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Newbie question about Refractors.

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#1 ReganJamesFord

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Posted 22 November 2019 - 05:20 PM

If I am not interested In astrophotography, is buying an APO worth the higher price over a regular refractor? In other words is the viewing image enhanced in addition to the photo image when using an APO? Would I be able to tell the difference as a rookie? And is a triplet better than a doublet for viewing only? Thank you
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#2 james7ca

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Posted 22 November 2019 - 05:35 PM

It's pretty much in the eye of the beholder. Some people are bothered more by chromatic aberration than others. That said, I doubt that you'd notice much difference between a good, two-element ED scope of modest focal ratio in comparison to a more expensive, three-element APO. The focal ratio matters and if you get a modern ED scope at f/7 (or more) then you'll probably have few issues with chromatic aberration. Then again, you might not even need to go to an ED scope if you are working much beyond f/10. I have an inexpensive 4" f/10 refractor (Celestron 102GT) that definitely shows color along the rim of the moon at high magnifications but in other use cases that color is not really that objectionable. So, YMMV.


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#3 photoracer18

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Posted 22 November 2019 - 05:37 PM

Well there is some difference at each level but depending on the scope quality it can be very small or very large. Not a lot of perceived difference when looking at DSOs. More on the planets, Moon, and bright objects in the way of color fringing comparing an achromat to an ED or APO. You can suppress some by using a Baader Semi-APO filter or a minus-violet filter. However without knowing your eyes and whether it annoys you or not I can't give you an absolute answer.


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#4 WilburTWildcat

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Posted 22 November 2019 - 05:53 PM

I found that an ED refractor made me happiest, even compared to a triplet, whereas the color in an achromat really bothers me. Triplets are most color-free for bright objects, but APO doublets have more contrast for deep sky.
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#5 havasman

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Posted 22 November 2019 - 06:12 PM

My 1st refractor was a triplet as I wanted to avoid aberrant colors I'd heard occur when viewing bright objects. It (f7 AT115EDT from Astronomics) is a fine scope I've not regretted buying. But observing with it and Wyatt's f9 SkyWatcher Pro ED 100 doublet one night at the dark site, side by side, it was really difficult to find a significant advantage that could be ascribed to its triplet configuration as we observed DSO's.

 

IMO, a modern ED doublet of a bit higher focal ratio is an excellent way to go for DSO observing and is absolutely competent for lunar and planetary too.


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#6 Jond105

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Posted 22 November 2019 - 06:22 PM

Detroit location. Got to love it. What up from D lol. Detroiter myself. Anyways. Yes. Simple answer, in our skies, visually, a doublet ED is far superior to a regular  achro. I’ve had both. In fact, I’m out getting first light on my 3rd 100ED which is a great scope for our area. Hope this helps. 

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#7 junomike

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Posted 22 November 2019 - 06:23 PM

The answer lies solely on the observer.  I know when I started our  I could see the CA surrounding the Moon but didn't think anything of it.......until I viewed through a Newt.

Then it became apparent that along with the CA the view was also tinted a yellow tone which I didn't prefer.

For Planets I found this a benefit but only on Planets.


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#8 Scott in NC

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Posted 22 November 2019 - 06:28 PM

...but APO doublets have more contrast for deep sky.

Yes, that's the common myth, but I believe that that's much more of a generalization than an absolute truth.  I think the best one can say is that some apo doublets have more contrast than some apo triplets, but that's all.


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#9 bobhen

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Posted 22 November 2019 - 06:35 PM

Brief answers to your questions…

 

Is buying an APO worth the higher price over a regular refractor?
YES

In other words is the viewing image enhanced in addition to the photo image when using an APO?

YES

Would I be able to tell the difference as a rookie?

YES, If placed side-by-side 

And is a triplet better than a doublet for viewing only?

That depends on the “quality” of the lens not how many elements are in it.
“Generally” triplets can have shorter focal lengths and still retain excellent color correction better than most doublets. But quality is mostly about how well the lens is figured.

 

Now…

 

Refractors are wonderful telescopes. Just like most things in life they have advantages and disadvantages. Presuming you have an understanding of those benefits and are interested in a first refractor then…

 

1. Set a budget and stick to it.
2. Consider size and weight and storage and your observing location carefully
3. Get a refractor that is a good general observing instrument as opposed to something specialized. Consider at least a 100mm aperture as a minimum for a first refractor. A 4” refractor can be a lifetime companion.
4. With regards to optical and mechanical quality, in most cases you will get what you pay for.
5. Even a modestly priced refractor will be a wonderful observing companion so don’t worry about getting the absolute best there will always be something more expensive – stick to your budget.
6. Read reviews, posts, manufacturer’s websites and retailer’s website and take each with a grain of salt but gather enough information so that you feel comfortable making a purchase.
7. If you want an easier setup and portability, consider an Alt/Az mount
8. If after a few years you want larger and or better you will have more experience to make a more informed decision.
9. Make your purchase and then just go and observe and enjoy. Refractors never disappoint

 

Bob


Edited by bobhen, 22 November 2019 - 06:36 PM.

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#10 Jond105

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Posted 22 November 2019 - 06:37 PM

Tell you what, you ever want to check out what an ED shows. Message me. Always willing to show others in the area. 
 


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#11 Garyth64

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Posted 22 November 2019 - 07:17 PM

I have a 5" Apogee, that I  have taken to many outreach events in the Detroit area and subs over the years.  It is just a doublet, but it is a very good doublet.  I use it because of the views it gives.

 

You may also want to see what a Sears or a Tasco 3" refractor can do on the planets.  They're just doublets too.

 

Last spring I got an AT130EDT, it gives much better views than the Apogee. I love it, and I am only visual.

 

It's a way off, but come to some our outreach events starting in the spring.  Ford Astronomy Club

 

Sometimes during the winter, and if it's not too terribly cold, we'll open up the HJRO Observatory at Lincoln Park HS.


Edited by Garyth64, 22 November 2019 - 07:19 PM.

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#12 Jond105

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Posted 22 November 2019 - 07:20 PM

HJRO Observatory at Lincoln Park HS.

My alma mater. 


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#13 Garyth64

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Posted 22 November 2019 - 07:39 PM

My alma mater. 

You may not know that the observatory was upgraded thru a grant that was coordinated with our club and a couple of teachers. 

IIRC, it now houses a 14-16 Meade on a Losmandy.  We meet at Henry Ford CC the 4th Thursday of each month, but for Nov we won't meet, and we will meet Dec 5.  More info is on the website.


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#14 Jond105

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Posted 22 November 2019 - 07:48 PM

We meet at Henry Ford CC

Lol, almost my other alma mater, as I dropped out eventually from there before the assiociates(accounting). To be honest, I didn’t even know that was an observatory while going there next to the field. It was almost invisible to me at the time. That’s amazing what it houses though. Shame the school doesn’t have an astronomy group, not saying I would have joined in my high school days(class of 03), but knowing what I know now and me being in this hobby, would make it nice. Hopefully one day I can make it out. 


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#15 Garyth64

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Posted 22 November 2019 - 08:30 PM

I did some searching, and I was wrong the observatory houses a C14, not a Meade.

 

Here's a video

 

https://www.youtube....h?v=sqFLzZRMLwE


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#16 Gary Riley

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Posted 22 November 2019 - 08:41 PM

I’ve owned an achromat refractor that put up some very decent views (Celestron 102mm f/9.8 Omni XLT) and a SW 120 ED Pro (f/7.5). I definitely prefer the views in the SW 120 ED. No CA to detect and sharp, crisp views. It’s a keeper as far as I’m concerned.
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#17 Kunama

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Posted 22 November 2019 - 09:27 PM

If I am not interested In astrophotography, is buying an APO worth the higher price over a regular refractor? In other words is the viewing image enhanced in addition to the photo image when using an APO? Would I be able to tell the difference as a rookie? And is a triplet better than a doublet for viewing only? Thank you

Many of the ED doublets are so close to apochromatic that it makes sense to choose them over 'true' apochromats.  I would recommend that as a 'newbie' you would be well served with a SW 100mm ED or even the 120mmED.  These are what I would term 'visual apochromats' they are essentially colour-free in focus in visual use, they are well made and give fine views.  For many these are lifetime scopes.

 

They are also very affordable when compared to the top tier stuff and give great views per $$$.  The cooldown of these doublets is about half of similar aperture triplets so they are ready to go very quickly.


Edited by Kunama, 22 November 2019 - 09:28 PM.

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#18 Astro-Master

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Posted 22 November 2019 - 09:51 PM

I would look for a used 100 to 120mm ED refractor on CN.  I saw a Sky Watcher 120mm ED just sold for $1100. on CN.

 

I have a Stellarvue 105T and my friend has a Stellarvue 115mm triplet.  I was amazed what an extra 10mm did on the globular M 13.  I've heard it said that the 115mm refractor is closer to a 5" refractor than a 4".  That said if you like DSO's from a dark site I'd look for a good used 115 or 120 ED.

 

You didn't tell us how much money you can spend, and I assume you'll need a mount also, that said, there is a Vixen 103 ED for sale on CN for $795 right now.  A Celestron AVX mount or similar size mount would work fine for visual.  Just don't buy a used Orion mount because they only sell replacement parts to the original buyer.

 

Don't be in a rush, good things come to those who wait.


Edited by Astro-Master, 22 November 2019 - 09:55 PM.


#19 drd715

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Posted 22 November 2019 - 10:01 PM

Many of the ED doublets are so close to apochromatic that it makes sense to choose them over 'true' apochromats. I would recommend that as a 'newbie' you would be well served with a SW 100mm ED or even the 120mmED. These are what I would term 'visual apochromats' they are essentially colour-free in focus in visual use, they are well made and give fine views. For many these are lifetime scopes.

They are also very affordable when compared to the top tier stuff and give great views per $$$. The cooldown of these doublets is about half of similar aperture triplets so they are ready to go very quickly.

Yes this is good advice.

Dollar value the skywatcher 100ed f-9 at $800 is great. The skywatcher 120ed is brighter, and half again+ more $$, but if its in your price range it's worth it for the extra light gathering and slightly better potential resolution.

There are other options: the AT130apo triplet but now you're getting pricey 2k+.

Or best lower cost sharp image, the TS102ED F-11, but it is long at 1120mm fl good value at $600+shipping (make sure its the ED version).

If you're going less than F-7 a triplet $$$ is best, F-7 to F-9 a better ED glass like FPL-53, F-9 TO F-11 FPL-51 or equivalent will do. Longer than F-11 in a 100mm scope for visual may not be very bright on objects other than the moon and planets. The planets could use a little bit more aperture to pull out some details.

If you want to push the powers up past 100X or so a tracking mount is helpful, otherwise a simple Alt/Az mount, a Telrad finder and a set of the Telrad sky guide books will will sky hop you through the heavens.

Sent from my SM-N950U using Tapatalk
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#20 Jond105

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Posted 22 November 2019 - 11:21 PM

I would look for a used 100 to 120mm ED refractor on CN.  I saw a Sky Watcher 120mm ED just sold for $1100. on CN.

 

 

That was my 120ED as well. Amazing scope for our area around Detroit. 



#21 Ihtegla Sar

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Posted 23 November 2019 - 12:03 AM

If I am not interested In astrophotography, is buying an APO worth the higher price over a regular refractor? In other words is the viewing image enhanced in addition to the photo image when using an APO? Would I be able to tell the difference as a rookie? And is a triplet better than a doublet for viewing only? Thank you

I've been observing off and on for about 40 years, but more off than on so I'm still quite the newbie compared to a lot of folks here who observe more in a few weeks than I do all year. I'm a visual only observer; no astrophotography because that's a whole nother level of experience that I don't have. So I can share my "newbie" experience with the 4" apo flourite doublet (Takahashi FC100DL) I purchased last spring.

Compared to my C-8 and my fast 4" f5 Celestron achromatic refractor, the 4" apo is light years better in terms of the quality of the viewing, especially for planets, the moon and splitting double stars. It's not just lack of color (the C-8 doesn't have chromatic aberration) but the sharpness of the focus is noticeably better than the C-8 or the f/5 Celestron on planets and the moon. I can see many more fine details.

A good florite doublet can compete with a triplet in terms of correction and a doublet is lighter and will cool faster than a triplet. Mine typically cools down in ten or fifteen minutes.

The FC100DL wasn't cheap but for me it was worth every penny for the ease of use and quality of the views it provides.

Edited by Ihtegla Sar, 23 November 2019 - 12:03 AM.

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#22 Nippon

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Posted 24 November 2019 - 09:55 PM

In my opinion yes an apo is worth the higher price over a regular achromatic refractor. Part of the reason is that there are not many achromatic refractors produced today in the long focal lengths and slow f/ratios where they perform well. ED and fluorite optics have more or less pushed quality achromats out of the market. There are some exceptions though but there is no denying the advantages of an easily managed f/7 or f/8 apo doublet or triplet. I'm visual only and I bought a quality 4" triplet in addition to my 4" ED doublet a few years ago. After using both now for sometime I do not see any real advantage of a triplet over a doublet for visual. Someone mentioned a Vixen ED103s in the classifieds and my doublet is the same model and I can tell you that the one I have has extremely good optics.



#23 PNW

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Posted 26 November 2019 - 11:08 AM

My first refractor was an Infinity 102. It's a cheap, F 5.9, Achro. It took me 2 years to notice a blue edge around the moon. Magnifying up to see individual craters was awesome. I still really enjoy using it. I've since upgraded to an AR 127, another Achro. My logic is, due to our high humidity, I can't usually use the highest magnification. I could be wrong. I suppose it's like buying a car with a 4 cylinder engine versus a big V 8. You'll definately notice a difference, but do you really need the extra power if you're driving on city streets?


Edited by PNW, 26 November 2019 - 11:09 AM.


#24 SeattleScott

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Posted 26 November 2019 - 07:47 PM

Florida has high humidity and it is the land of stacked barlows. Humidity shouldn’t keep you from using high power.

I am in Seattle and often use 200-300x on moon and planets.

Scott

Edited by SeattleScott, 26 November 2019 - 07:48 PM.


#25 Jond105

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Posted 26 November 2019 - 08:02 PM

Florida has high humidity and it is the land of stacked barlows. Humidity shouldn’t keep you from using high power.

I am in Seattle and often use 200-300x on moon and planets.

Scott

That’s pretty much what we’re getting here in Detroit as well. 




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