Refractor or SCT

[MurrayF]

I know this is a hard question but I will ask anyway.
I am thinking of buying an LX90 ACF 8" and am currently using an entry level refractor.
Would I be better off with the LX90 or should I buy say a 5" refractor?
The 8" LX90 would have superior light gathering but thr refractor should provide possibly sharper views and would not need collimation.
Perhaps I would be better off to save up a bit more and purchase a good quality APO?
HELP - I am confused.

Thanks All
:help:

[casstony]

There's bound to be a club or group of observers in Perth - looking through other peoples scopes will give you a good idea of what to buy.

[TrevorW]

Refractor APO 5" way more expensive but IMO far superior

[rogerg]

I agree with Tony, best you get a better idea about each type of telescope before jumping in, and visiting a club is one way to do that. Chatting to people at an ASWA HOW night (http://aswa.info/HOW.htm) might suit.

Refractors and SCT's are very different telescopes, suited to different things. What are you after? a general all-rounder? planetary or deep sky? photography or visual? not sure, just want a scope (fair enough)?

Suggest you research on the web about the different types, what their pluses and minsuses are. There's a lot of info out there regarding buying a telescope and the pros and cons.

It's not meant to be easy :)

Roger.

[toyos]

+1 :)

You can import a 127 APO from China at a bargain-bin price now :lol: Optical performance is sort of 'semi apo', the focuser is fairly stiff and the build quality detail is pretty 'China' but not bad for the money.

In my opinion, The Meade 8" SCT does not gather much more light than a decent multi-coated 5" refractor. Remember the central obstruction is nearly 40% and the mirrors' reflectivity even with UHTC is less than 89%. You will get less than 2/3 of the light at the focus point with an SCT, the rest was lost in the process of getting there. It doesn't have the superior contrast & sharpness of an APO either, and don't forget the SCT's notorious mirror flop & shift.

[Geoff45]

It really depends on what you want out of astronomy. For the same money, you will always see more with a reflector than a refractor, simply because of the aperture difference. A refractor and especially an APO refractor is always going to be a bit of an indulgence, but if you feel like spoiling yourself go ahead. You'll be rewarded with a beautiful instrument with tack-sharp planetary images and low maintenance.

BTW just buying a refractor to avoid collimating a reflector is a bit of a cop-out. Acquiring good collimation skills is neither difficult or time-consuming.
Geoff

[monoxide]

im going to make the assumption its for purely visual use...

a newt will always be superior for visual use when it comes to deep sky work, collimation isnt difficult at all and once you know what your doing it only takes a couple minutes, sometimes even less.

some people complain about the lack of contrast of a standard GSO dob but if you spend an extra $50 to flock or re-paint and baffle the inside of the tube you will notice a *huge* improvement, good quality eyepieces make a world of difference too. small modifications can be key to getting the most out of your equipment.

for the price of a 5" apo and mount to put it on you could have a flocked/baffled 12" dob with argo navis which in my opinion a 5" anything wont stand up to for visual use deep sky or planetary. even if you imported the chinese one for ~$1000, add the price of a mount.
dont get me wrong i do like the views through a refractor but i'll always drag out the dob for the majority of my visual observing.

8" dob flocked/baffled with Argo Navis ~$1300
12" dob flocked/baffled with Argo Navis ~$1700
8" sct ota only ~$1500
5" chinese apo + HEQ5 ~$2000

[Tandum]

Can you guys really see anything through any telescope from a city location ?

I've had scopes for years and using modern motor mounts, PC's and cameras am I only now seeing what I've been looking for.

If your in a city, you'll see bugger all no matter what scope you buy unless you pin a camera to it for an hour and process it.

[Geoff45]

Unless your main interest is planetary, lunar or solar observing, in which case the city is as good as anywhere.
Geoff

[Tandum]

Your right there Geoff, but binos would do for that.

[chris lewis]

I currently have the Meade LX90 with GPS and a Skywatcher Equinox ED120 [same as Orion EON] on a HEQ5 mount. I prefer the ED120 for planetary observations and the Meade for DSO's. As I am more into visual planetary observing the ED120 gets used more.
The CO on the Meade does affect low contrast details on planetary observations.
Coma is a mild concern – the AFC version should reduce that.
I sold a Celestron SE8i recently to help finance the ED120. I had issues with getting exact collimation with the Celestron. Images tended to be soft with noted coma. It may have been a faulty version.
Refractors and SCTs are different scopes and have different compromises and strengths.
The SCT does need a long cool down time and exact collimation. They are easy to view with and do give a bright image.
The APO does give ‘snap to focus’ sharp images. The images are contrasty.
Aesthetically I prefer this. Also as I get older I prefer fewer hassles with my equipment and have become a bit of a perfectionist with the images I am viewing.
Even at being ‘almost’ 5 in. it does give sharp DSO images with excellent contrast. The Meade does slightly ‘see’ a bit deeper.
APOs require less cool down time and they require less ‘maintenance’ to give perfect images. Of course cost is a concern esp. for the ‘top end’ versions.
Personally - and this is my opinion - get a 5 in ‘APO’ - like the ED120 or the new 127 Triplet on a HEQ5 / EQ6 type mount. These give excellent sharp CA free images without the cost of the ‘top end’ APOs and then later on get a 12 in DOB for DSO work.
Anyway if you could view thru various scopes this will give you more of an idea as it is a personal issue.

[iceman]

Sorry I don't agree with that at all. Binos provide nowhere near the level of detail and resolution of the moon or planets that you can get through and 8" or larger dob.

Murray, as others have said, tell us what your main goal is.. visual observing? Photography? Will you travel with the scope, or simply use it at home?

How light polluted is your home location?

What's your budget?

Do you need/want tracking or goto, or do you want to star-hop and manually push to?

[JohnH]

Have you actually used one of these 127s?

A sort of semi APO ? It is a air spaced triplet APO design I guess your comment is based on the use of ED glass? I am not an optician so I cannot critique the design or material choices however what I do know is mine out perfomed my vixen VC200L (8") in both resolution and contrast, colour correction is on a par (when carefully focussed) and the only area where the VC200L won is field flattness. Visually the stars a shaper and perfomanace on planets is superior with the 127 and there is no noticeable difference in light gathering (under suburban skies).

The VC (and most SCTs) need a focal reducer to be useable for AP and the APO does not.

My focuser is not stiff and the build quality seems to me to be on a par with the Vixen kit.

In short for the money I cannot fault the 127 APO - sure it is not the ultimate 5" APO - but then I did do not have $5000+ to spend on a scope.

5" APO vs 8' Meade SCT was the question - 5" APO is my answer.

[toyos]

I bought it last week for testing. You need to compare it to other quality APO refractors, then you'll know the difference. Don't get me wrong, it's good value for money; but the colour correction isn't on par with any quality APO's on the market (triplets or doublets). Try testing it in and out of focus with bright stars. I think the focuser needs some improvement, but that's just my opinion based on my standards.

[Starkler]

There was a discussion over on CN about this refractor. Its was tested against an orion ED120 and a Vixen ED115S and both bested the 127mm, with the Vixen coming out on top for colour correction.

[casstony]

Just to balance up the opinions, there's a lot to be said for the convenience and user friendliness of an 8"LX90 or Celestron equivalent. They are quick to set-up and align, the observing position is always comfortable and they will find and track objects easily. You can buy one used then sell it after a year or two without a big loss, should you discover that your interests require different equipment.

Schmidt cassegrains, semi-apo refractors and Chinese dobsonians are all middle tier scopes with variable optical quality, but generally decent, so I wouldn't get too caught up in which type has better optics when you're just getting into the hobby. Other factors are likely to be more important.

[JohnH]

We are going off topic here a bit. The question posed was budget 8" SCT vs refractor (equivalent cost) not a discussion about which 5"(ish) refractor is best, I am sure Televue and AP are better than even the Vixen.

I have read that CN review too and it covers more than the colour correction factor only (eg appature and cost even the EON is 2-3x the cost of the 127!). When it comes to colour one reviewer comments that the 127's correction gives it optimal perfomance on planets compared with the EON.

Like I said I am no optician so I can only let my images be my guide, for me my results with the APO are better than with the reflector and visually it is superior as well.