Reflector vs. Refractor - Differences?

[Satchmo]

With reflectors you actually really see a range of deep sky stuff, and great planatary when the seeing is good. With refractors , tha aperture is so minimal that you can boast about crisp star images ( as the scope isn't quite capable of resolving bad seeing ) and thats about it.

[csb (Craig)]

Originally Posted by prova

if it's a case of seeing a little less with the 100ED but getting more clarity on the image .. fine

Yes Prova, your own personal perspective is important.

I also agree - the clarity in a refractor has helped me to choose a skywatcher 120mm f8 over other types of telescopes.

For visual, I am never quite satisfied with what I see in newts, sct, etc.

[Geoff45 (Geoff)]

Originally Posted by csb

Yes Prova, your own personal perspective is important.

I also agree - the clarity in a refractor has helped me to choose a skywatcher 120mm f8 over other types of telescopes.

For visual, I am never quite satisfied with what I see in newts, sct, etc.

Remember though, not to compare a quality apochromatic refractor, costing several grand with a GSO dob costing several hundred. You get what you pay for. Get a top quality mirror and the performance of a reflector is superb.
Geoff

[prova]

this is why i was hoping to check one of these out locally -

http://www.bintel.com.au/SKPRO.htm (100ED on HEQ5 Pro in particular)

i am considering one but finding it quite difficult to find out how 'less bright' objects will be opposed to a 8" reflector and what clarity differences there are

difficult to judge without actually looking through one in person ..

[charsiubau]

Hi prova

I'm in Canberra. I don't have a 100ED but do have a Televue 85 mm refractor which you would be welcome to look through if you just wanted to see what sort of views a good refractor gives. If you're interested you can PM me.

[Starkler (Geoff)]

Originally Posted by ghsmith45

Remember though, not to compare a quality apochromatic refractor, costing several grand with a GSO dob costing several hundred.

This is the situation the vast majority of such comparisons are made on due to the lack of small aperture premium quality newtonians.

I cant wait to check out Daves 6inch tak newt when i get back.

[charsiubau]

I hesitated to offer a look through the Televue because it's not particularly relevant to prova's problem - is the 100ED worth getting. But since no-one else local replied I did. I don't have an opinion as to whether refractors or reflectors are better - they are just different. Size and quality matter more and quality can make up for size to a certain extent (but only to a certain extent). Dark skies can also compensate for size. I do enjoy looking through premium newtonians both large and small (the Canberra club has a 6 inch tak newtonian). Unfortunately not everyone can afford or wants to spend the money or has the skills to build a premium newtonian.

[Starkler (Geoff)]

Refractors offer nice sharp stars and contrast in a small aperture package.

Is 4" of aperture enough for you? Its not for me, which is why I own a number of scopes including a 15" premium dob, a 130mm newt on alt-az mount and a 115mm refractor.

The crisp view of the 115mm refractor comes at a cost of portability, being on a cumbersome heq5 mount in my case. For home set up, I find the 15" truss dob less hassle to set up.

I dare say the majority of people are buying refractors for imaging. If you want one for visual and must have a refractor, the tv102/gibraltor mount package in the buy/sell section would be a good deal and easy to use, again if 4" is enough for you.

[Stephen65]

When it comes to using APO refractors for visual (imaging is a different situation) they really fall into two classes (and I have one of each):

- small refractors up to about 4" either on alt-az or light EQ mounts, they are very portable and easy to set up, no collimation hassles, cool very quickly and give the best views of any scope of their aperature. You get pleasing views of the moon, star fields and bright DSO's with very sharp and contrasty views on a flat field. Expensive for the aperature. Look sexy.

- larger refractors from 5" up, need a heavy duty EQ mount (EQ-6 and up), a power source, are quite heavy and take a while to set up and polar align. No collimation hassles and cool quickly. Have enough aperature to show larger scale images of the Moon and planets. Best images of any scope in their aperature range. Because of the high degree of sharpness and contrast they often show more pleasing (albeit not brighter) images than larger reflectors. Very expensive for the aperature as the cost of refractors goes up exponentially (at least) with aperature increases. Look incredibly sexy.

Good quality achro refractors have almost all the qualities of an APO, save that on bright objects they will show colour and the contrast will not be as good. However, on star fields and DSO's they offer performance almost as good for a fraction of the price. Achros are generally not suitable for imaging though.

For imaging, f/ratio, flatness of field and colour correction across a broader range of the spectrum becomes much more important than it is for visual. A smaller very high quality APO may well be a better choice for imaging than a larger ED-type APO that would be excellent for visual.

[Kokatha man]

Well summed up Stephen, I certainly agree within the bounds of my knowledge/experience: though I know that with the Baader semi-apo filter in my achro I have almost zero CA. Yet to give it a go on imaging quality though: will test it when Eric's modded 20D arrives in my hot littel hands very soon!

Cheers, Darryl.

[Peter Ward]

Originally Posted by Satchmo

With reflectors you actually really see a range of deep sky stuff, and great planatary when the seeing is good. With refractors , tha aperture is so minimal that you can boast about crisp star images ( as the scope isn't quite capable of resolving bad seeing ) and thats about it.

Amen to that!!

I amazed this old chestnut still comes up.

In an ideal world , the ratio is "about" 7:5 ....i.e a perfectly made 7" reflector gives very similar images to a perfectly made 5" APO.

But don't expect "perfect optics" at bargain basement prices.

It is 2x as hard to make reflective optics as good as refractive ones (physical optics 101 )....hence optical quality is often confused with quantity.

Rest assured you will be *very* happy with and AP160 or Sutching 200mm Parabola...the design is very much secondary to the execution.

Cheers

[toyos]

I have tested 6" refractors and 8" - 12" Newtonians with similar price brackets & qualities side by side. As far as I know, there's no way a reflector will be able to produce the contrast of a comparably-sized refractor (much darker background showing the structures better). In this case, I believe what I can see myself.