Skywatcher 18" Dob 450p?

[GTom]

Looking at the SW 450p 458/1900, does anyone have experience with a relatively recent (less than 2 years old) model? This review doesn't sounds very encouraging.

[garryblueboy]

To be fair they are not that bad my one was fine and for the price great value I’d say it was the best truss pole one I’ve owned it is a beast though and although can be set up by one person I’d recommend two the GOTO worked flawlessly I purchased mine from FLO in August it was there demo model so had had a few things sorted it does break down into small transportable pieces the mirror is quite stunning on these for what I paid I was very happy 😃  

[GTom]

1 hour ago, garryblueboy said:

To be fair they are not that bad my one was fine and for the price great value I’d say it was the best truss pole one I’ve owned it is a beast though and although can be set up by one person I’d recommend two the GOTO worked flawlessly I purchased mine from FLO in August it was there demo model so had had a few things sorted it does break down into small transportable pieces the mirror is quite stunning on these for what I paid I was very happy 😃  

Have you done a star-test with the mirror? I see zoning and other issues reported by more than one user.

 

[garryblueboy]

Yes it was pretty good really not in the same park as my Zambuto was but still very sharp and with quality eyepieces and paracore no coma or distorted views I read there were problems with the early ones but the later coned out mirrors get great reviews 

[GTom]

4 hours ago, garryblueboy said:

Yes it was pretty good really not in the same park as my Zambuto was but still very sharp and with quality eyepieces and paracore no coma or distorted views I read there were problems with the early ones but the later coned out mirrors get great reviews 

There are very poor test results in the topic I've linked with scopes purchased in 2019. They might still be older models though. However, even a half-lambda quality mirror will give you details in that huge size, whereas the user might associate any defects with atmospheric effects.

Also found this: the primary is simply not supported adequately. 

[niallk]

An 'economy standard' 18" Lukehurst is "only" €750 more....

Or drop to a 16" ES truss for €1100 less and get some very nice EPs??

[garryblueboy]

9 hours ago, GTom said:

There are very poor test results in the topic I've linked with scopes purchased in 2019. They might still be older models though. However, even a half-lambda quality mirror will give you details in that huge size, whereas the user might associate any defects with atmospheric effects.

Also found this: the primary is simply not supported adequately. 

Well I must have got a good one as said I had none of the problems your links suggest I can only say on what I own 

[garryblueboy]

8 hours ago, niallk said:

An 'economy standard' 18" Lukehurst is "only" €750 more....

Or drop to a 16" ES truss for €1100 less and get some very nice EPs??

I had an ES build quality was shocking started to rust after few moths seemed to be made from monkey metal mirror was good 

[niallk]

16 minutes ago, garryblueboy said:

I had an ES build quality was shocking started to rust after few moths seemed to be made from monkey metal mirror was good 

Ok, scratch that suggestion so! I had hoped that the Gen II models were better... and the 20" model seemed to get a couple of good reviews.

A few yrs ago, I was originally was considering an ES, then I heard about the SW Stargates - was holding out for their release - then for both scopes initial reviews troubled me.  Personally, I made my decision to pay more for a tried and trusted design.

[Charles Kirk]

3 hours ago, garryblueboy said:

I had an ES build quality was shocking started to rust after few moths seemed to be made from monkey metal mirror was good 

Was that a first generation model or a second generation model?

[garryblueboy]

2nd gen 

[GTom]

2 hours ago, garryblueboy said:

2nd gen 

I am close to give up trusting any mass producers and thinking on building myself... We are in the 21st Century, still advanced materials (CF...) are nowhere in mass pruduced scopes.

[garryblueboy]

10 minutes ago, GTom said:

I am close to give up trusting any mass producers and thinking on building myself... We are in the 21st Century, still advanced materials (CF...) are nowhere in mass pruduced scopes.

Try reading the positive reviews for a change instead of the negative there’s good and bad in everything there are plenty of people happy with there mass produced scopes  they just don’t all write reviews on them 

[GTom]

52 minutes ago, garryblueboy said:

Try reading the positive reviews for a change instead of the negative there’s good and bad in everything there are plenty of people happy with there mass produced scopes  they just don’t all write reviews on them 

Right, there are good scopes too, but price is very much connected to quality. No wonder that an Obsession UC costs twice as much.

Anyway, I am listening, anyone measured 0.90+ Strehl, stable collimation after a year of use?

Edited January 10, 2020 by GTom

[garryblueboy]

53 minutes ago, GTom said:

Right, there are good scopes too, but price is very much connected to quality. No wonder that an Obsession UC costs twice as much.

Anyway, I am listening, anyone measured 0.90+ Strehl, stable collimation after a year of use?

A Takahashi or Astrophysics cost 10times as much as a Skywatcher but you don’t see 10x the detail nor do you in an obsession see twice the detail so what’s your point it’s what you see at the eyepiece not what you read on the net that maters why not get yourself an obsession then with a Zambuto mirror and you won’t have to worry about the above simple 

[GTom]

2 hours ago, garryblueboy said:

A Takahashi or Astrophysics cost 10times as much as a Skywatcher but you don’t see 10x the detail nor do you in an obsession see twice the detail so what’s your point it’s what you see at the eyepiece not what you read on the net that maters why not get yourself an obsession then with a Zambuto mirror and you won’t have to worry about the above simple 

You don't have to go as far as Tak or AP to get a mirror that doesn't fall out of collimation, doesn't delaminate and at least diffraction limited. Apparently vendors are shying away from giving replacement units on customer complains, they rather refund...

I am not 100% sure about that 10x details question in very good seeing (where it is worth to do planetary work anyway) between a decollimated, lambda/2 optics vs a decent lambda/6 orion kept in a good cell. I am not a quality snob (alright, a little bit), but there are some BASIC expectations towards a product which costs multiple thousands of $/€.

Or just turn the question around: apparently the optics is about lambda/2, mechanical quality is a weak beta version. As an absolute NOOB in mirror ginding and with little (but existing) experience in OTA building, could I produce the same quality? Very likely yes and the overall budget doesn't seem to reach $2k.

Edited January 10, 2020 by GTom

[Charles Kirk]

7 hours ago, garryblueboy said:

2nd gen 

Well that's disappointing to hear.  On the other hand, it's very good to hear that the mirror is good, as the rust and other minor issues I have read about would be solvable.

They do seem to have been quite well received in the comments I have read.

[garryblueboy]

3 hours ago, GTom said:

You don't have to go as far as Tak or AP to get a mirror that doesn't fall out of collimation, doesn't delaminate and at least diffraction limited. Apparently vendors are shying away from giving replacement units on customer complains, they rather refund...

I am not 100% sure about that 10x details question in very good seeing (where it is worth to do planetary work anyway) between a decollimated, lambda/2 optics vs a decent lambda/6 orion kept in a good cell. I am not a quality snob (alright, a little bit), but there are some BASIC expectations towards a product which costs multiple thousands of $/€.

Or just turn the question around: apparently the optics is about lambda/2, mechanical quality is a weak beta version. As an absolute NOOB in mirror ginding and with little (but existing) experience in OTA building, could I produce the same quality? Very likely yes and the overall budget doesn't seem to reach $2k.

You asked a question I gave an answer from being an owner of actual scopes with one in my possession and having owned a Zambuto in perfect optical finish there was some difference in quality but not overwhelming the Stargate  also holds perfect collimation much better than my previous custom Sumerian scope did I’d , also question the quality of the collimating device being used in your example and also having owned several Chinese refractors and now owning a AP and TMB I think my 10 x question is accurate so I stand by my answer I think for the money also a full Goto 18’’ Dob it’s great value there are better but for me it ticks the box 

Edited January 11, 2020 by garryblueboy

[garryblueboy]

3 hours ago, Charles Kirk said:

Well that's disappointing to hear.  On the other hand, it's very good to hear that the mirror is good, as the rust and other minor issues I have read about would be solvable.

They do seem to have been quite well received in the comments I have read.

My answer exactly as with the Stargate small niggles but solvable 

[Ships and Stars]

Hi @GTom,

I have the 500p with GOTO, I love it, it's mind-blowing, and to replace it with something better/larger will likely cost 2x to 3x more. I bought mine second-hand but unused, sadly the previous owner fell ill before he could use it. Surprisingly, most of the reviews are critical, but I think people were trying to use really high magnification or we are just hearing from a select few who had a bad copy. 

Mine is tack sharp, have used it up to 444x so far in the UK under a jetstream with probably 80%+ humidity. The mirror doesn't require any cooling. I can load it in my van in under ten minutes and set up in about 15 min. The base and mirror/rocker assembly are just over 30kg each, about what a big suitcase weighs when going on a long holiday, etc. The truss rods and top end weigh next to nothing. The GOTO system works great when the scope is properly balanced and levelled, and once on target, will track objects without fuss for long periods of time without correction. I rarely use a coma corrector, mainly only with the 21 Ethos, and even then I usually don't bother unless I'm concentrating on star clusters. I can also set mine up easily by myself, I'm 6" and a bit, but no weightlifter. 

I only had to do four simple things to mine:

1.) Cut small notches in the edges of my mirror cover to remove it more easily when the truss rods are in place.

2.) Use a 12mm socket on a 1/4" ratchet to tighten the base truss rod ends, a lot faster than the spring-loaded handles that can only turn 180deg.

3.) I put some tape on the end of the GOTO drive cable to cover the sharp cable end.

4.) I had to add a little more weight, like 1.5-2kg.

That's it. 

I've been into serious astro for less than a year and have already seen so many things, including the Horse Head. The Veil and M42 are amazing. Viewing the moon without a good ND filter hurts and I wouldn't recommend it, it's that bright.

The biggest *complaint* I have with mine is the fact that it has so much light-gathering ability, you can point it anywhere in the sky and the eyepiece will show so many stars that aren't on a sky atlas it's really easy to get lost/overwhelmed if not using GOTO. I couldn't tell which stars were my alignment stars, they were all so bright.  The only other complaint is that the GOTO drive cable can be fiddly to mess with in the dark if it pops off when setting up/taking down without a torch.

It's not insignificant, you will need a certain level of fitness, but to me it is the grab and go of 20" dobs. I mean a lot of people stick 5m long sea kayaks on their cars or load up for the car boot every weekend, so to me it's no big deal.  For the aperture it's quite transportable in my small van. I looked at getting a 350p or 400p for something more portable, and decided the difference in weight and volume when loaded into a car was negligible, the 500p is perhaps even lighter in individual component parts. 👍👍

One thing you won't need to do after all the moving and setting up is completed, is view some faint object thousands or millions of light years away and wonder what it would have looked like if you had bought that bigger scope! 

 

 

 

Edited January 11, 2020 by Ships and Stars

[GTom]

Thank you for the reassuring report! I am also looking forward to get a second hand scope (or build one myself). I will give it some thinking and of course careful testing why it is being sold. Haven't saw bad mirror reports on the 20" so far.

Edited January 11, 2020 by GTom

[Ships and Stars]

58 minutes ago, GTom said:

Thank you for the reassuring report! I am also looking forward to get a second hand scope (or build one myself). I will give it some thinking and of course careful testing why it is being sold. Haven't saw bad mirror reports on the 20" so far.

It's a lot of money, even used, so don't blame you. There's probably a genuine reason for the sale, maybe the current owner has difficulty moving it around or decided they aren't using it enough to justify the money just sitting there. My problem is time, we have a new family member and two of us (not me) were in hospital for a little bit, so I couldn't even think about getting out to my dark site. I'm hoping as the next new moon approaches in a week or so I'll get another chance.  It is a bit of a beast to lug around, but all 20" dobs are except maybe a small handful of ultralight ones costing 10k or more, and they still won't be light! 

[Ships and Stars]

PS I looked at making a very large mirror, something in the 25"-28" range (I truly have severe aperture fever), and decided there was very little chance I could do a 25-28" mirror within the next two to three years. Or five. I've read a lot about mirror making, but never ground or polished one, nor have I tested one. My plan was to buy a 8" blank to start with and then move up in size, but after reading some other posts, even they are spending loads of time and more money on grinding supplies than a second-hand 8" scope costs. 

Therefore an 18" or 20" dob with GOTO that's ready to rock under say £3000-£3500 suddenly seems like a bargain. I missed out recently on a 25" dob for only £2400 but it was on Tenerife and couldn't find a reasonable way to get it back. I think if I ever get something larger, I'll most likely have to have something shipped from the US where 24"-32" is relatively common.

[jetstream]

37 minutes ago, Ships and Stars said:

we have a new family member and two of us (not me) were in hospital for a little bit,

I hope all is well and they are recovered and also that you can get some time to observe.

[Ships and Stars]

9 minutes ago, jetstream said:

I hope all is well and they are recovered and also that you can get some time to observe.

Thanks Gerry! It's been a handful. From Dec 17th until three days ago my wife and newborn daughter were in hospital twice with only a few days at home in between due to complications and a chest infection for the little one right out of the starting gate - that was touch and go for a bit. They are back and resting comfortably and our daughter is alert and I dare say happy most of the time. Hoping by next new moon I'll be able to at least get away once they are asleep to my dark sky site and return before sunrise (I honestly sound like some kind of vampire now 🤣). Just need the weather to hold. We've had four really clear nights here lately, high humidity, but lunar with the 8" has been my only option. Hope to file another DSO observing report soon! I'd like to turn my attention to more galaxies now after reading your last report. And play with binoviewers on the brighter DSOs of course!

Sorry for going off piste with the thread GTom! Go for the big scope second-hand! 

Edited January 11, 2020 by Ships and Stars