Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Tele Vue NP101

  • Please log in to reply
190 replies to this topic

#126 JoeBftsplk

JoeBftsplk

    Messenger

  • *****
  • Posts: 412
  • Joined: 26 Sep 2007
  • Loc: North of the Fingerlakes-NY

Posted 02 October 2020 - 12:45 PM

I put a FT two-speed focuser spindle on my older NP101 shortly after I got it; mostly because I'd done the same with my TV102 and liked how it worked. Really hadn't used the NP101 enough to know if it was needed.

 

Now that I've used the NP more, I wonder how I would've gotten along with the OEM focuser. I get the precise, flat-field star images, but without that two-speed focuser they would be tough to achieve. Depth of focus with the NP101 seems very small.



#127 Poochpa

Poochpa

    Vanguard

  • *****
  • Posts: 2,072
  • Joined: 12 Feb 2005
  • Loc: Buffalo Burbs, NY

Posted 02 October 2020 - 12:58 PM

Joe,

Like you, I did the same thing, installing the FT Retrofit two-speed many years ago. While I thought the original single-speed focuser was fine for observing, the two-speed was a definite improvement for imaging.

Mike



#128 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 02 October 2020 - 01:55 PM

It's intrinsic to the Petzval design, they are more difficult in the collimation department than triplets and doublets.   I fell in love with the Pentax 125mm at NEAF about fifteen years ago, and would have bought it.  But it was a four lens design, a modified Petzval, and I had some reservations about sinking $7k into an optic that would be hard to get serviced if it needed it.   And no one would say how you got the optics serviced if they ever needed it.   

 

It also had a helical focuser and I wasn't sure how that would work out in visual use, and I was also thinking that the scope had a high degree of optimization for photography and maybe not for visual.   I asked around but there just weren't any people that I knew who had helical focuser on a refractor experience.  Back in the day one occasionally encountered helicals on Newtonians but again I never actually *met* one much less owned one.

 

Currently the WO Redcat (51mm?) is a petzval design and apparently they can't make enough of them.  These are also helical focusers.

 

One of the idiosyncrasies of the Petzval is that in spite of the short *optical* focal length, you get a longer *physical* focal length.   So maybe not quite as good for travel--which for example the GT130 is specifically build for.  

 

Anyhow the bottom line is that Televue is an established company with a reputation for servicing its products and if I had the NP101 and it needed collimation I would send it to them and pay what was needed.  I wouldn't not get an NP101 because of that.  I am a bit more skeptical about having sandpaper rather than classic baffles on the interior of the tube.  (I'm not making that up, but I know of only one instance in the past 20 years where the sandpaper actually peeled and that was in extremely adverse storage conditions)

 

But it doesn't matter what I think.  They're great telescopes with a very loyal user base.  In fact all the TV telescopes have a loyal user base, even the original Genesis, which I'm not sure I would be loyal to.   Maybe the later ones.

 

Greg N

I have 5 TV refractors, including an original Genesis Petzval, which is fine. I bought it new in 1990.

 

My concern is that having read of NP101s being bought miscollimated, internal cel structure &/or materials may have changed &/or lenses, so going out of collimation is easier, however that happens.

 

Long distance shipping to & from Tele Vue is also a nightmare for a scope owner in Europe. Not only for expense, but damage that can occur there and back. If NPs were half their new price, it would be more bearable. If owner or 3rd party collimation had been designed-in, it would be reassuring. Too much to be uneasy about. 



#129 doctordub

doctordub

    Vanguard

  • *****
  • Posts: 2,284
  • Joined: 11 Jan 2006
  • Loc: New Rochelle, New York

Posted 02 October 2020 - 02:13 PM

Jonathan:

 

I recognize you on the left but who is the guy on the right... smile.gif

 

post-14465-0-83024600-1601561752.jpg

 

 

(Another feeble attempt at internet humor, I hope someone laughs)

 

Jon

Jon,

I read and follow your recommendations all the time. How do you not identify my uncle Al?lol.gif

CS

Jonathan


  • Jon Isaacs, turtle86 and Sarkikos like this

#130 Oscar56

Oscar56

    Apollo

  • *****
  • Posts: 1,312
  • Joined: 25 Jan 2013
  • Loc: Okanagan, BC

Posted 02 October 2020 - 02:37 PM

Re collimation:  are these "issues" with the NP101is regarding used scopes or new right-out-of-the-box?

 

Jon's story about backing into his scope gives me comfort and I would think the folks at TV pack new scopes extremely well.



#131 gezak22

gezak22

    Gemini

  • *****
  • Posts: 3,325
  • Joined: 15 Aug 2004
  • Loc: On far side of moon. Send help.

Posted 02 October 2020 - 03:08 PM

I can only offer one data point.

 

I bought a second hand 127is, and it arrived out of collimation, so I sent it to TV (from the west coast to the east coast). I got a call from them saying that someone had unscrewed the back end of the tube and put it together the wrong way, hence the poor performance. They shipped the scope back via USPS, scope in its padded case, case wrapped with two relatively thin layers of bubble wrap. It came back in perfect collimation and remained that way after many trips on a bumpy road (though the scope was on a cushioned seat during those trips).

 

I would have zero hesitation about buying TV scopes.


  • doctordub, turtle86, Oscar56 and 1 other like this

#132 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,698
  • Joined: 09 Oct 2006

Posted 02 October 2020 - 03:12 PM

Re collimation:  are these "issues" with the NP101is regarding used scopes or new right-out-of-the-box?

 

Jon's story about backing into his scope gives me comfort and I would think the folks at TV pack new scopes extremely well.

 

TeleVue does pack their scopes well, and the hard case that comes with the NP101 affords a lot of protection.

I bought my NP101 used and it was shipped from Colorado to Florida in the original boxes and case.  It arrived in perfect collimation.   I’ve had the scope for a year now and it has held its collimation just fine.  Jon’s story suggests that it would take a lot to cause the scope to lose its collimation.



#133 Phil Cowell

Phil Cowell

    Fly Me to the Moon

  • *****
  • Posts: 6,306
  • Joined: 24 May 2007
  • Loc: Southern Tier NY

Posted 02 October 2020 - 03:12 PM

Congrats

It's a risk, but I would not worry too much either.

 

In fact, I scored the 101is that came up on Astromart yesterday grin.gif



#134 ianatcn

ianatcn

    Viking 1

  • -----
  • Posts: 562
  • Joined: 26 May 2010
  • Loc: Hampshire, UK

Posted 02 October 2020 - 03:39 PM

I have purchased four TV telescopes new from UK dealers and all arrived perfectly collimated.  My current TV76 and TV127is have remained in collimation while used as portable instruments.  I would have no hesitation recommending them to others.

 

Outside USA I think buying from a reputable dealer makes a lot of sense.

 

My SDF has only had two owners since I sold it to buy the NP101.    


  • Erik Bakker and 25585 like this

#135 Mr.Jim

Mr.Jim

    Sputnik

  • *****
  • Posts: 39
  • Joined: 25 Jun 2019

Posted 02 October 2020 - 11:34 PM

A few years ago I brought my TV101 to Televue for servicing. At one point during my inspection I stood it on it's nose, (with the cap on). Dave Nagler's eyes widened, to put it mildly,  and he told me to never do that because, in his words, "That's the collimation!!" I should add that despite frequent use my 101 remains spot-on. It was interesting though to see a video where Dave describes how the semi-rigid foam in the TV127 case now supports the scope by the tube only, with no pressure on the cell.



#136 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 03 October 2020 - 01:55 AM

What about NP refractors requires servicing? 



#137 imtl

imtl

    Apollo

  • *****
  • Moderators
  • Posts: 1,417
  • Joined: 07 Jun 2016
  • Loc: On earth

Posted 03 October 2020 - 03:43 AM

cleaning, collimation.



#138 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 03 October 2020 - 08:13 AM

cleaning, collimation.

I guess the outside facing rear lens might get some stuff on it. But collimating again?!

 

Do NPs, if OK to start with, need re-collimation periodically? What, if not, might make owners think they do?   



#139 havasman

havasman

    Voyager 1

  • *****
  • Posts: 11,819
  • Joined: 04 Aug 2013
  • Loc: Dallas, Texas

Posted 03 October 2020 - 08:44 AM

A dominant negative to CN is that it gives venue to folk's analysis paralysis and unreasonable fears, spreading both to those susceptible to these infectious negative patterns. The rest of us shake our heads and go about enjoying our NP101's.

 

I expect Grant is going to be extremely satisfied with his NP101is as it is an approximately perfect complement to a 16" Dob. Great purchase.


  • Jon Isaacs, turtle86, gnowellsct and 5 others like this

#140 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 03 October 2020 - 09:40 AM

A dominant negative to CN is that it gives venue to folk's analysis paralysis and unreasonable fears, spreading both to those susceptible to these infectious negative patterns. The rest of us shake our heads and go about enjoying our NP101's.

 

I expect Grant is going to be extremely satisfied with his NP101is as it is an approximately perfect complement to a 16" Dob. Great purchase.

Yes, that is true. 

 

I want a NP101 and would find a store which would be prepared to get one in stock for me to check out before buying, ideally. When we all have had our Covid shots.



#141 imtl

imtl

    Apollo

  • *****
  • Moderators
  • Posts: 1,417
  • Joined: 07 Jun 2016
  • Loc: On earth

Posted 03 October 2020 - 01:39 PM

I guess the outside facing rear lens might get some stuff on it. But collimating again?!

 

Do NPs, if OK to start with, need re-collimation periodically? What, if not, might make owners think they do?   

Just to clarify, I did not mean that they need periodically to be cleaned and collimated. The question was "What about NP refractors requires servicing?" not about periodically servicing. So my answer meant: In case you NEED service, cleaning and collimation are usually the reasons. I never had mine services and its collimation is spot on for years.


  • Jon Isaacs and 25585 like this

#142 Pezdragon

Pezdragon

    Ranger 4

  • *****
  • Posts: 349
  • Joined: 10 Jun 2013
  • Loc: Bay Area, Ca.

Posted 03 October 2020 - 01:57 PM

I bought my NP-101 several years ago through Company Seven and it’s collimation was very,very close but not perfect so I read up on this forum and found out just how easy it is to do it yourself and so I just did it. The process only evolves the front doublet cell and loosening it’s 3 screws and tapping in the alignment while looking  at a star’s diffraction pattern. Very straightforward and satisfying to know I can do it at anytime though it hasn’t needed any re-collimating as it’s been solid for years. The hardest part was waiting for a night steady enough to get a stable diffraction pattern....


  • 25585 likes this

#143 gnowellsct

gnowellsct

    Hubble

  • *****
  • Posts: 18,206
  • Joined: 24 Jun 2009

Posted 03 October 2020 - 07:11 PM

Yes, that is true. 

 

I want a NP101 and would find a store which would be prepared to get one in stock for me to check out before buying, ideally. When we all have had our Covid shots.

When you get into the domain of buying a brand new NP101 you pretty much can count the stores that will have one in stock on one hand.  And maybe one or two fingers.  After a certain point in this hobby you pass on to buying direct from OEM when not buying used.

 

The only two places I can think of where they might have one on display is Maison de l'Astronomie in Montreal and Company Seven in Baltimore.  Company Seven is very loyal to Televue.  They won't sell Pentax eyepieces.

 

Greg N

 

(bought my C14 from C7)


  • doctordub likes this

#144 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 04 October 2020 - 01:58 PM

When you get into the domain of buying a brand new NP101 you pretty much can count the stores that will have one in stock on one hand.  And maybe one or two fingers.  After a certain point in this hobby you pass on to buying direct from OEM when not buying used.

 

The only two places I can think of where they might have one on display is Maison de l'Astronomie in Montreal and Company Seven in Baltimore.  Company Seven is very loyal to Televue.  They won't sell Pentax eyepieces.

 

Greg N

 

(bought my C14 from C7)

C7's write-ups on TV gear is very cosy. They are probably #1 to get new TV stuff. All their Renaissance 102 & 85 focusers have brass draw tubes, while Joe & Jane Public get matt black draw tubes. mad.gif 

 

But C7 not selling Pentax eyepieces..that takes the cake! shocked.gif  



#145 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 12,443
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 06 October 2020 - 06:30 PM

Look what Fed-Ex delivered today - one day ahead of schedule.

 

 

Attached Thumbnails

  • IMG_6681.jpeg

  • Jon Isaacs, Scott in NC, doctordub and 10 others like this

#146 Jeff Morgan

Jeff Morgan

    Voyager 1

  • *****
  • Posts: 12,443
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 06 October 2020 - 06:40 PM

Then the issues begin ...

 

I wanted to test it on my Panther, which can accommodate Vixen or Losmandy plates. In terms of length, the plate on my NP is just barely long enough for the Panther dovetail. Any balance adjustment will require loosening the clamshell and sliding the tube. A bit of a risk for a DSC equipped mount.

 

So I thought I would try a Losmandy Universal plate - apparently not so Universal. The Tele Vue spacing does not match.

 

Looking at the Tele Vue plate, it appeared to be a Vixen-style. Kind of sort of. I put the Tele Vue plate back on, clamped it in the Panther head and gave it a lift test. Grasping the optical tube on either side of the clamshell, I lifted the combined unit 1/2" off the table. The 35 pound Panther head promptly separated from the telescope!

 

Taking a closer look, the Tele Vue plate is only tapered on one side - explaining the lack of holding power (Vixen comparison photo attached).

 

I think I will give this a try tonight (very gingerly of course), but I need something a bit more secure - and longer to accommodate the varying loads the scope will carry.

 

What do I need to buy?

 

 

Attached Thumbnails

  • IMG_6682.jpeg

  • NC Startrekker likes this

#147 25585

25585

    Voyager 1

  • *****
  • Posts: 10,781
  • Joined: 29 Aug 2017
  • Loc: In a valley, in the UK.

Posted 06 October 2020 - 06:44 PM

Jeff, get a pair of rings to replace the clamshell.


  • Sarkikos likes this

#148 NC Startrekker

NC Startrekker

    Viking 1

  • *****
  • Posts: 746
  • Joined: 28 Jan 2010
  • Loc: Sandhills of NC

Posted 06 October 2020 - 07:30 PM

I use a DiscMounts D-style rail with the clamshell on my NP-101. I believe that Stellarvue has some rails that also accommodate the Tele Vue clamshell hole spacing. I'm sure there are others as well. 


Edited by NC Startrekker, 07 October 2020 - 09:51 AM.

  • Sarkikos likes this

#149 Ken Sturrock

Ken Sturrock

    Cardinal Ximenez

  • *****
  • Posts: 9,419
  • Joined: 26 Sep 2009
  • Loc: Denver, CO

Posted 06 October 2020 - 09:05 PM

Anthony Davoli sells pretty nice dovetail plates that bolt up to the TV ring. This Vixen Plate is designed for the 4" rings and is seven inches long if that would be the right length. I use the smaller ones on my Pronto and TV-76.

 

Not a Losmandy, though.



#150 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 5,698
  • Joined: 09 Oct 2006

Posted 06 October 2020 - 09:18 PM

Then the issues begin ...

 

I wanted to test it on my Panther, which can accommodate Vixen or Losmandy plates. In terms of length, the plate on my NP is just barely long enough for the Panther dovetail. Any balance adjustment will require loosening the clamshell and sliding the tube. A bit of a risk for a DSC equipped mount.

 

So I thought I would try a Losmandy Universal plate - apparently not so Universal. The Tele Vue spacing does not match.

 

Looking at the Tele Vue plate, it appeared to be a Vixen-style. Kind of sort of. I put the Tele Vue plate back on, clamped it in the Panther head and gave it a lift test. Grasping the optical tube on either side of the clamshell, I lifted the combined unit 1/2" off the table. The 35 pound Panther head promptly separated from the telescope!

 

Taking a closer look, the Tele Vue plate is only tapered on one side - explaining the lack of holding power (Vixen comparison photo attached).

 

I think I will give this a try tonight (very gingerly of course), but I need something a bit more secure - and longer to accommodate the varying loads the scope will carry.

 

What do I need to buy?

 

 

Jeff—

 

Just this:

 

https://farpointastr...evue-clamshell/

 

I got one for my NP 101 and it works perfectly.  The price isn’t too bad either. Looks like it’s on backorder from Farpoint but maybe someone else would have it in stock right now.


Edited by turtle86, 06 October 2020 - 09:20 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics