6" Evo or Discovery ?

[SilverAstro]

Hi all,

Time I got back into astronomy ! And I was contemplating a 6" Evolution until I saw on this forum a pointer to the SW Star Discovery and I am totally a ) perplexed and b ) bemused at the price difference ! (Let alone what is available these days to the amateur astronomer !!

So I have composed a table of (required?) objects, facilities etc of the two and would appreciate comments on any mistakes or missing content, thanks :-

        Discovery    Evo
Optics        Newt        Cass
f        5        10
xMsupplied    30,60,75,150    38,115

fov/StarHop    g        p
Moon        y        yy
Planets        y        yy
Doubles        y        yy
Globular    y        yy
Open cluster    y        m
Star fields    yy        n
Nebulae/DSO    ym        p-n
{Star/Asteroid    ?        ?
{Limiting mag    ?        13.4
Galaxy/eg.M81    ?        ?

GoTo+PushTo    y        y
Portability    y        y
Stab./Wind    ?-        g
Dew        g        p

BuildQuality    ?        g
Price        yyyy        n!

Oooops it doesnt like tabs ! I hope you can see what I meant, and I forgot the legend :

g=good,, p=poor,, y=yes,, yy=very yes ! ,, n=no (of course),, m=maybe  and ?= I dont know

 

Thanks for trying to decipher ,,,

 

 

[SilverAstro]

So, the Evo clearly out performs on 'easy?' small angular dia commonly available objects, I think ??

but at a price ! ~£345 vs. ~£1055 !! Wot am I missing ?

I dont need WiFi, nor even computer support,

I do want GoTo+PushTo because I have spent too much time in the past star hopping* and not enough time, between clouds, observing ! time is short, and getting shorter !! 

* I pride myself on being able to navigate the sky (by principle stars and many secondary) and have kept my ' eye in ' with binos over the years since my last 'scope.

 

[happy-kat]

The freedom find on the discovery means with the clutches undone you can literally use your hands to move the telescope. It can be a totally unpowered experience. Engage the clutches and it will track again and if it had been aligned the goto goes to. There is an excellent video on youtube by astronomy and nature tv. I have the little version in the virtuoso mount. You could get the discovery and with the saving made look for a second hand 150 mak to swap and use on the mount (if the weight was within capability, the 127mm mak would be fine that can even go on my mount) 

[glynnlondon]

Hi silverastro the skywatcher is a simple Newtonian mirror reflector on an az mount , the celestron is a top end sct type telescope which uses glass and mirror in its use.

You could also look at a dobsonian type maybe like the Orion intelliscope range they use a push to system.

[Cornelius Varley]

Hello and welcome to SGL. The main reasons for the price difference is because the Star Discovery has been built down to a lower unit cost. The telescope has is a much simpler optical design (Newtonian reflector) which is much easier and cheaper to make than a Schmidt Cassegrain. Synta have also made use of cheaper plastic components for the Star Discovery compared to their other 150/750 reflectors to reduce the cost even further (plastic 1.25" focuser, plastic non collimatable mirror cell) . The Evo 6" SCT is in a different class to the Star Discovery and is aimed at the more experienced user and is priced and specified accordingly. The Evo range, as you have probably noticed, includes  built in WiFi and power pack which will increase the cost of the telescope over the budget Star Discovery (SCT's are also more expensive to manufacture due to their more complex optical design). The Star Discovery still seems to be great value though, so your choice will depend on what features you require.

[John]

Good advice already given on these choices. Worth bearing in mind that the actual optical performance, that is the view you see through the eyepiece, won't be radically different between the scopes. The newtonian scope will be able to show wider views and will need shorter focal length eyepieces, or the use of a barlow lens, to get higher magnfications but otherwise similar views.

 

 

[laudropb]

It really does depend on what you want for your money. In the long term I think the Evo is probably the best choice, but personally I think I would gofer the advantage of the larger FOV given by the newt.

[Chris]

As said, both the mount and the optics of the Evo are built to a much higher spec. However, fundamentally they have the same light grasp so will show similar things, only with a different field of view when using the same eyepiece.

[Alan64]

A refractive, go-to-mount option to consider instead...

http://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html

http://www.firstlightoptics.com/skywatcher-mounts/skywatcher-az-goto-mount.html

 

 

[BGazing]

Two different classes of scope, really. Slow vs fast, budget vs expensive, refractor vs sct...

I agonized over similar choices when I was thinking about buying my first scope. Finally went for the budget solution (as there were more expensive ones), sort of like finding my way around and testing my commitment. As I understand, rarely does one remain at one scope in total.

[Guest]

I looked at the EVO range before I bought a discovery. What put me off the EVO is as it's a sct there is also needed upgrades to actually use this scope being a dew shield and probably heat band for the corrector. This can't be powered from the mount so another extra would be a power pack leaving the battery option of the mount a quick get out and observe useless imo. If your lucky enough to live in a dry climate then the said issues won't effect you. But it's all added extras to get the usage of the scope needed to warrant it's price. My discovery has been running on its batteries now for around 20+ hours and is only just showing signs of power issues.....she still tracks a treat but almost used batteries struggle to slew to the correct position when asked. But batteries are like a fiver ? 

[SilverAstro]

Thanks for all your interesting replies everyone.However ! I was not asking which I should buy and yes I knew that one was a Newt and one a Cass, quite different beasts and it all depends upon what I want to see, indeed That was the purpose of drawing up the list of their relative capabilities and to see if I had correctly assessed them !

Cornelius surprised me with the lack of collimation in the Discovery,,,,, I thought " no really, how can that be with an f5 Newt " but sure enough - I have found a youtube in which it is so ! Extraordinary !!

 

3 hours ago, LeeRich said:

 before I bought a discovery.

Did it work 'outa da box' or did you need to install new updated software, because in that video he makes much of the inadequate SERIAL lead and the problems of a USB converter.

 

 

 

[Guest]

1 minute ago, SilverAstro said:

Did it work 'outa da box' or did you need to install new updated software, because in that video he makes much of the inadequate SERIAL lead and the problems of a USB converter.

 

 

 

Mine just worked matey, only thing i hated was the focuser but i swapped that straight away.

I assumed you knew the difference between the scopes too lol my intervention was purely in why i chose the cheaper option as the EVO with its battery pack etc was pointless to me

if i still had to buy a powerpack to power the heat element for the corrector plate.

My 150p however was off collimation from the factory but it is collimatable and still easy to do despite there been 4 screws to loosen and adjust, a little unorthodox but workable.

Good luck with your choice.

[SilverAstro]

8 minutes ago, LeeRich said:

My 150p however was off collimation from the factory but it is collimatable and still easy to do despite there been 4 screws to loosen and adjust, a little unorthodox but workable.

All good info, especially the battery life ( and not special built-in battery like in the Evo, which bothers me a bit for a few years down its line )

thanks Lee and I may ( but would hope not ! ) to need to get back to you for a "how to" on collimation on one lol!

 

 

[Guest]

No problem buddy, its actually easier in some respects then a 3 point system as you simply loosen all 4 screws so the cell moves without being slack

with your laser collimator set your elliptical up so its central to the primary marker then....

Imagine the 4 screws as north south east west axis.....

Now, hold the edge of the mirror cell and adjust the east west screws in/out until the laser dot is on the north/south line in the collimator view...not tighten slightly

Now hold the mirror cell and adjust the north/south in/out till the red dot lines up on the east west line and disappears in the hole lol..

did that make sense ? when and if you do it you will see how easy it really is. once the laser has vanished in the hole tighten all 4 screws...done.

[SilverAstro]

15 hours ago, LeeRich said:

did that make sense ? when and if you do it you will see how easy it really is. once the laser has vanished in the hole tighten all 4 screws...done.

Yes, I'm sure it will when/if I have one in my hands very reassuring.I am tending to think "enough" of all my fancy analysis of mine, just go get one and use it while I do fancy stuff later once I have got my eyes back in and see how my older bones stand up to winter temperatures these days

What was the prob with the focuser , did you hve a special requirement or was it plain bad ?

 

 

[Guest]

6 minutes ago, SilverAstro said:

Yes, I'm sure it will when/if I have one in my hands very reassuring.I am tending to think "enough" of all my fancy analysis of mine, just go get one and use it while I do fancy stuff later once I have got my eyes back in and see how my older bones stand up to winter temperatures these days

What was the prob with the focuser , did you hve a special requirement or was it plain bad ?

 

 

 

lol i am in the same boat there...needed a get me back into it scope so this 150p was a no brainer. Love the goto as time is of the essence for me as i hate the cold lol

Dream scope in a year or so will probably be the 12"LX90 but that s whole lot of saving

The focuser for me was the let down of the whole scope....sloppy, crude, stiff, course the ep / collimator has way too much room in the drawtube. I will send you it if you dont believe me hahah

Its marked for the bin.... lol

[SilverAstro]

On 26 February 2016 at 10:07, happy-kat said:

The freedom find on the discovery / There is an excellent video on youtube by astronomy and nature tv.

Thanks h-k, the "freedom find" sounds very useful, and the guy in the vid ( thank you yes found it ) is very enthusiastic about nearly everything about the 'scope except for the serial computer link/cable ! A bit luke-warm/unclear about one of the eyepieces supplied

On 26 February 2016 at 10:10, glynnlondon said:

You could also look at a dobsonian type

Tempt me not ! LOL thoughts are already turning to big dobs that could be afforded later if I go for the D. now

21 hours ago, Alan64 said:

A refractive,

Cant get the aperture ( =limiting mag) that I want ( 6" minimum) in my budget I dont think ?

21 hours ago, BGazing said:

Finally went for the budget solution / testing my commitment.

I have spoken with the "Chair of the Ways & Means Committee" and she is of the same opinion, I should see how much use the D. gets before getting other things, I like the implication in that !

 

On 26 February 2016 at 10:33, John said:

Good advice already given on these choices. Worth bearing in mind that the actual optical performance, that is the view you see through the eyepiece, won't be radically different between the scopes. The newtonian scope will be able to show wider views and will need shorter focal length eyepieces, or the use of a barlow lens, to get higher magnfications but otherwise similar views.

Thanks John, very good points, and a barlow is included with the Discovery. I have found the FoV app in FLO's website very handy for that, saved me ages of messing in Stellarium with ocular settings.

I may have to come back to you all on eyepieces shortly after I have done more thinking.

The good news is that "The Chief Secretary to the Treasury" has been approached and she is amenable

Many thanks to you all either unquoted or quoted

[Alan64]

18 hours ago, SilverAstro said:

Yes, I'm sure it will when/if I have one in my hands very reassuring.I am tending to think "enough" of all my fancy analysis of mine, just go get one and use it while I do fancy stuff later once I have got my eyes back in and see how my older bones stand up to winter temperatures these days

What was the prob with the focuser , did you hve a special requirement or was it plain bad ?

I have the same exact focusser on my 150mm f/5 Newtonian...

...and it's not that bad, but "worthy" enough to replace with one that would give better service.  

"Cant get the aperture ( =limiting mag) that I want ( 6" minimum) in my budget I dont think ?"

A 150mm f/5 Newtonian would reflectively-simulate a 120mm f/6 ED-doublet or apochromatic refractor; although not quite as refined, comfortable and portable a viewing experience as that with an 80mm ED refractor.

[SilverAstro]

1 hour ago, Alan64 said:

I have the same exact focusser on my 150mm f/5 Newtonian...

A 150mm f/5 Newtonian would reflectively-simulate a 120mm f/6 ED-doublet

Thanks Alan, good to know. Ok on 150 / 120, because of the obstruction on the Newt and Cass ? Good point.

So, new thought folks, am I correct in thinking that the obstructions are not significantly different between the Newt and Cass to be bothered about about at this stage ?

And, I have just spotted a significant omission from my original list - Comets ! (which no one picked me up on hahalol ) So, should I be blessed with a pretty comet and a clear sky in which to see it ( ) I guess the Newt FoV wins again ?

Lee has mentioned laser collimating*, not only does that add a bit to the cost it is entirely new to me, in my day we poked holes in 35mm film cans and squinted, followed by wishing for stable air ( in the UK ha!) to see star shapes, a labour of love.

*to badly translate Juvenal "Who collimates the collimators" (Quis custodiet ipsos custodes?) I'll get back to you all later if/when need arises for laser recommendations.

 

 

 

[happy-kat]

I use just a collimation cap. Admittedly I bought it £5 

[SilverAstro]

16 minutes ago, happy-kat said:

Admittedly I bought it £5 

Argh ! Just think what you could have done with that fiver if I had arrived here a bit earlier !! Not long ago I wanted to fake-up a webcam on one of my microscopes and being as how all my film cans are long lost in boxes in dark corners of the attic it was without much hope that I went to Boots-the-Chemist,,, and guess what  I was given a bagfull, surprised or what was I

[Guest]

I paid £17 for my laser collimator !!! DONT be fooled in thinking the Skywatcher and other better known branded ones are any different...only the price is !!!

They are dead easy to collimate too if you are unfortunate enough to receive one that's out a little.

Mine is a Vite and it produces a perfect dot rotation over 20m and as my scope is only 750mm in focal length this £17 budget one is more then adequate !

The more you pay the smaller the laser over a longer distance so yer....maybe better quality but upto 4X the price is just ludicrous to me.

I used the old focuser cover and drilled a 2mm hole in it on the works lathe to aid visual alignment but my cheapo laser does the rest and is spot on

Look at the SkyWatcher one and compare it to the Vite.......i bet it comes from the same factory yet a fraction of the cost.

http://www.ebay.co.uk/itm/191658175023?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.365astronomy.com/SkyWatcher-Laser-Collimator-7-levels.html

[Alan64]

A 150mm f/5 Newtonian makes for an excellent comet-hunter; so much so that the Newtonian design was combined with a Maksutov corrector-plate...

https://www.harrisontelescopes.co.uk/acatalog/Explore-Scientific-David-H-Levy-Comet-Hunter-152mm-Mak-Newtonian-4852740.html

I have found that a 150mm f/5 Newtonian is the closest one might come to an all-around visual instrument.  With a 1.25" 50° 30mm eyepiece, a magnification of 25x is realised; almost binocular-like, for observing the galaxy in Andromeda and the Pleiades during the winter, and for scanning and exploring the star-fields of the Milky Way during the summer.  In the 1.25" ocular format, it's hard to beat a Vixen 30mm Plossl...

http://www.firstlightoptics.com/vixen-eyepieces/vixen-npl-eyepieces.html

I have one, and chose it after careful research.  Click on the images for a larger view...

 

At the other extreme, I oft combine a 12mm ocular with a 2.8x barlow for a simulated 4.3mm(174x), and take shots through the eye-lens with a small camera...

Magnifications of 250x and beyond, under better to ideal seeing conditions, are certainly possible, particularly when observing the Moon.

 

In between, at the moderate magnifications, with a 12mm to 16mm, it's always show time...

 

Laser-collimators were developed for owners of far larger Newtonians.  With a 150mm f/5, one can easily position the eye at the focusser and reach back and adjust the tilt of the primary mirror.  A collimation-cap is adequate at first.  The kit may come with one; if not...

http://www.firstlightoptics.com/other-collimation-tools/rigel-aline-collimation-cap.html

Later, a Cheshire may be desired... http://www.firstlightoptics.com/other-collimation-tools/cheshire-collimating-eyepiece.html

One of the many sets of instructions found online for collimating... http://www.astro-baby.com/collimation/astro%20babys%20collimation%20guide.htm

The less-expensive laser collimators oft require collimating in and of themselves.  If you fancy the novelty, make certain it has grub-screws with which to collimate it.  Yes, laser collimators require collimating, too, and prior to use.  There are instructions online.

 

In so far as the planets, Saturn was an especially wonderful treat last summer through the 150mm f/5.

[John]

2 hours ago, LeeRich said:

...Mine is a Vite and it produces a perfect dot rotation over 20m and as my scope is only 750mm in focal length this £17 budget one is more then adequate !

 

Cant' fault your logic but remember that the laser has to travel twice the focal length of the scope to get back to the angled face of the collimator.

It's interesting to note that the "sweet spot" for accurate collimation of an F/5 newtonian is 2.8mm in diameter around the optical axis. Variation outside of this means that the scope won't perform to it's diffraction limits. For an F/8 this figure jumps to a relatively "sloppy" 11mm.