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StellaLyra 12" Dob - the good and the bad


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I've had this scope for a few weeks now and feel in a position to make comment about its good and bad points. Bear in mind any criticism ignores how inexpensive this scope is. It really is a bargain and you get a lot for your money.

Bad first:

  • Collimation is a nightmare. The primary mirror either adjusts, wont move, or clunks out of position; it's almost impossible to collimate accurately (to my standard). I've just replaced the springs (tonight) with something stronger. It's now much easier to adjust though one of the bolts is a bit tight - maybe nylon sleeves are required? I also got some Bob's knobs for the secondary. Although that is holding collimation just fine it is a bit primitive in action.
  • Mount is like jelly. This is 90% down to the rocker box. At the moment I can't decide whether to modify this one or create a new one from thick ply. Glued, screwed and braced is the way forward. I also think there's some movement in the Az due to the bearing assembly being only half the diameter of the base. I'm not sure if you can get larger diameters. I may look for an alternative.
  • Eyepiece position. Like all Dobs the eyepiece is in a position where you have to stand up and lean over - really hurts my back. I wish it was on the side so I could sit.
  • Alt adjustment isn't that easy. The scope needs proper offset balance weights to make this movement smooth and easy.

Now the good:

  • Optics. I've looked through some good scopes, ⅛ PV and better. This scope is right up there. A week ago, in perfect seeing, I had the best, sharpest, most detailed views of the moon I've ever had. The only way you will get this mirror off me is if I leave it to you in my will... I feel like I have premium optics but without the premium price. I don't know what other samples are like, but the one I have would be difficult to better.
  • The focuser is nice quality. It's not a Moonlight, but at this price it's really nice.
  • RACI finder. I'm not a contortionist, so a RACI is a must have. This one isn't too bad quality wise either.
  • Size and weight. Even with my dodgy back it's not too difficult to manoeuvre the OTA and base around and fit one to the other. Despite it's size. 
  • Price. This is a huge amount of scope for the money. Just buy one - you know you want to :wink2:

That's about it for now. As I keep saying, this is a lot of scope for the money.  Definitely the right choice for me. The Skywatcher equivalent looks really dated, expensive and underspecified by comparison; I'm so pleased I didn't go down that route.

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Mostly good then with a few irritating shortcomings. 

Do wish more dobs used tube rings to mount the tube so you could rotate the focuser round to the right position.

18mm marine ply does indeed make a far better base than chipboard / mdf but would bump up the price of the scope a fair bit but a price many would be willing to pay. Perhaps a deluxe version with a ply base would be a good option.

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Interesting review, especially as most of the cons seem to be only for your model.

My 8" has a solid base, with no play in it at all. In fact it's very smooth on both axes.

Mine has no problem holding or adjusting collimation.

The eyepiece position is perfect for me when I'm sitting down.

I use sliding magnets to balance the scope in alt.

It strikes me that the manufacturer designed the 8" first and later the 10"/12", just scaling everything up. Sorry to hear yours isn't what you want, MS.

I'm not trying to be smug but I would like to inform potential buyers that at least one scope in the range is extremely good.

Edited by cajen2
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Fortunately, most mechanical shortcomings can be addressed whereas poor optical optical quality remains.  Sounds like the mirror on this one is a peach rather than a lemon.    🙂

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Nice balance review. 

Having made a Dob base I’d make another. My experience of trying to strengthen something made out of wood is that you never quite get there and will never be happy. It’ll also bump up the weight.

Plywood is lighter and stiffer than chipboard/MDF which I assume is what it’s made out of. I used standard relatively inexpensive 18mm Far Eastern plywood for my base and it turned out as solid as a rock. 

And as for weights. Personally I prefer to balance a Dob with weights rather than totally depend on tensioning. I like to balance the OTA and use the tensioning knobs so that it moves in both directions with equal force. Having it move one way easier than the other makes tracking a less pleasant experience. 

Edited by PeterStudz
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Star testing both sides of focus Is also useful in judging optical quality. Clunky collimation i am familiar with. And its workable. Good idea to change the springs. A mount like jelly is more troublesome especially if some one wanted to image through one. Something i have been pondering. The report on optical quality is encouraging. 

Edited by neil phillips
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8 hours ago, Mr Spock said:

I've had this scope for a few weeks now and feel in a position to make comment about its good and bad points. Bear in mind any criticism ignores how inexpensive this scope is. It really is a bargain and you get a lot for your money.

Bad first:

  • Collimation is a nightmare. The primary mirror either adjusts, wont move, or clunks out of position; it's almost impossible to collimate accurately (to my standard). I've just replaced the springs (tonight) with something stronger. It's now much easier to adjust though one of the bolts is a bit tight - maybe nylon sleeves are required? I also got some Bob's knobs for the secondary. Although that is holding collimation just fine it is a bit primitive in action.
  • Mount is like jelly. This is 90% down to the rocker box. At the moment I can't decide whether to modify this one or create a new one from thick ply. Glued, screwed and braced is the way forward. I also think there's some movement in the Az due to the bearing assembly being only half the diameter of the base. I'm not sure if you can get larger diameters. I may look for an alternative.
  • Eyepiece position. Like all Dobs the eyepiece is in a position where you have to stand up and lean over - really hurts my back. I wish it was on the side so I could sit.
  • Alt adjustment isn't that easy. The scope needs proper offset balance weights to make this movement smooth and easy.

Now the good:

  • Optics. I've looked through some good scopes, ⅛ PV and better. This scope is right up there. A week ago, in perfect seeing, I had the best, sharpest, most detailed views of the moon I've ever had. The only way you will get this mirror off me is if I leave it to you in my will... I feel like I have premium optics but without the premium price. I don't know what other samples are like, but the one I have would be difficult to better.
  • The focuser is nice quality. It's not a Moonlight, but at this price it's really nice.
  • RACI finder. I'm not a contortionist, so a RACI is a must have. This one isn't too bad quality wise either.
  • Size and weight. Even with my dodgy back it's not too difficult to manoeuvre the OTA and base around and fit one to the other. Despite it's size. 
  • Price. This is a huge amount of scope for the money. Just buy one - you know you want to :wink2:

That's about it for now. As I keep saying, this is a lot of scope for the money.  Definitely the right choice for me. The Skywatcher equivalent looks really dated, expensive and underspecified by comparison; I'm so pleased I didn't go down that route.

Could you provide pics of the like jelly  base please.  Your scope is the twin to my skyline and I am interested in seeing what potential problems I might run into.  So far my base is solid as a rock.  I also had one primary adjuster become stiffer then the rest when I installed new primary springs, so this must be normal.  GSO makes some good glass, not just for the price, but in general.  I had the opportunity to look through a 16 inch with a GSO mirror, the image was breath taking and gave the 15 thousand dollar Obsession it was sitting next to a run for it's money.

Edited by Mike Q
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Whilst I agree a home built dob base can be a good improvement, there is no reason why the standard base should not be good, stable and with smooth motion. MDF is pretty rigid so this should be quite possible.

I had custody of a 12” Zhummel which is basically the same thing, and it was pretty good. The Az motion wasn’t the best so I put a lazy Susan bearing between the base and the rocker box and the improved things.

I guess I’m just wondering if there was anything wrong with yours? Worth checking with FLO for their views?

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Oh, and regarding collimation, I agree that the standard springs are not up to the job, but I found the best method was to get it basically right, then fine tune using the locking knobs rather than the collimation adjustment. This lead to a much firmer setting which held well.

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I use welding magnets on mine to balance properly like these at the base of the scope:

Welding Magnets

Although my RACI is quite heavy (an Altair 10x60) so when the scope is quite low down I lay an exercise weight (those things you wrap around your arm) across the top

I agree about the positioning - there's a certainly angle where you can't sit on an ordinary chair nor really standing up which is mighty painful after a while for the back.  I've seen people swear by the use of an adjustable ironing stool for as an economic option rather than go for one of the astro stools.

 

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4 minutes ago, Stu said:

Oh, and regarding collimation, I agree that the standard springs are not up to the job, but I found the best method was to get it basically right, then fine tune using the locking knobs rather than the collimation adjustment. This lead to a much firmer setting which held well.

I did exactly the same thing.  Then I put in Bob's Knobs and primary springs.  I collimated it once and have not done it since.  Those springs made all the difference

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9 minutes ago, Stu said:

Oh, and regarding collimation, I agree that the standard springs are not up to the job, but I found the best method was to get it basically right, then fine tune using the locking knobs rather than the collimation adjustment. This lead to a much firmer setting which held well.

This is exactly what I do now and wish I’d known - took me several months of trial and error before I worked it out!

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9 hours ago, Mr Spock said:

Just buy one - you know you want to :wink2:

Actually I don’t think I do anymore😒

Thanks very much for the review information and I hope yours is a sample of one that was built on Friday afternoon so to speak.

I am sure the optics are brilliant but I don’t want to have to build a new mount, or fiddle with collimation , (which I understand is a bit of a black art anyway and going to be a nightmare if the scope is malfunctioning). Or knacker my back using it.

These sound like issues that a semi newbie doesn’t need. I know someone with much more experience as you could overcome them.

Hopefully other examples of this scope will be ok.

If I had bought this specific example I would contemplate sending it back to the supplier stating it was defective and  not fit for purpose.

at the moment not sure why this is advertised as

The UK's BEST 12" Dobsonian telescope! 

Edited by Andy ES
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Did you have such an issue with the primary collimation on your old Skywatcher 10"?  I do have to collimate every time as the mirror does seem to shift quite easily from moving it in/out of the conservatory) however the primary mirror collimation knobs have always been quite responsive....  The secondary on the other hand I switched over immediately to Bob Knobs and did the "Milk Bottle Top" mod otherwise the collimation of the secondary was nigh-on impossible.

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9 minutes ago, Davesellars said:

Did you have such an issue with the primary collimation on your old Skywatcher 10"?  I do have to collimate every time as the mirror does seem to shift quite easily from moving it in/out of the conservatory) however the primary mirror collimation knobs have always been quite responsive....  The secondary on the other hand I switched over immediately to Bob Knobs and did the "Milk Bottle Top" mod otherwise the collimation of the secondary was nigh-on impossible.

I replaced the secondary screws and primary springs with stuff from Bob's Knobs.  I collimated and have not had to do it since.  I am convinced that the new springs have everything to do with that.  The other thing I did was to put a piece of foam between the OTA and the front panel.  Just to keep it from hitting the wood.

Edited by Mike Q
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I have a few days off work from tomorrow. I’m going to have a good look at the rocker to see if it can br tightened up. 

The Skywatcher 250 I had was fairly solid, didn’t have weak springs, and had decent optics.

 The optics on this one are so good it’s never going back! A few mechanical issues I can solve. 

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1 hour ago, Mr Spock said:

I have a few days off work from tomorrow. I’m going to have a good look at the rocker to see if it can br tightened up. 

The Skywatcher 250 I had was fairly solid, didn’t have weak springs, and had decent optics.

 The optics on this one are so good it’s never going back! A few mechanical issues I can solve. 

Do check the little ball race ring on the base axis. It may well be critical which way up this is installed, though of course the instructions don't show it! As I said, the base on mine is rock solid and smooth in rotation, unlike my Skywatcher scope....

 

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16 hours ago, Mr Spock said:
  • Mount is like jelly.

I find that hard to believe 🙂 

7 hours ago, cajen2 said:


My 8" has a solid base
 

So has my own 10" StellaLyra Dobsonian. 

I haven't yet tried the 12" model you own, Michael, but it sells well and looking through our customer returns records I cannot find a single Return. Literally - nobody - has returned one. (This is unusual because most Dobsonians are returned at one time or another, if only because the customer was surprised at how large it is). 

If you suspect your base is faulty then please email us to request another. 

16 hours ago, Mr Spock said:

As I keep saying, this is a lot of scope for the money.  Definitely the right choice for me. 

That is good to hear 🙂 

8 hours ago, johninderby said:


18mm marine ply does indeed make a far better base than chipboard / mdf but would bump up the price of the scope a fair bit but a price many would be willing to pay. Perhaps a deluxe version with a ply base would be a good option.
 

Indeed it would. 

The purpose and ethos of a Dobsonian telescope is to make large apertures and quality optics affordable. This is why the base is a simple flat-pack self-assembly design. When you buy a Dobsonian telescope you can be confident almost all your money is spent on the telescope. Not the base. This is good and how it should be. 

HTH, 

Steve 

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16 minutes ago, FLO said:

If you suspect your base is faulty then please email us to request another. 

@Steve I don't see what there is to be faulty. It's just pieces of particle board bolted together!

Here it is wobbling.

 

 

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Oh Michael. It is a large 12" Newtonian on a Dobsonian base that is, like you say, MDF boards screwed together. 

You could add some corner blocks or brackets if you want to make it stiffer but I doubt to will be worth your time. The telescope settles nicely when in use, when observing. For a Dobsonian this size it is par for the course. It is not faulty. 

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29 minutes ago, FLO said:

 

The purpose and ethos of a Dobsonian telescope is to make large apertures and quality optics affordable. This is why the base is a simple flat-pack self-assembly design. When you buy a Dobsonian telescope you can be confident almost all the money spent is spent on the telescope. Not the base. This is good and how it should be. 

HTH, 

Steve 

I'll take issue with this statement. A telescope is only as good as its mounting. Superb optics are a waste if it cannot be held on a target without shake and wobble. This was the essence of John Dobson's simple, yet sturdy, design.

I have seen many larger scopes that are simple 'scaled up' versions of their smaller siblings. Often they are under engineered as the bending forces don't go up linearly. Even Obsession made this mistake with their 22"UC.

Looking at Steve's video - there is a problem.

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