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kerrylewis

Which Takahashi refractor?

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I know the FC-100 throws its heat away with abandon, reaching its peak performance fast. (eg on one session I did it went from 18-19 deg to -2 deg in ~15 mins!)  How much longer would the 120 Triplet take?  This would have a bearing on my choice.

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My 130 triplet takes 30-40 minutes to cool from room temperature. I've used the FC100 striaight out of the house at 150x on Venus the other night and the image was very nice.

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To add my 2 penneth to the quality of Tak refractors.  My FSQ85 is sublime, a wonderful telescope, as it should be for the £3300 I paid for it  I bought it brand new in 2013 and it is fabulous. A couple of folks have had issues but I am not one of them.  Maybe a few with slight imperfections made it through.

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1 hour ago, John said:

My 130 triplet takes 30-40 minutes to cool from room temperature. I've used the FC100 striaight out of the house at 150x on Venus the other night and the image was very nice.

This is it John, a majorly important factor, especially when I recall many of my very good sessions being cut to an hour or less due to the many effecting forces of nature.

Edit: It was mikeDnight who is to blame for telling me about the scopes merits. 

Edited by jabeoo1
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6 hours ago, kerrylewis said:

Approaching 50? I wish - three score and ten is.......Still a few years observing left though Derek :happy11:

Thanks for your input - I am leaning towards a 120 

 

Oops! Sorry, Kerry, I was using the DRT algorithm when working out your age :evil:

Being a late March 1965 baby myself the DRT algorithm tells me I am approaching 41. My calculations include the effect of red-shift and gravitational lensing :wink:

 

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14 minutes ago, DRT said:

.... My calculations include the effect of red-shift and gravitational lensing :wink:

 

Thats why my wife thinks I'm overweight. I'm really skinny really but there happens to be a small supermassive black hole just in front of me all the time, altering my appearance.

(this has to be the worst excuse I've come up with yet !!! :rolleyes2:)

it's also just a tad off topic - sorry Kerry !

Edited by John
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On 11/03/2017 at 15:20, kerrylewis said:

Approaching 50? I wish - three score and ten is.......Still a few years observing left though Derek :happy11:

Thanks for your input - I am leaning towards a 120 

 

Here's a pic from a post on CN that shows the FC100DC and TSA120 side by side. The DC can be easily held in one hand of an outstretched arm  but I wouldn't want to try that for long with a TSA120. 

 

post-211726-0-70195800-1451557868.jpg

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On ‎11‎/‎03‎/‎2017 at 07:45, kerrylewis said:

But I do wear glasses to 'go about my business '!  :happy11: I find that I can't wear them for observing but I do also have contact lenses which I can use. I'm looking forward to trying Shane's binoviewers and perhaps I'll be persuaded. Certainly any advantage on planets would be attractive. 

I wear glasses too Kerry.  I also have to wear them for observing as I have astigmatism in both eyes, so I can't just focus out the effects like you can if you have short or long site.  The good thing is that because when using a binoviewer you can use comparatively long focus length eyepieces for planetary viewing.  This is because you usually have to use a barlow in the binoviewer nosepiece to allow the system to come to focus and also, just using a binoviewer on it's own causes an additional magnification increase as well.

Hence, when using a binoviewer with a X2 barlow, there is usually a magnification factor of around x4 when compared with using the same eyepieces on their own.  Thus the 16.8 Orthos I mostly use in effect act like 4mm eyepieces, or there abouts.  This is important for us glasses types since using longer focal length eyepieces means than you have more eye relief making it easier to keep your glasses on when observing compared with using a much shorter focal length.  I can use my 16.8s with glasses quite comfortably, while it would be impossible for me to keep them on using a single 4mm Ortho on the same scope.  :lol:

 

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Just to add to Paul's comment regarding binoviewer and 16.8mm orthos. You lose nothing in sharpness despite having the added barlow. The 16.8 orthos are as sharp in the binoviewer with barlow, if not sharper than a Pentax XW giving the same or similar mag, but without the 70° field, which is not needed with Lunar and planetary.

Mkke

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1 minute ago, mikeDnight said:

Just to add to Paul's comment regarding binoviewer and 16.8mm orthos. You lose nothing in sharpness despite having the added barlow. The 16.8 orthos are as sharp in the binoviewer with barlow, if not sharper than a Pentax XW giving the same or similar mag, but without the 70° field, which is not needed with Lunar and planetary.

Mkke

x2 16.8mm Orhos  = £80 or less.  x1 3.5mm Pentax XW = £249.     :hello2::headbang:    

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5 minutes ago, paulastro said:

x2 16.8mm Orhos  = £80 or less.  x1 3.5mm Pentax XW = £249.     :hello2::headbang:    

Are they the "Super Abbe" orthos like this ?:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Ascension.asp?p=0_10_5_1_1_1

Hmmm - that binoviewer must be doing something to enable them to outperform an XW !

(I've tried some of those Super Abbe's in cyclops mode and they were rather mediocre IMHO :dontknow:)

 

Edited by John

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2 minutes ago, John said:

Are they the "Super Abbe" orthos like this ?:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Ascension.asp?p=0_10_5_1_1_1

Hmmm - that binoviewer must be doing something to enable them to outperform an XW !

(I've tried some of those Super Abbe's in cyclops mode and they were rather mediocre IMHO :dontknow:)

a

Hello John.  Mine look like these, but they have KYSON written on them.  They came with a used cheap binoviewer I bought about five years ago.  I agree with what Mikes says about their performance.  I used to have a few XWs of shorter focal lengths and sold them exactly because of this.  When used on any planet or the Moon, the pair of Orthos (with the binoviewer)always gave a better view when compared with a single 3.5mm XW.  When I first noticed this I couldn't believe the difference, and kept going back to do the comparison again many times before finally selling the XWs. I'd also mention that this was using a Revelation binoviewer - which I used until I dropped it unfortunately and had to replace it.  I've also done a couple of comparisons, and I could not see any noteworthy advantage in using a much more expensive binoviewer. 

With a binoviewer of course, the difference is not because the Orthos are better eyepieces, it's because of how the right and left side of the brain interprets the information sent to each eye and then combines the information into one much improved image.  Not only is the image better, using a binoviewer also much reduces the visibility of any floaters you may have.

I can only say what works for me (and Mike at least :smile:), and it may be that some people don't see the improvement - even though I trained in psychology I'm not going to try and explain it though :smile:.

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I wish I could get on with binoviewers - I'd save a lot of £'s on eyepieces ! :smiley:

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12 hours ago, mikeDnight said:

Here's a pic from a post on CN that shows the FC100DC and TSA120 side by side. The DC can be easily held in one hand of an outstretched arm  but I wouldn't want to try that for long with a TSA120. 

 

post-211726-0-70195800-1451557868.jpg

 

Very nice. I know if I was in a shop and these two were side by side and a decision was to be made which to buy.  The 120 on the left would just bring such a smile on my face and just looks like a "proper " scope in comparison. I know bigger is not always better but when you see two Taks side by side like that , it would have to be the 120. I can certainly see why you are leaning towards the 120 Kerry ☺

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34 minutes ago, Timebandit said:

 

Very nice. I know if I was in a shop and these two were side by side and a decision was to be made which to buy.  The 120 on the left would just bring such a smile on my face and just looks like a "proper " scope in comparison. I know bigger is not always better but when you see two Taks side by side like that , it would have to be the 120. I can certainly see why you are leaning towards the 120 Kerry ☺

I know what you mean.  However, what's also important is how you want to use the scope and what other equipment you may have.  The weight of these two scopes is very different, and if a real grab and go is what someone wants (and by this I mean a scope than can be easily scooped up in your arms and carried out into the garden through the back door in one armful) then the choice is not so straight forward.  I must say though, I've owned a TSA 120 and used the FC 100 DC and anyone should consider themselves lucky if they own either.  :smile:

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The TSA 120 seems to weigh in at around 1.5kg more than the Skywatcher ED120 Pro or about the same as an Equinox 120, for what it's worth. Not overweight for a 4.7" triplet I'd say.

 

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Thanks everybody for the continuing input, especially to Mike for taking the trouble to find and post that photo. It's very useful to see the comparison in size. I agree with John that, although the 120 obviously weighs more than the 100mm versions, I don't believe it is excessive. 

However, having listed for myself all the pros and cons, I am still thinking that the 120 is best for my circumstances BUT this is subject to being able to see and handle one so that I can be sure of its usability - particularly for use with the Ioptron mount.

Thanks again everyone - it's proved to be a very interesting discussion. 

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2 hours ago, Timebandit said:

 

Very nice. I know if I was in a shop and these two were side by side and a decision was to be made which to buy.  The 120 on the left would just bring such a smile on my face and just looks like a "proper " scope in comparison. I know bigger is not always better but when you see two Taks side by side like that , it would have to be the 120. I can certainly see why you are leaning towards the 120 Kerry ☺

For me these two scopes are very different propositions - in the flesh the contrast between them is even more obvious than in this image. The FC-100DC tube is 2.8kg - while the TSA 120 is getting on for three times that. The entire set up I use, with tripod, mount, prism, adapters and eyepiece weighs less than the TSA ota. That's not to say I wouldn't love one - of course I would.....

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1 hour ago, John said:

The TSA 120 seems to weigh in at around 1.5kg more than the Skywatcher ED120 Pro or about the same as an Equinox 120, for what it's worth. Not overweight for a 4.7" triplet I'd say.

 

 

Hi John. That's very interesting information, especially as I have a Equinox 120. If  the TSA 120 is the same weight as the equinox, then I would definitely go for 120 TSA. I find my equinox fine to carry and mount. No problems. And I am afraid for me personally then I would have "the what if  " factor if I choose the 100 over the 120. Totally up to you Kerry, but 120 all day long for me😀.

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I'd be very reluctant to get a triplet of any kind ever again but maybe I am being over-reactionary to the one I had (not Tak of course). If they ever came up with a doublet then I'd consider it for sure although I really enjoy my 120 ED.

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You must have had a really bad time with a triplet at some point Shane! You'll have to tell me about it when we meet. 

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Sure will mate. I think I traumatized myself!

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11 hours ago, John said:

Are they the "Super Abbe" orthos like this ?:

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Ascension.asp?p=0_10_5_1_1_1

Hmmm - that binoviewer must be doing something to enable them to outperform an XW !

(I've tried some of those Super Abbe's in cyclops mode and they were rather mediocre IMHO :dontknow:)

 

Hi John,

Five years ago Paul loaned me his KYSON 16.8mm orthoscopics for use in my binoviewer. I used them continually for four years before he realised they belonged to him and wanted them back. Some friend! 😢 Over the four years I used them, I was continually amazed that they consistently gave as sharp a view of the moon and planets as my XW's. In time i simply stopped using the XW's for planetary as the bino ortho combination always showed me more.

The 16.8mm orthos didn't really thrill me in mono use. In my fast scopes they suffered from edge distortion and the XW's  we're clearly superior. Add a X2 barlow to the ortho and it gave a very nice view, and in the binoviewer, which needs a Barlow to be useable in my scope, the orthos are amazingly good. After paul stole his eyepieces back, i used a pair of 18mm TAK Le's for a few months. The Le's, which were second hand, proved to have fungal growth between the elements on both eyepieces so i sent them back. After a brief search, I found the 16.8mm orthos on 365 Astronomys web site fot £39, so i ordered a pair and they are just as good as those I borrowed off Paul. I've not tried any of the other focal lengths in the range, so i couldn't comment on those.

It's  a pity you struggle with binoviewers as they really do enhance the detail on show. 

I still use XW's for DSO's etc.

Mike

 

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I just can't conceive of an eyepiece that is really noticably better than the XW's from 10mm to 3.5mm. Goodness knows I've tried to find one but even the 5mm TMB Supermonocentric (which is often compared with a ZAO) only gave very subtle improvement, at times and on the best nights and at huge expense of FoV and comfort :icon_scratch:

The magic of binoviewers, eh ? :smiley:

 

 

Edited by John
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I'm not sure how the binoviewers do it but even the basic plossls offer outstanding views compared to mono high end eyepieces...mind you binoviewing high end eyepieces has its rewards too... Longish plossls and orthos really work in binoviewers for some reason.

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