SW 102 f10 Achro vrs LP 110mm f6 APO shootout .

[brian nordstrom]

A couple of saturday nights ago it was very clear apart from a little smoke haze from a burn off just south of us so I decided to set up both scopes for a little shootout on the Moon , Mars , Alpha Centarui and M42 .

Both scopes were set up about an hour before full dark with the 102mm f10 ( fl 1000mm ) on my wife's Mizar mount all sitting on a sturdy Celestron 2 inch s/s tripod .
The LP 110 f6 ( fl 660mm ) was on my Vixen SP all sitting on the solid Meade HD field tripod .

So as you can see vibrations were not going to add any aberrations at all as both these setup's are super solid .

Eyepieces used were all TV's , Plossls , Panoptics , Radians and Naglers giving magnifications ranging from 200x - 40x in the 102mm and ;) 200x -37x in the 110mm .

2 inch diagonals used were a nice Bintel 99% dielectric Mirror in the 102mm achro and a WO 2 inch 99% dieletric CF in the 110 APO , so any problems here would be invisable to the eye and this is a totally visual shootout :D .

Here are a few photos of the scopes settling down before the battle's begun :D .

As we see , eyepieces , diagonals , mounts and seeing wont add to any problems seen to the eye ,,,, it's going to be all about the optics , cool as .

So lets see if 8mm in diameter , 340mm in fl and the use of good quality ED glass makes any real difference ?? lets go ,,,

More to follow and comments are really welcome , as always :welcome: :thumbsup:.

Brian.

[brian nordstrom]

:D Forgot to add the ' Green Stuff ' here is the 102mm achro's eyepieces for the night .

Except the sneaky 3mm Radian ,,, kinda slithered over ,,

Brian.

[The Mekon]

Ok, I will back the LP110, if you were up late enough for Orion to get high, the LP should have shown the 5th star in the trapezium with ease. The 102 achro may have struggled. Mars is much smaller now but showing some detail - my prediction is that this will be readily apparent in the LP but not so in the 102.

[Slawomir]

Must have been a fun comparing both scopes Brian. And what an impressive collection of eyepieces!

I think both scopes should be capable of showing both E&F components of the trapezium, as I can resolve them quite easily with my 105mm even on humid nights in NQ.

[The Mekon]

OK Brian, waited long enough, Post the shootout

[Wavytone]

My instinct is they’re pretty much equal. Despite the LP having better glass capable of better correction in angular terms, a focal ratio of f/6 pretty much negates any advantage it may have had for lateral and longitudinal chromatic aberration.

Despite the availability of modern glass types, many refractor designs exploit this to achieve faster f/ratios or wider fields of view - but not image quality better than the basic ¼ wave criterion.

Provided you can accept a focal ratio of f/15 a humble 4” achromat can deliver superb high resolution images that would slay the fast LP.

So.. a draw is my guess.

If both had the same focal ratio ... now that would be a more interesting comparison.

[Slawomir]

That's why I could never really understand why some folks would be happy to pay in excess of $10k for a 5" F/6.3 refractor, a decade after they put their name on a waiting list.

[N1]

Brian, over to you ;)
(Cool photo BTW the first one, and the achro is too short - on paper - to be a serious challenger for a halfway decent ED, so if the Saxon wins, that will say more about the LP than the achromat)

[brian nordstrom]

:D Hi all and thanks for the imput , much appreciated .

So here goes with a few moon shots taken at very similar magnifications with both scopes taken at the eyepiece using my google pixel2 phone .

First 2 are with the 102mm f10 achro using a 25mm TV plossl @ 40x and 12mm Radian @ 83x .

Numbers 3 and 4 were the 110mm f6 APO using an 18mm Radian @ 37x and an 8mm Radian @ 82x .

It was not fully dark uet but at these lower powers the difference is small but at the 83x the APO has less CA , but this is very small as the camera shows more than is seen at the eyepiece .

More to follow .

Brian.

[brian nordstrom]

:shrug: The photos would not download in order so the 2 in the last post were the 102mm and these 2 are the 110mm .

Brian

[Joves]

Is this an ongoing shootout between the two or one that was conducted a couple of Saturdays ago?

[Lee]

Looking for CA around the moon against a blue sky is stretching it a bit.... you really need to do this in the dark.....

[Wavytone]

40X is meaningless and against blue sky even more so.

I was hoping to see a comparison at more like 150-200X and ideally 300X (Dawes limit is X80 per inch of aperture).

A photo of Sirius or Rigel from each at the sharpest focus in enough detail to show diffraction rings would be ideal.

[brian nordstrom]

;) On going when I finish this current night shift stint ,,,, and when the weather clears up , Thanks .

Brian.

[brian nordstrom]

:D Some of us gotta start somewhere mate !! What part of ongoing don't you understand ?? .

When was the last time you viewed Sirius at 400x with a 102mm f10 achro >> didn't think so , please keep remarks like this snobbery out until its finished ;) can you ? .

Brian.

[brian nordstrom]

:shrug: How many times do I need to say ,,,, MORE TO COME <<< please read the words before commenting please .

Look carefully at the 83x photo of the moon with the 102 and you will see CA starting to creep in , so please read above .

I have had a whole between 8 and 12 views on the photos and the experts are out in droves ,,,, too much ! .

Brian.

[N1]

Brian, you're gonna have to do a lot of explaining, I mean what where you thinking - daytime use, 40x. I'm surprised the space-time continuum is still intact...:poke: :P

[brian nordstrom]

:shrug: Please read and understand below comments ,,, man , this is terrible ! Gotta do something while the scopes acclimatise dont we ?

Brian.

[N1]

Mate I don't think you did anything wrong & will be reading on with interest

[brian nordstrom]

:thumbsup: No worries mate and thanks , at least you have the spine to reply on public forums .

On that , a big thanks to the good people who have taken the time to PM me massages of support . ;) about the poor taste and bullying that has happened .

Brian.

[LewisM]

I don't think this is a shootout - moreso it seems Brian just enjoying himself observing. :shrug:

[MattT]

Hey Brian,

Keep going and do your own thing. Shootout or having fun is all the same in my book. In the past I did my own comparison between a 90x1000 achro and a Skywatcher ED 100. The ED was better but not by much so only wanting to keep one I sold the ED..... it was easy to sell :)

I’m very partial to long fl achros, as you know. :D :thumbsup:

[Joves]

Good stuff, looking forward to further reports!

If it turns out that the achro is the winner, i’ll be going upstairs to my scope room with a very disappointed look on my face. I wont tell them they’re in trouble, i’ll just tell them i’m disappointed in them (hey, works with the kids... apparently!).

[Wavytone]

The first time was 45 years ago, through an 1880 Thomas Cooke 4.25" refractor, f/16 achro, with a truly exquisite objective. The views of Jupiter and Saturn through that scope are unforgettable. And it split Sirius, easily.

Ever since then I have been a high-magnification junkie mainly interested in lunar & planetary and to some extent double stars, as arguably the most severe optical test.

While I had access to the 9" Oddie refractor at Mt Stromlo - and pushed it to 900X while trying a few of the double stars in various catalogs and rapidly realised that in the 18th and 19th centuries, even though those old antique refractors were only 4" - 6" aperture:

a) didn't have modern glasses,
b) didn't have AR coatings,
c) had very limited eyepieces (try a Ramsden or Huygens and see how you feel about that)

... the records of the stars they were able to split indicate some of the scopes had truly exquisite objectives, even by modern standards.

Another clue lies in the notes from Dawes (the 'Dawes limit"), who concluded it is necessary to use magnification around 80X per inch to definitively split doubles at the limit of what the telescope can resolve. But for many modern refractors the useful limit is barely half that because the optics are frankly only "average", being designed to satisfy the ¼ wave criterion.

There really is a reason why premium old-school achro refractors were f/15-f/20, despite the massive equatorial mounting needed.

There really is a reason why people fork out $10k for an AP 130 GT. But aperture does rule and there are rare mythical beasts such as refractors with LZOS optics, or the premium big maks such as my MK91, or the TEC and AP 10" maks - if you can wait 20 years for one. The dinky little Takahashi's are toys in comparison.

[Joves]

Good write-up, Nick.

Now, what about my less mythical 8” Tec? :)

[Wavytone]

Aaron, if you are keen on lunar & planetary or double stars it should be a keeper. Put yours side by side with a C8 or Meade 8" and try them side-by-side at high power (200-300X) on various targets. The difference should be obvious.

Santel closed 10 years ago, ditto Intes 2-3 years ago. TEC ceased making maks several years ago too, so like the MK91 only a small number were made, and you probably have the only one in Oz.

As for the AP 10" maks... the wait list is 25-30 years and they've just started to ship, slowly. IMHO the most likely way to acquire one would be one sold by a previous owner now in old age, ill heath or possibly a deceased estate.

These scopes are rare and I was surprised to hear Matt had parted with it, but perhaps he has other priorities.

What's more recent changes in the way freight carriers charge for shipping mean that importing a large scope from the US is now prohibitively expensive. And I mean that, literally.

[brian nordstrom]

:thumbsup: Sweet Matt , this reminds me so much of the old days of CN's when the Purists (snobs) rallied against iStar , remember those days and they got shot down in the end ,,, history repeats .

Another instalment is on its way with more top quality photos taken with my cell phone ( CCD free zone ) and yes it would have been awesome to have an ED100 in this mix ( Tak free zone ) tho :lol: .

Thanks buddy , I am finding that a few ideal's here are starting to wear thin . :thumbsup:

Brian

[brian nordstrom]

:D Nothing better to do brother .


When I ain't doing 12 hour night shift's 13 days on 1 off . Oh I am on the 14th day ( night ? ) , it gets hard .

Brian.

[brian nordstrom]

:shrug: Ah well , looks like you can't wait until the end .

Comment's relevant to average 4 inch class refractors are more than welcome buddy .( 3-5 inch refractors as well )

Old school , yea they had ' Starbright ' coatings 75 years ago ? come on we have all seen that the coatings of today are 90% better than the old MgFl coatings of the 50's - 70's so why bother ???

FMC ?? another leap .

Brian.

ps.

ahhh well as you mention eyepieces ,, be-littleing H and R design's ? I have a 10 inch f10 Newtonion with easy 1/12 wave optics , My H6 .965 ( 416x ) shows Jupiter in this scope better than any modern eyepiece I have had the pleasure to put in this monster .

[brian nordstrom]

:confused2: This is a refractor 102-110mm shootout thread , please lets keep chit chat about Mak's out of it , thanks

Ahh well , well you guys are at hi-jacking my thread , here ! this a photo of my mates setting up their 20 inch PLUS Newt's , my 127mm iStar is all set up in the background ( we all arrived at this amazingly dark site together ) waiting for dark ,,, sound familiar ?


Brian.

[brian nordstrom]

;) For the nay-sayers , this photo was taken looking 180 degrees from the last shot .


Refractors only please .

Brian.

Would I put the 127mm iStar on this shootout ? ..... No not fair .:), but we did put my iStar 127mm and one of the 20inch + Dob owner's NP 127mm TV and a Meade 130mm triplet against each other on 3 occasion's and ,,, result's ,,, not here

[brian nordstrom]

:question: Ha ha , yes but as you know a lot depends on the eyepieces , family commitments , work , life , quality of seeing , eyepieces ( again ) , clouds , kid's , :help:( yep ) but yes if I won Lotto , you are invited to my observatory to use my SW ED 150mm its iOptron CEQ120 mount any time .

Brian .

[LewisM]

I’ll be honest - when it comes to imaging, yes I am very particular (might say snobby) and even though I cannot even begin to bring out the best in the scope, knowing it’s me that is the limitation and not the optics is reassuring.

For visual, I love using achromats, especially Vixen 80Ms and Unitrons ( all the SW achromats I had have been very underperforming unfortunately - bad samples). One of my favourite visual scopes I have ever had was the Vixen FL102S semi-apo. Absolutely wonderful. A Tak FC60 f9 (not FS60) I had was also a favorite.

For lunar viewing, I could care less if there is a blue or yellow fringe on the limb - I’m looking at the surface for pities sake not the damned sky :lol:. Doesn’t distract me one zot.

Too many seem to be continually assessing and analyzing rather than actually using and observing.

[N1]

Sounds fantastic. Can we expect a link to a veritable test/shootout/comparo where one of these instruments beats an appropriately sized Mewlon by a margin sufficiently big for the latter to be called a toy?

[LewisM]

And yet, SOOOOOOOOOOOOOOOO many imagers worldwide us those dinky Takahashi toys to extremely good effect (prize winning), as well as those AP's. There is a definite, quantifiable reason WHY Taks and AP's are used.

Don't hear of too many Santel, Intes' or other Maks being used for fantastic imaging :rofl:

Visual is FAR more forgiving than imaging.

[bigjoe]

Even trying combos always surprises me. A SW 72ed with Tak diagonal and Toe 3.3mm and Vixen barlow easily split Eta Orionis 1.7"..very close to its Dawes(CHECK IT OUT)..in average seeing
only 10mins after set up.
I wait 20 mins longer for the 130mm Triplet CPC9,or 150 Mak..So CONVENIENCE TOO comes into it..lovely FAT AIRY disks in these small refractors..something I enjoy seeing..though I know the others will pull ahead later on!
At the end of the day its what YOU ENJOY!
PS: NOT into brands only PERFORMANCE!
bigjoe.

[Kunama]

I don't always agree with Mental-Alex but I do today, might be time to put the egos back in their cages and drift back onto the topic :question:

I also like long achromats, I previously had a 6" F10 iStar and now have a nice 3.25" F15 that, given a modern eyepiece like a Tak LE, is a wonderful lunar scope.... I look forward to how these two scopes actually fare....

[LewisM]

100% agree Matt

[h0ughy]

OK I will say to all here on this post either keep it civil or you will have a nice long holiday. The mods have a life too and sometimes can't be every day reading the threads. If you can't be nice to each other then......

[brian nordstrom]

:thumbsup: IIS at it's best ;) thanks brother.

For the know it all's , achro or apo ? a hint here what refractor ? touching 150x , dark for a few that know better .

Brian.

[brian nordstrom]

:shrug: Lewis , was imagining mentioned once in this thread until you . Now ?

Brian

[brian nordstrom]

:D806x Takahashi M210 , hand held cell phone .

Jeeze , :shrug: Refractor shootout ? these are my photos , expect the same from the 2 refractors ! .

Brian.

[brian nordstrom]

:question: History my friend !

Brian .

[brian nordstrom]

:thumbsup: Simple remark ,,, Thanks .

This is exactly why I mentioned 20 inch plus Dob's , .

Beian.

[brian nordstrom]

:thumbsup: Yes , like these two 60mm's with 15 years between them , both beautiful .

There is really nothing between these 2 scopes . Refractor shootout , I have owned these 2 as well with notes and do you think I will do a thread titled

' 60mm shootout , ' FPL51 triplet vrs 60mm Fl doublet ' peel your ear's back ,,, after the 102 f10 vs 110mm f6 ..:eyepop: .

Brian.

[brian nordstrom]

:shrug: Yes please looking like a 102mmf10 achro vRs a 110mm f6 APO shootout ??

Brian QUOTE=N1;1407685]Sounds fantastic. Can we expect a link to a veritable test/shootout/comparo where one of these instruments beats an appropriately sized Mewlon by a margin sufficiently big for the latter to be called a toy?[/QUOTE]

[LewisM]

No mate, but it was all in agreement with you and making comments towards some of the prior posts by others (since completely deleted).

Besides Brian, you are posting images through your scopes. That is...errr....imaging :) :lol:

[Tropo-Bob]

Let's get back to the actual performance of the scopes. I had an early model Sinta 102mm, F9.8. At the time, I was impressed with its performance. I was only troubled by CA when viewing the Moon, Venus, Jupiter, Mars and any star of Mag 2 or brighter. It did however perform beautifully on Saturn. I suspect that there was a bias in the lens to favourably process yellow light.

The lens was not particularly of a high quality as it only beautifully handled magnification to just above 100x, before the image prematurely began to break down.

This was almost 20 years ago and even though they may have improved over time, I had a better than average scope for that era. I was President of a local Astronomy Group at the time and had several people contact me about problems with their same-Sinta scope. The problems ranged from CA that was far more oblivious, blurred images and a sky-background that was grey rather than black. All were comparatively tested side by side in comparison to my scope. I recommended that they be sent back for swapping, to which one person replied that he had already done so and the new scope was no better. :shrug:

Three years later I brought a far more expensive, ED Vixen 102mm, F6.5. The Vixen was a far better performer and more compact, so I sold the Sinta.

[Joves]

I think it is fair to say that achromatic refractors are a pretty incredible offering for the price they can be obtained. To the untrained or oblivious eye, I imagine the CA on certain objects likely goes largely unnoticed, or at least is looked straight past.

Like many “hobbies”, there is what is considered beginner equipment for what most consider very reasonable prices and then, as one progresses, they begin to look toward higher priced, “better performing” equipment. Often there is a law of diminishing return at play, possibly greater in astronomy than in almost any other hobby. I think this says as much by way of praise for the lower cost achro’s as it does the much higher cost apo’s, however, most of the praise and attention more often goes to the apo for its often marginal performance improvement. When one is prepared to spend the difference, it is in search of this often small percentage improvement. To the keen observer seeking the best views they can both find and afford, a few percent better is seen as more than marginal. The reality is, there are often so many factors working against a perfect view, that many amateur astronomers get to a stage where they want to be sure it isn’t their equipment letting their view down.

All of my refractors are apochromatic, however, I have the highest respect for how close a quality achromat can get for a mere fraction of the cost.

[bigjoe]

Brian ..they're
Lovely and CAPABLE!
Such convenience..ready to use at a moments notice!

bigjoe

[brian nordstrom]

;) Last nights Luna grazing occultation egressing seen here in Perth , anyone want to hazzard a guess as to what scope took this shot ? 102 vrs 110.

ps. look left ( North ) of the luna limb about 15* south .And for the purists's out there it was still twilight . Contrast anyone ? .

All bet's are on .

Brian .

[MattT]

102 Achro Brian....am I right?

[N1]

I think I'll go with the ED, but would not be surprised if it's in fact the achromat. Of the 2 pics posted by Brian earlier, the former (#40) looks like the achro, but I know how the EP and camera optics can affect an image captured afocally. Keep us posted Brian

[brian nordstrom]

:thumbsup:Achro owner , Yes Brother :D , Yep more to astronomy than CA.

15 minutes later with darker skies .

Brian.

[brian nordstrom]

;) Thanks for the positive remarks , bodes well for us peasants , Thanks .

Brian.

[brian nordstrom]

:thumbsup: awesome and a big thank you Joe , , both scopes ain't no Takahashi's but I have owned Tak's from 60mm's to 200mm's over the years
and yes they are very , very good , but 3 -4 x better than a good average telescope as the price suggests ? :shrug: No they aint .

Brian.
NO !C :lol2:

[brian nordstrom]

;) Yes , I had the hot's for one of those Vixen 102mm f 6.5's for years but sadly as a poor apprentice it was a dream until now , thanks for the memory trip my friend .

I like you started with an awesome 102mm achro as a real refractor ( after a sweet 1971 60mm f15 Meade refractor on EQ2 that started it all that I still own ) as well that I still own and enjoy ,:thumbsup: .

Brian.