Which 4" frac? - New development!!

[parallaxerr]

It seems that whichever discipline I concentrate on in astronomy, visual or imaging, I always start to miss the other. I have gone and got myself a reasonable imaging setup now, still only using an achro, but my first Ha image proved quite successful. I'm happy with the setup and don't plan on changing for an imaging ED/Apo any time soon. But...the weather has been rubbish of late. Mild enough, sure, but permanent cloud cover, which means I have had no time under the stars. Last night was the first clear spell at a reasonable hour, but I didn't fancy the hassle of setting up the imaging rig and really fancied a visual grab and go. So, I dug out my only other scope which so happens to be the first I owned, a Celestron Astromaster 90mm, F11 achromat.

I mounted the frac on my HEQ5/16" extension/2" CG5 tripod combo. Talk about over mounted, the scope only weighs about 2.5kgs, so despite it's length, it was solid as a rock I extended the legs to get the EP at a reasonable height only to be surprised at the height of the objective above the ground, a 6'2", I could only just remove the dew cap at full stretch. This was all looking rather cool I thought. I only placed the mount roughly North but got a good 3 star align with minimal Az error and a tad of cone error, corrected by the mount. Gotos were spot on, putting targets VERY close to centre in my 30mm NPL, I'm really rather pleased with the HEQ5.

Now it turns out the transparency was really rather good, but seeing was poor, very bubbly. However, I spent time scanning around the sky looking at globs and doubles with decent separation from the moon and was surprised to find the cheap achro put up a reasonable image at low-medium mag. I did a star test and whilst collimation was spot on, the diffraction rings were far from round. More like a rounded triangle and I also noted 120° diffraction spikes on brighter stars. I think the self-tapping style objective securing screws are causing this as they protrude into the ota just behind the objective at 120° spacing.

I then spent a good 1-2hrs on the Moon. After trying all available mags with my ES 68°s and 82°s, I settled on the 16mm 68° giving X62.5 mag, the seeing and the scope just wouldn't allow for any more. I spent a long while waiting for the ejecta to become visible around Copernicus and working my way up the Appenines, I always find myself at Mons Hadley when viewing Luna, picturing the Apollo 15 landing.

Anyway, the point is, I REALLY enjoyed the session and find myself hankering after a 4" frac (actually I have done for a while, last nights session just tipped the balance!). Now, budget is always a consideration and with baby #2 due in Feb it's unlikely the scope will get as much use as I'd like. Having said that, being as quick to set up as it was, it will likely get used more than the imaging gear. So, I've narrowed it down to two choices -

1. Altair Astro Starwave Classic 102mm F11 - Cheap, good reviews, I already have a Baader semi-apo filter to clear up any residual CA. Some concerns over focuser rotation not being smooth, which will be used a lot on the EQ mount.

2. Sky-watcher ED100 F9 - Not so cheap, had an ED80 before and found it necessary to replace focuser, would love a Feather Touch....

Notwithstanding budget, I know what the general concensus will be on this, but the question is (assuming the addition of a decent focuser to the ED100), @ roughly 3 times the price, is the ED100 3 times as good as the Starwave?

NB - I have considered Maks and have owned a C8 (which was great) but I just want refractor, for now!

[John]

34 minutes ago, parallaxerr said:

Notwithstanding budget, I know what the general concensus will be on this, but the question is (assuming the addition of a decent focuser to the ED100), @ roughly 3 times the price, is the ED100 3 times as good as the Starwave?

NB - I have considered Maks and have owned a C8 (which was great) but I just want refractor, for now!

How would you define "3x times as good" Jon ?

Both scopes will show you the same things and about the same level of detail. The difference is likely to be a small amount of CA on the brighter targets. For what it's worth I don't think the Tak FC-100 is 7x better than the Starwave 102 (which is the price difference there) but the Taks are really superb 4" scopes and the ED100 is not far behind them at all. The Lightwave 102 is probably the best F10-ish achromat available currently.

So the performance differences are small margins and it's an individual decision whether they are worth the additional dosh

 

 

[pete_l]

27 minutes ago, John said:

So the performance differences are small margins and it's an individual decision whether they are worth the additional dosh

But that is true of everything, not just telescopes.  Is a BMW 5-series twice as good as a Mondeo? It's twice the price, so it should be!
But generally, people decide how much they can afford or are willing to spend and then choose something at that level: hoping that it won't disappoint. (When it does, we call that buyer's remorse.)

 

So far as astronomy goes, the rational buyer would start with a list of requirements: I want to be able to see / photograph the following targets .... aand then do research to establish what instruments would achieve those goals, then buy the cheapest. But we are not rational, we all fall for the advertising and we are not good at defining what we actually want . We all buy stuff more in hope than in expectation. And we all defend our decisions with intangible descriptions of "quality" and other abstract concepts.

[mikeDnight]

The 100ED is an easier scope to use due to its shorter, more grab and go friendly, design and are excellent. I'd say go for the best optics you can afford, even if you have to save a little first. You won't regret it!

There is a 100mm Celestron ED on AB&S right now, (advert 133015), and its only £250.00. It's optically equal to the SW and is a great little Apo ED. You can rough it for a while with its rp focuser until you can afford a feathertouch!

 

[parallaxerr]

50 minutes ago, John said:

How would you define "3x times as good" Jon ?

Admittedly, an intentionally provocative question John, designed to pull out individuals opinions on what's better and why I know there's no clear definition of "what's better"!?

14 minutes ago, pete_l said:

But we are not rational

Agreed.  Especially so in my case, unfortunately.

13 minutes ago, mikeDnight said:

There is a 100mm Celestron ED on AB&S right now

Yep, seen it. Did a bit of research on focuser upgrades for the C100ED and it didn't seem as straight forward a task as it is for SW scopes, perhaps I've missed something.

Truth be known, I have considered all the factors mentioned. I guess it was a mere sanity check to see if there was something I'd missed. In my profession we regularly talk about "step changes" with regards to function vs value and I was trying to identify the step change point here where one scope is significantly better than the next for a little more money and nearly as good as the much more expensive scope, or if indeed that point even exists. I'm not sure it does.

One final thought...Bresser 102L/1350. Good specs on paper and the cheapest of all, little in the way of reviews to be read though.

[Peter Drew]

I think the s/h ED100 would give you a better upgrade from your 90mm achro than a new 4" achro would. From your star image description of the 90mm It sounds like the optics are pinched, back off any securing screws or lens retaining rings until you can just hear the objective rattle, then test again.   

[John]

1 hour ago, pete_l said:

But that is true of everything, not just telescopes.  Is a BMW 5-series twice as good as a Mondeo? It's twice the price, so it should be!
But generally, people decide how much they can afford or are willing to spend and then choose something at that level: hoping that it won't disappoint. (When it does, we call that buyer's remorse.)

 

 

I know that Pete but I was trying to be objective and realistic

Personally my choice would be the ED100 over the Starwave 102 although actually I'd not pick either currently because I bought a Tak FC-100DL last year

No buyers remorse with the Tak I'm pleased to say

I did have one of the very early ED100's (blue tube) and that was an excellent scope for the £300 it cost me

Good round up review of 4" refractors here:

http://www.doctordreviews.com/4inch-shootout.html

Roger Vine's reports are worth a read as well:

http://scopeviews.co.uk/TelescopeReviews.htm

 

 

 

[Timebandit]

 

Personally i would go for the Ed 100.  Easier to handle and mount . I would also go for a quality Ed over a Achro . The Ed in my opinion are the superior Optics, and as the optics are the heart of the scope, this is always my main priority.

There is always the problem of diminishing returns on the likes of scopes/eyepieces. But that bit better view is always worth that extra cash, within reason . Especially when a good quality SW ED 100 or possibly a celestron ED 100 can be picked up for very sensible money second hand.  That little bit of extra cash in my opinion is always worth paying to get the best you can .

 

Good luck with your choice☺

 

 

[parallaxerr]

2 hours ago, Peter Drew said:

back off any securing screws or lens retaining rings until you can just hear the objective rattle, then test again.

Thanks Peter, I'll try that. Admittedly I had the lens cell off yesterday to clean as the scope had been stored objective end down and the back of the flint was covered in dust. When I refitted it, I left everything loose then tapped away for 5mins before nipping up. Perhaps my nipping was a bit OTT, usually is

2 hours ago, John said:

Good round up review of 4" refractors here:

http://www.doctordreviews.com/4inch-shootout.html

That looks interesting, thanks John. A bit of reading for this evening.

57 minutes ago, Timebandit said:

Personally i would go for the Ed 100.

That's where I'm at right now to be honest. I think I'll give it a few months until funds are available for a new ED100, but keep an eye out for a used one in the mean time. A good used example with a shiny new Feather Touch would satisfy me, I'm sure.

[Stu]

Nice report and a great question thrown in to stir up some interest  

The 102 f11 scopes are very nice, I think I remember viewing Jupiter through Derek's scope and thought what a good image it was. CA certainly well controlled.

Out of the two, I too would chose the 100ED. The optics are reputedly excellent (to my shame I have never looked through one) and at f9 the tube will be shorter and easily to handle and mount.

I bought my Tak FC-100DC new having read excellent reports about them. The appeal to me was the fluorite optics, and the compact and light OTA. At f7.4 it is even shorter than the 100ED so is even more suitable as a grab and go.

I know people think there is a lot of hype over these scopes, but to me the optics are superb, the limit normally being the atmosphere rather than the optics, and I have had some wonderful planetary and solar views. It has delivered everything I wanted from it, and has nothing to apologise for in terms of price paid. No buyer's remorse here.

Of course a 4" scope is going to be limited on DSOs but it does very well considering under good conditions. Out of the probably 60 scopes I have owned, it is the one I have consistently used the most.

A lot of this comes down to what you enjoy. For me, it is all about how I see the image, the aesthetics of it if you like. Back to the BMW vs Ford argument, it will be down to the noise, smell, vibration and handling etc etc, they will both get you there in the same time. But budget is also very relevant, and you don't want something that is always at risk of being sold because it is too much of a burden or hard to justify with family commitments.

It does sound like your achromat still has something more to offer if you can sort the optics out, they definitely sound pinched to me. Give that a go and maybe keep an eye out for a used 100ED at a good price?

[Fozzie]

I can come at this from a different angle as I'm in the starwave owners club.. and the only ed scope I've owned is a 72mm lightsaber with fpl51 glass element.. 

I remember the first time I looked through the 72mm on the moon, which was about a year after I bought the f11, initially I thought "crikey that's sharp, imagine what a fpl53 100mm scope would be like!!" Undoubtedly better.. I think the 100 ed would be sharper and maybe go just a little deeper.. but my starwave has lasted whilst the others havent because it is a very good scope.. and I'm in no hurry to upgrade as I think our weather can be so limiting that "in my head" it's a rare night I'd get conditions that allowed ?X the seeing I get with the f11.. 

Obviously if I could by a tak or nice vixen115 I would in a heart beat, but I have had the opportunity on a 100mm ed and I haven't felt the need yet.. 

Might be tempted for 120ed though, but that's a different thread altogether..

For it's price point the f11 is not too shabby in build and views at all..

Ta

Fozzie 

[parallaxerr]

I did read your first light report @Fozzie and can tell you like the Starwave a lot.

I have been reading a lot on seeing and transparency recently and how conditions limit our observation. It's this that convinced me not to go down the Mak route as I think that 99% of the time the extra ability of the scope to resolve below 1" will be wasted as generally, my conditions are not great. In fact, as you say, it is unlikely that a 4" frac will be diffraction limited very often in the UK.

 

[Fozzie]

Just picked put c Herschel v on the moon... 2.1m across.. faint but there for sure.. with a vixen  7mm lv.. not too shabby for an achro... 

[ronin]

As you say you don't want an ED or apo for imaging then why are you considering one for visual? Just seems an odd way of doing things.

If you got the ED100 then I would expect you to try the ED100 for imaging, then almost certainly use that most of the time afterwards and so use the 120ST for visual.

The initial post seems to read you using the (possibly) better ED for visual (and also upgrading the focuser, another good move for imaging) and the not so good ST for imaging, which seems at odds with general practise.

If you actually want the ED for imaging then get the ED, otherwise get the Altair and save the money.

[parallaxerr]

2 hours ago, ronin said:

Just seems an odd way of doing things.

What I want from an imaging scope and a visual scope are two very different things....

Imaging: I like wide field narowband so a large aperture, fast scope is preferable, which the ED100 is not. The ST has proven to be good at this, but sometimes I want even more FoV, plus I do not strive to create images of the highest quality....because I know the investment is too much. If I were to upgrade the ST to an apo, I'd basically want the same objective dia. and FL = Expensive!

Visual: I want a refractor for globs, doubles and planets, not widefield or DSO because local conditions do not allow. So mid to long FL with good colour correction is preferable, which the ST is not.

 

[25585]

Quality of construction is an aspect. To have OG mounting screws causing diffraction spikes etc is poor construction. Like having a good engine in an inferior body/chassis for a car.

Costing more but better quality, better tube and oe focuser is the SW Equinox 100 ED PRO. If you can find one for sale still.

[parallaxerr]

Yeah the 90mm is a cheap scope to be fair, very much a begginners scope. The optics may have been pinched as Peter mentioned, I have since backed everything off and reseated, we'll see how it star tests next session.

I've noticed the Equinox 100's are out of production, I wonder why given that the 120 seems so popular?

[nightfisher]

I had a starwave and never really took to it, at the time i had my TAL100rs and felt it was a better scope, i sort of agree that a nice used 100ED would possibly be best scope but also consider the bresser 102 1350 you mentioned and the bresser 127

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127l-1200-refractor-ota.html

[parallaxerr]

54 minutes ago, nightfisher said:

I had a starwave and never really took to it, at the time i had my TAL100rs and felt it was a better scope, i sort of agree that a nice used 100ED would possibly be best scope but also consider the bresser 102 1350 you mentioned and the bresser 127

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127l-1200-refractor-ota.html

Now you've thrown a spanner in the works Jules! I hadn't realised the 127L was circa F10 and the reviews are good. That's a lot of scooe for the money! I read one review that said the ED100 didn't outperform it overall, only bettering it on CA and not by a massive margin.

[nightfisher]

I think if i was buying a 4" i would be very tempted with the bresser 4" 1350 and just use it on special nights, yes it would be a bit tricky on my EQ5, but 4" 1350 would show next to zero ca and would be very good on luna and planets plus stunning on double stars, and not so pricey....maybe i should get one

 

[25585]

4 hours ago, parallaxerr said:

Yeah the 90mm is a cheap scope to be fair, very much a begginners scope. The optics may have been pinched as Peter mentioned, I have since backed everything off and reseated, we'll see how it star tests next session.

I've noticed the Equinox 100's are out of production, I wonder why given that the 120 seems so popular?

Just browsing FLO, I would choose the Evostar 100 ED DS PRO. Same optics as an Equinox FPL 53 & Schott glass. And the kit included with it, is very impressive including a focal reducer!

There are less expensive replacement focusers than Featherlite, should you want one later. 

 

 

 

[parallaxerr]

Let's hope one crops up in the sale!

[mikeDnight]

1 hour ago, nightfisher said:

I think if i was buying a 4" i would be very tempted with the bresser 4" 1350 and just use it on special nights, yes it would be a bit tricky on my EQ5, but 4" 1350 would show next to zero ca and would be very good on luna and planets plus stunning on double stars, and not so pricey....maybe i should get one

 

In the mid 1980's I bought a Vixen 102 F13 achromat from Peter Drew for the princely sum of £400. That was a lot of money for me back then, but it was money well spent. The Vixen 102 F13 gave amazing views and the eyepieces, although being Kellners, gave very sharp contrasty images in the F13. No need for fancy expensive eyepieces!

If the 4" Bresser with a 1350mm fl is as good as that old Vixen, it would be a seriously good scope, though it wouldn't be as grab and go, or as easy to mount as the SW 100mm ED. The only question mark in my mind is "How good is the lens?" The better the lens the greater the power range, and the finer the definition will be. This is usually reflected in the price! 

A few years ago I bought a 105mm Antares F14.3. It was a great scope but a bit of a backbreaker when looking at the zenith. Though it had no fault optically, it didn't deliver the same purity shown in the SW ED. After the novelty of having a long focal length scope wore off, ( about 4 weeks), I sold it to Richard Day. 

 

[nightfisher]

8 minutes ago, mikeDnight said:

In the mid 1980's I bought a Vixen 102 F13 achromat from Peter Drew for the princely sum of £400. That was a lot of money for me back then, but it was money well spent. The Vixen 102 F13 gave amazing views and the eyepieces, although being Kellners, gave very sharp contrasty images in the F13. No need for fancy expensive eyepieces!

If the 4" Bresser with a 1350mm fl is as good as that old Vixen, it would be a seriously good scope, though it wouldn't be as grab and go, or as easy to mount as the SW 100mm ED. The only question mark in my mind is "How good is the lens?" The better the lens the greater the power range, and the finer the definition will be. This is usually reflected in the price! 

A few years ago I bought a 105mm Antares F14.3. It was a great scope but a bit of a backbreaker when looking at the zenith. Though it had no fault optically, it didn't deliver the same purity shown in the SW ED. After the novelty of having a long focal length scope wore off, ( about 4 weeks), I sold it to Richard Day. 

 

Mike, that last bit is interesting, i bought a used Antares 105 from Richard, it had a clamshell chip in the lens and a skywatcher dual speed focuser fitted, lovely scope but way to long

[25585]

Online & paper photos of refractors can be deceiving for size. 

Both width & length often appear smaller than is true. Not many same-scale photos of different models. SCT & Mak buyers can & are also caught off guard. 

Putting focal length in millimeters, a small unit, rather than meters does not help. 1.4 meters is long for a refractor to keep at home, unless it doubles as a lamp stand!