Can a Takahashi 100 DZ Outperform a Non Premium 120-127mm ED Refractor

[Stu]

2 hours ago, John said:

Sounds like you had different experiences with both your ED120 and your FC100-DL to mine then. 

My FC100-DL performs very much like a smaller aperture version of my TMB/LZOS 130mm F/9.2 triplet. No false colour visible (to me) in either scope.

 

I suspect your 120ED is a particularly good example John. I think I’ve had three now and something never quite clicked with me. As I’ve mentioned (ad naseum, my apologies), for me it’s all about performance in the small package. I found I rarely went to the effort of putting the 120 out as it needed a bigger mount, so I get a lot more use from the Tak. It’s something I’m well aware of with the FS-128, although I find it quite manageable and a lot easier than the LZOS 130mm which was heavier and much more front heavy so more difficult to handle.

[F15Rules]

+1 for David, Mike and John's remarks..all good, sensible opinions from highly experienced UK based people who have first hand experience of the vagaries of UK seeing conditions.

I have come to believe that as we get older, factors other than just optical ones become more important to the practice of our hobby..

In no particular order, I'd suggest the following have become, and are becoming ever more important to me and my observing (I'm now 67)..

- weather, in terms of temperature, (how cold, how warm) seeing (sky steadiness), transparency (sky clarity), light pollution, atmospheric pollution (local fires, log burners, bonfires, Saharan Dust, etc)..

- weight of equipment, ease and speed of setting up, (here, refractors have a big advantage versus reflectors, needing little or no collimation or other adjustments)..

- local micro climates- wind direction, local horizon, temperature inversions, neighbour's  lighting and late night interior lighting 

- age related factors..the call of the TV on a cold night, fatigue, inertia against spending a long time in the cold setting up, family ties, unexpected phone calls, physical deterioration eg tolerance of cold, bronchial/rheumatic and other health/age related problems, compliant (or not) partner, unexpected phone calls and visitors etc etc.

For younger observers other factors can be more influential:

- work early start, young children responsibilities, fatigue from daily grind, lack of funds, and need to sell equipment and/or take a break from hobbies.

My take from the factors that affect me personally where I am in my life now are slowly starting to  convince me that a 100mm to 115mm high quality refractor on a relatively lightweight EQ or Altaz mount and wooden tripod are the way to go.

As someone said above (Stu, I think), a smaller instrument that you use more, can actually show you more than a larger scope that you don't use so much due to any combination of the above "what counts" factors.

So, taking everything into account, it's hard to argue against a really good 4" or so refractor. I wish you well with your new 100mm Tak, and I also wish you many healthy years in your later life to enjoy it! 😉 

Dave

[mikeDnight]

 I've had several observing sessions with two separate DL's and false colour was totally non-existent visually. I think that Roger Vine does a honest review of all the FC100D series on his website ScopeViews. They are definitely well worth reading. Perhaps colour was produced by the eyepiece, which can certainly be the case with some wide angle multi element designs?!

 When I bought my DC in 2015 I had to sell off much of my kit to fund the purchase, so eventually I ended up with no other scope but my DC. As such the DC became my scope for every purpose. When you're limited to just one telescope and use it for everything, you quickly learn how capable it can be, even in areas where some might imagine such a scope would be very limited. To me the FC's are powerful all rounders. I even glimpsed the Horse Head with my DC, though it took a great deal of patience and a transparent sky. 

[Deadlake]

8 hours ago, Stu said:It’s something I’m well aware of with the FS-128, although I find it quite manageable and a lot easier than the LZOS 130mm which was heavier and much more front heavy so more difficult to handle.

I find the LZOS 130 mm the best balanced of all my scopes, (C11 and 105 mm LZOS). 
I think this is down the FT that adds 1 kg more on the end, otherwise it would require Y axis balancing all the time. The 105 mm LZOS I have is a pain to balance and swapping out the FT would make it easier to balance. Makes you think about the TOS’s that come with built in counterweights. But yes it’s another step in set up.

[John]

15 hours ago, Stu said:

I suspect your 120ED is a particularly good example John..... 

I have come to that conclusion. It is the only ED120 that I have used so I can only share my experience with this one example. I have seen excellent optical reports of a number of other examples, published by Herr Rohr. 

Similarly with my Tak, Vixen and TMB/LZOS - they are the only examples of these types that I've used. All the rest out there might be rubbish 😁

 

 

[johnturley]

I finally picked up the Takahashi FC 100 DZ from Rother Valley Optics yesterday, taking over a week to come from their supplier, apparently this was the last one available in the country before further stocks arrive from Japan, although according to FLO’s website they currently have one in stock. I went to Rother Valley Optics mainly because they are only 30 minutes drive away from me, so that I could pick up the scope in person, and avoid possible subsequent damage, or misalignment of the optics, in case of rough handling by the courier. In addition RVO were £60 cheaper than FLO at £2,905, and are currently offering a free Zygo Test on ED Refractors up to 120mm. According to the test the scope came out as Strehl 0.987, in line with what would be expected.

The scope was certainly well packed compared to some other scopes that I have bought, being ‘triple boxed’, and on inspection appeared in perfect condition with no visible marks on the tube or dust on the lens. To me it appeared incredibly small, light, and compact compared to my ES 127mm Refractor, especially with the dewshield retracted.

It had been my original intention to purchase some Stella Lyra black tube rings to mount it on my Skywatcher AZ-EQ 5 mount, but @mikeDnight kindly offered me a Tak 95mm Clamshell with dovetail, so I thought I would give it a try, and it does appear to grip the tube quite firmly. The AZ-EQ5 feels like a bit of overkill for such a small light scope (I originally purchased it for the ES 127 Refractor), and I may consider selling it and buying a smaller and lighter mount in the future, so that I can carry everything out as one unit. However with now only requiring one balance weight, plus not the extension bar (2 balance weights plus extension bar were required with the ES 127), the mount and tripod are a bit lighter to carry out. In addition at present, I can potentially mount both scopes on the AZ-EQ5 in AZ mode, which would be useful when it comes to comparing them, although the large difference in weight between them (4kg as opposed to 9kg) could cause balance problems.

I wanted a larger finder than the standard Tak 6x30, but did not want to pay as much as £322 (plus £90 for mounting bracket) for a Tak 7 x 50, so instead paid £30 for a second-hand Skywatcher finder (including bracket), which turned out to be like new. It had been my intention to mount it on the DZ utilising a More Blue Finder Base from FLO.

More Blue Universal Finder Base for Tak | First Light Optics

However these are currently out of stock, and not likely to come in before December, so after checking that the Skywatcher finder would fit, I splashed out what I though was an exorbitant £90 on the Tak bracket when I picked up the scope, but it does at least match the colour of the rest of the scope, although as Tak purists will note, the Clamshell is a slightly different shade of green, I assume that Tak must at some stage have changed the colour.

Overall the finish of the Tak is excellent, although I must confess to being a bit disappointed with the focusing mount, which I gather is not a strong point of Taks, and understand why some fit Feathertouch focusers. I found it rather stiff even after slackening the adjustment knob, has a limited travel distance of about 62mm (although better than the 45mm of the ES 127), and only course focusing. More Blue do make a Precision Focuser Retrofit Kit, available from FLO, and wondered whether anybody had purchased one of these, and how they rate them. 

 More Blue Precision Focuser Retrofit Kit for Takahashi Telescopes | First Light Optics

As can be seen from the photo below I have fitted a Baader 2in Click Lock Diagonal (which used to be on my CPC 9.25), and was planning to get another Click Lock 2in to 1.25in Reducer (I have these on both my 14in Newtonian and Esprit 150), however the Tak one which came with the scope, although not click-lock, appears to be of very good quality, so I might not bother. I wasn’t sure whether I would need the extension tube that came with the scope to reach focus with the diagonal, I think that @Mr Spock mentioned that with the Baader M72 ClickLock Clamp and diagonal, he didn’t require any extension tube, but will find out by trial and error.

Baader 2" ClickLock M72 Clamp (Takahashi) | First Light Optics

As mentioned it is my intention over the next few weeks to compare the performance of the 100 DZ with the ES 127 before selling the latter, and see whether Taks are as good as some claim. However I will not be unduly disappointed if the DZ turns out to be not quite as good on planets as the ES 127 with its extra 27mm of aperture (although not as good quality lens), as I wanted a smaller lighter scope anyway.  I would not expect it to compare on Deep Sky Objects, but I have two other scopes (my 14in Newtonian and Esprit 150) better suited to this purpose.

John

Edited November 16, 2023 by johnturley

[dweller25]

Those DZ’s are nice scopes @johnturley 

Especially with a Binoviewer 👍

Edited November 16, 2023 by dweller25

[Mr Spock]

Nice scope! You won't need the extension tube 👍 This is focused on Venus.

I would add for best planetary performance, the Tak prism shows Jupiter's belts easier and cleaner than the Baader. I just use that now for wide field and doubles.

[Jim L]

For future reference, here’s another source for the Tak style universal finder bracket:

https://www.amazon.co.uk/Ninyoon-Universal-Aluminium-Telescope-Finderscope/dp/B09TKYY7LY/ref=sr_1_41?crid=3RUNBABAM9NU3&keywords=Telescope+Finder+bracket&qid=1700169554&sprefix=telescope+finder+bracket%2Caps%2C272&sr=8-41

Here’s the one I use, and which I prefer because it’s secured through holes rather than slots:

https://www.aliexpress.us/item/3256804477322418.html?gatewayAdapt=glo2usa

Here’s the slotted version for under $10 if you aren’t in a hurry:

https://www.aliexpress.us/item/2255800598317172.html?spm=a2g0o.detail.0.0.6b281cafcEQtoU&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.362094.0&scm_id=1007.40050.362094.0&scm-url=1007.40050.362094.0&pvid=b81b895b-2733-47d6-b614-c2c5a16d7d56&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40050.362094.0,pvid:b81b895b-2733-47d6-b614-c2c5a16d7d56,tpp_buckets:668%232846%238112%231997&pdp_npi=4%40dis!USD!14.01!8.97!!!14.01!!%402103247117001700664644481e9142!10000007813430415!rec!US!2861702980!

 

 

Edited November 16, 2023 by Jim L

[johnturley]

18 hours ago, Mr Spock said:

Nice scope! You won't need the extension tube 👍 This is focused on Venus.

I would add for best planetary performance, the Tak prism shows Jupiter's belts easier and cleaner than the Baader. I just use that now for wide field and doubles.

Will think about getting a Tak Prism Diagonal if you think its worthwhile for improved high power planetary views, they are not as expensive as I thought at £108 from FLO.

Looking at your photo, have you fitted a micro focuser, if so is that the genuine Tak one, FLO just list the More Blue version.

More Blue Precision Focuser Retrofit Kit for Takahashi Telescopes | First Light Optics

John 

[Mr Spock]

10 minutes ago, johnturley said:

Looking at your photo, have you fitted a micro focuser, if so is that the genuine Tak one, FLO just list the More Blue version.

Yes, Tak MEF3. I have heard others say they prefer the More Blue version. Though the MEF3 does match better.

The Tak prism surprised me. I didn't really expect there to be a difference. 

[IB20]

I have the More Blue microfocuser on my 76DCU. It’s very nice, an easy fit and has a finer gear reduction at 12:1 than the MEF3. Cheaper too!

[John]

I use the FT micro pinion on my FC100-DL and the Baader Zeiss T2 prism or an AP Maxbright if I want a 2 inch diagonal.  I've not tried an MEF-3, More Blue or a Tak prism. They are probably very nice 🙂

Edited November 17, 2023 by John

[johnturley]

On 16/11/2023 at 19:33, Mr Spock said:

Nice scope! You won't need the extension tube 👍 This is focused on Venus.

I would add for best planetary performance, the Tak prism shows Jupiter's belts easier and cleaner than the Baader. I just use that now for wide field and doubles.

Got my first fleeting glimpse through the 100 DZ last night, at Jupiter through a gap in the clouds, apart from making out the 2 main bands, I didn't have sufficient time to assess the performance before it clouded over again, and I don't think that atmospheric conditions were very good.

With the Baader diagonal (like yours, which has a light path of 112mm) and a Tele Vue 7mm T6 Nagler, it reached focus with the drawtube just 20mm out., some of my eyepieces focus further in. I didn't need the Tak 2in extension tube that came with the scope, which I assume you only need if you don't use a diagonal. I assume that the Tak 1.25 in Prism Diagonal has a shorter light path, so that the eyepieces will focus further out, do you know whether the Baader M72 Click Lock clamp has a longer or a shorter light path than the Tak M72 to 2in adaptor that came with the scope.

I also found the coarse focusing a bit hit and miss, and at some point will probably get a Precision Focuser Kit, at present a bit undecided between the More Blue, and the TaK version. 

John 

[Mr Spock]

9 minutes ago, johnturley said:

Got my first fleeting glimpse through the 100 DZ last night, at Jupiter through a gap in the clouds, apart from making out the 2 main bands, I didn't have sufficient time to assess the performance before it clouded over again, and I don't think that atmospheric conditions were very good.

With the Baader diagonal (like yours, which has a light path of 112mm) and a Tele Vue 7mm T6 Nagler, it reached focus with the drawtube just 20mm out., some of my eyepieces focus further in. I didn't need the Tak 2in extension tube that came with the scope, which I assume you only need if you don't use a diagonal. I assume that the Tak 1.25 in Prism Diagonal has a shorter light path, so that the eyepieces will focus further out, do you know whether the Baader M72 Click Lock clamp has a longer or a shorter light path than the Tak M72 to 2in adaptor that came with the scope.

I also found the coarse focusing a bit hit and miss, and at some point will probably get a Precision Focuser Kit, at present a bit undecided between the More Blue, and the TaK version. 

John 

I have found with the Tak 1.25" prism I need a 35mm extension tube (I have a SL) though a 50mm might be better. The Tak extension which came with mine is too long (72mm) for anything other than straight through so it sits in the box.

The Baader is 42mm and the Tak 40mm, so not much in it.

The MEF3 I have feels a little 'bouncy' - I can't answer for the More Blue. The poor focuser is why I've gone to the great expense (gulp) of ordering a FT focuser. These scopes have great optics but everything else is out of the dark ages 

[vlaiv]

For those who are a bit more interested in performance of refractor telescopes and impact of different types of glass - this is well worth reading:

https://www.telescope-optics.net/commercial_telescopes.htm

Even if you don't understand what's being said on the page - you will notice that things are far from those often heard:

- FPL53 is the best

- FPL51 is good enough on slower optics

It turns out that selection of mating glass types and scope parameters in general have a huge impact on what can be achieved. I was particularly surprised that F/6 FPL51 scope can have higher hypothetical Strehl in green than say FPL53 F/6.6 scope of the same aperture - because of selection (or rather even availability) of suitable mating element.

There is section dedicated to Tak 100 DZ as well - so again, worth a read.

[bosun21]

I have owned a couple of FPL51 doublets and there is definitely CA visible at higher magnifications. For a doublet FPL53/Lanthanum make a great combination with no CA visible in my Starfield at >200x. I would only consider FPL51 in a triplet or long focal length doublet. Fluorite being the best of all.

Edited November 22, 2023 by bosun21

[Mr Spock]

Agreed. Both my (former) Starfield 102 and (current) Tak 100 show no signs of CA. Both are even inside and outside of focus.

Strange observation in green: my 120mm achro fitted with a Baader Continuum for solar (540nm, 10nm) is significantly sharper and more detailed than the 100/102 apos.

[vlaiv]

4 minutes ago, bosun21 said:

I have owned a couple of FPL51 doublets and there is definitely CA visible at higher magnifications. For a doublet FPL53/Lanthanum make a great combination with no CA visible in my Starfield at >200x. I would only consider FPL51 in a triplet or long focal length doublet. Fluorite being the best of all.

If you read the text, you will find that lanthanum glass is used because it filters out violet part of spectrum and reduces CA that way. There are filter that can do that if one wishes CA free view.

To be honest, I have F/10 Achromat and I prefer unfiltered view of the Jupiter and I personally don't find CA to be distracting at all. I see it, it just does not bother me that much. Maybe because I owned F/5 achromat and I'm aware how severe and degrading CA can really be - but it's not nearly that much with F/10 achromat and view is still very sharp.

[vlaiv]

2 minutes ago, Mr Spock said:

Agreed. Both my (former) Starfield 102 and (current) Tak 100 show no signs of CA. Both are even inside and outside of focus.

Strange observation in green: my 120mm achro fitted with a Baader Continuum for solar (540nm, 10nm) is significantly sharper and more detailed than the 100/102 apos.

After reading the above, I don't find this strange. Most achros suffer from contrast loss because of other wavelengths and green part of spectrum (around 500-540nm) is very sharp in them.

I remember having very sharp view of the Moon with 4" F/5 fast achro with Continuum filter. Even spherochromatism is often corrected at that wavelength.

[Mr Spock]

3 minutes ago, vlaiv said:

If you read the text, you will find that lanthanum glass is used because it filters out violet part of spectrum and reduces CA that way.

That sound a little odd as DZ users report the view is a bit cooler than other non Lanthanum Taks. As it's reported they both have the same level of correction and detail one wonders why the Lanthanum version is necessary for visual (it may reduce blue bloat for imaging).

[bosun21]

1 minute ago, vlaiv said:

If you read the text, you will find that lanthanum glass is used because it filters out violet part of spectrum and reduces CA that way. There are filter that can do that if one wishes CA free view.

To be honest, I have F/10 Achromat and I prefer unfiltered view of the Jupiter and I personally don't find CA to be distracting at all. I see it, it just does not bother me that much. Maybe because I owned F/5 achromat and I'm aware how severe and degrading CA can really be - but it's not nearly that much with F/10 achromat and view is still very sharp.

I also don't like filtered views and prefer observing without them. CA is a very personal thing and doesn't seem to bother some people at all. I didn't know about the green part of the spectrum and that probably accounts for the many people who use an achromat for solar with a continuum filter 

[Stu]

3 minutes ago, Mr Spock said:

Strange observation in green: my 120mm achro fitted with a Baader Continuum for solar (540nm, 10nm) is significantly sharper and more detailed than the 100/102 apos.

I keep saying I’ll do a similar comparison using my Celestron Omni 120 f8.3, but I guess provided the scope is well corrected in SA, the extra aperture should give you a detail benefit, particularly as you are filtering on a narrowband green frequency to elongate any CA.

[mikeDnight]

1 hour ago, johnturley said:

Got my first fleeting glimpse through the 100 DZ last night, at Jupiter through a gap in the clouds, apart from making out the 2 main bands, I didn't have sufficient time to assess the performance before it clouded over again, and I don't think that atmospheric conditions were very good.

With the Baader diagonal (like yours, which has a light path of 112mm) and a Tele Vue 7mm T6 Nagler, it reached focus with the drawtube just 20mm out., some of my eyepieces focus further in. I didn't need the Tak 2in extension tube that came with the scope, which I assume you only need if you don't use a diagonal. I assume that the Tak 1.25 in Prism Diagonal has a shorter light path, so that the eyepieces will focus further out, do you know whether the Baader M72 Click Lock clamp has a longer or a shorter light path than the Tak M72 to 2in adaptor that came with the scope.

I also found the coarse focusing a bit hit and miss, and at some point will probably get a Precision Focuser Kit, at present a bit undecided between the More Blue, and the TaK version. 

John 

 I use both the Tak 1.25" prism and the Baader Zeiss BBHS 1.25" prism. The latter actually has a larger prism so that you can use a 30mm Ultra Flat 2"  eyepiece without it vignetting if you use a 2" click lock on the prism. I also use a 2" nose piece on my BBHS prism.

 When it comes to the microfocusser issue, I used to use a Tak micro focuser on my DC, but found I didn't really need it with my DZ. I do however sometimes use a 1.25"  Baader helical focuser attached to the BBHS prism for double stars, especially at high power. It offers an excellent, precise, and cheap alternative to the Tak or More blue versions. The down side is that the BBHS prism isn't cheap, though it is excellent!

[Mr Spock]

1 hour ago, mikeDnight said:

 I use both the Tak 1.25" prism and the Baader Zeiss BBHS 1.25" prism.

Do you find there to be a difference in planetary performance between the two?