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How much increase in aperture to see a difference?

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#51 walt99

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Posted 05 June 2017 - 04:43 PM

 

I agree with your points. But I stand by my statement that "If every last detail is what we seek, than a 20% or more increase in light gathering and resolving power should make a noticeable difference at the eyepiece...."

 

 

Very true.  I guess just depends where one want the focus point to be at the moment.  One thing that always makes me chuckle when folks scoff at optimizing to best eyepieces and to focus on increasing aperture instead is that it sort of leaves a current problem and lets it propagate to a new scope.  Optimized components like eyepieces and diagonals seem to hold their stature for decades really.  So the scopes/objectives really come and go over time, often moving up in aperture.  However, the optimized accessories like the diagonals and eyepieces really stay around as the scopes change.  So it that light they are a bit more important because they will bring their magic to any aperture one gets.

 

I use a 5"  refractor.  It is the heaviest scope  I will ever want to lift up on its tall pier.  My EP's are almost all minimum glass with the exception of a Nag 13mm T6.  I choose the EP's that go as deep as possible.

 

I'll bet my 5" goes as deep as some 6"  with lesser or more complex glass.  I also use the best diagonal I can afford.

 

So,  I figger I save my back and thousands of dollars.  Far cheaper to optimize the rest of the optical train (as long as you stay away from wide-field mania!).



#52 gnowellsct

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Posted 05 June 2017 - 05:19 PM

I have an AP 130 F/6 which I use for visual observations primarily of double stars although anything is game. I have read so many impressive things about CFF I have thought about getting one. What is your experience in terms of the need for increased aperture moving from a 130 refractor to see a difference? Is a move to 140 enough or would I really need to get a 160 to make a visible difference?

Why not just get a 9.25 and find out.  Whatever mount you have carrying the 5" AP will carry a 9.25.   Then think about the experience before shelling out $10 to $20k on a six to 8 inch apo.


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#53 TheFacelessMen

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Posted 05 June 2017 - 05:25 PM

I have an AP 130 F/6 which I use for visual observations primarily of double stars although anything is game. I have read so many impressive things about CFF I have thought about getting one. What is your experience in terms of the need for increased aperture moving from a 130 refractor to see a difference? Is a move to 140 enough or would I really need to get a 160 to make a visible difference?

IMO 140 will only be a small difference whereas 160mm will be very noticeable so I would go with the 160....

 

Vixen had what I thought was quite a informative/reasonable guidance table in their 2014 Catalogue...it was removed in later catalogues ....but the 2014 is still available online.........

 

https://www.vixenopt...egory-s/165.htm



#54 JimP

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Posted 05 June 2017 - 07:23 PM

Very  interesting stuff. As for the article comparing a 140 directly with a 200 remember that once you've seen it in a larger scope it is easier to see in a smaller one. Seeing something in the 140 after having seen it in the 200 is different than seeing it in the 140  alone. The writer hit on this when discussing the Companion to Sirius. As I recall he stated something like he would've never been able to have seen the Companion in his 140 if he had not seen it first in the 200. So it is always difficult to compare telescopes side-by-side of different aperture if you are allowed to first observe with the larger aperture scope.

 

It always tickles me that when we discuss refractors sooner or later someone will come in with the "well for the money you could buy a much larger reflector with money left over for blah blah blah". I have owned larger reflectors up to and including 20 inches aperture including one with a quartz mirror, etc. One was an 18 inch with an excellent Zambuto mirror. They are all gone. I don't like Dobsonians. Period! I am a refractor man.

 

In asking about the move from 130 to 140 or 160  I was only interested in thoughts regarding the  move from 130mm to those two sizes, a 140 or a 160 as I also have a TMB(LZOS) 203 F/9. 


Edited by JimP, 05 June 2017 - 07:26 PM.

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#55 JimP

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Posted 05 June 2017 - 07:36 PM

And, just personal choice, I do not care to own any more Celestrons either.



#56 Jon Isaacs

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Posted 05 June 2017 - 08:47 PM

 

I agree with your points. But I stand by my statement that "If every last detail is what we seek, than a 20% or more increase in light gathering and resolving power should make a noticeable difference at the eyepiece...."

 

 

Very true.  I guess just depends where one want the focus point to be at the moment.  One thing that always makes me chuckle when folks scoff at optimizing to best eyepieces and to focus on increasing aperture instead is that it sort of leaves a current problem and lets it propagate to a new scope.  Optimized components like eyepieces and diagonals seem to hold their stature for decades really.  So the scopes/objectives really come and go over time, often moving up in aperture.  However, the optimized accessories like the diagonals and eyepieces really stay around as the scopes change.  So it that light they are a bit more important because they will bring their magic to any aperture one gets.

 

I keep my scopes and only occasionally change them.  

 

The thing of it is, once you have a solid set of eyepieces, there's not much to be gained in that department.. 

 

I agree with your points. But I stand by my statement that "If every last detail is what we seek, than a 20% or more increase in light gathering and resolving power should make a noticeable difference at the eyepiece...." It's not just the increase in light and the ability to use a larger exit pupil at a given magnification. Angular resolution also increases with aperture. However, a "noticeable" increase is not synonymous with a meaningful increase. The later is in the eyes of the beholder. When one factors in the extra cost, convenience of use, cool down, etc., the marginal gain in details hardly seems worthwhile... to me.

 

 

In the refractor world, a 20% increase in resolution is accompanied by a 41% increase in light gathering.  Both are significant..  

 

I think more in terms of ergonomics than in light gathering and resolution.  What's the biggest scope that I can comfortably fit through the door, observe with while seated.. 

 

Jon


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#57 SeattleScott

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Posted 05 June 2017 - 10:51 PM

Like Jon points out, resolution increases more linearly while light grasp more exponentially. 

 

The way I see it, getting the 140 means paying what, $7k, for something like a 15% increase in light grasp, and $5-10% increase in resolution. Barely detectable. Compared to spending maybe $11k and get a very noticeable improvement. You may spend 50% more, but you are getting 3-4 times the increase in brightness and resolution. So in that sense the 160 is a good value. Pricing assumes a CFF 140 or 160 based on listed prices on cloudbreak optics. Obviously could vary based on make and model. When you look at it this way it seems like a no brainer, at least to me.

 

Scott


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#58 Codbear

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Posted 06 June 2017 - 01:48 AM

 

I'm with you, Bill.  As I said in my earlier post, a difference of at least one magnitude (factor of 2.512 or 250%) will provide significantly brighter views.  If one's small scope is an 80 mm, then upgrading is not that demanding on mount and pocketbook.  But with the "small" scope being 5+ inches, one must think very hard about upgrading to a larger refractor if looking for brighter DSO images.  That is why my "upgraded" scope is a 10" Newt.

 

 

If I had a nice 130mm as my only refractor and was looking for an upgraded visual experience, and I had the cash for something like a TEC180, I think I would be looking at a premium Newt or MCT instead.  Let the 130 do what only it does best, and look for a compliment instead of an upgrade.

 

So let's see...a TEC180 goes for around $20k I believe, so what could I get some premium maker like Teeter or someone to make me a custom 14" f/4.  I choose not to go over 14" because then I can still get 1.5deg TFOV out of it with something like a 21 Ethos.  I personally do not like being limited to less than 1.5deg TFOV from a scope.  At f/4 it will really be a small scope too.  Could easily deck that thing out with all the accessories and a complete set of eyepieces for less than the TEC180 cost.  So would enjoy what refractors can offer with the 130 and then enjoy in a small package what a 14" mirror can offer for fainter fare.

 

Bill,

 

I couldn't agree with you more about upgrading along the Mak direction instead of a TEC180. This April I wanted to find the asteroid JO25, but when I looked at my stable, all I saw was some barely over 1 degree TFOV scopes staring back at me. My only option was a poorly collimated 4" Genesis sdf (which I have since sent back for collimation and am going to sell for obvious reasons to come). Two hours later and feeling like a total newb for not being able to detect its movement. I dejectedly packed it in, realizing I wanted a bit larger, quality wide field refractor.

 

I decided on a used AP130 and lo and behold the next day one popped up for sale so I snapped it up. I absolutely love the crisp wide field views of the130mm, but I immediately (and pathetically) started to think of how amazing the views through an AP175 or TEC180 would be!

 

Thankfully, fellow CNer Phillip Creed gave me the virtual equivalent of a slap upside the head about that idea, considering the huge leap in size, mount, angular momentum, etc of a 180mm. I didn't need to go up to a TEC180 when my Questar 7 accomplished most of the upgrade at a fraction of the inconvenience.

 

It's a fantastic pairing to have the Q7 and the AP130 set up together. With the temperate climate removing cooldown issues, I get amazing binoviews of Saturn, Jupiter and the moon with the Q7 and get fantastic wide-field views of the same with the AP130. I want to get a Losmandy AZ8 and mount them side by side.


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#59 Allan Wade

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Posted 06 June 2017 - 06:31 AM

I've had a few nice sessions with my TOA130 and a friends TEC160. The differences are as you would expect for a small increase in aperture. Images are very slightly brighter at the same magnification. Maybe there was slightly more detail on Jupiter when we observed it around opposition. But, as has been reported, once seen in the 160 the same detail can be observed in the 130.

 

I'm more of a dob person, so am in the camp that believes a lot more performance is gained by spending the refractor upgrade money on a dob, where the much bigger aperture provides a significant difference.

 

I get you're a refractor person. If you currently have a 130 and 200 I see that as a nice setup, which covers many observing options. Swapping the 130 for a 160 will give you a very minor increase in performance, but I see that as a backward step in the balance of your refractor lineup.

 

1.jpg


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#60 JimP

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Posted 06 June 2017 - 07:01 AM

I agree. I have decided to keep the 130 and not worry about either a 140 or 160 apo. I think I had a momentary lapse of clear thinking or perhaps just the normal degree of lunacy. LOL! In my opinion, for what it's worth, Once you get a scope larger than 160 mm and I'm talking refractors, you need some type permanent set up whether that is an observatory or, as I am doing right now, permanently set up under a Tele gizmos 365 tarp. And I too am a big fan of Maksutovs. My first one, a quantum 4, is the reason I am such a big fan of double stars. I am certain that a Questar seven is a fantastic telescope!!
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#61 BillP

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Posted 06 June 2017 - 07:57 AM

The thing of it is, once you have a solid set of eyepieces, there's not much to be gained in that department.. 

 

Well need to be careful here because "solid" is a very loose term.  If solid means good enough then you are indeed compromising.  So if one compromises in one place, they tend to compromise in others, and any compromise affects the entire chain. 

 

IMO and IME the key is optimization of each component.  Optimize one, then move on to the other, until all are completed.  And aperture has upper bounds for many of us due to a myriad of reasons.  And let's be clear...a 25" scope is still a compromise if one has the fever as there are virtually no bounds on aperture so it gets silly.

 

IMO, the perfect eyepiece "line" still does not exist.  I have what I consider some of the best of what there is (multiple sets because no one set does it all perfectly)...but am still waiting for some improvements to come along that are not yet there.  So for me there is still more to be gained, just not yet available.  Main objectives, especially refractive, I feel have gotten about as good as can be as long as glass is used.  So not much more to be had there IMO as quite a few examples of essentially perfection.  Mirrored equipment on the other hand I feel still needs improvement...mostly in the realm of making them more thermally behaved as delivered.


Edited by BillP, 06 June 2017 - 10:47 AM.

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#62 Jeff B

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Posted 06 June 2017 - 10:19 AM

I agree. I have decided to keep the 130 and not worry about either a 140 or 160 apo. I think I had a momentary lapse of clear thinking or perhaps just the normal degree of lunacy. LOL! In my opinion, for what it's worth, Once you get a scope larger than 160 mm and I'm talking refractors, you need some type permanent set up whether that is an observatory or, as I am doing right now, permanently set up under a Tele gizmos 365 tarp. And I too am a big fan of Maksutovs. My first one, a quantum 4, is the reason I am such a big fan of double stars. I am certain that a Questar seven is a fantastic telescope!!

Good for you.  Always nice to check out options though.

 

Like I said in another thread, my TEC 7, when thermally stable, gives my high end 152mm triplets a hard time of it.  At F 15, it's best suited for me to lunar/planetary/double/small open cluster viewing, thing at which it excels.  Don't need fancy pants eyepieces to get get good high power views either.

 

Jeff



#63 Jon Isaacs

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Posted 06 June 2017 - 10:51 AM

 

The thing of it is, once you have a solid set of eyepieces, there's not much to be gained in that department.. 

 

Well need to be careful here because "solid" is a very loose term.  If solid means good enough then you are indeed compromising.  So if one compromises in one place, they tend to compromise in others, and any compromise affects the entire chain. 

 

IMO and IME the key is optimization of each component.  Optimize one, then move on to the other, until all are completed.  And aperture has upper bounds for many of us due to a myriad of reasons.  And let's be clear...a 25" scope is still a compromise if one has the fever as there are virtually no bounds on aperture so it gets silly.

 

IMO, the perfect eyepiece "line" still does not exist.  I have what I consider some of the best of what there is (multiple sets because no one set does it all perfectly)...but am still waiting for some improvements to come along that are not yet there.  So for me there is still more to be gained, just not yet available.

 

 

One has to look at the system,  some parts of the system are far more important than others.  In optimizing the system,  the relative contribution of each part of the system must be considered.  Optimization is the process of compromise.. 

 

This thread is about aperture.  Along with optical quality,  this is clearly the most important factor. 

 

Can an eyepiece make up the difference between a 10 inch scope and a 12 inch scope? 

 

If the first eyepiece is a "solid" eyepiece,  the answer is definitely not.  That's a working definition of a solid eyepiece.. 

 

If one is looking to see more,  fainter objects,  more planetary detail,  resolve more difficult binary stars,  the eyepiece plays a minor role..  

 

I have a good set of eyepieces.  They do the job.  They let me see what the scope has to offer.  

 

When I look for ways to see more,  better optics,  darker skies, better seeing, better dark adaptation..  

 

I will say this.  You've settled on a particular telescope and look for better views via the eyepiece.  I have settled on a set of eyepiece and look for the better views via the telescope..  

There's way more differences between Scopes than between eyepieces.. 

 

Jon


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#64 gnowellsct

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Posted 06 June 2017 - 11:16 AM

And, just personal choice, I do not care to own any more Celestrons either.

I'm confused.  If you've owned so many other apertures, then you would have an idea what larger refractor apertures would bring, more or less.  There is a general view that good planetary observing begins at 5 inches, and it's a view with which I agree, on the whole.  This is in part because you can get to 300x with larger exit pupils.  

 

The larger answer to your question is that the improvements, while they will be there, will be infinitesimal.  Think of it this way. Take a 5 mm pupil and a 102mm as a ratio.  The leap from no scope to a 102mm is vast.  It transforms one's sense of the sky.  So as a ratio what's the next step up of comparable dimensions?  Well to make a 102mm proportionately as small as a 5 mm pupil, the next step up is about 210 cm (83 inches).  

 

Therefore, we can conclude that the gains to be had in moving from 130 to 140 or 160 are very small relative to what the 130 is bringing you in the first place.  And i fact that whole of the amateur class instruments are in the strict sense simply improvements at the margin.    To some extent that's true, which is why so many 60 and 70mm refractor buffs like to show off how much they can see through their preferred instruments.

 

I can see most of what I see in my 4" that I can see in my 5" apo.  But the 5" brings the views to me with a larger exit pupil and makes for more relaxed viewing.  A six inch refractor might further improve on this consideration.   Of course getting to 300x with a larger exit pupil is only one performance criterion; it comes at the expense of wider fields at the low magnification end.

 

If you take a 4 inch and mount it on top of a 14" and inspect Mars or lunar details, etc., it takes quite a bit of time to see the additional details.  However, improvements in color are pretty obvious.

 

GN


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#65 k5apl

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Posted 06 June 2017 - 01:35 PM

IMO the optical path is a chain and somewhere there is a weakest link that needs replacing.  I use top quality diagonals and eyepieces.  They do make a difference whether 130mm or 160mm or 180mm aperture.

Wes



#66 Jon Isaacs

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Posted 06 June 2017 - 03:38 PM

IMO the optical path is a chain and somewhere there is a weakest link that needs replacing.  I use top quality diagonals and eyepieces.  They do make a difference whether 130mm or 160mm or 180mm aperture.

Wes

I use top quality eyepieces and diagonals.  Regardless, most eyepieces are very good..  The weakest link in nearly always the telescope, the seeing or the observer. 

 

From the ATM Bible, Jean Texereau's How to Make a Telescope, page 1, paragraph 2:

 

"It is not usually made clear, that these elements, objective and eyepiece, are by no means comparable in importance. The astronomer's hopes are almost wholly tied to the size and quality of the objectve. The objective of even the smallest telescope, because of its larger dimensions, the severe optical requirements it must meet, and the difficulty of its construction, completely overshadows the eyepiece."

 

Jon Isaacs



#67 GeneT

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Posted 06 June 2017 - 03:51 PM

For refractors, and smaller objectives, the ratio may be slightly different, but when I wanted to see a 'difference' based on an increase in aperture, I would double the area of the lens. I went from an 8 to a 12 and to an 18 inch. Maybe the same would hold for a smaller lens refractor. Any increase in size of the objective will show a difference, but for me the question is would the difference be worth while to purchase a larger instrument?



#68 Mel M

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Posted 06 June 2017 - 05:28 PM

Very  interesting stuff. As for the article comparing a 140 directly with a 200 remember that once you've seen it in a larger scope it is easier to see in a smaller one. Seeing something in the 140 after having seen it in the 200 is different than seeing it in the 140  alone. The writer hit on this when discussing the Companion to Sirius. As I recall he stated something like he would've never been able to have seen the Companion in his 140 if he had not seen it first in the 200. So it is always difficult to compare telescopes side-by-side of different aperture if you are allowed to first observe with the larger aperture scope.

 

It always tickles me that when we discuss refractors sooner or later someone will come in with the "well for the money you could buy a much larger reflector with money left over for blah blah blah". I have owned larger reflectors up to and including 20 inches aperture including one with a quartz mirror, etc. One was an 18 inch with an excellent Zambuto mirror. They are all gone. I don't like Dobsonians. Period! I am a refractor man.

 

In asking about the move from 130 to 140 or 160  I was only interested in thoughts regarding the  move from 130mm to those two sizes, a 140 or a 160 as I also have a TMB(LZOS) 203 F/9. 

I imagine your reflectors were top-notch. Do you think it's likely the right amount of tinkering or the right combination of parts could give a reflector better views than a refractor? Did you find thermals in the dobs were vexing? Did you decide it would be just too much trouble? 



#69 noisejammer

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Posted 06 June 2017 - 06:57 PM

I can easily distinguish between my 115 and 150... The 150 is way heavier. :D

 

Through the eyepiece, it's pretty easy too.


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#70 JimP

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Posted 06 June 2017 - 08:02 PM

Of course a reflector can give excellent views.

 

My dislike of modern day reflectors starts with something entirely personal. I thought the reflectors of my youth, Cave-Astrola, Optical Craftsmen, etc., looked magnifient on their equatorial mounts. They were elegant and looked professionally made. Dobsonians, to me and only to me, look like they were made in Uncle Bob's basement with his new cabinetry setup, a stack of plywood glue and a bucket of spar varnish. Now, that's just a personal opinion and has nothing to do with quality at the eyepiece. I just don't like the tube in a box look.

 

Next, I have had it with telescopes requiring collimation. Lots of folks have no trouble collimating, a few probably enjoy it, and hallelujah to them. I was having trouble with my last big Dob and was told by the mirror maker that after the laser collimator, go to a high power view of a star just out of focus to tweak the collimation and then, after that, look at the disc of a star in focus for any sign of brightness difference across the disc then tweak things even further until any light bulge on one side was removed. Forget that. NOT interested. By the time I finished it was time to pack up and go inside for the rest of the night.

 

Finally, I do lunar and planetary imaging with my telescopes. The drives are pretty crude on the Dobsonians I have seen and owned compared to that of say an AP 1200 GOTO mount, a mount that includes drives in both axis, variable speeds, including sidereal, lunar and solar,etc. I was considering having a custom dob made and when I asked about including a drive that would have in addition to sidereal tracking, lunar tracking ,the gent seemed to think I was asking for the Moon itself. Told me it was not possible. Keeping the high power image on a laptop screen was very difficult with Saturn while imaging with my Dobsonian and pretty much impossible, for me, with the Moon. I'm done with Dobsonians. Love to look through yours visually if YOU have it collimated. Don't need another one of my own. 

 

I love Refractors and Maksutovs.


Edited by JimP, 06 June 2017 - 08:05 PM.

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#71 gnowellsct

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Posted 06 June 2017 - 08:23 PM

 

 

Finally, I do lunar and planetary imaging with my telescopes. The drives are pretty crude on the Dobsonians I have seen and owned compared to that of say an AP 1200 GOTO mount, a mount that includes drives in both axis, variable speeds, including sidereal, lunar and solar,etc. I was considering having a custom dob made and when I asked about including a drive that would have in addition to sidereal tracking, lunar tracking ,the gent seemed to think I was asking for the Moon itself. Told me it was not possible. Keeping the high power image on a laptop screen was very difficult with Saturn while imaging with my Dobsonian and pretty much impossible, for me, with the Moon. I'm done with Dobsonians. Love to look through yours visually if YOU have it collimated. Don't need another one of my own. 

 

I love Refractors and Maksutovs.

I don't see why he would say it is not *possible.*  It might not be *offered,* which is altogether different.  It's just a question of how fast you turn the gears fer cryin' out loud.  You can think of a tracking dob as an equatorial mount pointed straight up.

 

In any event I agree to the extent that I greatly prefer the precise OTA control I have with my G11 and AP900.  

 

Greg N



#72 Jon Isaacs

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Posted 06 June 2017 - 09:14 PM

I asked about including a drive that would have in addition to sidereal tracking, lunar tracking ,the gent seemed to think I was asking for the Moon itself. Told me it was not possible. Keeping the high power image on a laptop screen was very difficult with Saturn while imaging with my Dobsonian and pretty much impossible, for me, with the Moon.

 

 

Tom Osypowski Equatorial Platforms offer both sidereal tracking and lunar tracking with the flip of a switch. Compared to a AP-1200, they're inexpensive and capable of handling large aperture scopes.. A Tom O. Platform capable of handling a 18 inch scope weighs under 40 pounds and is an easy one hand carry..  

 

6344666-10 inch Dob on EQ platform.jpg
 
Jon


#73 Badger1992

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Posted 06 June 2017 - 09:48 PM

If you have a LZOS 203 APO, no need to upgrade your 130 to a 140 or even 160. You will see a little difference increasing to 160, but you'll lose the portability of the 130. I think you have a great kit as is!

#74 Mel M

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Posted 06 June 2017 - 10:23 PM

Of course a reflector can give excellent views.

 

My dislike of modern day reflectors starts with something entirely personal. I thought the reflectors of my youth, Cave-Astrola, Optical Craftsmen, etc., looked magnifient on their equatorial mounts. They were elegant and looked professionally made. Dobsonians, to me and only to me, look like they were made in Uncle Bob's basement with his new cabinetry setup, a stack of plywood glue and a bucket of spar varnish. Now, that's just a personal opinion and has nothing to do with quality at the eyepiece. I just don't like the tube in a box look.

 

Next, I have had it with telescopes requiring collimation. Lots of folks have no trouble collimating, a few probably enjoy it, and hallelujah to them. I was having trouble with my last big Dob and was told by the mirror maker that after the laser collimator, go to a high power view of a star just out of focus to tweak the collimation and then, after that, look at the disc of a star in focus for any sign of brightness difference across the disc then tweak things even further until any light bulge on one side was removed. Forget that. NOT interested. By the time I finished it was time to pack up and go inside for the rest of the night.

 

Finally, I do lunar and planetary imaging with my telescopes. The drives are pretty crude on the Dobsonians I have seen and owned compared to that of say an AP 1200 GOTO mount, a mount that includes drives in both axis, variable speeds, including sidereal, lunar and solar,etc. I was considering having a custom dob made and when I asked about including a drive that would have in addition to sidereal tracking, lunar tracking ,the gent seemed to think I was asking for the Moon itself. Told me it was not possible. Keeping the high power image on a laptop screen was very difficult with Saturn while imaging with my Dobsonian and pretty much impossible, for me, with the Moon. I'm done with Dobsonians. Love to look through yours visually if YOU have it collimated. Don't need another one of my own. 

 

I love Refractors and Maksutovs.

Is permanent collimation on a dob possible? Must be a good reason why I haven't seen it.



#75 JMW

JMW

    Soyuz

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  • Posts: 3,792
  • Joined: 11 Feb 2007
  • Loc: Nevada

Posted 06 June 2017 - 11:08 PM

I have an observatory mounted 10 inch f/4 newtonian. I check collimation regularly but most of the time I do not need to make any adjustment.  It helps that it always stays on the mount. My truss dob needs collimation each time it is assembled.

 

Back on subject. I have a SV115 and later purchased a TEC 140. I feel the difference is quite noticeable. I do give up some true field of view with the wider scope. I am not sure I will ever buy a larger aperture refractor. The increase in size comes with a tremendous increase in cost and I think a TEC 160 would be the most I would consider in a scope that needs to be transported to dark skies to enjoy.  My at home grab and go refractor is an SV102T which is so much easier to move around on a FTQ/Gitzo mount tripod. I get a lot of enjoyment out of it because of the low effort involved in using it.

 

If you have great dark skies with a permanent backyard observatory then go with what ever size you can afford and handle. I would consider a TEC 180 if I could enjoy it in my backyard.




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