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Why your refractor and not the newt?

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#26 StarBurger

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Posted 08 January 2021 - 02:16 PM

All this discussion would cease if the question were to be re-phrased to "Why your refractor AND the newt".

Errrr...maybe not...


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#27 Codbear

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Posted 08 January 2021 - 04:11 PM

For those of us with disabilities, refractors offer a very stress-free observing experience...within limits of course, depending upon one's disability.

 

For me, up to about a 5" refractor set on a Stellarvue M2 Alt-Az, I'm good! no fuss, no muss. My large refractor is permanently mounted and is wonderful at planetary and splitting doubles. When my dobs are not showing pinpoints, my refractor still is. Of course, on above average excellent nights of transparency my refractor is abandoned and one of the Big Boys (depending on what part of the sky I'm observing dictates which dob I use) is putting up great DSO views.

 

Since my two large dobs are also permanently located I almost never have to worry about collimation. The fly in the ointment is my 11"Teeter with a Zambuto mirror. I still love it's wonderful views in almost any conditions, and it is purposefully not permanently mounted so it can observe anywhere in the sky on my property, and can occasionally go on trips to dark sites.

 

But with the prospect of collimating the 11" inch, I feel like the constipated guy with hemorrhoids...sooner or later you know it's gotta happen, but it's sure as heck not gonna feel very good when it does!!!

 

Sam


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#28 Suavi

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Posted 08 January 2021 - 05:48 PM

I have a 4" oil-spaced fast refractor because it easily fits in a dry cabinet; humidity in the tropics is generally high most year round and so is temperature - not sure how long would a mirror last in such conditions, or a lens, if not kept in a dry cabinet. When I lived in a cooler and drier climate I had an affordable 6" f/8 Newtonian - she was a beauty and so were the views waytogo.gif 



#29 PETER DREW

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Posted 08 January 2021 - 06:07 PM

Also, refractors are good for solar observation and make good finders, I have a 150ED mounted on my 16" SCT.



#30 ABOAS

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Posted 08 January 2021 - 06:18 PM

$3000ish vs $300ish You’d be surprised. Or maybe you wouldn’t. 😁

#31 ABOAS

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Posted 08 January 2021 - 06:23 PM

I suppose I could attach the pic.

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#32 ABOAS

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Posted 08 January 2021 - 06:29 PM

My point is, they’re all great. I enjoy all of them, from budget scopes and eyepieces, to the ultra premium. Some just take a bit more patience which is part of the fun imo. But the games are over when I break out the 14.5 Starmaster. That scope has left me speechless countless times.


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#33 BFaucett

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Posted 08 January 2021 - 07:20 PM

However, one must remember that Galileo used a reflector ......

 

noway.gif   No soup for you!

 

Bob F. 


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#34 John Huntley

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Posted 08 January 2021 - 08:12 PM

I have a 12 inch dobsonian and 4 very good refractors. I like them all. The 12 inch scope is the one that is least expensive and has given me the most "firsts" and "wows" over the years. I must be fascinated with refractors though to have spent so much more on them and to spend more time in this section of the forum than the other scope designs. Can't explain that really ...... shrug.gif


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#35 Scott in NC  Happy Birthday!

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Posted 08 January 2021 - 09:10 PM

However, one must remember that Galileo used a reflector ......

Are you sure?  Galileo Galilei died the same year that Sir Isaac Newton was born (1642) and I’m reasonably sure that Newton invented the “Newtonian” reflecting telescope.  Galileo used a small handheld refractor.


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#36 McGarnicle

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Posted 08 January 2021 - 10:23 PM

From my limited research & experience, I think I’m more of a refractor guy. In fact, the noob scope in my sig is going back to Best Buy and I’ve ordered an AT102ED. I’m now researching goto mounts to pair with it. This means I’m likely going to go several months with nothing but a pair of binos and an expensive collection of eyepieces I can’t use, but I know I’m going to be much happier in the long run. The Starsense scope needed collimation before every session, and my plan was to get a 10” dob which would likely be the same situation, plus it’s big and bulky. 

 

The dob I was considering (Zhumell/Apertura) has a 62-page mod thread. I don’t feel like spending $750 on a telescope only to discover I have to replace knobs & springs, rub soap on bearings or place old CDs underneath because the thing doesn’t track properly out of the box. Others see it as a journey and enjoy tinkering. I can see the appeal, but right now I just want to learn the sky with a scope I can set up quickly. 

 

One option I’m thinking about is getting a really beefy tripod that I can use with my AT102ED first, and later accommodate an 8” newt if I go that route. And the only reason I’m still considering the newt/dob is if I’m not getting the detailed views of galaxies & nebulae that I’m craving. I think for planetary, moon and star clusters, the AT will be more than adequate and those things will keep me busy for at least my first year. 


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#37 Ihtegla Sar

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Posted 08 January 2021 - 10:30 PM

Are you sure? Galileo Galilei died the same year that Sir Isaac Newton was born (1642) and I’m reasonably sure that Newton invented the “Newtonian” reflecting telescope. Galileo used a small handheld refractor.


You are correct that Galileo used a refractor but incorrect that Newton "invented" the reflector. Newton may have been the first one to successfully build a reflector but the design had been floating around in the writings of several others including Galileo long before Newton.

Edited by Ihtegla Sar, 08 January 2021 - 10:36 PM.

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#38 HydrogenAlpha

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Posted 09 January 2021 - 04:02 AM

Refractors give nice tight stars. Nice for visual but fantastic for imaging



#39 dan_1984

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Posted 09 January 2021 - 05:06 AM

What are the real benefits of a refractor over a newt (I Y O) ? Is it just the portability issue?

It is a matter of personal preference, and also the intended purpose: visual or imaging? or both?

My first scope was a small achromat, then a 10 inch newt, then a 12 inch SCT, and finally settled on a 8 inch APO refractor. Unfortunately I had to try different designs to see what is best for me.

I find the refractor the most versatile instrument, virtually plug and play.

 

A few benefits:

  • closed design
  • no thermal issues
  • no collimation issues
  • no obstruction
  • more than enough backfocus
  • apochromatic for visual band pass (premium scopes anyway, can't comment on Chinese made apos)
  • rigid assembly ( really important for tracking, guiding, mount modeling etc)
  • solid focuser (the FT3.5 inch is a monster)
  • better contrast inch for inch
  • better light throughput, specially for oil spaced triplets
  • very low maintenance
  • no or little dew problems (guess it depends on the weather in ur location)
  • not so sensible to seeing as bigger mirrored scopes
  • excellent for both visual and imaging (talking triplets here)
  • they look nice :)
  • very good resale value for the premium stuff, if you can find any on the second hand market
  • they silently do their job, and do it well, without demanding constant user input

Cons:

  • above 5-6 inch they are heavy so they need an obsy
  • they need a corrector/flattener (don't know if its a con, most scopes need a corrector)
  • COST

The most annoying thing about them is cost. It is up to the user to decide if the benefits are worth the cost. 

For my seeing, my backyard conditions, my budget, the refractor was the best choice, although it took me some 12 years to reach a conclusion :))

Clear skies!


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#40 25585

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Posted 09 January 2021 - 10:50 AM

No dust, no recoating the lens, no collimating, no coma or little, no secondary spikes, better contrast, punches slightly above its aperture, and chicks dig refractors....what more do you need!

My lady was stroking the 100 Equinox's OTA the other night. I was worried about its paintwork as she wears several rings! 

 

Done in fun to mimic the old Celestron advertisments.


Edited by 25585, 09 January 2021 - 10:52 AM.

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#41 Mitrovarr

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Posted 09 January 2021 - 12:46 PM

I have both. Why wouldn't you?

 

Advantages of my refractor:

1. Works on a EQ goto mount, so it has goto and tracking.

2. Less cool down time.

3. Far fewer problems with tube currents, etc. even when it is cooled down.

4. Doesn't need to be collimated.

5. Doesn't have to be assembled onsite (my newt is a truss dob).

6. Higher optical quality.

7. Textbook optical images, no spikes or obstructions.

8. Better for photography for a number of reasons.

 

Advantage of my reflector:

1. Is twice the aperture.

2. Was half the price.


Edited by Mitrovarr, 09 January 2021 - 12:46 PM.

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#42 Jon Isaacs

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Posted 09 January 2021 - 01:13 PM

The dob I was considering (Zhumell/Apertura) has a 62-page mod thread. I don’t feel like spending $750 on a telescope only to discover I have to replace knobs & springs, rub soap on bearings or place old CDs underneath because the thing doesn’t track properly out of the box. Others see it as a journey and enjoy tinkering. I can see the appeal, but right now I just want to learn the sky with a scope I can set up quickly.

 

 

Many of the mods are to the mount. Not much needs to be done to the scope.. 

 

My suggestion:

 

Do not set up next to a 10 inch Dob..

 

Galileo used a refractor. Add a tribute, I refractors as finders, no reflectors. A 50 mm GSO finder is likely better than Galileo's ~30 mm refractor. He worked wonders with what he had.

 

Jon


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#43 Hesiod

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Posted 09 January 2021 - 02:54 PM

I think that Newton is credited to the introduction of the flat to observe with better comfort; I do not know who "discovered" the reflector.
Leonardo described how stars could be observed reflecting in a basin filled with water, but the concept could date back to classical time (the legend about burning mirrors deployed against the besieging Romans by Archimedes were likely vulgarization of hellenistic studies about mirrors; and indeed burning mirrors were described to kindle fires in temples).
Galileo used just refractors (and tried to improve them as were pretty awful).

#44 Hesiod

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Posted 09 January 2021 - 03:58 PM

As for the original post, I had the impression that there is a little confusion about product category and design.

Most issues ascribed to reflectors (and advantages credited to reractors) are consequence of the fact that often are compared telescopes belonging to different product categories.

Every single refractor I could think of sold at the same price of my Heritage 130 is clearly and undoubtedly worse than the little reflector.

A 12" Dob sells at 750$, but try to think what kind of refractor assembly could purchase at the same price. Nothing too fancy, for sure.


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#45 Sketcher

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Posted 09 January 2021 - 04:10 PM

Well, since I have refractors and I also have Newtonians; and since I choose to use my refractors far more often than I choose to use my Newtonians, I suppose I should make a contribution to this thread:

 

It's not easy to pin down why I prefer using my refractors.  The simple (and rather meaningless) answer is: "Personal Preference."  But the likely followup would be: "Why?"

 

Well, it's easier for me to take my refractors outside and to bring them back inside.  So that may be a part of the situation.  On the other hand, back when I kept one of the Newtonians in a roll-off-roof observatory, the Newtonian tended to get used more often.  On the other hand (It's OK, I have two hands smile.gif )  I switched to my current refractor preference a few years prior to removing the Newtonian from the ROR observatory.  So . . .

 

I don't care much about being able to resolve closer doubles or to see smaller and fainter DSOs.  I can resolve "close enough" doubles and still see plenty of small, faint galaxies, etc. without having to use one of my Newtonians.  It doesn't matter to me if they're not the same doubles nor the same DSOs.  Similarly, I can see plenty of detailed, structured DSOs with either class of telescope.  So, I might as well choose one and enjoy all that I can see with it.

 

So why does my choice always end up being a refractor?  Hmmm . . . Well, it's easier, more intuitive, for me to point a refractor at an object (before looking through a finder) by sighting along the OTA.  After all, the eye is nearly always near the back of the OTA.  So that probably contributes to my preference.

 

What about planetary observation?  Well, from my location it would be a rare night that I would be able to use a magnification with one of my Newtonians that would not be practical for use with one of my refractors.  So, either telescope will work for planetary observation.  Besides, I'm not into this hobby to always see more.  I'm happy to see as much as I can when using whatever telescope I might choose to use.

 

That last sentence might the key for me.  The telescope and the level of detail, light-grasp, etc. are not that important to me.  I just want to make observations.  So what if someone else can see more with their 92-inch telescope?  That doesn't matter to me.  All that matters is what I can see with the telescope I'm using.

 

Am I making any progress here?

 

It's easier for me (during takeout, use, bring-in, and storage) to keep my refractor optics clean than it is to keep my Newtonian optics clean.  It's also easier to safely clean my refractor optics (if they were to ever need it!)  So this might be a factor in my preference.

 

I do prefer my generally "cleaner-looking" refractor views.  Yes, I have some CA with some (but not with all) of my refractors; but my Newtonians collect more light, so any light scatter (more of an issue with mirror optics) and diffraction effects are going to be more obvious to the eye when using a Newtonian.  I simply prefer my refractor views -- personal preference (again).

 

So it looks like, for me, the preference (for the refractor) tends to be related to:

 

     a) easier to take out and bring in

     b) easier to keep clean and to safely clean

     c) easier to direct toward targets of observation

     d) cleaner views

     e) My refractors show enough to satisfy my needs.

     f) The usual Newtonian advantages are of no importance to me.

     g) (not mentioned above) Cool down times for large mirrors -- not an issue.

     h) Oh, and I needn't check/adjust collimation

 

I'm sure there are other reasons that just aren't coming to mind right now.

 

But more seriously, for me, it's really just a matter of my own, personal, preference.  I gain more pleasure out of using my refractors.  And that's really the only reason that matters.


Edited by Sketcher, 09 January 2021 - 04:13 PM.

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#46 Tyson M

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Posted 09 January 2021 - 04:15 PM

Why not both? 

 

bb0ec3d5987cff5c6bf8699b0d4e53b2.jpg


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#47 Bomber Bob

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Posted 09 January 2021 - 06:11 PM

One option I’m thinking about is getting a really beefy tripod that I can use with my AT102ED first, and later accommodate an 8” newt if I go that route. And the only reason I’m still considering the newt/dob is if I’m not getting the detailed views of galaxies & nebulae that I’m craving. I think for planetary, moon and star clusters, the AT will be more than adequate and those things will keep me busy for at least my first year.

 

I really like the combination of 8" reflector & 4" refractor.  I sold my AT102ED, but that's not a slam on this ED.  At $600 it is a Best Buy!   But I really didn't need a 4" F7.  My 5" F5 RFT is a better DSO frac, and my one-of-a-kind Dakin 4" F10 has better quality optics (possibly vintage Bausch & Lomb).  And:  I bought my APM 152ED as a "reward" for my civil service retirement; unfortunately, with my arthritis, it became too much to loft up to a usable cradle height, so I sold it.  Now my plan is to reward my military retirement in SEPT with a top-tier 4" APO (I have a separate thread on weighing ALL those options!).


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#48 Kunama

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Posted 09 January 2021 - 07:20 PM

undecided.gif I'm more interested in "why does this topic come up every few weeks.......?bangbang.gif

This site should have a "Search" feature tongue2.gif

 

 


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#49 junomike

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Posted 09 January 2021 - 07:29 PM

Not sure if this has be mentioned but on cold nights I find the collimation of newts needs to be tweeked several times.


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#50 Ihtegla Sar

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Posted 09 January 2021 - 07:35 PM

I think that Newton is credited to the introduction of the flat to observe with better comfort; I do not know who "discovered" the reflector.
Leonardo described how stars could be observed reflecting in a basin filled with water, but the concept could date back to classical time (the legend about burning mirrors deployed against the besieging Romans by Archimedes were likely vulgarization of hellenistic studies about mirrors; and indeed burning mirrors were described to kindle fires in temples).
Galileo used just refractors (and tried to improve them as were pretty awful).


Mirrors are great for starting fires. Years ago I met someone who lined an old style satellite dish with some reflective house wrap (similar to reflectix but without the bubbles) and used the thing to roast hot dogs. It was far from "mirror quality" but it worked well and would roast a hot dog quicker than a campfire. He even cooked a 20 pound rack of chateaubriand. There is a lot of dispute about whether Archimedes "death ray" was fact or fiction, and it seems to me that getting the focal length right to hit a ship with the focal point would be challenging. But you wouldn't need anything close to an optical quality mirror to start a fire pretty quickly in the noon day medeterrainian sun.

Which brings up one advantage of refractors. The white light solar wedge. They give great detailed views of sun spots.


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