Archive for the ‘Visual Observing With a 6-Inch f/6 Imaging Reflector’ category

Visual Observing with a 6-inch f/6 Imaging Newtonian Reflector

February 10, 2018

The above photo of my “prized” 6-inch f/6 reflector telescope.  

This telescope was a gift to me:  (Winter 2018) 

When I first became interested in amateur astronomy, during the 60’s, the 6-inch reflector was “definitely” the most popular telescope for the backyard observer.    

I always wanted a 6-inch f/8 Edmund EQ reflector, but as a middle-schooler, this was not possible.

So, it would be quite a few years later before I would purchase my very own 4.25-inch Edmund f/10 EQ reflector.  But, a couple years later in need of more aperture, I sold the 4.25-inch, to purchase a 6-inch Criterion f/8 reflector.  Then life got really busy and I sold the 6-inch.  

It would be almost ten years before I would come back to amateur astronomy.  However, the hiatus might have been a good thing, as I came back as a much more serious observer, with a new 10-inch EQ reflector.        

Preserving the past:    

One of my desires has always been to bring back the excitement of the glory days of amateur astronomy, when all kids wanted a telescope.  This is primarily one of the reasons for my blog, which you are now reading. 

The nights of the solitary observer in the backyard, attempting to locate and observe a few of the Messier objects with a 6-inch reflector.   

Testing my new 6-inch f/6 reflector: 

But how would this telescope perform on a couple of difficult tests?  

A larger secondary mirror:

An imaging reflector has a larger secondary mirror, and this can have a negative effect as related to resolution of fine detail, and the separation of difficult double stars.   

The Trapezium in the heart of the Orion Nebula:   

Starting with 232x, I was surprised how easy it was to see the E star, but the F star was not seen.   

February 8th 2018, an observation of the Trapezium stars: 

There were beautiful airy discs rings surrounding the “four” primary Trapezium stars, at the 232x magnification.   

Note:  An imaging reflector most often requires the use of an extender tube when observing visually to achieve proper focus.  

The optical tube assembly:  

6-inch OTA, f/6, with a 2-inch focuser, a 6 x 30 finder and it also included tube rings, designed for a narrow-Vixen style dovetail.  An excellent quality telescope in all aspects.  

The original dovetail was too short, but I found a unique way to utilize the “too short” original.  I ordered a 13-inch dovetail to replace the short one, which allows for better balance. 

The telescope optical tube is fairly heavy, and it was difficult to set up on the mount.  I needed a handle to more easily mount the telescope.  

So, I just flipped the original dovetail upside down, and it bolted perfectly on the top of the optical tube.  This became the perfect handle I was looking for. 



I added an 8 x 50 finder:   

This is the minimum size to effectively locate the location of that very faint deep-sky object, when using a sky atlas. My primary reason for purchasing this scope was for portability, ease of carrying and set-up, and take-down time.     

Fortunate for me, I had a Vixen GP equatorial mount from a refractor purchase in mid-90’s.  I did have to purchase an additional counterweight to properly balance the reflector.   

There was a problem, but not with the telescope:  

My older Vixen GP tripod was designed for a refractor, and too tall for a reflector.  It’s important or should I say it’s “absolutely” essential that I’m seated when attempting to sketch deep-sky objects.  I’ve tried too many times over the years to sketch while standing, and it’s just not possible for me.  

Fabricating a shorter tripod: 

I didn’t realize until later that Vixen offers a short tripod, designed for Newtonian reflectors, but just the shortened aluminum legs with a base sells for ~ $200 dollars.

I just remembered:

About 15 or more years ago, I bought a set of Vixen (standard) tripod legs for $20 at a local astronomy event.  They appeared to have never been used, and I’d had them in storage ever since. 

Why not attempt to shorten my extra set of standard tripod legs to Vixen specifications?  

So, for most of the afternoon, I spent several hours, sawing, drilling, and filing.  The results were worth my time and effort, and all modifications looked really good, or what I would call….factory.  

And now, I can enjoy observing with my 6-inch while seated, using an adjustable astro-chair.  


A great review as following of a TPO 6-inch Newtonian by James Dire:

Dire, J.R. 2016, The TPO 6-Inch Newtonian Telescope, Astronomy Technology Today, 10, 3, 67-70.