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Light 4" Apo - any and all suggestions

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#26 SeattleScott

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Posted 24 January 2020 - 06:41 PM

Did you weigh your ED103s with rings, dovetail and RDF? I have found Vixen Optics USA specs to be less than reliable. Brian on the other hand has always taken good care of my needs. But the printed specs???

Yes I weighed it. I haven’t had my bathroom scale certified though. About one pound heavier than a Orion 100ED. More robust focuser and dew shield.

#27 tadam

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Posted 24 January 2020 - 07:16 PM

The Borg has very good correction (especially at the focal length), but it is not a triplet.  The 5 pound weight and ability to fit in any airline case (or a backback) with ease is a big plus.  The best reason to consider Borg is if one is looking for something that is both lightweight AND superportable.



#28 YAOG

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Posted 24 January 2020 - 07:59 PM

I have a TV NP101. Anything lighter? Thanks.

The Takahashi FC100DC is over 3 pounds lighter including the Takahashi clamshell. But the FC100DC also packs about 3" longer. 



#29 YAOG

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Posted 24 January 2020 - 08:03 PM

Borg followed by a ES 102 FCD100 carbon fiber followed by a FC-100DF

Carson the ES 102 FCD CF spec weight is heavier than the FC100DC including the Tak clamshell. 



#30 dr.who

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Posted 24 January 2020 - 09:17 PM

Chip - I was just checking my answer. For some reason I thought the ES was lighter. You are right. I have to change my answer to:

 

FC-100DF 6.1 lbs -> ES 102 FCD100 CF 7 lbs -> Borg 107 9.4 lbs 



#31 klim

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Posted 24 January 2020 - 10:04 PM

If my priority in a 4” refractor was light weight, I would consider the Takahashi FC100 DC, and stick with 1.25” eyepieces.  What’s the point of getting a 5 pound telescope and adding a 2 pound eyepiece?

 

I did consider this but ended up with an NP101 since weight wasn’t the highest priority.

 

And then got a 3” refractor as my light weight travel scope.

 

I am not sure what the OP’s goal is, but sometimes the best light weight 4” scope is a 3” scope.

I've considered this.



#32 Lookitup

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Posted 25 January 2020 - 12:02 AM

Still light with binoviewer Tak DF with denkmeier bino & powerswitch. The SV M1V mount makes all the difference weight wise.  Ed100 F9 is about same weight and is better suited to small mount IME. 

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#33 YAOG

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Posted 25 January 2020 - 12:04 AM

Chip - I was just checking my answer. For some reason I thought the ES was lighter. You are right. I have to change my answer to:

 

FC-100DF 6.1 lbs -> ES 102 FCD100 CF 7 lbs -> Borg 107 9.4 lbs 

Dr. W.,

 

Do you or have you had a Both 107mm?  I'm curious about them but they seem rare in the wild.



#34 hama-san

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Posted 25 January 2020 - 10:00 AM

my borg 107fl weighs around 6.6 lbs with LMF-1.

Edited by hama-san, 25 January 2020 - 10:01 AM.


#35 dr.who

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Posted 25 January 2020 - 02:17 PM

Dr. W.,

 

Do you or have you had a Both 107mm?  I'm curious about them but they seem rare in the wild.

No. I have seen them but don't own one. Woodland Hills Camera and Telescope sells them. I have a Borg 125 somewhere between here and Japan. When it gets here I am happy to meet up and let you use it...



#36 SeattleScott

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Posted 25 January 2020 - 04:03 PM

There are two Borgs, the 100mm F6.4 doublet and the 107mm F3.9 with six lenses. It appears the 100 may be discontinued now. At least it doesn’t seem to be very available. The 107 is available new but with six lenses it isn’t that light, and at F3.9 it is more of an astrograph. And it is very expensive, similar to a TV NP101. The 100mm wasn’t exactly cheap either. So yeah not a lot of them in the wild.

Scott

Edited by SeattleScott, 25 January 2020 - 04:04 PM.


#37 UnderOvercast

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Posted 25 January 2020 - 05:19 PM

There are two Borgs, the 100mm F6.4 doublet and the 107mm F3.9 with six lenses. It appears the 100 may be discontinued now. At least it doesn’t seem to be very available. The 107 is available new but with six lenses it isn’t that light, and at F3.9 it is more of an astrograph. And it is very expensive, similar to a TV NP101. The 100mm wasn’t exactly cheap either. So yeah not a lot of them in the wild.

Scott

Scott,

 

Being a Borg, the 107FL is available in various configurations, including visual. At 2.5kg it is considerably lighter than the astrograph version:

https://www.sciencec...gPackage/21.htm

 

With dewshield extended it has a sort of "spyglass" look to it :)

https://digiborg.fil...16/12/1223a.jpg

 

Grant


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#38 aa6ww

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Posted 25 January 2020 - 08:59 PM

you can actually see something at 300x to 400x on an alt az platform? if so, what?

 

 

..Ralph? 

 

 

The Takahashi FC100DC is a very light scope but still retains the superb thermally compensating Tak lens cell. It's light yet still well engineered and with outstanding optical quality. At very high powers you may want the MEF micro focuser. I find it a great advantage when observing between 300X &400X. 

 

attachicon.gif2019-01-28 19.57.27.jpg



#39 YAOG

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Posted 25 January 2020 - 10:42 PM

No. I have seen them but don't own one. Woodland Hills Camera and Telescope sells them. I have a Borg 125 somewhere between here and Japan. When it gets here I am happy to meet up and let you use it...

Any ETA? We gotta get you over to Dr. W's do the planets this season. 



#40 dr.who

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Posted 25 January 2020 - 10:52 PM

It is sitting in a warehouse in Japan as of today. I need to arrange shipping tomorrow or Monday. Back on topic, the most cost effective high quality and lightweight scope will be the FC-100DF. If it is too long then the ES FCD100 CF would be my next choice. A bit more weight but it is a true APO not a ED Doublet...



#41 Lookitup

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Posted 26 January 2020 - 12:44 AM

The mount and tolerance to shakes pushed the weight down. Comparing ED100 & Tak DF, the ED takes 2-3 sec. to settle at F9 length, but moves smoother on M1V mount, not shown on pic. They both have similar weights, while the ED has an excellent ML 2.5" focuser which elevates it's value a lot. 

Still trying to figure out, why the ED at F9 and X140 provides such comfortable views vs the Tak. Could it be the type off glass, focal length or color tone interacting with personal eye condition. Going x200 and above the Tak shows off and is generally a bit brighter with better CA control.

The ED100 with upgraded focuser is a good alternative, while it also softens somewhat the need to protect scope investment.  

 

CS Pete  

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#42 SeattleScott

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Posted 26 January 2020 - 01:21 AM

I found my 100 ED to be about equal to my Vixen ED103S up to about 100x. Above that the Vixen would start pulling away. For low to medium power there isn’t much difference between a mass produced or premium brand Apo. You are paying a premium for better high power planetary viewing.

The ED103S is also better from a mounting/stability perspective. The balance point on the Vixen is much closer to the focuser. And the focuser is smoother. Of course you could put an excellent, heavy focuser on the ED100 to move the balance point and still be cheaper than the Vixen.

Scott
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#43 Lookitup

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Posted 26 January 2020 - 02:35 AM

The Vixens, in my case the ED115s I had, are close in CA to the Tak DF.  Must be a Japanese thingy. ED100 still handles x207 well in SW FL ski conditions.

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#44 Axunator

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Posted 26 January 2020 - 04:19 AM

What’s the point of getting a 5 pound telescope and adding a 2 pound eyepiece?


Magnificently glorious wide field views, 3.6 degrees of optical perfection, and still being at 7 pounds. That’s the point, in my humble opinion ;-)
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#45 SeattleScott

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Posted 26 January 2020 - 06:43 AM

Yep

#46 SeattleScott

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Posted 26 January 2020 - 06:48 AM

The Vixens, in my case the ED115s I had, are close in CA to the Tak DF. Must be a Japanese thingy. ED100 still handles x207 well in SW FL ski conditions.

Likely the better CA control of Vixen and Tak can be attributed to more precise optical figure, and mating elements. It is somewhat surprising what a difference the optical figure can make. It can be easy to forget my Vixen achro isn’t an Apo. Not saying there isn’t any CA but it isn’t “in your face” like with other achros.

Scott
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#47 mkothe

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Posted 26 January 2020 - 10:37 AM

I have a KSON 102ED f/6 on an Az-GTi for my grab and go/carry-on setup. 5.7 lbs and 20.5” with dew shield retracted (8lb 6oz with rings and diagonal).

Michael

Edited by mkothe, 26 January 2020 - 12:44 PM.



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