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Tele Vue NP101

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#51 Jeff Gardner

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Posted 24 August 2020 - 09:15 PM

My TV NP-101 on a Gibraltar mount makes a great travel companion. It's a wonderful user friendly, system designed package and bonus, my Coronado 90mm H-Alpha filter screws right on the front cell without any adapter.

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Edited by Jeff Gardner, 24 August 2020 - 09:24 PM.

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#52 gwlee

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Posted 24 August 2020 - 09:44 PM

It's hard for me to imagine that the lack of robustness had anything to do with the design of the TeleVue Dovetail, either in it's strength and rigidity.  It's possible it did not mate properly with the dovetail but on my mounts, it's rock solid.

 

In terms of strength and stiffness, it's incredibly over designed. 

 

Jon

Jon,

 

I haven’t seen or used a “TV” rail/dovetail as far as I know, or a true Vixen rail, but have used quite a few dovetails that claimed to be “Vixen Compatible” on a few different mounts that claimed to be “Vixen Compatible.” The dimensions of all of them were similar if not exactly the same. From using them for many years, I am comfortable mounting scopes up to 80mm using the Vixen pseudo standard, but not going much larger. My concern is about the quality of the engagement (angle, depth, and uniformity of both) between the “vixen” rails and the jaws of the “vixen” saddles. 

 

I don’t remember the details about why DiscMounts recommends against using the Vixen standard with 4” scopes, but I agree with their recommendation based on trying it. I also don’t know why A-P supplies a Vixen Compatible rail with 92mm Stowaway, which is an implied endorsement of the Vixen standard for scopes up to at least 92mm, but I tried it, wasn’t comfortable with it, so replaced it with a larger D compatible rail that I like much better. 

 

Gary 


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#53 gwlee

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Posted 25 August 2020 - 12:46 AM

This does not match my first hand experience. My NP101is is very solidly mounted on a DM4 with 4" ADM Vixen dovetail. If I had the slightest doubt in the security of the interface I would have used one of several other longer Vixen or Losmandy dovetail bars I have in a storage closet. The DM4 carries the 2-way receiver that accepts either "V" or "D" dovetail. So it is no more than a matter of selecting what works that determines what I have chosen to use. 

 

The scope also mounts securely to my UniStar Deluxe and Stellarvue M2C with the Vixen plate.

 

It is certainly a valid choice if a user opts for the wider "D" plate but it is very certainly not correct to say that the "V" plate is insufficient.

I think it’s possible for the same piece of gear to be sufficient for one person and not for another because we all have different needs and expectations for our gear. Based my experiences with Vixen plates, I am not comfortable using them with scopes above about 3 inches, so I wouldn’t recommend them to you for that purpose, but I hope that I didn’t say they were not sufficient for you. 

 

Like you, I have the DM4 and the optional DM adapter that allows using Vixen Compatible rails with it. When the adapter is used, only one jaw of the DM4 saddle fully engages the Vixen Compatible rail. The other only makes contact along a thin ridge, which I believe is sufficient engagement to hold a 3” scope securely, but I wouldn’t hang a 4” scope on this kludge. Hopefully, your mount doesn’t have this problem. 

 

To address concerns about engagement without resorting to the weight and bulk of a true D plate for which the DM4 was originally designed, DM sells a proprietary hybrid rail that combines the shorter height of a Vixen rail with the engagement depths and angles of a D plate. To use it, you must remove the Vixen adapter mentioned in the first paragraph, rotate it 180 degrees, and reinstall it, so the bottom jaw now has the correct angles for a D rail. 
 

I am evaluating the DM hybrid rail now. It’s holds my 92mm scope very securely with full engagement, and it would probably hold a 4” scope like an NP101 well too. The DM hybrid rail is roughly the size and weight of a Vixen Rail, which is good, but the mount p doesn’t work with any Vixen Compatible rail now, including the vixen rail on my 3” scope. 

 

So, for the moment, my 3” scope has a true Vixen Compatible rail on it, and it’s securely mounted on a true Vixen Compatible UA mount, and my 92mm scope has the proprietary DM hybrid rail on it, and it’s securely mounted to my DM4. Haven’t yet decided whether to stick with hybrid rail since it works well, or install  a proper D rail on the 92mm, but I don’t consider a Vixen Compatible rail secure enough for me to want to use one, but if you think it’s sufficient for you, then it’s sufficient for you. 
 

I think a 4” scope is the sweet spot for the DM4, and DM4 was originally designed to work with a D Plate, and I prefer the robust connection offered between a D plate and D jaws, and there many different sizes of D plates readily available, so I will probably want to set up both of my refractors with D plates, so both can be used with the DM4. 


Edited by gwlee, 25 August 2020 - 02:10 AM.

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#54 25585

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Posted 25 August 2020 - 06:09 AM

For me the more a tube ring or clamshell base is in contact with the top of a bar, the better. TV clamshells have broad bases so a D 3" is what I choose, a Gibraltar "seat" is that wide anyway, so why go against the size width TV designed for their own scopes?

 

More generally, because I like tube rings/clams that attach to a bar with 2 or more bolts, preferably parallel, D 3" width accomodates that option, Primaluce being an example.

 

Securing expensive & hard to attain OTAs less well than could be done, to save a few dollars, or small amount of weight makes no sense to me. Its your stuff & choice though, my gear is too precious to me, not to avoid taking every precaution I can to keep it as secure and intact as possible.


Edited by 25585, 25 August 2020 - 06:11 AM.


#55 Jon Isaacs

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Posted 25 August 2020 - 07:19 AM

For me the more a tube ring or clamshell base is in contact with the top of a bar, the better. TV clamshells have broad bases so a D 3" is what I choose, a Gibraltar "seat" is that wide anyway, so why go against the size width TV designed for their own scopes?

 

More generally, because I like tube rings/clams that attach to a bar with 2 or more bolts, preferably parallel, D 3" width accomodates that option, Primaluce being an example.

 

Securing expensive & hard to attain OTAs less well than could be done, to save a few dollars, or small amount of weight makes no sense to me. Its your stuff & choice though, my gear is too precious to me, not to avoid taking every precaution I can to keep it as secure and intact as possible.

 

The TeleVue Dovetail attaches with three 1/4-20 bolts.  This is unbelievably strong for something that weighs 12 pounds.  

 

I think it’s possible for the same piece of gear to be sufficient for one person and not for another because we all have different needs and expectations for our gear. Based my experiences with Vixen plates, I am not comfortable using them with scopes above about 3 inches, so I wouldn’t recommend them to you for that purpose, but I hope that I didn’t say they were not sufficient for you.

 

 

 

I am thinking in terms engineering and design, evidence that the dovetail is not sufficiently strong or results an a connection that somehow allows deflections or unwanted vibrations.  It's certainly not the weak link in the chain.  

 

Some people are not comfortable riding in a car or flying.  The safety factors in the design of the TeleVue Dovetail are far greater than those in an airplane or motor vehicle. 

 

Jon


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#56 Galicapernistein

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Posted 25 August 2020 - 09:33 AM

In the dark, it’s much easier to mount a scope that has a Losmandy style plate than a Vixen rail, if you have a mount that accepts both. That alone is reason enough to go with a D plate for me.


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#57 Ken Sturrock

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Posted 25 August 2020 - 09:50 AM

As as Losmandy rail fan (who usually only uses Vixen rails on smaller scopes) this discussion is getting off track from whether the OP should buy an NP101 (which he subsequently missed out on).

 

There are several threads talking pros & cons for rails over in the imaging fora. Perhaps a new thread (somewhere else) from a visual perspective would be interesting?

 

Thanks.


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#58 imtl

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Posted 30 August 2020 - 08:52 PM

To the OP,

 

I have actually been using the NP101 both for visual and AP for a year and a half now. It is an incredible scope in my opinion. I cannot even find words to describe the views I get from my bortle 1 site with the Nagler 31mm. 

 

I actually upgraded it with a feathertouch dual speed focuser and then for my AP (which is what I do 99 percent of the time now) I added a feathertouch motor to it. The flat field huge FOV is just incredible from an AP point of view. I can actually get almost 2 degrees FOV with the NPR1073 reducer and the ASI183mm pro camera. Which is a relatively small chip. This is all thanks to the amazing capability of the NP101 as a wide field scope.

 

One thing I would say is that if you are planning to observe from a light polluted area you should consider what is best. You're going to get quite washout views by using anything with more than 4mm exit pupil with this scope. And that is from a bortle 5 site. If you are in a worse environment you might consider going for some other cheaper and slower scope since the NP101 will loose its edge in those conditions. So, its really dependent on what you plan to do with it.

 

I'm gonna quote Jon Isaacs (I think it was you Jon) from a few years ago in a post that really influenced me in trying to take a look through a TV petzval. It went something like this (Jon feel free to correct me if I was wrong):

 

"In this life, the closest to perfection of the heavens is when I have been looking through the eyepiece of my NP-101.."

 

I agree and that sums up my opinion about it if its worth something at all.


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#59 gnowellsct

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Posted 30 August 2020 - 09:16 PM

I bought a TV101 used, but in flawless condition. The views were excellent, from its widest fields to planetary viewing. I sold it to partially fund a 130mm refractor when I was surprised (it had been a while) to find out I had come up on a waiting list. Ideally, I’d have both scopes. The TV was lighter and I miss the widest fields.

Well now that you're stuck with that narrow field GT130 (pretty much the only 130 mm that people "come up on a list" for which leads to sale of another prized scope) you can always stack another scope on top of it and get some of those wide fields back...

 

Greg N

 

 

20190425_180731-1_resized.jpg


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#60 Stanislaus

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Posted 01 September 2020 - 04:01 AM

Is there any other 4 inch refractor that comes close to the NP 101 with regard to flat fields? We always hear that the Televue's main attribute are the glorious wide and flat fields so is there any competitor out there? Just curious.



#61 Jon Isaacs

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Posted 01 September 2020 - 04:05 AM

Is there any other 4 inch refractor that comes close to the NP 101 with regard to flat fields? We always hear that the Televue's main attribute are the glorious wide and flat fields so is there any competitor out there? Just curious.

 

There is the Takahashi 106 FSQ series but they are even more expensive than the NP-101 and quite a bit heavier as well.

 

Jon


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#62 JoeBftsplk

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Posted 01 September 2020 - 10:09 AM

For all that's been said about the NP101, we hear very little about the NP127. Too expensive? Mediocre? Rare?


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#63 Spikey131

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Posted 01 September 2020 - 10:31 AM

For all that's been said about the NP101, we hear very little about the NP127. Too expensive? Mediocre? Rare?

NP127 is everything the NP101 is but bigger.  It is fabulous and fabulously expensive.


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#64 JoeBftsplk

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Posted 01 September 2020 - 10:46 AM

Thanks for that, Spikey. Had a shot at a used one once for about $4K and was seriously considering it. In retrospect, it would've been a bargain if in good shape. I was on a 5" refractor kick at the time, but never got one.



#65 Jeff Morgan

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Posted 01 September 2020 - 11:51 AM

For all that's been said about the NP101, we hear very little about the NP127. Too expensive? Mediocre? Rare?

 

Not mediocre. Just lacks the caché of the Big Name brands.

 

When I had the chance to compare a NP 127 to several Astro-Physics scopes, I actually liked the NP 127 better. 


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#66 Tyson M

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Posted 01 September 2020 - 01:53 PM

For all that's been said about the NP101, we hear very little about the NP127. Too expensive? Mediocre? Rare?

Great scope that can do everything well.  Excels at rich field viewing, might not be my first choice for planetary but no slouch by any stretch.


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#67 Jon Isaacs

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Posted 01 September 2020 - 02:15 PM

Not mediocre. Just lacks the caché of the Big Name brands.

 

When I had the chance to compare a NP 127 to several Astro-Physics scopes, I actually liked the NP 127 better. 

 

My own thinking:

 

A 4 inch F/5.4 is a sweet spot.  It's got the focal length of a 80mm, the zoot of a 4 inch and it's got that flat field to boot.  It's still reasonably portable and offers fields of view as wide as 4.9 degrees.  

 

The 127 is a substantially bigger, it's better than the NP-101 at doing the things bigger scopes do better than smaller scopes but it is substantially bigger and more expensive, it's no longer an overgrown 80mm.  

 

Another factor is that as focal lengths get longer, field curvature becomes less.

 

Jon


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#68 gezak22

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Posted 01 September 2020 - 03:02 PM

For all that's been said about the NP101, we hear very little about the NP127. Too expensive? Mediocre? Rare?

I always thought of the 127-owners as the silent group that just enjoys their gear. smile.gif

 

I used to have the 127is as a photography scope, where it did a very nice job. But once I got out of photography and back into visual observing (moon/planets from light polluted skies), I realized that the 127is did not offer any unique features that met my needs (wide fields from light polluted skies are not as exciting as from a dark location). So I sold the 127is, bought the 140mm APM, had cash left over, and had zero regrets (the 140 mm APM is great on the planets).

 

The 127is is a wonderful scope for photography and for wide field views. If I were to get back into either field, I would not hesitate to get another NP127(is). But if you aren't doing either, than the scope is perhaps too special for you (cost, Petzval design = longer tube than a doublet/triplet of same f-ratio). Maybe a doublet will do just as well? Maybe the TEC140 will get you more aperture at a similar cost?


Edited by gezak22, 01 September 2020 - 03:02 PM.

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#69 Mikew9788

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Posted 01 September 2020 - 03:23 PM

This is my np-101 on a stellarvue m2c head and denali tripod. 



#70 Mikew9788

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Posted 01 September 2020 - 03:24 PM

I tried to attach the image but I guess I don't know how.

#71 Mikew9788

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Posted 01 September 2020 - 03:31 PM

20200901_163010.jpg

I think I got it


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#72 Ken Sturrock

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Posted 01 September 2020 - 04:33 PM

Is there any other 4 inch refractor that comes close to the NP 101 with regard to flat fields?

The Chinese-sourced quads (such as the Stellarvue SVQ) - which are not Petzvel designs but rather triplets with a very steeply curved single-element field flattener - have pretty nice and wide flat fields as well. I do not know how they compare to the NP-101, it may depend on your camera.


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#73 SteveG

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Posted 01 September 2020 - 06:53 PM

Is there any other 4 inch refractor that comes close to the NP 101 with regard to flat fields? We always hear that the Televue's main attribute are the glorious wide and flat fields so is there any competitor out there? Just curious.

The original Genesis, SDF and then the 101.

 

Aside from the Tak FSQ, nothing else in 4".

 

There are the Vixen NA 120 and 140 Petzval refractors (4 element achro's). These were also sold by Orion years ago, but you don't hear much about them.

 

At 80 mm, there was this very nice WO 5-element flat-field scope:

https://agenaastro.c...tt-magazine.pdf


Edited by SteveG, 01 September 2020 - 06:56 PM.


#74 25585

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Posted 02 September 2020 - 04:37 AM

There may be a Redcat 90mm coming?

 

But Tak's FSQ-85 is a tempting mini-Petzval. 



#75 tjugo

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Posted 02 September 2020 - 10:55 AM

To the OP,

 

I owned a NP101is for 5 years, I bought it brand new. IME it is a nice all around instrument and the accessories are not as expensive as other premium brands. I also have owned an FSQ106 an a FC100DL and I find the Taks to be better instruments than the NP101is.

 

If super wide filed visual observation is not your top priority I suggest that you also consider an FC100.

 

Cheers,

 

José


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