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The ubiquitous, wonderful 4" Apo!

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#1 Levine

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Posted 03 December 2012 - 02:08 PM

To round out my lineup (see sig line, below), I have been thinking seriously about picking up a 4" Apo. They are readily available, portable, relatively light, cool down quickly, and have virtually no collimation issues. Prices are within reach of most, new and used.
Lotsa choices!
If you expand the range of candidates to include the 90 to 110mm range, then the field of choices really explodes.
But which one?
I am a visual observer, and have both driven and undriven mounts.

So, a poll: Which is the best one for the job?
What is it about your choice that makes it stand out?

Thanks! :cool:

#2 MikeBOKC

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Posted 03 December 2012 - 02:20 PM

I could not be happier with my TMB92L. Clear, sharp, snaps to focus, sturdy and quite attractive. Never seen a hint of false color.

#3 csrlice12

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Posted 03 December 2012 - 02:24 PM

Omni 102XLT-ED?? Nice APO version of the Omni 102XLT on a CG4 mount.

#4 John Huntley

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Posted 03 December 2012 - 02:29 PM

I love my Vixen ED102SS F/6.5 :)

Just 7lbs in weight and capable of showing both sides of the Veil nebula in the same field of view and then fine planetary detail at 190x or more.

Real easy to mount too.

I tried a William Optics Megrez 90 before the Vixen. Nice scope but 90mm was just not quite enough aperture for me.

#5 mgwhittle

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Posted 03 December 2012 - 02:40 PM

I think we need to know your price point to make a real recommendation. Lots of difference between the price of a Takahashi on the high end and one of the new Lunts on the low......

#6 waso29

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Posted 03 December 2012 - 02:52 PM

fs128 lil bro
used tak fs102nsv.
fluorite doublet in more compact version.

or
baby bro
used sky90
great travel scope

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#7 M13 Observer

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Posted 03 December 2012 - 02:57 PM

To round out my lineup (see sig line, below), I have been thinking seriously about picking up a 4" Apo. They are readily available, portable, relatively light, cool down quickly, and have virtually no collimation issues. prices are within reach of most, new and used.
Lotsa choices!
If you expand the range of candidates to include the 90 to 110mm range, then the field of choices really explodes.
But which one?
I am a visual observer, and have both driven and undriven mounts.

So, a poll: Which is the best one for the job?
What is it about your choice that makes it stand out?

Thanks! :cool:


OK, here are my choices based upon what I prefer - consistent extremely high quality optics and hardware in a very portable package.

#1: AP (105mm, f/6) Traveler - exquisite. Small at f/6, solid focuser, super optics, exceptionally well designed telescope.
#2: TEC (110mm, f/5.6) APO110FL - I haven't looked through one but reports from friends are that it is just a tad larger, longer and heavier than the aforementioned Traveler. Another superb optic assembly.

For sub 100mm apertures:
#3: AP (92mm, f/4.9) Stowaway - Virtually impossible to acquire. Nothing else comes close at this aperture and focal length.
#4: TAK (90mm f/5.4) Sky90NSVII. Readily available, compact, solid performer. Some blue/violet colour on very bright objects. Focuser is good but better with Feathertouch upgrade.

#8 Levine

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Posted 03 December 2012 - 03:07 PM

I think we need to know your price point to make a real recommendation. Lots of difference between the price of a Takahashi on the high end and one of the new Lunts on the low......


Need not be a "budget" Apo, and I don't do astrophotography.

I am not averse to buying in the aftermarket, either! :grin:

#9 iceblaze

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Posted 03 December 2012 - 03:13 PM

I give a +1 for the SV110-25BV.. The scope is just fantastic, and I love how they've modified it to use with a bino by removing the extension. No barlow/corrector required! It's Stellarvue's largest ED doublet and a really well made, quality product.

-James

#10 mgwhittle

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Posted 03 December 2012 - 03:14 PM

Based on that, although hard to find, I agree with waso29, a used Tak FS102NSV would be what I would get. You get world class Tak fluorite quick cooling doublet optics in a compact package that accepts a binoviewer without optical correctors.

#11 Erik Bakker

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Posted 03 December 2012 - 03:25 PM

Based on that, although hard to find, I agree with waso29, a used Tak FS102NSV would be what I would get. You get world class Tak fluorite quick cooling doublet optics in a compact package that accepts a binoviewer without optical correctors.


+1 :waytogo:

#12 Doug Culbertson

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Posted 03 December 2012 - 03:34 PM

The best 4" class apo that I ever used, though it's just shy of a full 4", is the TMB 100/800 with LZOS lens. The image of the moon through that telescope made me gasp out loud. They pop up once in awhile here and on Astromart at better prices than I paid for the one that I used to own.

Barring that, I would echo the previous recommendations for the FS102.

#13 Levine

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Posted 03 December 2012 - 03:35 PM

Great ideas so far. Keep 'em coming!

Some I have had my eye on, too:

AP: 102 f/8 Starfire; "NASA Glass"; Blue tube superplanetary.
TMB 100/800 LZOS CNC

Like to keep the F-ratio 7 or slower to preserve some depth of focus, and to further control color.
:smirk:

#14 richardlowney

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Posted 03 December 2012 - 03:42 PM

Hi John,

Hows that C-14 working?

Don't forget the Televue NP101. The wide field views are fantastic.

Richard

#15 jrbarnett

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Posted 03 December 2012 - 03:45 PM

Lots of nice options, really.

Today my 4" "Apos" are an Astro-Tech AT111EDT (111mm f/7 FPL-51 triplet) and a TV-102 (102mm, f/8.6 ED doublet).

I paid $1600 for the former, new, and $1900 for the latter, also new, during a Televue sale a few years ago. I like and use them both.

Were I going to have just one, and didn't already have a 4" Apo, I would look for an LZOS 100/800 OK4 triplet. Probably the best 4" refractor optic ever made.

Regards,

Jim

#16 Levine

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Posted 03 December 2012 - 03:47 PM

Hi John,

Hows that C-14 working?

Don't forget the Televue NP101. The wide field views are fantastic.

Richard


PM sent

#17 Rich V.

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Posted 03 December 2012 - 04:18 PM

I would love to have a LOMO 102/800. Too bad this Skylight/LOMO 102/800 is a one-off build; the LOMO OK4 triplet is another example of the very finest 4" objectives.

A really pretty scope! :jawdrop: Posted on the Vendor and Group Announcements forum back in July:

Skylight/LOMO 102/800

Rich

#18 Jon Isaacs

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Posted 03 December 2012 - 04:24 PM

Don't forget the Televue NP101. The wide field views are fantastic.



:waytogo:

After a couple of years of really enjoying my AstroTech 102ED, I had so much fun and it was getting so much use, I decided it was time to treat myself to a topnotch apo.

I really didn't do a huge amount of research but I did know that Tom Trusock had given good marks to the NP-101 and it seemed like one the obvious choices though I did not know at the time what sets it apart from the others. I watched an NP-101 go buy on Astromart for about $2000 and later I regretted having let it go. The next time one was available, I bought it.

The scopes discussed so far are 4 inch class scopes and at high powers they all are quite good, the NP-101 has what is to my eye perfect color correction even out of focus, the CA is not there and it does a great job on double stars and the planets. But a 4 inch scope can only do what a 4 inch can do when viewing the planets, splitting double stars, a decent quality reflector of sufficiently larger aperture is a more effective tool for viewing the planets, splitting doubles... 4 inches is 4 inches.

So... what is it that a 4 inch scope does better than an 8 or 10 inch Newtonian, Mak or SCT? It's portable and compact and Bingo... low power, wide fields...

This is what sets the NP-101 apart from the others, when the skies are dark and clear and the Milky Way is shining bright, it's short focal length combined with it's flat field takes it to the next level. A 31mm Nagler in an NP-101, there is no field curvature, no astigmatism, it's 4.5 degree field of view is about as close to heaven as I'll ever get.

So... my take: There are a lot of good 4 inchers around. The AT-106 and the very similar scopes from StellarVue and others look attractive. But if you want the scope excels visually at doing what 4 inch refractors excel at, the NP-101 is it.

Jon

#19 cjc

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Posted 03 December 2012 - 05:46 PM

Here in Europe, the Skywatcher Equinox 100 F/9 (or Evostar 100ED) would commonly be the default option.

#20 mikey cee

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Posted 03 December 2012 - 06:31 PM

I'm very sure that all of the above folks are very happy with their pride and joys. But that's just what they happened to be blessed with at the time and have grown quite comfortable with their use of them. You are starting out. I'd go for the biggest aperture I could handle....seeings how everyone seems to be photon grabbing greedy anymore. :lol: Mike

#21 Kon Dealer

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Posted 03 December 2012 - 06:43 PM

I love my Kson102ED f/6 in carbon fibre. The OTA weighs just 2.6Kg. Very little CO and a brilliant travel scope.
I use it alot more than my 6 and 8SE.
Sold in the USA at http://store.smartas...opmiedapor.html

#22 Sky Muse

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Posted 03 December 2012 - 07:17 PM

Although hardly ubiquitous, and long discontinued, the Takahashi FS-102 with its f/8 ratio is, for myself as a purely visual observer, the sweet spot and without peer, save the rarely-offered, legendary Astro-Physics "Traveler"...

http://www.scopereviews.com/aptak.html

The FS-102 is superior in sharpness and contrast compared to its current successor, the TSA-102, and has been described, albeit biasedly perhaps, as nothing short of "mythical", its only disadvantage being that it leaves one forever yearning for its larger sibling, the FS-152.

Alan

#23 johnnyha

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Posted 03 December 2012 - 07:48 PM

I'd go for the NP101 with your lineup, since you already have the FS128. Otherwise I would also suggest the FS102NSV.

#24 Moonglum

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Posted 03 December 2012 - 08:36 PM

1st. Lomo 102/800. Mine is Stellarvue's, actually a pretty compact tube. (12lbs) Threaded extension though, pain in the @$#&$$$.
2nd. Lzos 100/800. Just cuz I've always wanted one.

#25 Fomalhaut

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Posted 04 December 2012 - 08:18 AM

The Takahashi FCT100/640 fluorite-triplet which I happen to have been the lucky and happy owner for 20 years now.
This is the one and only telescope I'm sure I'll never sell as long as being able to use it. Here is it (first post):

http://astro-foren.d...shi-FCT-100-640
(just move cursor on images to enlarge)

Chris






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