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80mm class and 100mm class (reason to keep both?)

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#1 GOLGO13

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Posted 25 November 2019 - 08:07 PM

I have a situation which I need some help with. I have a 103s and 81s and I'm wondering what the benefit of having both is. The reason this is tough is both scopes are quite similar. Even though the 81s is smaller, it's about the same for me mounting it up on my Vixen Porta Mount (with wooden legs and an extension). Both come to zenith. 

 

I'm having a hard time imagining needing both. Both have near perfect star tests and perform the same.

 

The only difference is my 103s has a moonlite and the 81s has the original single speed focuser. I have a reducer meant for DLSRs which will only work on the 81s. I don't currently do astrophotography and I am unsure I will ever want to. I did have this up for sale, but realized the focuser pinion needed replaced and I took it down. But now I have that fixed but was unsure if I should put it up again (well, let the dude know who was interested). With my Vixen GPD2 which is upgraded to GOTO with a SynScan I certainly could give DSLR imaging a try. But quite frankly I'm not even sure I could get a real polar alignment done and my DSLRs are older Nikon ones (D40 and 3100) which are probably not great for doing AP. My patience for learning and doing something like that is low. Which is why I enjoy night vision astronomy.

 

I do night vision astronomy, but these scopes have higher F-ratios and are more used for planets and ultra wide fields (well, wide for my situations). They are really good for 3 degree+ wide fields with my 34mm 68. 

 

Can you think of any reason to keep the 81s? Because of the fixed dew shield and F7.7, it's not exactly portable. I can say with certainty it's extremely good optically though. Just can't think of a reason where it would be needed. It's slightly wider FOV, but not sure that's enough to keep it. Seeing that I have so many other scopes that fit a purpose. The 60mm being my ultra portable setup. The two newts are night vision and the 10 inch is my deep space setup. The 8 SCT for night vision small objects. The 90mm mak is my solar observing setup (the filter does work on the 81s). The 103 is my main refractor for planets, wide field, etc.

 

Thanks for any suggestions.



#2 Justin Fuller

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Posted 25 November 2019 - 08:22 PM

My take: sell the 81, get a nice eyepeice or something for the money.
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#3 GOLGO13

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Posted 25 November 2019 - 08:28 PM

My take: sell the 81, get a nice eyepeice or something for the money.

Still making up for all the night vision equipment...so it's probably the right choice.



#4 csrlice12

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Posted 25 November 2019 - 08:38 PM

I'd say sell the 81s as well....but only because you have the 103s.



#5 GOLGO13

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Posted 25 November 2019 - 08:41 PM

Both the 81s and 103s are really good. Either one would be a great companion scope to a larger dob. These are under-rated scopes in my opinion. I of course understand some of the push back on them, but at the same time the price of them (especially used) bears that out. 



#6 Joe Eiers

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Posted 25 November 2019 - 09:10 PM

  My take is to sell the 81 and invest into the 103.  I've been in your shoes many times, and the 103 gives you much bigger bang for your buck.  If you've got lots of cash laying around you could keep both and use the 81 for those times you need something more portable.  Thing is, most of the time, you'll wish you'd brought the 103!

   Joe



#7 DeanD

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Posted 25 November 2019 - 11:13 PM

Sounds to me like you have already made up your mind, you just don't know it yet! ;)  I can't see any reason for you to keep the 81s given the summary you have provided of your own reasoning.

 

I agree with Justin: and if I were you even if I was still "making up" a bit for the night vision stuff, I wouldn't put the money into general revenue unless that was absolutely a necessity, but I would see it as a bonus and get something else I have been wanting/needing...

 

All the best,

 

Dean


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#8 Jon Isaacs

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Posted 26 November 2019 - 02:17 AM

For me, there is a significant difference between an 80mm and a 100mm scope in terms of portability and capability.  For example, I use my 80mm's for terrestrial photography including birding, a 4 inch is kind of big for that.  Of course my 80mms are faster than yours and have sliding dewshields so they're airline portable and easier to transport than my 4 inch.

 

Jon



#9 areyoukiddingme

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Posted 26 November 2019 - 02:40 AM

Another angle is to sell both and replace with a ~90mm.

 

You get close to the portability of a fast 80mm, and closer to the aperture/punch of a 100.


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#10 Erik Bakker

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Posted 26 November 2019 - 04:14 AM

The biggest difference between an 81 and 103 for me is portability. And the shorter focal length gives a substantially wider view in any given eyepiece.

 

I find a 60mm class scope too small in aperture and a 100mm class refractor to big in size for travel portability. That's where the 80mm scopes come in for me. The smallest scope that can really show me the (deep) sky. Under good skies they are phenomenal.

 

A near perfect startest is not easy to come by, so if you don't NEED to sell it, just keep it until you've made up your mind about the things that matter most to you regarding these instruments.


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#11 sg6

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Posted 26 November 2019 - 05:47 AM

Just keep them both, you have them now so they cost nothing more to use.

103 and 81 are just over 60% different in light collection, nice amount.

Believe me a small(er) scope is or will be a very good idea.

 

I have a 61mm WO, 70mm ETX, 72mm SW, 81mm WO, 90mm WO, 100mm TAL, 102mm Bresser.

Not one is going anywhere, just thankful they tend to make them in 10mm steps and not 5mm steps.


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#12 Nippon

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Posted 26 November 2019 - 06:19 AM

I have a 103s also and had an 80mm SV triplet. I found that I just never used the 80mm. Yes being an F/6 it was much smaller but that did not make it easier to set up and use. The 80 had really good optics but was very noticeably outdone by the 103 so I sold the 80 eventually.

I agree with  GOLGO13 the Japan made ED Vixen's are excellent scopes especially optically.


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#13 GOLGO13

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Posted 26 November 2019 - 09:16 AM

For me, there is a significant difference between an 80mm and a 100mm scope in terms of portability and capability.  For example, I use my 80mm's for terrestrial photography including birding, a 4 inch is kind of big for that.  Of course my 80mms are faster than yours and have sliding dewshields so they're airline portable and easier to transport than my 4 inch.

 

Jon

I agree on this point in principle, but the 81s with a fixed dew shield doesn't "feel" much different to me than the 103s. Sure, if I put them side by side you can see the size difference. But they both ride on the same mount. Technically I maybe able to carry the 81s on my dwarfstar, but I think it's too much scope for that. Or at least too much for the tripod I'm using with the dwarfstar. The 81s does have less vibration on the Porta mount, but it's not by much. And using Celestron vibration pads eliminates any extra vibrations (those things are worth their weight in gold....well, maybe silver).

 

If it were a smaller 80mm with a sliding dew shield and a case I'd probably keep it. Still, it's an excellent scope and will make someone quite happy.

 

So in usage I just don't see a portability difference. 


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#14 Jon Isaacs

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Posted 26 November 2019 - 10:16 AM

I agree on this point in principle, but the 81s with a fixed dew shield doesn't "feel" much different to me than the 103s. Sure, if I put them side by side you can see the size difference. But they both ride on the same mount. Technically I maybe able to carry the 81s on my dwarfstar, but I think it's too much scope for that. Or at least too much for the tripod I'm using with the dwarfstar. The 81s does have less vibration on the Porta mount, but it's not by much. And using Celestron vibration pads eliminates any extra vibrations (those things are worth their weight in gold....well, maybe silver).

 

If it were a smaller 80mm with a sliding dew shield and a case I'd probably keep it. Still, it's an excellent scope and will make someone quite happy.

 

So in usage I just don't see a portability difference. 

 

If I had to decided between my 80 mm ED/apos and my 4 inch NP-101, I'd definitely keep the 4 inch. It does nearly everything the 80mm do but does it better. The 80 mm F/6 provides a 0.6 degree wider field but it's messy by comparison.

 

In your situation the 81 mm provides a significantly wider but otherwise, it seems the 103 does everything better..

 

I'd probably keep the 81 mm but not use it much. :)

 

Jon



#15 GOLGO13

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Posted 26 November 2019 - 11:07 AM

Yeah...the 101 is basically a portable 4 inch scope. That would be a great scope for night vision. If I ever have the money I would consider getting the 127is someday. But every time I consider that, I figure a nice 16 inch F4 newt would be a better choice. But I am not sure I want to deal with that large a scope so maybe the 127 would be a better choice. All that being said, I believe a cheap 120mm F5 achromat would probably be good enough for night vision purposes...and much cheaper. Just not the flat field.



#16 Tyson M

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Posted 26 November 2019 - 11:20 AM

That 103S is basically a larger, scaled up version of the 81S.  Unless your mounting requirements dictate one or the other, you wont need the smaller aperture. 

 

The 103S doesnt have a sliding dew shield as well, so its transport length is getting quite long.  Knowing Vixen scopes though, they feel a lot lighter than they look, so I have no doubt it just rides well enough for the Porta II with upgraded legs. 

 

I loved the 81S, it is a fine scope.  Throw it on a smaller mount like an M1 or DSVM or fluid head and I would prob chose to keep that one. 

 

It is still large for an 80mm scope though.



#17 GOLGO13

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Posted 26 November 2019 - 11:31 AM

While the focal length is a bit long, I actually find that's a positive for visual work. My eyepieces work very well in these scopes...so I am happy they are F7.7. But it does make for a longer scope.

 

They are very light weight which I really do like. And the reason they are light are some of the compromises people complain about. So that's a real positive thing.

 

The case that came with my 103s is such that it barely fits inside...which makes it just a bit longer than the OTA. So that's nice. It's a cheap case, but it works.

 

I don't think I "need" a 4-5 inch F5 refractor since I have the 6 inch F4 newt (for night vision). But I am personally a fan of refractors. I wouldn't mind a 5 inch refractor again sometime, but I don't see going 6 inch. Just requires too much mounting and cooling for my taste.

 

All that being said I am comfortable with the 103s's aperture for my purposes.



#18 dr.who

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Posted 26 November 2019 - 11:38 AM

If your end state goal is more NV observing and possibly DSLR AP (you can use a DSLR for EAA too) I would suggest you sell both scopes and buy a AT92. It is in the middle of both, it is more portable, it is better for NV and EAA because it is an f/5.5, and it has a good focused on it as well as accessories for AP/EAA that are affordable. It is here:

https://www.astronom...ractor-ota.html

Remember as a CN member you get a extra discount on equipment bought from Astronomics so that helps too. You just have to mention in the notes field on the order that you are a CN member and give your user name.

If you are going to remain a visual observer then keep the 103. It has 21mm more aperture than the 82. And that 21mm is enough to see a noticeable difference in objects.
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#19 GOLGO13

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Posted 26 November 2019 - 12:16 PM

The AT92 is a good suggestion for future consideration NV wise. The 103s is used for visual only (though I tried NV through it and it wasn't horrible).



#20 Bomber Bob

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Posted 26 November 2019 - 01:02 PM

I'm in a similar situation:  Just got a new Astro-Tech AT102ED F7, and already had an outstanding vintage Vixen FL80S.  The 102 can ride on the same mount(s) as the 80.  The views so far are comparable.  And, we're gonna be moving in about 18 months, so I'm trying to whittle down my Collection.  OTOH, I just got a vintage Vixen Custom alt/az that matches the 80's green trim (HARD to find!)...  Whew!

 

Will I use the 102 more than the 80?  Yes.  More aperture, fine views, and a good 2" focuser (the 80 has the original 1.25").

 

I'd be inclined to sell the 80 & mount, BUT our daughter bought a beach house in OCT, and just got settled in.  She's already agreed to take my Questar & my 1964 Sears (Royal) 6336, but I'm gonna talk with her over Thanksgiving about the Vixen 80 kit -- see if she wants it for a front porch ship-spotting scope.

 

IF I were you, with 2 Vixens, and no option to keep one in the family, I'd sell the 81 and spruce up the 103.  I bet you can find some gotta-have-its for the larger ED.

 

Don't wanna hijack your thread, but I just LURV my new Power-Duo:

 

AT102ED S26 (AR-1 & FC-50).jpg

 

My AT102ED + 1980s Takahashi FC-50 on a rare vintage Mizar AR-1 rig.


Edited by Bomber Bob, 26 November 2019 - 01:05 PM.

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#21 BillP

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Posted 26 November 2019 - 09:26 PM

I have a Vixen 81S on a Porta II and a TSA-102 on a more robust alt-az for steadier view.  I used to have the TSA on the Porta II as well, but it was top heavy given the thin aluminum legs on the Porta II.  So I have the TSA now on a mount using the sturdier tripod legs from a CG5.  Given all of that, the mounted rigs are quite different and the 81S is way more portable for quick carry outs.  I also mounted my PST to the rings of the 81S so the dual scope solution still rides very well on the Porta II and great setup for dual white light and HA solar viewing.  In any event, I find lots of reasons for keeping the 81S as it is just a whole bunch lighter and easy and quicker to use day or night.  When I want more umpf or for planetary then I use the TSA.  Binoviewing with the TSA is also easier as very hard to balance any 80mm with a binoviewer attached.  So I find I like having both and they are not redundant for me.


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#22 grif 678

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Posted 27 November 2019 - 08:21 PM

The best scope is the one that is easier for you to use, especially as you get older. I would not sell either, because as you get older, you will probably wish you had the 81 back ( if you sold it )Use the 103 now, and when the back problems of old age occur, sell the 103 and you will have the 81.


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#23 WyattDavis

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Posted 27 November 2019 - 09:25 PM

I have a Vixen 81S on a Porta II and a TSA-102 on a more robust alt-az for steadier view.  I used to have the TSA on the Porta II as well, but it was top heavy given the thin aluminum legs on the Porta II.  So I have the TSA now on a mount using the sturdier tripod legs from a CG5.  Given all of that, the mounted rigs are quite different and the 81S is way more portable for quick carry outs.  I also mounted my PST to the rings of the 81S so the dual scope solution still rides very well on the Porta II and great setup for dual white light and HA solar viewing.  In any event, I find lots of reasons for keeping the 81S as it is just a whole bunch lighter and easy and quicker to use day or night.  When I want more umpf or for planetary then I use the TSA.  Binoviewing with the TSA is also easier as very hard to balance any 80mm with a binoviewer attached.  So I find I like having both and they are not redundant for me.

I have the Vixen 81mm and a Stellarvue 102 Access and have recently asked myself the same question. I have been thinning the herd and thought maybe I might sell the 81mm. But...

 

The Vixen works well on a Porta II with the HAL-130 tripod. The 102 seems to me like it needs a larger mount, so I use it on Stellarvue M2 mount on a CGEM tripod. That entire rig weighs about 16 pounds more than the Vixen on the Porta II - 60 percent more. The 102 is a nice step up in light gathering ability, but then again neither of these scopes compares to my dobs in that department.
 

At the moment, I have decided that am keeping the Vixen and will keep it set up and ready to use for when I don’t want to roll out the dob or set up the 102. Its light weight makes it very easy to move the entire setup (scope, tripod, finders, dew heaters, etc.) in one movement from my shed. I used it last week early in the AM and really enjoyed it - no set up, finders all pre-aligned, no cooling. I just walked out, set it out, and was able to get 90 minutes of Winter Circle observing in.  

 

I am physically able to haul the entire 102 setup in one piece as well, but it isn’t as easy to do and I don’t have room in my shed to keep both set up alongside my 10” dob. 


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#24 dscarpa

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Posted 27 November 2019 - 09:34 PM

 I've got a similar question  on a bigger scale with my WO ZS110 triplet and new to the Collection Vixen 130ED SS doublet . The Vixen only about 3-4 lbs heavier and isn't hard to carry around on a Unistar- AP tripod though the WO is easier on it's Twilight II-Oberwerk tripod. Both scopes take about 20 minutes to cool down  and the Vixen shows considerably more. Still on the nights just the WO is out  I enjoy it and don't find it's performance wanting. For me it comes down to that.  David


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#25 gene 4181

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Posted 27 November 2019 - 09:46 PM

 Thing is GOLGO doesn't sound like a guy slowing down ,  just seems as the 81 is a tweener  (60mm-103 mm )  that doesn't  get  much  attention  ,     Vixen 130  ss , sound familiar GOLGO  , I might be mistaken but I thought you had one at one time




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