TPO 12" f/4 Imaging Newtonian Telescope

  • Aperture: 12 inch
  • Focal Ratio: f/4
  • Focal Length: 1220mm
  • White rolled steel exterior, flat black interior for higher contrast
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  • Regular price $799.00
  • $719.10
  • You save: $79.90 (10%)

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TPO 12" f/4 Imaging Newtonian Telescope

If you are looking for a telescope that does a great job of imaging but doesn't come with the cost of a Ritchey-Chretien, check out the TPO Imaging Newtonian line of telescopes! All of our Imaging Newtonian optical tube assemblies, offered in apertures from 6 inch- 12 inch, have very fast optics for the widest fields possible. Image with a DSLR or small webcam all the way up to large sensor CCD camera with these inexpensive yet effective Newtonians.

The optics on all TPO Imaging Newtonians consist of a parabolic primary mirror and an elliptical secondary, or diagonal. The mirrors are made from B270 white water optical crown glass, which is more thermally stable than glass traditionally used on other reflectors. A 91% aluminum coating is applied, and then over-coated with a layer of quartz for the ultimate in durability. The primary mirror cell is very sturdy, and has six collimation knobs that can be adjusted by hand with a push or pull of the knob. Collimation is made even easier due to the center spot marked on the primary mirror. The diagonal mirror is held in place with a thin four-vane spider.

The optical tube assembly on the 3rd Planet Optics Imaging Newtonian telescope is made of rolled steel and painted white. The ends of the tube are die-cast aluminum, which contribute to the OTA's rigidity. Steel is a bit heavier than traditional aluminum, but since it has a lower coefficient of thermal expansion, your telescope will tend to hold its shape (and therefore, hold focus) as temperatures fluctuate throughout the night. The inside of the OTA is painted in a matte black finish, which stops stray light in its tracks.

A low vibration cooling fan is built into the primary mirror cell of the telescope to assist in cooling your optics down quickly. The fan is powered by a eight (8) AA batteries (not included) which are housed in an external battery pack.

A 3.3 inch dual-speed Crayford-style focuser rounds out this package. The ridged focusing knobs are easy to turn, even with gloves on, and the 10:1 microfocusing dial allows for very small changes, or tweaks, in focus. It takes ten turns of the microfocusing knob to equal just one turn of the larger knob. There is also a little knob on the bottom of the focuser that controls the tension, so that you can make adjustments depending on the weight or distribution of your load. The 3.3 inch opening steps down to a 2 inch compression ring adapter, and you will receive 1.25 inch compression ring adapter so that you can make use of all your eyepieces. A 35mm extension tube is also included to help you match the back-focus requirements of your imaging equipment. This is one nice focuser, and due to its steel drive rail and other upgrades, you will find that it suffers from very little flexure, even under heavier imaging payloads.

The telescope comes with dual split-hinged mounting rings that are made of die-cast aluminum and felted on the inside to cradle the OTA without scratching. There are threaded holes on the underside of the rings that allow installation on either a Vixen-style or Losmandy-style dovetail plate. The top of the rings is also drilled so that you can mount accessories.

All TPO Imaging Newtonians come with an 8x50 straight-through finderscope. The ocular has a non-illuminated crosshair and has 13mm of eye relief. A quick-release mounting bracket is also included.

  • 3.3 inch dual-speed 10:1 linear Crayford-style focuser with 35mm extension, 2 inch & 1.25 inch adapter
  • Dual hinged rings with Losmandy-style dovetail
  • Cooling Fan included.
  • Push/pull oversized collimation knobs for easy adjustments
  • Weight: 40 lb.


TPO Product Number: 12IN


Aperture305 mm (12")
Focal Length1220 mm
Focal Ratiof/4
Free ShippingYes
Optical DesignNewtonian
Warranty2 Year Warranty

Customer Reviews

4.5 Based on 6 Reviews
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Christopher F.

Great value for a tough scope

I am very hard on my astro-gear. It get moved weekly as I travel around the country and bounces around in the back of my SUV all the time. When I am stopped it sits outside in every weather condition you can imagine. I bought this scope nearly two years ago and it has been wonderful. I will say that I quickly replaced the focuser with a Moonlight but what did you expect for $800.00 when buying a 12" F4. The optics are good and it will take a beating, that's all I wanted. If you are looking for a imaging light bucket you could do much worse than this baby.

Richard W.
United States

TPO 12" tube assy - excellent

The tube box was one more drop away from being useless but it survived UPS anyway. I broke all the rules and was given a clear night after mounting the tube on my CGEM DX mount. I laser aligned the tube assy and was pleased with the scope's performance. I was glad I read comments and ordered a 50mm extension for the eyepieces, the 35mm that came with it was not enough. I would recommend this tube assy as long as your mount handles 50lbs easily.

Hernando R.

Very Good!

It is an excellent OTA for the price offered by Optcorp. It is built with very good materials, its optics is excellent. Something that I definitely like about this OTA, is that I can customize it to my liking or needs and I have been improving it little by little with accessories from other brands that are appropriate to make this OTA, an excellent telescope. Acquire the knobs and springs of Bob's Knobs immediately because the ones she brings are not very good. Other accessories that I have been acquiring, have cost me but I'm sure I can get to have a telescope as good or even better than other brands much more expensive .., and all because those others are well-known brands. It is an OTA made in Taiwan but carefully manufactured and you will be pleased to have invested a low cost for such a good OTA. I also recommend that you buy the CGX-L mount to this OTA because of the size and weight it has to support; that mount has excelled me and the telescope needs a minimum of a sturdy mount like that ... although I have read about some people that they use them in less robust mounts but I would not be so calm ... This Newtonian deserves the 5 stars for its cost and quality

Michael Z.
United States

TPO 12” Imaging Newtonian

Overall it was good. Not great, but good. The TPO focuser needs an extension for photography and the only one they provide is for visual use. How they can justify this when the scope is clearly named for imaging I don’t have the foggiest. A Newtonian of this size needs a coma corrector. Because of the lack of a proper extension tube this necessitated the use of a parafocal ring on the coma corrector. Not ideal as this is another place for tilting of the imaging plane to occur. The focuser is 3.3 inches yet they choke it down to 2” right away. Why not go down to 3”, then adapt to 2”? That being said, with a coma corrector and my KAF-8300 camera, the field was perfectly flat with no sign of astigmatism. Nice tight stars all the way to the edge. TL;DR The scope performs adequately but is being held back by the focuser. But it’s under $1000.


Awesome OTA

Been taking shots with this thing on my Atlas EQ-G. Was surprised the mount could handle it well. Comes with everything you need. They even designed the tube rings to be light weight. Well thought out astrograph and worth every cent. Can't wait to do some planetary work with it.


This one's a keeper

I have owned several scopes in this size range from newtonians to cassegrains. I love refractors with great optics. I purchased this scope for public nights to mount on my modified atlas mount. After using this scope a couple of nights, I feel like I won the chinese mirror lottery. This scope has excellent optics. It shows coma away from the center as all f4 scopes will, but the detail it pulls in is incredible. The star test rivals my refractors. I find myself taking dso's to 250x+ magnifications regularly with this scope to look at details. Planets are great through this scope. Collimation is critical on this scope. When collimation is dead on, this scope is on par with much more expensive scopes. I have bought and sold a lot of scopes. I think I will be keeping this one for the long haul. Opt was great to deal with as usual.