Would you buy Skywatcher 20” Dobsonian Collapsible GOTO?

[bobson]

This is once in life time opportunity, for me anyway, to buy such a big scope.
I wanted to buy 16” $6000 and was showing it to my wife and how it would be impossible to fit the base (unless dismantled) into my Corolla station wagon. And the price is a bit too high as well.

Then I showed her 20” $12000 and how nice and portable that one is. She said: “Well get that one then” WOW!

Now I am thinking every day about it with a lot of questions in my mind. Should I buy it, or is there something better and not costing so much?
Your suggestions and opinions are welcome!

I used to have 8” Dob, sold it and got Bintel 12” Dob. Loved it, especially for deep sky observing. Then looked through 16” Meade Lightbridge and was blown away.
Then I cooled down, sold my 12” Dob and bought early 8” NexStar Celestron for planets mainly.
Now I got again very interested in deep sky observing and 8” simply can’t give me views that I used to see with 12” Dob.

Cheers

Bob

[AG Hybrid]

They a pretty darn good value for what they are. I've spent a lot of time looking into these and I've concluded it isn't really portable which is important to someone who lives in Sydney and needs to travel to darker skies for a better visual experience.

Furthermore, the size of the ladder required due to the eyepiece location also needs to be factored in for travelling with it. With the 18" non-goto you can get by with a short step stool. One of our club members has one. The 20" goto dob telescope is collapsible perhaps, or should I say dismantlable, but what about the ladder you require to actually use the thing.

[OzEclipse]

HI Bob,

If you live in Perth then portability is a key issue. I have an 18" f5 with a Galaxy Optics mirror. It's very similar construction to an SDM. It is portable but not as portable as the SW20".

I live on a a rural property with Bortle 1-2 skies and the scope lives here all the time so portability is not an issue for me. .

Yes you can use big instruments from the light polluted city for planet observing. But they won't give you much advantage for observing faint details in DSO's. Doesn't matter how big the telescope is, if the object is fainter than the light pollution, you won't see it.

I have seen some amazing planetary and lunar detail through the 18" but where they really shine (no pun intended) is on deep sky objects under a really dark sky.

Some examples: - the Dumbbell nebula is a full orb, not just a dumbbell, you can see the Orion nebula fully loop and close up again and on nights of high transparency, I can see a hint of red in the brighter parts of the nebula. Look at Markarian's Chain and you'll easily see 9 galaxies. Globulars like Omega Centauri and 47 Tuc just blow apart.

If you live in Perth's LP, I would place a high premium on the portability.

cheers

Joe

[bobson]

Thanks Adrian and Joe,

Yes, portability is very important. I live near Perth Airport, so travelling to dark site and ability to fit scope in my Corolla wagon is a must.
Availability is another issue, scopes are advertised but they don’t have them in shops. Would have to put deposit and wait.
You raised good point about how high the eyepiece will be on those big Dobs. I have seen some nice solutions on YouTube. I could make it myself.

Thinking about it too much and it’s a lot of money as well.
Maybe I shouldn’t make big jump from 12” I used to have to 20”
I could get 16” Meade Lightbridge that is advertised for $2,500 here in Perth.
It’s portable, base would fit in my car without dismantling it, and there is no need for steps or ladder to rich eyepiece.

Cheers
Bob

[strongmanmike]

This is my take on it :)

Firstly I am in a very similar position to Joe and have the SW 18" goto Dob (https://pbase.com/strongmanmike2002/image/173397228/original) under excellent dark, steady and transparent skies and it is simply fantastic viewing!! Were I not permanent and was keen on a dob for dark sky viewing that required pack up and significant travel and was keen to make the most of my trips out to great skies, I would snap up the biggest scope that would fit in my car and one of these SW20 goto dobs would be perfect :). The way to look at it is and certainly if you have received the finance go ahead (:2thumbs:) why go to all that trouble to travel to a dark sky, only to get there and set up a piddly 10 or 12"..?just becasue it takes 10min less time to setup, and three steps less to view the eyepiece!? (although I do have one of those too (https://pbase.com/strongmanmike2002/image/173358176/original) :D) the views will be well worth the slightly extra setup and packup time! I've looked through a few large dobs over the years, under some of the best skies on the planet and a 20" class dob under a truly dark sky is truly amazing, you wont regret it!

So, if you can indeed fit it in your car and that's your main method of use, go for it I say, the views will be worth it!

Mike

[bobson]

Mike,

Remember this movie line:

“Just when I thought I was out, they pull me back in” – The Godfathe

I have to admit you make perfect sense. Now I have to read more about dimensions and reviews of SW 20” GOTO.

Weight doesn’t bother me, still deadlift every now and then 230kg for reps.
Not bad for 61 year old f..t :)

Do you still lift Mike, just for keeping fit I mean?

Cheers
Bob

[strongmanmike]

You're welcome :P

230kg for reps at 61 is bloody awesome mate! :eyepop: wow! I don't know what I might be able to pull if I went back into a gym today..? Pretty sure I would struggle to match you, maybe after a couple of months getting back in to it. I'm 57 now and I haven't lifted in a gym since 2005. At my peak in 2001, in the full deadlift (with no straps or suit) I did a set of 10 with 275kg and a single on 325kg (regular stance not summo), but my real bazar forte was the so called, silver dollar deadlift (bar 19" off the floor) in which I pulled 475kg without straps or a suit and a whopping 500kg with straps (but no suit!), it was World class at the time easily top 5, still is really :shrug:...I was just even more disproportionately strong in that particular reduced range than everyone else. :) Here is Rauno Heinler, the current best in the World at this event, doing the current Silver Dollar Deadlift World Record last year, with an amazing 580kg. (https://barbend.com/rauno-heinla-world-record-silver-dollar-deadlift-580-kilograms/)

Ah sigh....those were the days, I do sweet FA now and my body is already starting to develop some arthritis, mainly shoulder, and old age body aches :help:

Now go get that 20" Dob, I really want to upgrade my 18" to it too but my finance minister is pretty well at her limit :sadeyes:

Mike

[OzEclipse]

Bob,

The SW 20" dob is a 20" f3.9. When viewing the zenith & looking at the design, I would guess that the eyepiece would be no more than 1.8m off the ground. Most of the time it will be lower. Depending upon your height, it may well be more comfortable than a 12" f5 and you won't need a ladder, maybe a step if you are shorter than 1.8m.

At age 61, your maximum pupil dilation is probably around 4.8mm. I and 3 friends are all in the 58-62yo age group and we have all recently measured our pupil dilations at 4.7-4.9mm.

Assuming you, at age 61, are similar, the longest eyepiece focal length you can use for 100% light transmission to your eye is: -

Pupil diam x f ratio =. 4.8 x 3.9 = 19mm.

Using the supplied 28mm LET eyepiece to attain a wider field, the light transmission will be equivalent to a 14 inch diameter scope. So you will want a wide field <19mm eyepiece such as a 17mm Nagler as your killer DSO eyepiece. Of course you can use the longer focal length eyepieces if you accept the light loss. A 31mm Nagler will give you the light transmission equivalent to a 12-13 inch aperture.

Providing you are aware of the interactions between pupil dilation & exit pupil, you can gain great enjoyment from such an instrument as Mike and I and many others do.

I have a whole article about this on another forum: -
https://theskysearchers.com/viewtopic.php?p=283294#p280632

cheers
Joe

[bobson]

Mike,

That’s some crazy weight you moved around! I was more on bbuildung side of it but liked to lift heavy especially deadlifts. I still believe deadlift is the best overall exercise you can do. I watched that video 580kg!!!
In my best days only once I lifted 380kg 12 times so called partial reps in power rack setting pins higher and with wrist straps.
Good old days mate.

Joe,

You are pushing right buttons too :) I already have 17mm Nagler and am 185cm tall.

Going to work now but will read your article.

Thanks guy's

Bob

[Derek Klepp]

Listen to you old lifters cracks me up.The joys of youth.But seriously Bob good to see you still training.Go the big scope.I have a SW 16” and my best moment was when the kids were younger and they saw the moon through it.As Mike said you won’t regret it.Time is ticking enjoy the view.
Cheers Derek

And yes I am one of those old lifters as well.

[AG Hybrid]

The 20" has an eyepiece height of 2 meters at zenith. OK we don't often observe at zenith, but the GOTO has extra height added on top of that due to the mechanics of the motors.

Sky Watcher themselves stated that number. Once again a decent ladder is required for these larger Sky Watcher dobsonian's. We don't observe from the tops of out heads.

At least the 20" the focuser is at a 90 degree angle. Some genius thought it was a good idea to have the 18" focusers at a 45 degree angle.

[Rainmaker]

These big scopes are certainly rewarding with the views they give and a 20” that can still be portable is excellent way to go.

I went from an 18”F5.6 to my current 18”F3.5 “ Excalibur “ DIY job as I needed a more compact scope to fit into my motorhome through a hatch. In the process I brought the focuser down almost a metre and saved a lot of weight. Sit down viewing even at zenith is a nice bonus and it fits in the back of my Subaru XV Hatchback. Though as I’m getting closer to 70 I’m now considering building a baby version of Excalibur using my 13”f4.3 mirror set….

[alan meehan]

Our society has a 16inch collapsible goto dob skywatcher which i look after its a great scope but is heavy i built a purpose built trailer for transporting it with a fiberglass lockable top and i just have a ramp into the trailer to it goes and straps in ,the views with the scope are terrific and the goto works so well last public viewing night we tracked the moon for 3 hrs and it just worked they are lovely scopes

[strongmanmike]

:lol:...ah yes, the good old fishing stories, ala the Four Yorkshiremen (https://www.youtube.com/watch?v=ue7wM0QC5LE), when we were luds..we had it toof! :P

Looks like there is no choice Bob, its unanimous, the decision has been made for you :thumbsup:

Mike

[Startrek]

Hey Mike,
Nothing wrong with a “piddly” 12” under my darkish B3 skies down South
My SW 12” Goto using my array of TV eyepieces is unbelievable no
matter what you observe
However I’d imagine a 20” would be absolutely another world under even darker skies as you said ……..
I use an adjustable gas strut bar stool for comfy viewing plus from my garage to my car bay observing location is only 6m away. Very convenient
The 20” is very enticing !!
Cheers
Martone

[strongmanmike]

Oh yeah, I have a 12" goto Skywatcher too, it has provided great views for sure! :thumbsup:...buuuut still piddly, compared to a 20" I am afraid, especially under true dark skies! :stargaze: :astron: :)

Mike

[strongmanmike]

God damn it! that's a beautiful scope Matt :love:...you need to bring it up to Eagleveiw one clear Moonless night...we could have two 18"ers hammering away :)

Mike

[bobson]

Thank you guys!

Yes, we were lifting some serious iron :) And still bloody do, those young guys have no idea ;)
I knew I could rely on you to convince me to buy it.
I was like a frog sitting on the rock above beautiful lake thinking should I jump into it or not :)

Now, the question, where to buy it from?

I checked a few websites and Andrews communications has the best price. Just called them and confirmed $11,499 plus delivery, will let me know on Monday how much.

Cheers

Bob

[Rainmaker]

For that money you could almost buy my Excalibur…… almost …… ;)

[Rainmaker]

Thanks Mike, I was up there recently to check out 135 Calabash….. decided against it……(actually my wife did) :lol:

[strongmanmike]

Doh!...What a shame! Together we could have owned the whole of Mt Eagle, guaranteed each other dark skies for ever ...kings of the mountain, rulers of dark skies! Mu hu ha ha haaaa :)

Mike

[bobson]

I ordered 20” from local BinoCentral here in Perth. Keith matched the other shop price 👍🙏

Matt,
You should have told me earlier, maybe we could have come to agreement 🙏

Thank you all for very detailed valuable info!
I will keep you informed once I got the scope 👍

Cheers
Bob

[strongmanmike]

Awesome :thumbsup: good luck with it, Im sure you will love it ...and make me jealous :)

Mike

[EpickCrom]

G'day Bob. Wow congratulations on your purchase :eyepop:
I'm also about to purchase a large dob from Binocentral, mine won't be as large as yours, a 14 inch dob!

Keith is a great guy, and I'm sure the views through your 20" will be incredible. Enjoy :thumbsup:

[gaseous]

I've had my 20" Stargate GOTO for about 6 years now, and the views from it have been spectacular. I generally only use it after a decent drive to a dark site - there's a fair bit of faffing about to set it up if you're moving all the bits, and under Bortle 5 skies at home it's not really worth it in my opinion. They do take up a fair bit of space when dismantled, but another guy I know can fit his into the back of a medium sized hatchback, fully disassembled. I try to keep mine semi-assembled (poles at full length, mirror on the base) in the back of a trailer, and have detachable wheelbarrow handles with wheels bolted to the sides so it can be easily rolled off the back of the trailer. Lugging the base and mirror assembly separately gets a bit tiresome even for someone with a strong back, and being able to wheel it into place saves both time and vertebral wear and tear.



As Adrian mentioned, the eyepiece height at zenith is around 2m at least, and at 183cm high, I certainly need a small aluminium two-step ladder to see through it, although the finding/tracking for objects in the "dob hole" is a bit hit and miss, so I normally avoid anything this high. Even above 70° you'll often need at least the bottom step of a small stepladder, depending on how tall you are. I'm sure you'll be "wowed" by the views you get though, it's a great scope.

[bobson]

Thanks guys,

Joe,

I wanted to get 16” SW GOTO but realised the base is too big to fit in my Corolla wagon. 14” apparently has the same base as 16”. Not sure why they couldn’t make mount like Orion used to do, easy to disassemble and fold so it can fit in small cars.
If you are with AGWA it would be interesting to compare views of our new scopes.

Patrick,

That’s great mate that you have this scope and happy with it. I watched some videos people having issues with drives and scared me a bit.

Cheers

Bob

[gaseous]

I've had no issues at all with the drives, and once aligned I've found it tracks beautifully smoothly and accurately for hours. Like most GOTO scopes, the better your initial alignment, the better the rest of the evening's viewing will be.

[EpickCrom]

Hi Bob! Thanks for this information! I'm planning to pick up my Skywatcher 14 inch GoTo using my Mazda 3 sedan once I purchase it, it has a big boot but you mentioned the size of the base mmm..I might have to get it delivered or try to borrow a truck from work.

I'm not with AGWA but will definitely be joining soon. Would be great to catch up with you and compare views! :eyepop:

Clear Skies
Joe

[bobson]

Patrick,

Will I get shroud with telescope? It’s a bit confusing, if I check USA SW website it mentions shroud from light material. But on Australian SW website it’s not mentioned under what’s in the box.

Thanks
Bob

[strongmanmike]

I would imagine the shroud is extra, but I don't use a shroud with my 18" SW truss, as with one, anything over a variable light breeze and your views are highly frustrating, wobbly blurs.

To slow down dew, a nice stiff black cardboard cylinder, that you can simply slip around the mirror, about 20" long and a hair dryer, will do the trick, without acting as a wind catcher.

Mike

[gaseous]

Hi Bob,


if memory serves, the shroud was included when I bought mine back in 2018, but as you say, the current websites don't mention the shroud, and it might be an extra. Mike is correct in saying that the shroud can certainly pick up the prevailing breezes and give you a bit of wobble, but I normally use my shroud and take it off only when it's too breezy. You'll need to check with the supplier to see if the shroud is included. It connects with three rather flimsy tie-up ribbons and a 2m long velcro strap along the edge, which is a bit awkward to make it sit nicely. I invested in a 2m long black zipper for about $20 off ebay, which my wife sewed over the velcro, and it's now very easy to put on. I normally only use my scope at dark sites, but still think it's worthwhile having a shroud.

[bobson]

I got the scope, it’s really big!
I have to say manuals are almost useless. Assembling instruction says: refer to figure 1.9 and there is no figure 1.9? It has 1.8 and 1.10
The cover to cover tensioning spring doesn’t fit on top 2 holes, might need to shave the shoulder a bit if I want to use it. Bottom holes fit though. It can be fit only one way so there is no mistake in assembling it. Not that I will need or use cover for spring but since they supply it, why not.

Also tensioning bolt that attaches to spring supposed to have limiting nut on it but it doesn’t! Will have to try and see if altitude doesn’t slip and how much to tension the wing nut. Instruction is saying to tension it to limiting nut and that it’s been tasted in factory that to be appropriate tension :(

Didn’t get Allen key for secondary mirror adjustment. It looks aligned though.

Now something I really don’t understand, I can not use laser collimator because it absorbs laser light to the point I can’t see it! Maybe need a new batteries, but if I put paper in front of both mirrors I can see laser light clearly.

Collimation screws, I asked my wife to turn each while I look through collimating eyepiece that came with scope and she turned two but third one she couldn’t. I checked it was was really, rally hard to undo and after a few tries it’s still very tight to turn, sprayed it with WD40 and it s a bit better now. The mirror is so heavy that Collimation screws can only freely be turned when scope is upright.

After collimating it turned it around, up and down and collimation is out! Will have to try again and make sure everything is tightened

So yea, a lot of fun so far, hopefully will try to use it tonight if I get around all those issues.

Shroud came with it :) and some other bits and pieces I have to check them out.

Cheers


Bob

[bobson]

Thanks Nate,

Getting there slowly. It’s frustrating at times but also enjoyable when it works.

Cheers

Bob

[bobson]

I found out that Cradle sits on two small pulleys that are used to tighten steel rope around Altitude pulley. I don't think Cradle should even touch those small pulleys because there are two Allen key 1.5mm screws on each one of them. Those screws are making Cradle to jump or even jamming it when I try to operate scope up and down.

Because of this, those small screws are loose and one even fell out (lucky I found it) but thread is damaged and it barely hold this tiny screw.

Looks like I bought myself 12k headache :(

Please help!

thanks

bob

[gaseous]

Hi Bob, I've sent you a PM too. Cradle should definitely not be sitting on those small wheels, and mine has a small gap between the cradle and the screws. I'd try tightening those screws a little bit.

[bobson]

Thanks Pat,

Yes, I tried tightening those screws as well but they are still about 1-1.5mm proud. And as you can see from pic above cradle sits flat on the small wheel/pulley and every time that pulley turns and screw comes around it jammed cradle or motors slip and jump over it!

Will have to call Keith from BinoCentral tomorrow and see what to do. Because I noticed my alignment at altitude was always wrong, at least now I know why.

Cheers

Bob

[By.Jove]

Easy - remove the screws and replace with ones with countersunk heads, flush with that surface.

[bobson]

Hi Jove,

I just bought this scope, didn’t even have time to go under dark sky yet.
I don’t want to remove or replace things and void the warranty. Besides, where would I get such a tiny screws from, and to be right size, flash with pulley surface? Those screws are tiny with 1.5mm Allen key, very short, pointy tip so they sit inside and lock pulley sleeve to shaft.

Another thing is I don’t think cradle should sit on those small pulleys anyway. I think they are connected to digital circles so you can release clutch, move scope and scope still would know where it is.

Patrick already messaged me that there is a gap between cradle and small pulleys on his 20” scope.


Thanks
Bob

[EpickCrom]

G'day Bob and best of luck in getting your monster 20" up and running.

I look forward to your first light report :eyepop:

Clear Skies
Joe

[bobson]

Thanks Joe,

Looks like it will take some time till I am able to use the scope because of this issue with mount.
Keith from BinoCentral sent the pics to Tasco yesterday morning. Someone from Tasco is supposed to call me to discuss about the issue with mount. But today is second day waiting and no call :(

Did you pick up your 14” yet?

Cheers

Bob

[strongmanmike]

That sucks, I hope it is a simple solution, or they send a replacement, I'd hate to have contributed to encouraging you to buy a huge lemon :scared:

The most likely outcome is it will get sorted and you will have so much fun and be so delighted with the views that your rocky start will become a distant hazy memory :prey: :thumbsup:

Mike

[EpickCrom]

Hi Bob. No, I haven't bought my 14 inch yet, still saving up me last pennies:) At this stage I'll be ready to purchase it in early December. Really looking forward to it :thumbsup:

[bobson]

Michael,

You couldn’t have known this is going to happen. It’s one of those things, you buy something and expect it to work as described before you buy it and then this happen. Imagine you buy a car and found out you can’t drive it because the gearbox it faulty.
Keith from BinoCentral is onto it. He said Tasco was closed on Monday and Tuesday because of Melbourne cup. That means they had 3 business days to respond.
I don’t like waiting, nobody does. As soon as I know more I will let you guys know here.

Cheers

Bob

[AstroJunk]

Often grub screws fix to a flat surface rather than the barrel itself. With a bit of over zooming, it looks like the pully wheels may be incorrectly rotated and hence the grubs protruding. Rotate them around so that the grubs align with the surfaces marked with an x. Maybe.....

[bobson]

Jonathan,

Thanks mate, I thought the same when I first time looked at it. But no, bolts are concentric, it doesn’t matter which way you turn them the small pulleys with grub screws remain the same height.

The issue here are those 4 grub screws, they are in the way when altitude is operated. Why are they there?

According to other members here who have the same scope or 18”, those small pulleys clearly do not touch cradle! There is a clearance between them and cradle.

One of them lost all 4 screws and it doesn’t affect operation of the scope!?

Why are they there then, if scope operates normally without them?

Hopefully it’s nothing serious.

Those 2 small pulleys can not be adjusted. The bigger pulleys at the ends also can not be adjusted. In both cases there is simple threaded hole, not adjustable in any way.

Cheers

Bob

[bobson]

https://youtube.com/@bobkrsmanovic2601?si=EDxlJp6Qco5PR 9Ak

I made a video how those grub screws in question are jamming cradle, hand operated.


Cheers

Bob

[bobson]

https://youtu.be/euX6gJR0r3c?si=y3jUk-N6EY7L7-a-

A video showing grub screws jamming cradle when SynScan altitude operated.

[strongmanmike]

That looks pretty clearly a fault, have Skywatcher fixed it yet?

Even with flush grub screws that would be incredibly tight....

Mike

[bobson]

Hi Mike,

Sky-Watcher didn’t respond yet!

BinoCentral, place where I bought scope from, asked me to bring the scope to them to have a look. After long examination they couldn’t find out what is the purpose of those grub screws, so they removed them. Then operated the scope without them and it seems it’s working fine.
I am yet to take scope for real test, at least now it’s not jamming and jumping up every time altitude is operated.

Cheers

Bob

[strongmanmike]

Ya kidding?!!...fair dinkum! :rolleyes: Crazy stuff.

Hope it's all fun and games from here now :thumbsup:

Mike

[bobson]

I wish it is mate, but wait there is more :)

While I was occupied with mount I just realised they packed wrong eyepieces in the box. This is not BinoCentral fault but Skywatchers.

I am supposed to get: 1.25" Plossl 10mm, 2" LET 28mm
I got 12.5mm and 20mm, both 1.25”

I called BinoCentral and they are investigating.

Cheers

Bob

[Tom30887]

At 20” isn’t the collapsible part a little meaningless :lol:

But yes, I would buy a 20” GoTo DOB

[OzEclipse]

If the optics in your 20" scope are decent, and SW optics usually are, they deserve better eyepieces than the crap starter eyepieces they throw in the box. A 28mm eyepiece will have a 7mm exit pupil. Unless you are 20 years old, your eye won't be able to accept the light from the telescope and you are unwittingly converting your scope to the equivalent of a much smaller scope.

If you are in your 50's, you'll only get the equivalent light of a 14" scope. If you are 50+, a good quality eyepiece around 20mm with a wide apparent field 70-84 degrees will give you maximum light transmission to your eye.

Look at eyepieces like:
Baader Morpheus, 17.5mm 76 deg
Denkmeier D21mm, 68 deg
Pentax XW 20mm, 70 deg
Televue Nagler 22mm, 82 deg
Televue Ethos 21mm 100 deg
Explore Scientific 18mm 82 deg
Explore Scientific 20mm 100 deg

Joe

[bobson]

Hi,

I should have mentioned that eyepieces that came with the scope are actually 12.5mm and 20mm, both 1.25” and both 70°

I already have Nagler 17mm and Pentax 10mm XW

Last night I finally took my new scope to dark sky. Unfortunately I never was there before and arrived when it was already a bit dark. Well, dark enough that I had to use my laser collimator. Usually my laser collimator gets it within 1mm accuracy and then collimation eyepiece or long Cheshire for final collimation.

One of the guys who was there looked through my 17mm Nagler and was really impressed with the view of Orion Nebula. He asked me do I have anything bigger than 17mm Nagler? I said; yea but it’s very cheap 31mm Bintel eyepiece that I bought long time ago or it came with Bintel 12” Dob I bought from them long time ago.

It was good in centre but everything else was a mess. He offered me to try his “Astromania” 30mm 80° eyepiece he got from Amazon for $200
WOW! I am 60 years old and he is 64 years old. I told him what I was told about exit pupil at my age and how my Nagler 17mm will be maximum I could use, he just laughed and said yes, I heard that too.

It’s like saying we all should have 120/80 blood pressure but do we?

I guess, it all depends what object you are looking at.

With my 17mm Nagler I simply can not see whole Orion or Eta Carinae nebula. With his 30mm 80° I could, and the view, which is of course personal thing is more pleasing for me for those two objects.

As Joe suggested above: Televue Ethos 21mm 100 deg would most likely be perfect eyepiece for me. But I don’t have it :(
I might look into it to get one, preferably I would like to look through one before I spend $1,769.00 for it!!

The views for other objects last night were very good and I was assured from those two gentlemen that optics are good. That was my main concerns considering other things about this scope that I had issues with.

GOTO was hit and miss. Sometimes you select an object and it’s within field of view in wide eyepiece and sometimes I had to look through finder and adjust a lot till I could see it. And then some objects are dead in the centre right away?!

All up, I am happy with the scope and finally can relax and start enjoying it more and think how the hell am I going to convince my wife that I need 21mm Ethos.

Thanks everyone!

Cheers
Bob

[EpickCrom]

G'day Bob, what a nice first light report for your 20"!

I'm glad everything is sorted now and you can finally get some observing done. Gee Orion Nebula through a 20" from a dark site must have looked spectacular! Yeah those Ethos eyepieces are mighty tempting, I just purchased a 17mm Ethos, can't wait for it to arrive. Enjoy your beast:thumbsup:

Clear Skies
Joe

[gaseous]

Bob, I'm pleased to hear that your teething issues have been resolved and you can finally get some proper time at the eyepiece! As far as your eyepieces go, yes the exit pupil for someone your age is probably not going to elicit maximum illumination value from a 28-31mm eyepiece. Same for me, but my 31mm Nagler with an exit pupil somewhere north of 7.8mm (maybe closer to 7mm with the GSO coma corrector) spends an awful lot of time in my Stargate for the expansive views it produces. Am I losing photons? Undoubtedly. Do I give a rat's? Not one. You mention having a bit of a mess around the periphery of your views - have you got a coma corrector? I found even the really good eyepieces suffer at f3.94 without a coma corrector. And while a 21mm Ethos is on a lot of people's Christmas list, the price is pretty daunting. I bought a 20mm 100° APM eyepiece a few years ago on the advice of Don from Eyepieces Etc, and it's a cracker. Don advised that it's similar/the same as the Stellarvue Optimus, but quite a bit cheaper (and about 70% cheaper than the Ethos). I also note that there is a range called "Skyrover" available on Aliexpress which look identical to the APM model and if you can get free shipping and one of the current discounts, you could pick one up for less than $350 including GST.

[bobson]

Patric,

I used GSO comma corrector, it improved views slightly. I couldn’t reach focus with my 17mm Nagler so I had to pull comma corrector a bit out.
I was really impressed with Astromania 30mm 80° eyepiece. Currently $162.99 plus $15 postage. I might buy this one until I try some better quality eyepiece.

Cheers
Bob

[AstroJunk]

I had a 20" F5 and the 17mm Nagler was used 90% of the time. I had the Holy Hand grenade (31mm Nagler) too, but I would quickly swap back to the extra reach of the 17 to bask in all the detail. I used a 4x powermate for planetary etc.

You may wish to consider a paracorr to fully correct the FoV which wasn't strictly needed in my F5 but it did make a noticeable difference and would also bump up the magnification of the 17mm by 10% which may also be better in your f4 configuration.

Xmas is coming ...