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Equipment Discussions >> Refractors

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Randal
journeyman
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Reged: 10/05/09

Loc: Upstate New York, USA
Re: Best mount / tripod for Televue 85 or NP101 [Re: chaoscosmos]
      #5677110 - 02/13/13 07:11 AM

My 2 cents-

1. Consider the Quarter Hitch mount currently on A-Mart for $450.
2. Search for a 6-7 year old TV85 pkg for <$1,200.
3. Place scope and mount on good quality photo tripod.
4. Enjoy viewing from your patio.

Since I'm spending your money, don't forget the Nagler 3-6mm, Nagler 9 or 13mm, and Panoptic 35mm eyepieces.

I currently use a variation of this simple setup, and am very happy with it.

My 3rd cent-
Regarding TV scopes - I offer an automotive analogy.
I have a friend that owns a really nice Lexus.
He always boasts to his friends that it's almost a Mercedes.

There is more than specifications at play in this hobby.


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BCNGreyCat
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Reged: 08/06/12

Loc: Virginia, USA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: chaoscosmos]
      #5677266 - 02/13/13 09:12 AM

My 2 cent. Here is my setup:

TV-85, diagonal, Nagler 16mm, 3-6 zoom
Takahashi Teegul Alt-Az mount
DM-4 wood tripod

The Teegul has slow motion controls. And the DM-4 tripod is rock solid. You can go upto 200x and the damp time is below 1sec on my deck.

My TV102 works on this mount tripod combo as well. NP101 probably is okay. (Teegul probably can handle 15lb OTA)

Only issue, the tripod is not height adjustable and not easily foldable. So transporting from my living room to my deck is a little bit clumsy. But the height of the tripod matches my height (5'9). So not height adjustable is not a big issue to me.

Sometimes, I use an Induro AT-413 photo tripod. Damping on this one is not so well under high power. But if on solid ground, it still acceptable. The AT-413 is light, foldable, height adjustable, yet sturdy enough for quick G-n-G.


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la200o
Carpal Tunnel


Reged: 09/09/08

Loc: SE Michigan, USA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: John Rhodes]
      #5677354 - 02/13/13 10:16 AM

Quote:

Quote:

This is not an APO OK, it does not deserve APO prices.




Actually, the TV85 does have apochromatic performance and uses the best fluorite substitute and matching glass currently available.




+1

The TV doublets are as "apo" as any doublets out there. But $1600 is waaaay too much!

Bill

Edited by la200o (02/13/13 10:20 AM)


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Eddgie
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Reged: 02/01/06

Re: Best mount / tripod for Televue 85 or NP101 new [Re: chaoscosmos]
      #5677590 - 02/13/13 12:21 PM

Quote:

I'll wait.






Right call. Too much for the scope in question.

As for the mount when the time comes, I personally found the Gibrater to be the least enjoyable mount I have ever used. It will have its defenders, but I found the nose dive risk to be a huge frustration. Just about every eyeppeice change meant having to fuss with the altitude friction, and going from a heavy eyepiece to a light one and forgetting to tighten the tension on the altitude setting can cause a huge nose dive on the scope.

But if you have your target centerd (Jupiter for esample) and change from a 22mm Nagler T4 to a Nagler zoom, it is almost impossible to keep the target in the field unless you tighten the friction locks, but the you have to loosen them to make fine adjustments, then rememeber to tighten them, then remember to loosen them, then remeber to tighten them..................

I used it three times. Tried tried tired to love love love it for simplicty and beauty, but as a working mount for anything but fixed low power sweepting, found it miserable.

Just me though. I prefer a light gear driving Alt-Az. It eliinates the fussing with balance during eyepeice changes.

You only really need it in altitude, but some of the mounts now come with slow motion in both axises.

Good luck whith your search.


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Eddgie]
      #5677638 - 02/13/13 12:52 PM

Quote:


Just me though. I prefer a light gear driving Alt-Az. It eliinates the fussing with balance during eyepeice changes.






An added note:

For about 2 years, I used my NP-101 with a Portamount with the HandsonOptics wooden legs. I really like everything about that mount except that it is on the small side and I had switched to another mount which is solid, has all the features but I just don't like it.

This morning I was looking at the Portamount and realized that the azimuth axis had some slop. I dismounted the mount, adjusted the center bolt tension (actually a nut), reassembled it and gave it a try. My Portamount is back to it's old self, I am enjoying the NP-101 again and I will probably find a new home for the other mount.

Jon


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FirstSightModerator
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Jon Isaacs]
      #5677788 - 02/13/13 02:32 PM

Quote:

Quote:

Quote:

This is not an APO OK, it does not deserve APO prices.




Actually, the TV85 does have apochromatic performance and uses the best fluorite substitute and matching glass currently available.




Historically, the TV-85 has always been considered an apochromat. Not all apochroamts are created equally. Roland Christen can probably find signs of chromatic aberration in any refractor...

Among the rest of us, it varies.

Jon




The reason for the ambiguity about the TV85 being an "apochromat" vs only a "semi-apochromat" (as in, not quite a true full-fledged APO) is because it's a doublet, rather than a triplet or Petzval (four-element) lens design. The argument for considering some of the higher-end doublets to sufficiently qualify for true APO status is because though two lenses still cannot as completely correct refractive differences in where different wavelengths of light focus as can high-quality triplets etc., nevertheless through use of the right glass and lens design it's possible to come close enough that the differences are near-vanishingly small to most people's eyes, or at least supposedly. So, to some extent it's in the eye of the beholder whether a doublet such as the TV-95 is a true apochromat or merely an almost, but not quite true apochromat. Nevertheless, it's not misleading marketing to describe a high-quality doublet like the TV-85 as an "apochromat", so long as the fact that it's a doublet is included in the description.


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: FirstSight]
      #5677874 - 02/13/13 03:35 PM

Quote:

The reason for the ambiguity about the TV85 being an "apochromat" vs only a "semi-apochromat" (as in, not quite a true full-fledged APO) is because it's a doublet, rather than a triplet or Petzval (four-element) lens design.




I am not sure that is the reason. There are many doublets that have long been considered apos, fir example, the TV-102, the various Takahashi's using fluorite and synthetic fluorite. Roland's article says that a doublet is capable of producing the necessary three color crossings but one is not in the visual.

I think the reason people question the TV-85 as an apo is that at 85mm F/7 with presumably an FPL-53 based objective, it's pushing the limit in terms of being color free visually.

Jon


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FirstSightModerator
Duke of Deneb
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Reged: 12/26/05

Loc: Raleigh, NC
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Jon Isaacs]
      #5678111 - 02/13/13 06:14 PM

Quote:

Quote:

The reason for the ambiguity about the TV85 being an "apochromat" vs only a "semi-apochromat" (as in, not quite a true full-fledged APO) is because it's a doublet, rather than a triplet or Petzval (four-element) lens design.




I am not sure that is the reason. There are many doublets that have long been considered apos, fir example, the TV-102, the various Takahashi's using fluorite and synthetic fluorite. Roland's article says that a doublet is capable of producing the necessary three color crossings but one is not in the visual.

I think the reason people question the TV-85 as an apo is that at 85mm F/7 with presumably an FPL-53 based objective, it's pushing the limit in terms of being color free visually.

Jon




I'm explaining the reasoning in many folks' minds when they question whether a doublet is a true APO, rather than the authoritative technical answer. I've come across the reference from Roland Christian you cited above.

I still think it's best practice to always be sure that when you refer to a given doublet scope as an "APO" that the audience understands that the scope is a doublet. That way, at worst some folks may regard the assertion as somewhat debatable, but none as misleading - and if applicable to the scope in question, you still have the Roland Christian trump card to pull out in response.


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tomchris
professor emeritus


Reged: 12/22/10

Loc: Connecticut, U.S.A.
Re: Best mount / tripod for Televue 85 or NP101 new [Re: FirstSight]
      #5678157 - 02/13/13 06:43 PM

I use my 85 on a Bogen/ Manfrotto tripod and it works very well. If I really want steadiness, I get out my DM-4 mount and tripod. I found the "apo" debate interesting. All I know is that the TV85 is very sharp and provides wonderful colorful views. However, $1600 is way too much to buy the 85 used!

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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: FirstSight]
      #5678183 - 02/13/13 06:59 PM

Quote:


I'm explaining the reasoning in many folks' minds when they question whether a doublet is a true APO, rather than the authoritative technical answer. I've come across the reference from Roland Christian you cited above.

I still think it's best practice to always be sure that when you refer to a given doublet scope as an "APO" that the audience understands that the scope is a doublet. That way, at worst some folks may regard the assertion as somewhat debatable, but none as misleading - and if applicable to the scope in question, you still have the Roland Christian trump card to pull out in response.





This the way I look at it:

There are doublets that are not apos, there are doublets that are.

There are triplets that are not apos, there are triplets that are.

There are quadruplets that are not apos, there are quadruplets that are.

Generally one should specify whether a scope is a doublet, triplet, quadruplet and some designation of the color correction.

I think Thomas Back's discussion Defining Apochromatismhit's the nail right on the head.

" After designing, testing and selling many different apochromatic lenses I can state this: There is no "definite" line where a lens becomes "apochromatic" in the world of commercial apochromatic lenses.

But any lens, be it a doublet, triplet, quad, air-spaced or Petzval, that has a peak visual null (~5550A - the green-yellow) with a Strehl ratio of .95 or better, coma corrected and is diffraction limited from C (red) to F (blue) with 1/4 wave OPD spherical or better, has good control of the violet g wavelength with no more than 1/2 wave OPD P-V spherical and optical spot sizes that concentrate the maximum amount of photons within the diffraction limit -- a result of the low spherical aberration, which can be seen with modern optical design programs, as the "spot rays" will be seen concentrated in the center of the spot, not evenly or worse, concentrated outside the center -- will satisfy the modern definition of "Apochromatism.""

Jon


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tomchris
professor emeritus


Reged: 12/22/10

Loc: Connecticut, U.S.A.
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Jon Isaacs]
      #5679020 - 02/14/13 09:35 AM

Excellent. Thanks, Jon.

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KerryR
Carpal Tunnel
*****

Reged: 12/05/07

Loc: SW Michigan
Re: Best mount / tripod for Televue 85 or NP101 new [Re: tomchris]
      #5679042 - 02/14/13 09:46 AM

I suspect that one of the reasons for the continuing debate about what makes an apo an apo has a lot to do with CCD cameras and their sensitivity to the blue end of the spectrum. A scope that a visual observer finds to have excellent color correction may produce a raw ccd image with heavy blue-end fringing. A "ccd apo" might be considered as having more stringent tolerances than a "visual apo" if the user wishes to avoid some post-process reduction of the fringing.

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Panotaker
sage


Reged: 09/12/03

Loc: Austin, Texas
Re: Best mount / tripod for Televue 85 or NP101 new [Re: KerryR]
      #5679079 - 02/14/13 10:04 AM

I have both a TV-85 and an NP-101. I bought my TV-85 used 10 years ago, so it is a pretty old one. I haven't looked through a late model TV-85 to compare to mine, but my TV-85 gives perfect color free views, that is the main reason I bought it. I have a Gibraltar V mount that I mount all kinds of scopes on, from my Questar Birder, to my AP-130. It doesn't have slow motion controls, but unless you are looking at the planets, you don't really need them. I have the digital setting circles on mine and they work excellent. There are better alt/az mounts out there, but I got mine pretty cheap, so I'm not upgrading any time soon. The nice thing about the mount, is that it looks fantastic, so you can leave it setup inside the house and it looks like a piece of furniture. You can't say that about most mounts.

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la200o
Carpal Tunnel


Reged: 09/09/08

Loc: SE Michigan, USA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Panotaker]
      #5679333 - 02/14/13 12:16 PM

I had my (f/6.3) TV 76 out last night and was once again impressed at how color-free it is. It is an APO.

I have it over-mounted on a Gibraltar, which I retired for awhile a few years ago after buying a Half-Hitch. When I got the TV 76, I brought the mount out of retirement and use it constantly with that scope and now and then with my 4" TV's. I have come to appreciate its virtues. Simple, steady, and, with proper adjustments, pretty smooth. You can pick them up inexpensively used (300--400 bucks and they are well worth the money IMO).

Bill

Edited by la200o (02/14/13 02:55 PM)


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KerryR
Carpal Tunnel
*****

Reged: 12/05/07

Loc: SW Michigan
Re: Best mount / tripod for Televue 85 or NP101 new [Re: la200o]
      #5679356 - 02/14/13 12:26 PM

I have a TV Telepod head that I used with my Pronto and Genesis. I believe it's the same as the Gibralter.(?)

Functional enough, but I prefer the PortaII head-- far easier to maintain position while switching ep's, and, of course, the slow motion controls add additional ease when tracking.

I now only use the Telepod with my PST.


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la200o
Carpal Tunnel


Reged: 09/09/08

Loc: SE Michigan, USA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: KerryR]
      #5679365 - 02/14/13 12:31 PM

Kerry, I've never used a PortaII; I believe what you say. For me, changing ep's w/the Gibraltar ain't so bad--a finger on the diagonal pretty much keeps the scope in place, and if it does move, it's generally strictly in the altitude axis, so it's pretty easy to recover the target. Now changing ep's with my HH--that's another story!

Bill


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Patrik Iver
professor emeritus


Reged: 07/29/03

Loc: Kaarina, Finland
Re: Best mount / tripod for Televue 85 or NP101 new [Re: John Rhodes]
      #5679677 - 02/14/13 02:52 PM

Quote:

Actually, the TV85 does have apochromatic performance and uses the best fluorite substitute and matching glass currently available.




This is the first time I've seen someone "in the know" imply anything about the glass prescription of a TV doublet. So effectively you are saying that the ED-glass used is Ohara FPL53, as it can't very well be a Russian glass with similar properties?

Why the big secrecy about it? The scopes are doublets, and sold as such. Specifying the glass prescription (particularly if it is "the best fluorite substitute and matching glass currently available") should not be a bad thing? Just about anyone agrees anyway that your telescopes are very nice, both optically and mechanically.


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la200o
Carpal Tunnel


Reged: 09/09/08

Loc: SE Michigan, USA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: Patrik Iver]
      #5679689 - 02/14/13 02:57 PM

Patrik,

I agree. I think the TV scopes are great, and I imagine they use FPL53. So why not tell us?

Bill


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johnnyha
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Reged: 11/12/06

Loc: Sherman Oaks, CA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: la200o]
      #5679721 - 02/14/13 03:15 PM

Quote:

This is not an APO OK, it does not deserve APO prices.



OK OK, I officially withdraw my original post implying that the TV85 was not an APO.


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Best mount / tripod for Televue 85 or NP101 new [Re: la200o]
      #5679915 - 02/14/13 05:20 PM

Quote:

Patrik,

I agree. I think the TV scopes are great, and I imagine they use FPL53. So why not tell us?

Bill




I think the "what glass is it" game started quite some time after TeleVue began making refractors. Many vendors play this game by telling you when they do use FPL-53 but choose more vague descriptions when they use something with a significantly lower Abbe index.

TeleVue may be somewhat unique in that they don't broadcast exactly which glasses they use but then they are unique in a number of ways.

One aspect that is interesting is that Roland C. is well known for pointing out that it's not only the ED glass used but also the mating element. I am as guilty as anyone else of referring to the ED glass only.

I would like to know what glasses the NP-101 uses, that the focal ratio of the objective is... Don't think I will be finding out.

Jon


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