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120mm to 150mm ED/APO "budget" choices (non-premium!)

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#26 25585

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Posted 27 August 2019 - 01:16 AM

 

My story:

 

When I was looking at ~5 inch ED/Apo Refractors that were more capable at high magnifications than my 4 inch apo but still "grab and go" I decided a full 5 inch was just too big to be handy.

 

The Skywatcher 120 mm ED looked to be a nice size but I wanted something with a nicer build and a sliding dew shield. I settled on the Orion Eon 120 mm. It has the 120 mm Skywatcher ED optics but in a nicer OTA. They are no longer available new but they pop up on the used market

 

I am most happy with the Eon. It's a stunner to look at and to look through. I will admit to selling it after 2 years in a moment of financially induced guilt but I got to missing it so I recently bought a second one.. 

 

 
 
Jon

 

Same as the Sky Watcher Equinox I think. https://www.365astro...ractor-OTA.html


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#27 Jon Isaacs

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Posted 27 August 2019 - 07:15 AM

You shouldn't get too hung up on FPL-53 Glass or any single glass type. I see this allot out here. Its never that glass alone that makes for a quality scope. Focal length plays a big part of the equation as well as the mating element.

FPL-53 is great in shorter focal length scopes but at F8, its not needed for the same color correction as needed at F7.That's why the SW-150ED or APM 152ED does not need that same glass type for excellent results.

Read up on why the lens designers balance glass type to mating element to focal length and even how all of this factors into the cost of scopes.

You could save quite a bit of money by doing your homework by not being so hung up on one glass type vs another once you understand the differences.

...Ralph




 

 

Color correction depends on both focal ratio and aperture.  With otherwise identical designs, a 75 mm F/8 will have half the color error of a 150 mm F/8.

 

Jon


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#28 YAOG

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Posted 27 August 2019 - 10:30 AM

Color correction depends on both focal ratio and aperture.  With otherwise identical designs, a 75 mm F/8 will have half the color error of a 150 mm F/8.

 

Jon

Which explains why people, myself included, love the little generic 80mm f/7.5 FPL-53 doublets, they are virtually color free, compact, sharp and CHEAP. 

 

Chip


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#29 YAOG

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Posted 27 August 2019 - 01:16 PM

If people are searching for alternatives in Europe, you might as well add the 130mm FPL53 triplet 2.5" focuser though I would spend the extra and get the 3.7" (but you are now at 11kg)

 

https://www.teleskop...-Refractor.html

 

https://www.teleskop...r---FPL-53.html

The issues with the TS Optics EDTs and similar EDTs for the OP are that they are very nose heavy in these lighter builds with smaller focusers which could be improved by ordering the excellent 3.7" focuser but the cost is of course much higher, and double the cooling time before they come into best usable figure. The TS Optics FPL-53 EDTs are impressive values to be sure. For visual observation and narrow band imaging a full triplet apo is not really called for - IMO anyway. 

 

Chip 


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#30 MalVeauX

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Posted 27 August 2019 - 02:06 PM

For visual observation and narrow band imaging a full triplet apo is not really called for - IMO anyway. 

 

Chip 

This does raise a good point Chip. While there are those who champion both sides of this coin, visually using a doublet instead of a triplet and vise verse, I suppose I need to put my eyes on both to really know. My ED80 with FPL53 doesn't show me much if any false color. So if that means the SW120ED can do that with 120mm aperture, that just makes a lot of sense. At the same time, if the EDT FPL53's are affordable enough, it's interesting to know... but as you pointed out, if the color correction isn't noticeable to the eye, then it doesn't matter. And I narrowband image with achromats because it truly just works fine focusing a single wavelength.

 

So the fussy stuff to include would be the focuser itself (to handle heavy imaging trains and heavy visual trains including binos) and the ability to get a flattener/reducer that works properly with it.

 

Very best,


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#31 YAOG

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Posted 27 August 2019 - 02:13 PM

There are no bad 120 to 130mm ED or triplet refractors on the market today. Find one that makes you smile when you look at it, is comfortable on the mount you plan to use it with and you can afford comfortably and you absolutely will not be disappointed with it.
Some people are hung up on sliding dew shields, some like the black tubes, some the white tubes, I don't like the pebble finish scopes but that's just me.

Any focuser you get, regardless of the scope, can be upgraded to a better aftermarket one if you want one.

I've noticed in this hobby, there's plenty of wiggle room in costs even if you claim to have a tight budget. Sacrifice something else in your life for a few months and get the scope you want most of all or you will not be happy in the long run.

Its a great hobby, the equipment is half the fun. Spoil yourself and get what you want. Refractors are Great and fun even just to look at. Take a bunch of photos of it when you get it and enjoy life!!!!

..Ralph

Ralph, 

 

I beg to differ, there are plenty of both new and old FPL-51 class doublets and triplets that are a poor value IMO. These entry level triplets NEED FPL-53 to show a significant optical edge to justify their additional cost over even cheap FPL-53 doublets which are a lot less money. A good FPL-53 ED class doublet like the slower Synta 80mm, 100mm and 120mm tubes are all better performing than the moderate speed f/6 - f/7ish low cost FPL-51 ED class triplets and MUCH better optically than the typical FPL-51 ED class doublets. Glass DOES matter if looking for modern, larger, faster objective scopes for imaging, especially for OSC imaging and for visual use unless the scope is very long and slow which is a legitimate goal if impractical for most. 

 

I have been down this road and back more than once and have come to the conclusion that if you want to buy a lower cost but still reasonably well corrected visual or narrow band capable doublet it needs to have an FPL-53 class ED element and be on what is considered the slower side by today's standards. Triplets for the picky visual user willing to wait an hour or two to cool down and imagers shooting OSC or at high pixel pitches nothing but an FPL-53 ED class triplet or a Tak TSA or TOA will get the job done at the highest levels optically, don't even talk about focusers. To say or think otherwise about glass types has IME been wishful thinking which I had to give up on. 

 

The real issue nobody seems to mention or understand is the cost of using a less expensive ED glass type is the hidden cost of owning and using a much longer slower scope chasing the performance of the faster FPL-53 ED class lenses. Sure maybe you could buy a longer FPL-51 ED doublet but to match the color correction of an FPL-53 doublet the lower class ED lens would need to be much longer and require a heavier more costly mount and unless you already own a big SUV or larger station wagon transporting a refractor much longer than a 1,200mm focal length scope is a Royal PITA.   

 

As you say astronomy is a hobby. But for many people astronomy is not just a "hobby" but the pursuit of technical and aesthetic perfection and control over the outcome at the eyepiece or image is where the joy of astronomy comes from for them. Amature astronomy is a lot cheaper than a lot of hobbies, like say being a vintage Ferrari collector but allows the same passion and pursuit of the details that make the person happy. I'm not a vintage Ferrari collector because IMO if something costs that much I'm going to drive the bejeezus out of it. 

 

Chip 


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#32 YAOG

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Posted 27 August 2019 - 02:41 PM

This does raise a good point Chip. While there are those who champion both sides of this coin, visually using a doublet instead of a triplet and vise verse, I suppose I need to put my eyes on both to really know. My ED80 with FPL53 doesn't show me much if any false color. So if that means the SW120ED can do that with 120mm aperture, that just makes a lot of sense. At the same time, if the EDT FPL53's are affordable enough, it's interesting to know... but as you pointed out, if the color correction isn't noticeable to the eye, then it doesn't matter. And I narrowband image with achromats because it truly just works fine focusing a single wavelength.

 

So the fussy stuff to include would be the focuser itself (to handle heavy imaging trains and heavy visual trains including binos) and the ability to get a flattener/reducer that works properly with it.

 

Very best,

Marty,

 

As a recently mostly visual observer with a taste for imaging to make pretty pictures I love the bespoke Parallax/AT130 f/6 FPL-53 EDT, it is a stunning visual optic. I think a 130-140mm refractor is where I want to be visually, for imaging this is also good general purpose scope range. Just big enough but not too big while offering good flexibility with a reducer/flatteners and PowerMates. I also think a high quality 80mm EDT makes a good companion for a 130mm-140mm apo imager on the wide field side. The exciting thing I am slowly working up to - if it actually works fingers crossed - my optimised Meade 10" native f/6.3 SCT combined with a Starizona SCT II 0.63x coma remover @ f/4 will make a good companion for the deep stuff that needs a light bucket to gather NB data I hope to combine with the fine resolution of the 130mm apo.  

 

I had this other crazy idea, buy several 130mm-150mm short tubes and mount them in an array and gather NB data all at once to save time. But it works out a lot cheaper to try using my existing M10" SCT f/6.3 with a Starizona SCT II .63x/coma corrector to collect NB data while the Parallax/AT130 gathers OSC data on a single mount as a shortcut. It might work but I don't know because I have not tried it and I have not seen anyone else doing this yet. 

 

But I'm wander again...     

 

Chip


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#33 MalVeauX

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Posted 27 August 2019 - 02:49 PM

Marty,

 

As a recently mostly visual observer with a taste for imaging to make pretty pictures I love the bespoke Parallax/AT130 f/6 FPL-53 EDT, it is a stunning visual optic. I think a 130-140mm refractor is where I want to be visually, for imaging this is also good general purpose scope range. Just big enough but not too big while offering good flexibility with a reducer/flatteners and PowerMates. I also think a high quality 80mm EDT makes a good companion for a 130mm-140mm apo imager on the wide field side. The exciting thing I am slowly working up to - if it actually works fingers crossed - my optimised Meade 10" native f/6.3 SCT combined with a Starizona SCT II 0.63x coma remover @ f/4 will make a good companion for the deep stuff that needs a light bucket to gather NB data I hope to combine with the fine resolution of the 130mm apo.  

 

I had this other crazy idea, buy several 130mm-150mm short tubes and mount them in an array and gather NB data all at once to save time. But it works out a lot cheaper to try using my existing M10" SCT f/6.3 with a Starizona SCT II .63x/coma corrector to collect NB data while the Parallax/AT130 gathers OSC data on a single mount as a shortcut. It might work but I don't know because I have not tried it and I have not seen anyone else doing this yet. 

 

But I'm wander again...     

 

Chip

Interesting Chip,

 

I do think about it because when I think of the SW 150mm F8 ED EVO, I don't think for even a moment for imaging of DSO. I only think of solar system imaging and visual with it. A 120~130mm instrument, around F6~F7 however, I do think of imaging (with flattener/reducer) DSO potentially (galaxies mostly) as well as solar system bodies and visual. It puts a more functional argument towards the smaller aperture scope in general. That and I have to always weigh in that I have a C8 Edge and 8" F6 Quartz Newt, so do I really need a 6" F8 ED Frac? What I don't have is a greater than 4" frac and I don't want a small mirror. So that leaves an APO in the 5" range. As much as I'd love to believe a 150mm F8 ED frac (entry level here with SW) is excellent, I can't see it beating a good 8" mirror at much of anything for imaging if pointed at solar system bodies, so it leaves visual only, which.... I think a 150mm F8 ED frac (specifically the Skywatcher) vs my 200mm F6 quartz newt is not a fight and ultimately the newtonian does this job, so it would be like doubling up on things in a sense. So again, I waffle back to thinking a 5" frac is the way to go. Then again, if the SW 150mm F8 ED is great, maybe it would replace my 8" F6 newt? Neither replace my C8 Edge thankfully, so that's not a fight.

 

So the context is.... 150mm F8 ED (SW EVO) vs 8" F6 Quartz Newt vs 120mm ED (FPL53) (SW) in a fight for visual use and imaging use.

 

Is there a decent known reducer/flattener for the SW 120ED?

 

Very best,



#34 scooke

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Posted 27 August 2019 - 03:29 PM

I have the Stellarvue 125 Access and the SV150ED and I think they represent some of the best bang for the buck in the industry today.  I recently got the 125 on sale.  The mechanics and optical quality are excellent.  High contrast on Jupiter and Saturn, handles high power effortlessly, no CA seen on any object, and an extremely clean diffraction disk.  The SV150ED is very much the same, just bigger and better.  This particular sample I bought used from Chas and he had replaced the focuser with a Moonlight.  If you don't want to invest in an aftermarket focuser, get the deluxe model with the 3.7" focuser.  The Stellarvue focuser is excellent as is.  If size doesn't bother you (It is much bulkier than the 125, measurements do not convey an appreciation of the difference), then get the 6".  If you think the size will limit its use, get the 125.  I use the 125 as a grab and go.  M2 mount on Meade field tripod and mounted scope carried out together.  I have the 150 mounted on an AP900 on a scope buggy in the garage.  Just roll it out, align, and observe.  You can't go wrong with either choice


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#35 Jond105

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Posted 27 August 2019 - 03:55 PM

 

 

Is there a decent known reducer/flattener for the SW 120ED?

 

Very best,

https://www.skywatch...x-for-proed-120

 

they have one themselves. 


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#36 MalVeauX

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Posted 27 August 2019 - 04:00 PM

https://www.skywatch...x-for-proed-120

 

they have one themselves. 

Durr.... thanks, didn't see that :p

 

Very best,


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#37 MalVeauX

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Posted 27 August 2019 - 04:05 PM

Dang, so, the SW 120mm ED just has a strong case. Used it's around $1k (commercially even!). Even better. I could buy two more scopes for that difference from $2k.

 

So that just leaves that comparison.... 120ED or 150ED. *tries not to order 150ED*

 

The 120ED can image DSO. The 150ED is not well suited to this.

 

The case for the 120ED grows stronger!

 

Very best,


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#38 YAOG

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Posted 27 August 2019 - 04:44 PM

Interesting Chip,

 

I do think about it because when I think of the SW 150mm F8 ED EVO, I don't think for even a moment for imaging of DSO. I only think of solar system imaging and visual with it. A 120~130mm instrument, around F6~F7 however, I do think of imaging (with flattener/reducer) DSO potentially (galaxies mostly) as well as solar system bodies and visual. It puts a more functional argument towards the smaller aperture scope in general. That and I have to always weigh in that I have a C8 Edge and 8" F6 Quartz Newt, so do I really need a 6" F8 ED Frac? What I don't have is a greater than 4" frac and I don't want a small mirror. So that leaves an APO in the 5" range. As much as I'd love to believe a 150mm F8 ED frac (entry level here with SW) is excellent, I can't see it beating a good 8" mirror at much of anything for imaging if pointed at solar system bodies, so it leaves visual only, which.... I think a 150mm F8 ED frac (specifically the Skywatcher) vs my 200mm F6 quartz newt is not a fight and ultimately the newtonian does this job, so it would be like doubling up on things in a sense. So again, I waffle back to thinking a 5" frac is the way to go. Then again, if the SW 150mm F8 ED is great, maybe it would replace my 8" F6 newt? Neither replace my C8 Edge thankfully, so that's not a fight.

 

So the context is.... 150mm F8 ED (SW EVO) vs 8" F6 Quartz Newt vs 120mm ED (FPL53) (SW) in a fight for visual use and imaging use.

 

Is there a decent known reducer/flattener for the SW 120ED?

 

Very best,

 

Marty,

 

I've used the SW150 f/8 ED, it makes a very good planetary scope but yes the 8" Newt will match or better it for color if not contrast. Not surprisingly the SW120 f/7.5 ED has slightly better color correction and also seems sharper to me but I only have used one SW150ED and used several SW120EDs and not side by side. The diagonal can make a noticable difference as can the eyepiece, we were using a Baader 2" Zeiss BBHS prism and Zeiss and TMB monos worth as much as the SW150ED when doing a side by side with a really good TEC140 which the SW150ED matched once equipped with the same back half optics. So pick your poison carefully, even with these exotic items the SW150ED cost would only be 2/3 the cost of the TEC140 OTA only! 

 

 

If you didn't have the other scope options and had a mount up to it for imaging the SW150ED is fully capable of imaging DSOs but it is f/8 do a reducer/flattener will speed up data acquisition. The SW120ED is a bit faster though you give up significant objective aperture it is the sharper, better color corrected optic IME. 

 

So listening to your situation I suggest the SW120ED and know you will need to replace the focuser for imaging and use a really small-light astro cam. If you really are going to image with the scope I highly recommend the StellarVue Access 125 on sale right now for a bit less than the SW120ED. The SV Access 125 has excellent optics a MUCH better focuser, heavier and stiffer hinged rings and a retractable dew shield. Simple stuff, but if you only added the cost of a new focuser to the SW120ED you'd be stupid to not buy the SV Access 125. Anyway my two-cents.

 

 Chip


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#39 ButterFly

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Posted 27 August 2019 - 10:11 PM


Skywatcher 120mm ED (FPL53) has a lot of information and support. Focuser looks meh.

...

ExpSci 127mm F7.5 FCD100 Triplet (FPL53) has info, less support. Focuser looks ok, not sure.

 

I'm really curious at this point about the Skywatcher 120mm ED vs an ExplSci 127mm FCD100. Both are FPL53. The ExpSci has triplet. No one seems to push for this one though.

 

Does everyone think the Skywatcher 120ED is better or equivalent to the ExpSci Carbon Fiber 127mm FCD100 triplet really? Both can be had at $2k or less.


 

This was my choice a few months ago.  I went SW120ED becuase it is mostly for visual use.  The stock focuser handles a 21 Ethos at zenith well.  I replaced the stock visual back because it is an awful compression ring-less two screw deal.  Imaging with that focuser ...?  EAA sure.  And you can't collimate, which is not an issue at all visually.  And there is the cooldown time of the doublet and the weight.  If I align the mount it's ready by the time I'm done.  If I just stick it on a video head, I wait a little.

 

If you are mostly imaging, I would head for the ES (maybe not the carbon fiber though, it's just too little gain for the added instability and price at 127; it's great at the 80mm level though).  The focuser is better and you can collimate.  I'm not sure what you mean about the support on the ES.  The warranty is rather good, lasts forever, and transfers if you register soon after buying.

 

Take them for a test drive if you can and look through images on astrobin.


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#40 fate187

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Posted 28 August 2019 - 03:13 AM

SW Equinox 120ED or the EON 120 flavor. With the SW120ED (standard) I don't like the focuser, which is probably the weakest part on the otherwise nice scope. The focuser on the Equinox ist much more stable and can be rotated. So no need to change it. I don't know if the EON120 can be bought new, but the Equinox is discontinued here in Europe I think. Got it used for unser $1000... a bargain. Very light also als with retractable dewshield. If you get either SW120ED or 150ED do yourself a favor and get a Baader Clicklock that can be threaded on the drawtube.

 

regards

Michael


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#41 zirkel 2

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Posted 28 August 2019 - 03:50 AM

Marty, for sale : https://astromart.co...ic-refractor-te oups! 6 years ago...

 

I chose a 100 ED - f / 9 refractor for the FPL-53 glasse but also and especially for its focal/aperture ratio which gives me excellent performance in visual observation (crisp image, pin point star and no CA).

Now the question of a larger diameter arises for me, great subject for me...


Edited by zirkel 2, 28 August 2019 - 10:39 AM.

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#42 jag767

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Posted 28 August 2019 - 05:08 AM

Oh I forget about the non compression back on the 120. Yeah that annoyed me. I bought the compression back from scopestuff then returned the scope so I have it laying here. Thats really the weakest point on the 120, unless you want the higher quality build on other variants with the same optics. Not that its bad mind you, but there's many out there who would want to opt for the more robust versions. A sliding dew shield is nice going through a doorway.

Also, I'd be curious how much improvement could be made with flocking the interior and maybe adding a baffle or two. It may not be much, but its not the darkest black paint internally that I've ever seen.
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#43 CHASLX200

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Posted 28 August 2019 - 05:41 AM

Hey all,

 

I am waffling all over the place. Looking to talk about non-premium ED/APOs for context. Both visual and some imaging application. Mounting is not an issue at all for me at these sizes, so weight and length are not an issue here. My only issue is overall value for aperture, correction (good doublet vs lesser triplet) and the focal-ratio to help figure out FOV and for imaging the speed of it. Imaging would be mostly for galaxies and solar system bodies. Visually it would be for literally everything.

 

At first, I thought I would just go for a Skywatcher EVO 150mm F8 ED. Not a great piece of glass, but better than my 150mm F8 achromat. Good reports. Would probably do everything I need and would be fine visually too. I'm not super sensitive to CA. $2k shipped for me. But, why get this when I have a C8 Edge HD and an 80mm FPL53 APO? This makes me waffle.

 

Then, I started thinking, well, when I want to take a refractor with me, do I really want or need a 150mm? Maybe I can explore the smaller ones. I already have an 80mm APO, so I don't need something that small. I would want something in the 120~150mm range, because I don't want something close to my 80mm. I really think the 127mm and 130mm options for budget have the most bang, it seems. So this started me looking at potential "5 inch triplets" options in the same price ranges at the 150mm F8 ED doublet. While I get more aperture with the 6" doublet, why not entertain the idea of a 5" triplet?

 

I started looking at the Skywatcher 120mm ED (FPL53?) naturally. Supposed to be excellent for a doublet. I also looked at the AstroTech AT130EDT (FK-61?), also supposed to be pretty good. Then I looked at the ExploreScientific 127mm F7.5 FCD100 Triplet (FPL53?) and can get it in carbon fiber. Other options similar in price?

 

Then of course, I wonder... back to 150mm F8 ED doublet vs... the 127ish" triplets/doublets. Get the biggest cheapest ED? Or get a better corrected 5"?

 

Let's keep it centered around that $2k USD mark and would love to not have to replace the focuser.

 

Thoughts?

 

Very best,

Find a used Sky watcher 150ed. I sold mine for $2100. And that included a new 2.5" Moonlite. And Parallax rings.


Edited by CHASLX200, 28 August 2019 - 05:43 AM.

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#44 YAOG

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Posted 28 August 2019 - 09:07 AM

Marty, for sale : https://astromart.co...ic-refractor-te

 

I chose a 100 ED - f / 9 refractor for the FPL-53 glasse but also and especially for its focal/aperture ratio which gives me excellent performance in visual observation (crisp image, pin point star and no CA).

Now the question of a larger diameter arises for me, great subject for me...

 

That ad is from 6 years ago but I respect the choice you made in the 100mm ED. They are the best deal in the used 100mm class scopes, IMO of course. 

 

Chip



#45 25585

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Posted 28 August 2019 - 12:54 PM

Interesting Chip,

 

I do think about it because when I think of the SW 150mm F8 ED EVO, I don't think for even a moment for imaging of DSO. I only think of solar system imaging and visual with it. A 120~130mm instrument, around F6~F7 however, I do think of imaging (with flattener/reducer) DSO potentially (galaxies mostly) as well as solar system bodies and visual. It puts a more functional argument towards the smaller aperture scope in general. That and I have to always weigh in that I have a C8 Edge and 8" F6 Quartz Newt, so do I really need a 6" F8 ED Frac? What I don't have is a greater than 4" frac and I don't want a small mirror. So that leaves an APO in the 5" range. As much as I'd love to believe a 150mm F8 ED frac (entry level here with SW) is excellent, I can't see it beating a good 8" mirror at much of anything for imaging if pointed at solar system bodies, so it leaves visual only, which.... I think a 150mm F8 ED frac (specifically the Skywatcher) vs my 200mm F6 quartz newt is not a fight and ultimately the newtonian does this job, so it would be like doubling up on things in a sense. So again, I waffle back to thinking a 5" frac is the way to go. Then again, if the SW 150mm F8 ED is great, maybe it would replace my 8" F6 newt? Neither replace my C8 Edge thankfully, so that's not a fight.

 

So the context is.... 150mm F8 ED (SW EVO) vs 8" F6 Quartz Newt vs 120mm ED (FPL53) (SW) in a fight for visual use and imaging use.

 

Is there a decent known reducer/flattener for the SW 120ED?

 

Very best,

Yes SW make a 0.85x reducer/flatteners for the 80 to 150. Decent, I have no idea.


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