Takahashi or Televue 4" Refractors

[heyjojos]

Hi
After doing some research and attending some star parties.. I have narrowed down to 2 Refractor scopes. Namely Takahashi TSA 102 and Televue NP101.

Both in my opinion are very good scopes and I'm torn as to which to choose. The NP101 has a in-build flattener and a fast scope of f5.4. Not sure about the back focus part... (if anyone knows please let me know).

Whereas the TSA102 is of course (ahmmm... good!!) Its slightly cheaper. But if I were to buy a flattener and a focus reducer it prob will end up the same price. Advantage is that it comes with a metal casing whereas NP101 don't. My intention for the scope is for viewing and progressively will move on to imaging

Can anyone give advice as to what else is there to consider and which is the better of the two?

[orly_andico]

the TSA102 might need a flattener/reducer. And all Tak accessories cost an arm and a leg (things like extension tubes, etc).

I assume your goal is imaging, and not visual? if so, how much money in total do you wish to spend?

To image well with a TSA102 or NP101 you'll need at least a GM8. Or an Atlas or CGEM or GP-DX / GP-D2 / Sphinx SX-W. The cost of those things also need to be factored in.

With the clarity of hindsight, if I had say $5500 USD to spend (which is the cost of an NP101 + Chinese mount e.g. Atlas/CGEM) I would splurge all the money on a great mount and let the OTA be damned.. a not-so-good mount like a Chinese one will fight you every time you set up. You can get a cheap OTA from William Optics for $500 and it will be "enough" until your skill set is high enough.

And if you have a great mount from the start, you'll not have to fight its limitations or discard it when you want something better.

On the other hand if you have $10K USD to spend, then by all means get either the Tak or TV and a great mount as well

[wucheeyiun]

All these are fine scopes. which is design for Astro-Photography.

You can consider a Williamoptics, 100ed or 120ed and for APo, a flt 110 or 132. even a astrotech 127ed if you can find a good one.

In most cases you will find them cheaper then a Tak or Televue, but there is really no discernible difference visually. Optical Photography .. could be

For the money saved as Orly put, you can get a better mount ie Vixen SXD, atlux or tak mount etc so you don't need to change the mount as you upgrade to a heavier scope.

[orly_andico]

optically there will be a difference for photography. for example my sub-$500 william-optics 70ED shows a tiny bit of CA around bright stars on a DSLR. how tiny? this much (at 100%)



I believe that is Rigel. Which is a pretty bright star.

and this is the extreme corner on APS-C (with a flattener)



Note that these are 100% images with a 15MP APS-C DSLR.

So.. unless you are using a full-frame DSLR or really really care about residual CA, then even the inexpensive Taiwan or Chinese refractors will be more than enough, to start. Check out shirox's great photos in the other thread with a Tak FS-60. Granted an FS-60 costs much more than a W-O 70mm but it still is at the $900 USD range, a far cry from the NP101 or TSA102. Notice that he is significantly over-mounted (FS-60 on a Losmandy GM8).

The advantage of getting a cheap ED refractor is that you can use it as your guide scope later on when you move up. If however you buy the end-all refractor now but skimp on the mount... down the road you will ditch the mount which would be a waste of money.

Again, if you have the luxury of not compromising on budget today, then by all means get the best. But if you (like many of us..) needs to scrimp on something, then do not "buy the best you can afford" -- buy the best mount (in absolute terms), and scrimp on the OTA.

I will also add -- being over-mounted is a great luxury. Being adequately mounted, frankly, sucks. If you are only adequately mounted, things like cable stretch and the wind will conspire to ruin some of your subs. By being significantly over-mounted, you can forget about mount issues completely, which initially will be your bigger enemy rather than the last 5% of optical performance that the Taks and TV's will give you.

[orly_andico]

Another thing to think about -- great mounts are great. But mostly they are also heavy (example Tak EM-200). If money were no object, everybody would have an Astro-Physics Mach1.

Unfortunately for those of us where money is an object, we have to compromise.

The China mounts (Atlas, CGEM) are adequate, and due to their high load capacity (30lb+) if you mount a small scope they will perform very well for their price. But.. they are quite heavy.

The Losmandy GM8 and G11 are old reliable standbys, but the Gemini 2 is still immature.

Vixen has always come through, and their extensive use of aluminum means their mounts don't weigh as much as the China mounts. Problem is that the Starbook has some rather serious DEC guiding issues that make it problematic for astrophotography, so if you can get an old SkySensor 2K-based Vixen (GP-DX, Sphinx SXD, or Atlux) that would actually be a better choice. Or, get a Sphinx/Atlux and replace the main board with the NexSXD. A lot of Sphinx users have ended up going this route.

[MooEy]

There's always the option of fsq-106ed if u like the faster f/ratio Personally I will take the TSA-120 over the NP101.

[Slightly off thread]
Anyone have any experience with the NexSXD? Btw, there's a new firmware update for the SXD, version 2.3. I wonder if it will improve anything. And what's with the Mach1GTO

~MooEy~

[acc]

I had Televues before and I like their powder-coated finishing which is very durable. In contrast, I have seen two Tak scopes whose paintwork flaked off; IMO this is inexcusable.

[cloud_cover]

I recall a friend saying that Vixen is a hardware company and its equipment is top notch. Unfortunately its software is a mere afterthought.
With my SXD I find tracking to be reasonably smooth only if I don't use goto, i.e. no alignment = no declination movements. Otherwise once goto is employed, if the mount is slightly off polar alignment, the declination jerks are very obvious even in a mid-power reticle eyepiece, not to say on a CCD.
The skypod is another matter altogether. Pressing one button can result in movement in an entirely different direction.
I really wish vixen would put more effort into engineering its software. they already have such good hardware (and the weight to loading ratio for given quality can't be beaten), its such a pity their software stinks to the point people have to invent replacement control boards to over-ride their software and worse, implement a competitor's protocol.