mih

11 hours ago, Grumpy Martian said:

I purchased my Eqinox 80 mm for £250. It has a focal length of f6.2. An older but very good Celestron C 80 mm is f6.5 and do come up as good used at times.

I am a visual observer so the Equinox performs very well. Resolves stars sharper  than a Newtonian in my opinion. So the combination of an 80mm ed refractor and a 150mm Newtonian would allow quality viewing with the ED and brighter deep sky viewing g with the Newtonian. My opinion. 

Yes, my opinion as well. I found a SkyWatcher EvoStar ED-APO 100/900 at a reasonable price. I think I will settle on that one. Its 870 dollars, so its is in my budget

19 minutes ago, mikeDnight said:

There are numerous books that are dedicated to deep sky using a 4" refractor, so here are some. Also, many amateur observers keep observing logs and sketch books full of their observations using such instruments. Just a handful are piled up in the attached pic. So deep sky can be a great source of entertainment and interest using relatively small refractors. I've also attached a couple of sketches of Messier objects made using a 100mm refractor from the suburbs of a north England town.

Thanks, i will for sure check the books out. I think i found a refractor that fits my needs. It is a SkyWatcher EvoStar ED-APO 100/900. Sounds good?

5 minutes ago, John said:

You can't compare them - totally different strengths and weaknesses.

If DSO's are more interesting then a larger dobsonian is both much less expensive than your budget and will do the job better on DSO's and will do a decent job on the moon and planets as well.

 

Yeah, I've gathered that, but i'm curious about the strengths of a refractor. I will get a larger dobsonian as well eventually. The one I have seems to be decent, but you know, bigger is better.

28 minutes ago, Stu said:

Sorry to say, read my post again! For widefield objects a refractor can give views a dob can’t, because their field of view is too narrow. If you didn’t have the Newt already then a 152mm refractor would be fun on DSOs, but I don’t see that it gives you anything different enough.

A 4” f7 ish ED refractor would give you widefield DSO and planetary/lunar performance to get to know refractors.

What sort of budget do you have?

My budget is about 1200 dollars. Hope thats enough. Maybe even 1400. Did you ask me for the budget to do the looking for me? Cause you would be a god

I think might buy refractor because of its portability, so i can go camping ans stuff and stick to the dob i have for now.

8 minutes ago, Stu said:

Then get a bigger dob!

I probably will, but i want to get to know refractors as well. Also, there are people saying refractors are good for DSOs, other saying they re not, idk what to believe

2 minutes ago, John said:

Good for deep sky but not so good for planetary use due to CA. But I sure you realise that given the advice that has been provided

Also heavy as Stu says.

I think you need to think things through more carefully. You seem to be all over the place with your choices at the moment ?

 

Yes, i am quite a bit. Which one of the two would you say is better in general? The ED80 has a focal length of 600mm.

I think I would be ok with the planet problem, i think DSOs are what interests me

5 minutes ago, John said:

It is a popular focal ratio (F/7.5) with an ED 80mm scope because it's suitable for imaging as well as visual.

You do realise that your 150mm newtonian will out perform such a scope on practically everything though ?

An 80mm ED is a nice "grab and go" alternative though.

 

Right. I found an Achromatic refractor AR152 AIR-SPACED Doublet, 988mm focal length. Thing is it is not ED

Its from Explore Scientific

4 hours ago, Grumpy Martian said:

Hello much.

I have a great skywatcher 80 mm Equinox ED refractor. It give nice wide field views. Point like stars when viewing. Good with observing moon and planets. I like the way it resolves stars. But I am considering buying a six inch f5 Newtonian to compliment the 80 mm. So why not keep the Newtonian and look out for an 80 mm or 100 mm ED refractor.

What is the optimal focal length for an ED80. I found one with a 600mm. Is that good?

4 minutes ago, Stu said:

Did you read my post @mih? I tried to explain the differences in there.

Oh, sorry, ill check it out

Edit: Thanks, i must have overlooked it. Great explanation!

Sorry, i am a bit confused. What is an optimal focal length, or focal ratio for a refractor, since i am seeing a lot of big ones, a lot of small ones, i dont know what i should look for

2 minutes ago, John said:

Another good but older (out of production) refractor is the Vixen 102mm F/9.8 achromat. Japanese made and fine optics often for quite a low price if you can find one on the used market.

 

Thanks, i'll check it out!

Also @mikeDnight, do you recommend an achromatic one or an apochromatic one?

2 hours ago, mikeDnight said:

Refractors can be good for all kinds of targets, including deep sky. Obviously the greater the aperture the deeper you'll be able to go, but how deep do you really need to go? There are countless deep sky objects that can be observed through a 100mm refractor, and a 120mm or 152mm refractor will take you deeper still. The best view i ever had of the Orion Nebula (M42) was through a 102mm Vixen F6.5 ED apo and a 20mm Nagler eyepiece. No other scope I've ever used, no matter how big, has ever given me a better view of that object. I've observed M51 (the Whirlpool galaxy) in many large aperture scopes, but the most memorable view was through a 150mm F8 achromatic refractor, which easily showed the spiral structure and the bridging arm between the two galaxies. Refractors make great all round scopes but their ability to produce piercingly sharp star images enables them to give some of the finest views imaginable of rich star fields and star clusters; views that no other design can match. A 150mm F5 achromat will give you arguably the finest view you'll ever have of the Double Cluster in Perseus. Other scopes may show it well but they'll never match the refractors view. So refractors can give you a lifetime of pleasure with deep sky targets in mind, but they can also excell at lunar and planetary too. 

I've attached some images to wet your appetite. This first one is a rich field achromat with a 152mm lens. This is a great deep sky refractor!

The second is another great deep sky scope, an NP101. At only 4" aperture you might think it wouldn't be so good, but its images of nebulae, galaxies, star clusters and comets are spectacular from a reasonably dark site.

Then there's the affordable but excellent Skywatcher 100DS Pro ED, which is a great all round refractor. If you like to do a bit of everything this scope will not disappoint!

Then there's the higher spec offerings from Takahashi, which again are great all round performers designed for very high powers when the seeing conditions allow.

 

There are many more you might consider too. Doublets are all you'll really need if you're a visual observer, as they cool quickly and will often be cheaper than a triplet. You might even find your reflector gets used less and less if you did buy a good refractor.

 

 

Thanks, i think i might consider buying one after all, you convinced me! I might need to save some money for a very good one. I'll buy it without the mount, which i'll buy separatley, since i want it to hold my reflector as well.

5 minutes ago, John said:

Think through what you want it to do for you. Then work out if a refractor is the tool you need.

 

 

is a refractor a good tool for DSOs? Or is it better for planet viewing?

1 hour ago, Alkaid said:

Aesthetics and ergonomics are also factors...it’s really nice to sit down behind a refractor, very relaxing.  Much better than standing up all the time with a newt and having to rotate it in the rings to get the eyepiece into a good position when moving to another part of the sky.

Refractors just look better too. (Hope I haven’t started a war now).  There was a guy on here that made me laugh when he said his wife had nicknames for his two scopes - the short fat 10” dob was named R2D2 and the elegant refractor was called Princess Leia.

So you reckon i get a refractor?

1 hour ago, John said:

Just for information, a newtonian reflector is also an apochromatic telescope

The more you know

22 minutes ago, mikeDnight said:

If you're thinking of saving for a refractor, you probably better off looking at an ED which will give you good colour correction but will still have a relatively short tube length. These are easily mounted on an equatorial mount and will give some very pleasing views of pretty much every kind of object. Skywatcher offer some seriously nice 80mm, 100mm and 120mm ED refractors that are near impossible to beat for the money. An EQ5 would carry any of these well if the tripod is sturdy.  There are other brands you might consider too, but prices can get a little scary for the higher spec refractors, and you can find yourself paying a premium just to gain a slight edge in performance. To some its worth the price while for others it isn't. Also, for many, the larger aperture of a reflector has real appeal, while others would sacrifice aperture for superior image quality of a premium refractor every time. 

By ED you mean an apochromatic one? Does Extra Low dispersion mean that when light passes through the lenses it does not go in all directions as much?

Edit: Ok, so ive looked it up, so the chromatic aberration is gone

27 minutes ago, andrew s said:

If it were my me I would put all the money into the best mount I could afford and get the best out of the Newt. You can improve the image with a a coma corrector, pump up the focal length with a Barlow or PowerMate and turn it down with a reducer corrector.

Regards Andrew 

 

Yeah, i will also get a good mount for the reflector, but want to check out a refractor as well. Maybe ill compromise and get a mount and a refractor with no mount

4 minutes ago, John said:

Yes, that is quite possible.

Probably best to get a refractor that compliments what your 150mm newtonian can do so you get a different experience when you use each scope. They will have different strengths and weaknesses.

 

 

 

Ok, thank you so much!

2 minutes ago, John said:

Refractor optics cost more per mm to make because there are 4 or more optical surfaces to figure, polish and coat compared to just the two surfaces for a newtonian. A 150mm refractor is expensive and sizes above that comparatively rare whereas reflectors can easily be made in 200mm, 250mm, 300mm and up to around 500mm.

So if you want a larger aperture for deep sky objects, a reflecting telescope is the way to go.

Refractors have a lot of fans though for the purity of their image, their relatively robust collimation, their lack of a central obstruction etc, etc.

The subject of these different designs of telescope is the subject of many books, articles and, many, many posts, on forums

Here is a piece by our own Steve Richards ( @steppenwolf ) with a contribution from Paul Money, on these designs:

https://www.skyatnightmagazine.com/advice/buyers-guides/first-telescope-reflector-or-refractor/

 

Thanks! I wanted to buy an eq mount, so i was thinking maybe i could get a refractor on an eq and put my reflector on it as well. Is that an option?

14 minutes ago, ScouseSpaceCadet said:

You have a decent 6" newtonian already. Why do you think you need another telescope? What are you not seeing now that you think a smaller aperture refractor will provide?

I dont know, just asking if a refractor would have any advantages. Also I dont plan on buying it right now. In the future maybe. Sorry for saying that in the description. Or what should i get if I ever want to upgrade in the fiture

Hi, i want to buy a refractor, equatorial mount. I already have a 6 inch Bresser Newtonian, f/5(750mm focal length) with two eyepieces, one 9mm and one 25mm and a barlow 2x and solar filter. I am seeing all these apertures like 90, 100, 70, while for reflectors like i have that is pretty low. Of course, for refractors, the focal ratio tends to be higher. What do I look for in a refractor? I want to be able to see some deep sky objects and planets. I am very confused, does the low aperture mean you gather less light and see worse? What does the focal ratio indicate? I just want to buy a good refractor, or maybe another reflector woud be the next step? Let me know!

Ok, then i want to ask about the Orion Nebula. Is that easier to observe?

Hi, i have a 6 inch newtonian, 150mm focal length(f/5), 25mm and 9mm eyepieces. I currently have observed M13(Great hercules cluster), but you know, its a fuzz. i have a 2x barlow on the way. Will that 2x magnification(83x -> 167x) make any difference?