  No common sense any more ?   LOL !



#14 junomike

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Posted 11 November 2014 - 02:20 PM

So, after a long hiatus when I was living abroad, I decided to recently get back into astronomy. Years ago, I had an f/5 150mm Orion Newtonian reflector on an EQ mount. There were many things I liked about that and wanted to start off with something similar again...

So I got to thinking - and mathing... and I wondered if the 150mm reflector was all that brighter than the 120mm refractor that is also now offered. After crunching several numbers, considering average reflectivity of mirrors, the fact that there are two of them, and the fact that fast reflectors have a considerable amount of blockage by their secondary... I came to the conclusion that the light gathering potential would be virtually identical.

So it would be easier to carry, more compact and robust, has a 2" focuser just begging for some astrophotography... the 120ST was sounding like a good idea. So I bought it.

 

And then it was cloudy for a week. Of course. Anyway, begin review by the beginner.

 

First I will start with the mount and tripod - it is a EQ mount with polar alignment scope. It's reasonably stable although one's opinion of it will greatly depend on where they are coming from. To someone who has only dealt with "toys", it's going to really introduce someone to a real mount. If I had a complaint, it's more with the tripod. The tripod feels a wee bit shaky and I would say its quality does not match the mount. Overall, for the price though, it isn't bad.

Moving on to the OTA

 

The tube itself has a feeling of quality to me, quite substantial. The cylindrical areas of the tube are a black enamal coated metal and the transitions are graphite wrinkle paint. Overall, I feel that it is a tasteful job and has a professional look to it. Between the short fat tube, respectable aperture, EQ mount, and dark paint, this refractor looks like it means business. High marks for appearance.
 

To the mechanicals – the focuser is a 2” rack and pinion. I am pleased they decided to go with this size, as will many people who want to use this scope for photography. There was no backlash or harshness on my focuser at all, but it was quite stiff which can make precise focusing tricky. One can easily overshoot because of the heft it takes. Upgrading the focuser would be a good idea for some, but, once again, considering the price I think it is a reasonable unit.

The dew shield is integrated into the OTA and cannot be removed. On the plus side, there is a mildly rough surface with a dark flat black coating on the inside of the dew shield. This should reward one with both better contrast and some improved dew protection.

The lens itself has some sort of multicoating that appears violet in some light and green at other angles. It is a doublet so there will be some chromatic aberration present… we will get into how much in a bit.

 

Let’s get to the views! With three hours of clear skies and average seeing conditions, I thought I’d see what this is all about. I will only be reviewing the telescope with equipment that ships with it, just to be fair.

 

First light – The Double Cluster in Perseus. Easy to find and beautiful even to guests that wouldn’t consider this their hobby, I’ve always thought this is a great one to show people… and the results are great through this scope! With the 25mm eyepiece, I can clearly see the majority of the blue-white stars, with a few orange spattered in as well. Each star is as sharp as I’ve ever seen through a telescope, although this is my first time ever using a “real” refractor. While the overall view as far as brightness and field of view go are more or less identical to my old Newtonian (as math would support), the refractor’s sharpness and, despite fairly light polluted skies in unfavorable conditions, contrast, absolutely trump the Newtonian. First view, and now I finally understand the hype.

No CA whatsoever, but we wouldn’t expect that on this type of object, nor at this magnification.

 

Next object was the Pleiades. Overall, I can report a similar experience. Brightness was more or less identical to the Newtonian, but each star was so much sharper. By this time, I’m feeling pretty hyped. My favorite things to observe before were DSOs and this scope was really showing some real potential there.

Just as before, I saw no false color whatsoever at either 25 or 10 mm. This shouldn’t be *too* surprising, although these stars may be bright enough to provoke CA in very low quality scopes.

 

By this time, clouds are starting to roll in and I feel it may be time to get on with a real test to determine the amount of CA. The moon has cleared the tree line so I adjust and look at that. With the 25mm, the view is as sharp as I could expect given the circumstances, but rapidly deteriorating seeing conditions are making this test challenging. Still, at 25mm I am not detecting any noticeable false color. I change over to the 10mm and take a look. The moon now covers most of the view. Out of focus, I can see violet and yellowish arcs offsetting each other, but they fade to reasonable levels when proper focus is achieved. While looking at the moon with the 10mm is showing a tiny fringe around the border, it is not even close to bad enough to obscure the view. To anyone familiar with photography, this would be easily rectified in Lightroom if one could be bothered.

 

Curious to how much of an effect it would make, I place the lens cap with the center cap removed to stop down the telescope. The results are, from my point of view, probably around a 70% reduction in CA (that wasn’t that bad in the first place). While I cannot see any ill effects at this magnification, it bears mentioning that under greater magnification, stopping down a telescope this much will lower its resolution. Try it out, see what works.

 

Cloud cover now is moving over the moon and the seeing conditions have deteriorated from not so good to absolute ****. I pack it up and head in.

 

So, what is my conclusion? Well, I’ve heard people all over the board about the CA with these scopes and decided to take a gamble and buy it. I am completely pleased. It has exceeded my expectations quite a bit. If I were doing high magnification planetary viewing, I may have stuck with the Newtonian or gone with the similar package deal with the cat, but for what I mostly use it for, this cannot be beat.

This is my first impression with a moderately sized refractor (as opposed to the **** kids have) and I'm absolutely loving this so far. Just to pick hairs, what would I change?

The tripod could be more secure, the focuser isn't really a pleasure to use, the polar alignment scope isn't as high quality as the one my Newtonian had, and a removable dew shield might have been nice.|

My first upgrade will certainly be a motor drive though so I can get into astrophotography.

I used a 120ST for a few years as a RFT on my NS11GPS.  I only recently sent it to a new owner as It's since been replaced with APM 100 Semi's (also piggybacked on NS11GPS).

Great scope for the money!

 

Mike

Attached Thumbnails

  • NS11GPS - 120ST.jpg

Edited by junomike, 11 November 2014 - 02:21 PM.


#15 Peter Besenbruch

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Posted 11 November 2014 - 03:29 PM

Haha the forum censorship makes it look like I've said worse things than I have. Each time I said a word that starts with c and ends with "rap". Go figure.

You could have used a different word:

 

BM, balls, baloney, bilge, blague, blah, blah-blah, bloody flux, bop, bosh, bowel movement, buffalo chips, bull, bunk, bunkum, ca-ca, cast, catharsis, claptrap, coprolite, coprolith, cow chips, cow flops, cow pats, defecate, defecation, dejection, diarrhea, dingleberry, drivel, droppings, dung, dysentery, evacuate, evacuation, eyewash, feces, feculence, flam, flapdoodle, flimflam, flux, gammon, gas, guano, guff, gup, hogwash, hoke, hokum, hooey, hot air, humbug, humbuggery, jakes, jiggery-pokery, lientery, loose bowels, malarkey, manure, moonshine, movement, natural, nick, night soil, number two, ordure, piffle, poppycock, purgation, purge, roll, rot, runs, scat, sewage, sewerage, shot, stool, throw, tommyrot, tripe, trots, ****, turistas, twaddle, void, voidance, wind

 

The above is lightly edited from a thesaurus. I've always been partial to tommyrot, myself.

 

Regarding your pictures, it's fun to play, isn't it.



#16 Peter Besenbruch

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Posted 11 November 2014 - 03:31 PM

throw, tommyrot, tripe, trots, ****, turistas, twaddle, void, voidance, wind

 

It seems I didn't edit it enough. :blush:



#17 AstroSteve

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Posted 11 November 2014 - 04:01 PM

I love mine on the Orion Versa-Go II Alt-Az mount. Did some slight improvements on the R&P Focuser and it is much smoother including upgraded focus knobs. A great scope!!!
 
 
Orion ST120 on Versa-Go II Alt-Az Mount


#18 Crow Haven

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Posted 11 November 2014 - 05:53 PM

So, after a long hiatus when I was living abroad, I decided to recently get back into astronomy. Years ago, I had an f/5 150mm Orion Newtonian reflector on an EQ mount. There were many things I liked about that and wanted to start off with something similar again...

So I got to thinking - and mathing... and I wondered if the 150mm reflector was all that brighter than the 120mm refractor that is also now offered. After crunching several numbers, considering average reflectivity of mirrors, the fact that there are two of them, and the fact that fast reflectors have a considerable amount of blockage by their secondary... I came to the conclusion that the light gathering potential would be virtually identical.

So it would be easier to carry, more compact and robust, has a 2" focuser just begging for some astrophotography... the 120ST was sounding like a good idea. So I bought it.

 

And then it was cloudy for a week. Of course. Anyway, begin review by the beginner.

 

First I will start with the mount and tripod - it is a EQ mount with polar alignment scope. It's reasonably stable although one's opinion of it will greatly depend on where they are coming from. To someone who has only dealt with "toys", it's going to really introduce someone to a real mount. If I had a complaint, it's more with the tripod. The tripod feels a wee bit shaky and I would say its quality does not match the mount. Overall, for the price though, it isn't bad.

Moving on to the OTA

 

The tube itself has a feeling of quality to me, quite substantial. The cylindrical areas of the tube are a black enamal coated metal and the transitions are graphite wrinkle paint. Overall, I feel that it is a tasteful job and has a professional look to it. Between the short fat tube, respectable aperture, EQ mount, and dark paint, this refractor looks like it means business. High marks for appearance.
 

To the mechanicals – the focuser is a 2” rack and pinion. I am pleased they decided to go with this size, as will many people who want to use this scope for photography. There was no backlash or harshness on my focuser at all, but it was quite stiff which can make precise focusing tricky. One can easily overshoot because of the heft it takes. Upgrading the focuser would be a good idea for some, but, once again, considering the price I think it is a reasonable unit.

The dew shield is integrated into the OTA and cannot be removed. On the plus side, there is a mildly rough surface with a dark flat black coating on the inside of the dew shield. This should reward one with both better contrast and some improved dew protection.

The lens itself has some sort of multicoating that appears violet in some light and green at other angles. It is a doublet so there will be some chromatic aberration present… we will get into how much in a bit.

 

Let’s get to the views! With three hours of clear skies and average seeing conditions, I thought I’d see what this is all about. I will only be reviewing the telescope with equipment that ships with it, just to be fair.

 

First light – The Double Cluster in Perseus. Easy to find and beautiful even to guests that wouldn’t consider this their hobby, I’ve always thought this is a great one to show people… and the results are great through this scope! With the 25mm eyepiece, I can clearly see the majority of the blue-white stars, with a few orange spattered in as well. Each star is as sharp as I’ve ever seen through a telescope, although this is my first time ever using a “real” refractor. While the overall view as far as brightness and field of view go are more or less identical to my old Newtonian (as math would support), the refractor’s sharpness and, despite fairly light polluted skies in unfavorable conditions, contrast, absolutely trump the Newtonian. First view, and now I finally understand the hype.

No CA whatsoever, but we wouldn’t expect that on this type of object, nor at this magnification.

 

Next object was the Pleiades. Overall, I can report a similar experience. Brightness was more or less identical to the Newtonian, but each star was so much sharper. By this time, I’m feeling pretty hyped. My favorite things to observe before were DSOs and this scope was really showing some real potential there.

Just as before, I saw no false color whatsoever at either 25 or 10 mm. This shouldn’t be *too* surprising, although these stars may be bright enough to provoke CA in very low quality scopes.

 

By this time, clouds are starting to roll in and I feel it may be time to get on with a real test to determine the amount of CA. The moon has cleared the tree line so I adjust and look at that. With the 25mm, the view is as sharp as I could expect given the circumstances, but rapidly deteriorating seeing conditions are making this test challenging. Still, at 25mm I am not detecting any noticeable false color. I change over to the 10mm and take a look. The moon now covers most of the view. Out of focus, I can see violet and yellowish arcs offsetting each other, but they fade to reasonable levels when proper focus is achieved. While looking at the moon with the 10mm is showing a tiny fringe around the border, it is not even close to bad enough to obscure the view. To anyone familiar with photography, this would be easily rectified in Lightroom if one could be bothered.

 

Curious to how much of an effect it would make, I place the lens cap with the center cap removed to stop down the telescope. The results are, from my point of view, probably around a 70% reduction in CA (that wasn’t that bad in the first place). While I cannot see any ill effects at this magnification, it bears mentioning that under greater magnification, stopping down a telescope this much will lower its resolution. Try it out, see what works.

 

Cloud cover now is moving over the moon and the seeing conditions have deteriorated from not so good to absolute ****. I pack it up and head in.

 

So, what is my conclusion? Well, I’ve heard people all over the board about the CA with these scopes and decided to take a gamble and buy it. I am completely pleased. It has exceeded my expectations quite a bit. If I were doing high magnification planetary viewing, I may have stuck with the Newtonian or gone with the similar package deal with the cat, but for what I mostly use it for, this cannot be beat.

This is my first impression with a moderately sized refractor (as opposed to the **** kids have) and I'm absolutely loving this so far. Just to pick hairs, what would I change?

The tripod could be more secure, the focuser isn't really a pleasure to use, the polar alignment scope isn't as high quality as the one my Newtonian had, and a removable dew shield might have been nice.|

My first upgrade will certainly be a motor drive though so I can get into astrophotography.

 

 

 

Congratulations on the ST120!  I still have and use mine -- great views on DSOs!  I also have used it with a Baader solar film filter and found it possible to take white light solar photos with it.  It's a lot of fun to use!



#19 ylem

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Posted 11 November 2014 - 08:23 PM

 

Haha the forum censorship makes it look like I've said worse things than I have. Each time I said a word that starts with c and ends with "rap". Go figure.

You could have used a different word:

 

BM, balls, baloney, bilge, blague, blah, blah-blah, bloody flux, bop, bosh, bowel movement, buffalo chips, bull, bunk, bunkum, ca-ca, cast, catharsis, claptrap, coprolite, coprolith, cow chips, cow flops, cow pats, defecate, defecation, dejection, diarrhea, dingleberry, drivel, droppings, dung, dysentery, evacuate, evacuation, eyewash, feces, feculence, flam, flapdoodle, flimflam, flux, gammon, gas, guano, guff, gup, hogwash, hoke, hokum, hooey, hot air, humbug, humbuggery, jakes, jiggery-pokery, lientery, loose bowels, malarkey, manure, moonshine, movement, natural, nick, night soil, number two, ordure, piffle, poppycock, purgation, purge, roll, rot, runs, scat, sewage, sewerage, shot, stool, throw, tommyrot, tripe, trots, ****, turistas, twaddle, void, voidance, wind

 

The above is lightly edited from a thesaurus. I've always been partial to tommyrot, myself.

 

Regarding your pictures, it's fun to play, isn't it.

 

:blush:  :rofl: ! What a bunch of krap :lol:



#20 cpuoverclocker64

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Posted 11 November 2014 - 09:22 PM

Bloody flux dysentery sounds like a positively terrible fate.

Besides that, I'm going to get more info on that rack and pinion modification. I hope this unplanned huge influx of info will help some new people as well.


Edited by cpuoverclocker64, 11 November 2014 - 09:23 PM.


#21 star drop

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Posted 12 November 2014 - 09:15 AM

Stay on topic please, folks.



#22 LDW47

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Posted 12 November 2014 - 09:24 AM

Stay on topic please, folks.

It appears this slap on the wrist use of simple, time immemorial words is the topic ?



#23 cpuoverclocker64

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Posted 12 November 2014 - 10:28 AM

Anyway, I'm going to bring my lube and tools home from work with me today and see what I can do about that tight rack and pinion. Whenever I get that taken care of, I'll post up some pictures of that as well so if anyone else with a similar 2" focuser wants to improve its function, it's all there out in the open.



#24 LDW47

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Posted 12 November 2014 - 10:36 AM

 

I love mine on the Orion Versa-Go II Alt-Az mount. Did some slight improvements on the R&P Focuser and it is much smoother including upgraded focus knobs. A great scope!!!

 

I put mine on a VersaGo as well, as well as my other two refrac, best moves I ever made for my type of viewing ie. low power, wide field. I went the focus knobs route as well, I agree 100%.


Edited by LDW47, 12 November 2014 - 10:37 AM.


#25 t.r.

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Posted 12 November 2014 - 01:47 PM

 

 

Haha the forum censorship makes it look like I've said worse things than I have. Each time I said a word that starts with c and ends with "rap". Go figure.

You could have used a different word:

 

BM, balls, baloney, bilge, blague, blah, blah-blah, bloody flux, bop, bosh, bowel movement, buffalo chips, bull, bunk, bunkum, ca-ca, cast, catharsis, claptrap, coprolite, coprolith, cow chips, cow flops, cow pats, defecate, defecation, dejection, diarrhea, dingleberry, drivel, droppings, dung, dysentery, evacuate, evacuation, eyewash, feces, feculence, flam, flapdoodle, flimflam, flux, gammon, gas, guano, guff, gup, hogwash, hoke, hokum, hooey, hot air, humbug, humbuggery, jakes, jiggery-pokery, lientery, loose bowels, malarkey, manure, moonshine, movement, natural, nick, night soil, number two, ordure, piffle, poppycock, purgation, purge, roll, rot, runs, scat, sewage, sewerage, shot, stool, throw, tommyrot, tripe, trots, ****, turistas, twaddle, void, voidance, wind

 

The above is lightly edited from a thesaurus. I've always been partial to tommyrot, myself.

 

Regarding your pictures, it's fun to play, isn't it.

 

:blush:  :rofl: ! What a bunch of krap :lol:

 

 

One does indeed need to be creative here to get their point across...Beotchs!!! :rockon:

 

As for the ST120...it is a good scope for the money. Low power to mid range with a filter, it can do a lot.


Edited by t.r., 12 November 2014 - 01:49 PM.



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