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8" DOB overview


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So I had some spare time and decided to do a basic side by side of 8 inch dobs currently available from FLO (Other dobs are available elsewhere). The information is as given from the website so anyone with more accurate info on stats etc, fire away.

The (subjective) results which form my opinion are given below.

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The Bresser has a lot going for it, I really like that big Alt bearing, the upgradeable focuser a nice touch (pity it's not std) and the glass seems decent quality. If your a W/L solar fan then that is also a worthwhile extra. What I am not so keen on is the adjustable tube ring design, over complicates a beginners scope whilst adding to the price I would guess, might have been better spent on the focuser. I hate those finders, they are cheap and yuk. But that's only my opinion! (prepare for repeats of the last phrase)

Skywatcher need to, in my opinion up their game. Firstly I think I was generous giving them 4 from 5. The focuser is pretty basic at best, finder the same, couldn't find detailed spec for glass, weight etc and, wellll they are just falling way behind even at the lowish cost. Note lowish, better options imho are available at a lower price.

StellaLyra is the pick of the bunch in my opinion (told you it would be repeated). Just great all round, excellent glass, cooling, dual speed focuser with compression fittings and a base fan. To top it off they have thrown it a very useable 2" 30mm eyepiece. A first time buyer could do a whole lot worse than stump up the cash on this package.

Ursa Major are new to me, until recently they were just a bunch of stars but this is the surprise package. Good glass again, only basic finder and single speed focuser although the latter looks a nice piece of kit, better than dare i say the SW? Nice they have added the base fan, would again have preferred a dual speed focuser over that but hey, the cheapest in price of the lot and if on a tight budget, easily the pick of the bunch. (IMHO)

So who is the winner? (kop out statement) it's the consumer because competition in a tight market can only be to the benefit we would hope of the end user.

Feel free to correct me and/or add your own thoughts.

Steve

 

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Posted (edited)

None is perfect but I have to admit the Bresser is my favouote as the essentials are there and no upgrades needed other than the dual speed knob and finder however simple to sort out. There is now a replacement finder shoe for the Bresser that allows the use of any Synta type finder bracket  as well as the Bresser. 

The Bresser also has a six point CNC mirror cell not a cheapie cast one like the others.

The Bressers use of tube rings is very  useful. You can slide the tube in the rings for balance and you can rotate the tube to put the focuser in just the right spot. Irritating when you go back to a dob that can’t be rotated. Also just fitting a dovetail bar will let you use the OTA on a regular mount. 

Agree the SW dobs are long overdue for an update / upgrade.

Edited by johninderby
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The Bresser is JOC made (sold as Explore Scientific FirstLight in the US).  I like the giant alt trunnions just like custom made Dobs use.  The azimuth bearing design is also closer to custom made Dob designs.  I've read it does need a bit of bar soap smeared on it to get the motion smoother, though.  Overall, it seems like the best starting point of the bunch.

Skywatcher is Synta made, which is not surprising when you think about it.  Synta specializes in basic scopes of all types.  They work, but the mechanicals leave a lot to be desired.  For example, that focuser is inexplicable having to swap the entire adapter to change from 2" to 1.25" eyepieces.  Literally no one else does it that way for good reason.

Stellalyra and Ursa Major are both GSO made.  The former is the premium scope while the latter is the entry level scope.  In the US, the former is sold by Orion as Skyline and by Apertura as AD8/10/12.  The latter is sold by Orion as SkyQuest (with a slightly restyled base) and probably others.  Both are good deals, but I'm not a fan of their small altitude trunnions.  They don't hold their position when switching out heavy eyepieces unless high tension is applied via either tension springs or tension knobs.  Large trunnions don't needs such crutches to hold position.  I also have my doubts about the durability of their lazy Susan azimuth bearing.  That, and it can have too little stiction to resist slight motions at the eyepiece such as when swapping eyepieces.  The focuser seems nice, though.

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Posted (edited)

The crayford on the StellaLyra is the basic GSO one. Quite nice for a basic crayford. The Bresser focuser is much heavier duty though with more adjustability and of course is R&P and uses an extenstion for visual but without the  extension convenient for BV use.

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Edited by johninderby
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I had the SW 250px, and its focusser too could be upgraded cheaply with the excellent Lacerta 10:1 dual speed kit.  I only used 1.25" EPs in that scope to keep things simple.  Overall, a great scope!

However, now the Bresser large diameter bearings would probably clinch it for me.

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10 hours ago, johninderby said:

None is perfect but I have to admit the Bresser is my favouote as the essentials are there and no upgrades needed other than the dual speed knob and finder however simple to sort out. There is now a replacement finder shoe for the Bresser that allows the use of any Synta type finder bracket  as well as the Bresser. 

The Bresser also has a six point CNC mirror cell not a cheapie cast one like the others.

The Bressers use of tube rings is very  useful. You can slide the tube in the rings for balance and you can rotate the tube to put the focuser in just the right spot. Irritating when you go back to a dob that can’t be rotated. Also just fitting a dovetail bar will let you use the OTA on a regular mount. 

Agree the SW dobs are long overdue for an update / upgrade.

Yes never noticed the 6 point mirror fixing to be honest John, another plus point to be sure. 

I also though did fail to point out the stellalyra roller bearing in the dob base.

I know what the SW Alt bearings look like, I would like to see up close the stellalyra bearing. The Bresser and Ursa Major bearings are on full display but you only have a description for the SLyra.

I didn't know about the replacement shoe for the Bresser, much better to have a standard type. Add a RACI and Telrad and away you go. I hate those Bresser shoe fixings that come attached. 

I think with hindsight I would have to see both the Bresser and StellaLyra side by side to make a final decision if I were buying. I think the Alt bearing would be the deciding factor.

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At astro camp, @cajen2and I had our Bresser and StelllarLyra 8" dobs set up next to each other. But to tell the truth, I don't recall us trying out each other's scopes. Should have done, though.

The Bresser can be moved within the rings to help balance, but I found that there is so little room in the base, one can't move the tube down far enough to balance out a heavy finder. One of my jobs this summer is to extend the base height by a few inches, to let me do this.

I'm more than happy to admit that the basic plastic straight finder that comes with the Bresser is terrible. I've no idea why they do that. An RDF would be better. Perhaps this will change.

Bresser did miss out on a golden opportunity these past few years. The dobs haven't been available for around 18 months! They are only just on sale again now! But given the choice again, I would still stick with the Bresser.

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Posted (edited)
23 minutes ago, johninderby said:

Only just released but should be the standard base so you can fit whatever you like.

https://www.telescopehouse.com/Telescope-Accessories/Finder-Scopes/EXPLORE-SCIENTIFIC-Hybrid-Finder-Scope-Base-black.html

Ah yes a definite improvement there John.

.........................

I was giving things a little more thought after my last post and came up with some interesting pioints.

I used to have an Orion xti 10" and this had a single compression type Alt fixing similar to the stellalyra however there was just the one. This made it a little sticky with tendencies to be jerky but in fairness when I slapped on the Nikon 17mm and 2x powermate it was heavily loaded with glass (2lb 6oz). Also it was not very well balanced which didn't do it any favours either.  The SLyra has clamps on either side so may be a little more forgiving.

A simple magnetic strip mod at the bottom of the dob tube with a metaliic weight to slide up and down is far easier to adjust. (Here I am, don't even own one and already modding it 😅)

1 hour ago, Pixies said:

At astro camp, @cajen2and I had our Bresser and StelllarLyra 8" dobs set up next to each other. But to tell the truth, I don't recall us trying out each other's scopes. Should have done, though.

The Bresser can be moved within the rings to help balance, but I found that there is so little room in the base, one can't move the tube down far enough to balance out a heavy finder. One of my jobs this summer is to extend the base height by a few inches, to let me do this.

I'm more than happy to admit that the basic plastic straight finder that comes with the Bresser is terrible. I've no idea why they do that. An RDF would be better. Perhaps this will change.

Bresser did miss out on a golden opportunity these past few years. The dobs haven't been available for around 18 months! They are only just on sale again now! But given the choice again, I would still stick with the Bresser.

Seems no one of the above is perfect out of the box given this. However good to hear you are still happy even with the Bresser even with the above points.

Would be interesting to hear if @cajen2 has any input regarding the StellaLyra 8", particularly on the Alt bearing.

Steve

Edited by bomberbaz
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Posted (edited)

As @Pixies said, we had our scopes next to each other at Astrocamp. The Bresser looked to be a quality bit of kit but I'd go for my StellaLyra again in a heartbeat. I've had no trouble at all with the alt bearings: a quick tweak on one of them is all that's needed to adjust tension. The azimuth bearing is a peach - it's smooth and light to rotate (much easier than the one on my Skywatcher Heritage) and is again easy to adjust for stiction: just reach down and turn a knob.

A couple of things haven't been mentioned: the SL has adjustment of the alt bearings so that balance can be achieved. Admittedly, it's a bit of a pain as you have to take off the OTA and mess about with an Allen key, but at least it's possible. Also, there are gradations marked on the bearing so you can adjust exactly on both sides.

I also have no idea why Pixies and I didn't swap scopes! It didn't occur to me until later.

Edited by cajen2
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5 minutes ago, cajen2 said:

As @Pixies said, we had our scopes next to each other at Astrocamp. The Bresser looked to be a quality bit of kit but I'd go for my StellaLyra again in a heartbeat. I've had no trouble at all with the alt bearings: a quick tweak on one of them is all that's needed to adjust tension. The azimuth bearing is a peach - it's smooth and light to rotate (much easier than the one on my Skywatcher Heritage) and is again easy to adjust for striction: just reach down and turn a knob.

A couple of things haven't been mentioned: the SL has adjustment of the alt bearings so that balance can be achieved. Admittedly, it's a bit of a pain as you have to take off the OTA and mess about with an Allen key, but at least it's possible.

I also have no idea why Pixies and I didn't swap scopes! It didn't occur to me until later.

I suppose you make a call on where to balance it based upon your eyepiece weight, focuser etc then use a small adjustable weight as aluded to earlier. It's all personal taste in the end.

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Re…

couldn't find detailed spec for glass, weight etc and, wellll they are just falling way behind even at the lowish cost.”

On what evidence are you making this assertion? To make such a bold statement I would expect some evidence.

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The SW dobs are not “bad” but rather more a case of needing many upgrades to bring them up to the standard expected nowadays. Hence the common opinion that SW needs to freshen up the solid tube dobs to bring them up to date. 

Mirror wise there is nothing to choose between the various brands. All are made to a good standard.

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This is an interesting thread with some fact and also some speculation. Interesting and helpful to see @bomberbaz tabulating the comparison - thanks for that. It would be interesting to add the new Celestron StarSense Explorer 8” Dob (from Synta ) into the mix now as well. There isn’t an outright winner overall and I suspect this is by design. The glass quality differences are probably (possibly?) negligible when it comes to actual at the eyepiece work late at night, (unless one is very experienced - I’m certainly not) but I’d say overall having experienced both SL and SW Dobs the only extra features that makes a compelling difference are the roller bearings for smooth AZ control and the included RACI finder (both of which can be sorted post purchase although the latter is much easier). I can’t quite see the appeal of the large Alt bearings on the Bresser, (may be ignorance) but even if a bonus in practice is surely not worth the ridiculously long lead times just for that. The tension control system on the SW works perfectly well with no issues balancing heavier 2” eyepieces, and in practice adjusting the SL/GSO with an allen wrench is not particularly practical and quick. Still this makes for a good academic debate in the absence of any opportunity to actually observe! 

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49 minutes ago, Spile said:

Re…

couldn't find detailed spec for glass, weight etc and, wellll they are just falling way behind even at the lowish cost.”

On what evidence are you making this assertion? To make such a bold statement I would expect some evidence.

See below

31 minutes ago, johninderby said:

The SW dobs are not “bad” but rather more a case of needing many upgrades to bring them up to the standard expected nowadays. Hence the common opinion that SW needs to freshen up the solid tube dobs to bring them up to date. 

Mirror wise there is nothing to choose between the various brands. All are made to a good standard.

I think @johninderby encapsulates what I was referring too, it's not that they are bad, just that others in the market have overtaken them and of course this is "IMHO".

So if someone came onto the forum asking for advice on a DOB in the range of the 8", I would be considering all options before I put my two penneth forward, but SW need to up their game or risk not being in the short list of myself and possibly of others. I stick with my opinion that StellaLyra currently lead the way, but only just.

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I broadly agree with FLO’s marketing claims - The SL is currently (probably) the best 8” Dobs on the market in the UK in terms of standard package and quality - aesthetically too although that’s subjective - but those Celestron’s are compelling. SW will no doubt up their game and release a more modern package soon enough. They’ve recently innovated in a design and performance sense with their modern take on the EQ1/2 mount (Starquest - I am a fan) so who knows what is in the pipeline. 

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The Starsense 8” has a handle! I’d almost buy it just for that. Although I drilled holes in my Skyliner and fitted a handle so if I bought a StellaLyra one of the first things I’d do is take it apart drill some holes and fit a handle. And while I was at it I’d flock it too. Although I don’t disagree with the overall conclusion much of this is subjective.

I also really do not like the all black look. But for me white with black trim is really nice. This maybe down to the little reflector that my parents bought me as a kid. It was white & black so there’s some nostalgia. I also like doing solar and the bottom section  of my home made base is black. And it really heats up - it feels like you could almost fry an egg on it. Meanwhile the white sections stay cool. Because I don’t like all black I’d also spray paint a black OTA white (I’m serious) while I was fitting a handle, flocking, fitting bobs knobs and the milk bottle mod to the secondary. 

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3 hours ago, Astro_Dad said:

The tension control system on the SW works perfectly well with no issues balancing heavier 2” eyepieces, and in practice adjusting the SL/GSO with an allen wrench is not particularly practical

The tension control on the Stella Lyra is done by turning one or both side knobs which are capable of accepting the 2” ES eyepieces. The Allen key is only needed to alter the pivot point of the tube. I must admit that I do like the large alt bearings on the Bresser.

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