Vixen Porta mount and R130 newtonian

[Starkler]

In my search for a grab and go scope of reasonable aperture and portability I came to a decision to purchase a Vixen Porta mount bundled with a Vixen R130sf newtonian. A few weeks later it finally arrived last Friday giving me a new toy to play with for the weekend :)

Porta mount.
As can be seen its a single arm alt-azimuth mount on an alumium tripod. This mount can be manually pushed in both axis with adjustable tension and has full 360 degree slow motion controls. It accepts a standard Vixen or Synta dovetail.

Underneath the rubber pad in the base the included allen keys needed to adjust and dissassemble this mount are held by small magnets.
The Portas' height at full extension is sufficient that the little newt had an ideal standing eyepiece height for me, and a little too tall for my observing friends last night. Im am 6ft 2" :lol:

What can I say, this mount performs beautifully and is clearly a cut and a half above over cheaper offerings like the AZ-3. Tracking Saturn in this scope at 162x with a 4mm ortho was a breeze using the slow motion controls with the stability of this mount at full extension a nice surprise, with damping time of about two seconds. Everybody in our observing party last night was very impressed with this mounts smoothness, ease of use and stability. It has a real "premium feel" to it.

If you are looking for an alt-az mount for a small scope, say a 100mm refractor, they dont come much nicer than this ;) There are limits and the geometry of the arm means ota size is limited to about 170mm diameter without hitting the ota at zenith.

R130sf Newtonian

The R130sf is a 130mm f5 newtonian of Chinese manufacture. Unlike most other small newtonians, this one has a real metal spider and fairly decent components including a collimatable mirror cell with hex grub lock screws.
The exception is the focuser, being entirely made of plastic, which lets down the general quality of this scope.
The scope came with two silvertop plossls, 20mm and a 6.5mm. They both work very well in this scope and amongst cheap plossls, I quite like the silvertops so these were a nice surprise :)

First light star testing showed astigmatism from a pinched primary, so it was time to strip down the scope and loosen off the mirror clamping blocks. I also took the opportunity to centre spot the mirror.

After sorting out the collimation, the optics were found to perform quite well for the size and price of this scope. On Saturn, cassini was well visible with banding visible on the planets globe. Later on details were visible on the equatorial belts of Jupiter at 162x and still I was limited by the seeing.
Not too bad for a small rich field newt :)

About the focuser and design of this scope, you can see that it sticks out a long way from the ota. The design is such that you use the extension tube for visual, or remove it with the focusers top being threaded, designed to take a camera fitting. This might even work with a binoviewer ( I wish Steve was there ;) ).
The plastic focuser does flex when you put heavy eyepieces into it and the image shifts as you adjust focus. It is annoying when trying to focus at high power and this focuser is certainly the weak point of this scope.

The secondary is quite large at 45mm, giving a 35% central obstruction. The dual role photograpic/visual design of this scope with the focal point so far out of the ota means that the secondary is so close to the primary to only just catch the light cone. I am tossing up whether to get a new ota tube made so that I can push the primary back, or to just mount a better focuser on a high self made adapter.

To put all this in perspective, the OTA including two plossl eyepieces, dovetail and tube rings (nice I might add) only added about $240 over the price of a Porta mount on its own. Considering its optical performance, I still reckon I got a good deal ;)

As it is, it's a great grab and go package. If I get a better focuser, it will be close to perfect for my needs as a lightweight grab and go travelscope :)

Many thanks to Steve at http://www.myastroshop.com.au

[janoskiss]

Sounds pretty damn good Geoff. Just upgrade the focuser and add a barrel extension if necessary. :)

[Starkler]

Just been checking out Joop in it again and the jewell box is something else with pinpoint stars with little diffraction rings around them. The seeing is great tonight, who needs a refractor ;)

[dhumpie]

Hey Geoff,

Nice purchase :) You say that the OTA is of chinese manufacture??? I though it was of Japanese origin????

Anyway....

Darren

p/s: How heavy is the whole assembly? Looks pretty light....

[Starkler]

I have been told that model numbers containing an S or F are of Chinese make. Anyway the Chinese glue-grease in the focuser is a dead giveaway :lol: I'll try cleaning and regreasing it and see if that helps.

Yes it is very light easily picked up and carried around. Total weight is 9.5kg.

[Dave47tuc]

Very nice Geoff. ;)
My thoughts were what a great set up. After using the porta mount and looking into the scope I say you are on a winner.:thumbsup:
The mount was very easy to use, a big plus. Tracking was very smooth even with the 4 mm Ortho.:eyepop:
The scope itself was a big surprise. Images nice and sharp and Saturn in the 4 mm very good. Yes the focuser was it’s only down fall. Fix that and you got a great scope there.:thumbsup:
Well done mate on a great purchase. I hope to look through it again soon.;)

[h0ughy]

you could get one of those bintel or andrews crayford focusers for $140 odd dollars, nice setup!

[iceman]

Sounds great! That would fit in the back of the car on family holidays.. something my 10" dob certainly can't do right now.

[Starkler]

I upgraded the crayford on my dob to a new one with 10:1 fine focus control, so the old crayford is going on the R130 :D

[iceman]

Nice one Geoff.. add it to the review! :whistle:

[Starkler]

Done and maybe looking a bit silly :lol:

On this rather lightweight scope the gso crayford is a big heavy thing.
Its mounted on whats basically a wooden box of a suitable height to get the right focus range for the eyepiece combinations that I use.

I started by covering the old focuser hole with a piece of paper with a small centred hole to aid alignment with a laser. I marked the point geometrically opposite on the wall of the ota with a small dot of white paint .

Then came a lot of work with a dremel and sandpaper to get the feet of the wooden box square so that the laser lined up and the new focuser square.

I did some other mods relating to the spider assembly. The collimation screws as supplied had a conical tip with a small hole in the middle designed to bite into the metal :mad2: , which is exactly the opposite of what is desired.
These screws had made divots in the aluminium secondary holder, making it impossible to rotate the secondary to fine tune collimation.

I rounded off the edges of these screws with the dremel, and I made up a washer made of thin steel which sits between the collimation screws and the secondary holder. Much nicer :)

I also added flocking material opposite the focuser and around the bottom end of the ota. You can pick it in the second photo.
So does this focuser look like an overkill or what? :lol:

[Striker]

Not an overkill at all Geoff...I just dont know which has more aperture...the focuser or the Newt....lol

[Astroman]

So when you putting the ED80 on it for a finder scope?

That certainly looks impressive.

[beren]

Whack in the 31mm nagler and then we"ll see if its a overkill :D nice mods/setup :thumbsup:

[stringscope]

Hey Geoff, assuming the secondary is large enough, I calculate the 31 Nagler should give you just under 4 degrees TFoV. Wow, not bad:eyepop:

[janoskiss]

Yeah Geoff, drop that 31mm Nagler in and take a photo! :jump2:

[dhumpie]

Holy cow Geoff. The focuser looks bigger than the whole scope ;)

Darren

p/s: and yea do what Steve suggest and drop the 31 nagler in...lol

[Dave47tuc]

:rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl:

Better still put the 2" Barlow then the 31 mm Nag in:eyepop:

Looks funny but I hope it works a treat.:thumbsup:

[janoskiss]

Then anyone trying to look through the back of the primary mirror instead of the eyepiece would be excused! :lol:

[Starkler]

Do I win the prize for the widest field newtonian on IIS ? :D



I sold the ED80 after buying this one and seeing how much brighter it was :)
The R130 kills the ed80 as a visual scope.



Yep the 31 nagler has been in it, but Im sorry to report that such a wide fov on an f5 scope comes at an unfortunate cost of excessive coma :(

My 24mm panoptic gives a 2.5 degree view which is enough, so the ideal would be a nice 1.25" focuser, but do you think I can find a suitable one? :shrug:
I was considering the JMI 1.25" crayford which was for sale here, but the problem with that is that the drawtube is 3 inches long, and the inner diameter is 1.25" and not bigger, meaning that Im going to get vignetting :(

[Starkler]

Ive got the collimation a lot better now. That secondary was hard to align properly the way it was.

I've just come inside and I have changed my mind, the nagler isnt that bad in this scope :) Im looking forward to taking it somewhere dark :)

[dhumpie]

Geoff,

Same train of thought here. I had a 102mm f/5 refractor for a while but sold it as the C6 (6" f/5 Vixen/Celestron) was just so much brighter and more detailed. And I think you would probably win the widest field newt on ISS ;)

Darren

[gbeal]

Nice review Geoff.
One thing that struck me as I read it was, are you ever intending to image with it? If not, then lengthen the tube, or get the primary further away from the secondary/focuser, and get a nice small light smooth helical, something lower profile. If it ever does get used for imaging, then maybe you are stuck with having an extension for visual, and nothing for imaging. I would still set it up so that the focuser is almost at min when you image, and you may find that no extension, or very minimal extension is required. This is how my 10" is set up.

[Starkler]

I have been lucky enough to have not been bitten by the imaging bug and this is unlikely to change considering the number of excellent images posted on ISS by others :)
This scope was always intended to be a light, convenient grab-and-go cum travelscope and it fills this role nicely.
If i do decide to take up imaging I could put this ota on the eq5 that i have ;)

[dhumpie]

No imaging for a visual guy like me other than the occasional dabble in moon photography and wide field stuff :) I much prefer spending time at the eyepiece thank you....anyway still thinking of getting one of them Porta Mounts. They look soooo cool and light.

Darren

[Starkler]

What scope do you want to put on it Darren? Its not quite big enough to take the 6" unfortunately. The dimensions are such that max ota diameter is limited to 150mm and be able to reach zenith :(

Anyhoo....

I took the R130 to my fave dark sky spot tonight and gave the new mods a try.

Panning the milky way with the 31mm nagler was awesome, giving 21x mag and 3.9 degrees fov :eyepop:
I saw the dark lanes and features of our own galaxy as I never had before.
Who needs binoculars :D

Getting good focus with the original plastic focuser was a tricky task with the focuser tube shifting sideways and its body flexing. The crayford works like a charm, and now that the collimation is right, images are nice and crisp :)

The downside, (there always seems to be one) is that the crayford weighs a lot and the ota balance point is now more than half way up the tube. What this means is that what was a good standing eyepiece height with the tripod fully extended, is now a bit less comfortable and the tripod a bit more shaky.

Overall I'm happy with the mod and this scope makes a nice RFT, while also quite capable of planetary viewing :)

Can you tell I like this scope :D

[redsquash]

Hi Geoff,and everybody.
Sorry to hear you live in Melbourne.
I suffered for 20 years.

1
I bought this scope home tonight and having a break while I put it together.
I wonder , If you or any others professionals, who were starting out with this scope as a beginner, what additional lenses might you get.
I am a beginner.

I am in Japan for a while so I have a wide range to choose from though prices on everything are often very expensive.

2
This is my first scope and I am more then a little concerned as to how to colimate.:eyepop:

Is getting a laser gadget the most practical and efficient
way to go? I will se how things are tomorrow

3
Two years later I wonder if the collimation screws which you referred to have been changed in Manufacture.
Was your problem related to th e4 screws on the outside of the tube?

4 How do you rate your R130 now, 2 years down the track ?
up the magpies

[rjbokleman]

It's 10 years later since these original posts, but I'm looking at buying this scope myself as a beginner (and totally new to this forum). I like the Newtonian design as someone mention already it probably will gather more light than an ED80mm. My main reason for looking at this scope is 'Grab & Go' as I don't have the best viewing, save East, from my backyard.

My question is, if you were to buy a 130sf today, which focuser on the market would you buy to replace the original Vixen unit?

[DavidLJ]

rjbokleman


If I can add my two pennies worth. I bought a R130sf a year ago and yes the focusser is still plastic and if you are VERY determined you can finger push it from side to side just a bit. But the two supplied plossl eyepieces are so light they don't seem to affect the focusser's axial alignment no matter which way the OTA is oriented. Maybe the plastic has been upgraded? Maybe I just got lucky? Or maybe I'm not so demanding but with these two eyepieces I have not noticed any image shift at all. And because my aging eyes + spectacles need all of the eye relief they can get I sometimes use the Baader 8-24 Hyperion zoom eyepiece for comfortable viewing. This is quite a heavy eyepiece. But again I can't say that I've noticed image shift and of course once focus is set changing the zoom level has no adverse affect. In any event this 'scope's strength is the wide fovs that it delivers – 2 degrees using the 20mm plossl - and any image shift at that level could only be very small and would easily be corrected by slightly tweaking the mount's controls. In short, I'm not planning to change away from the supplied focuser any time soon.


The primary mirror arrived already centre spotted. The OTA holds collimation very well which is important for a highly portable 'scope. But occasional checking with my laser collimator is easy. The OTA has a back plate that is apparently designed to keep out stray light. You have to remove it to access the primary's collimation screws. Not a big deal but if that bugs you I doubt that permanently leaving it off will have much, if any, affect on performance.


As already reported, optically the 'scope punches well above its weight – certainly in terms of price. And for non-eyepiece use it marries very well with my GStar video camera. AstroShop has an article about that – http://www.myastroshop.com.au/guides/vixen-r130sf.asp. I reckon that the camera's frame accumulation and gain adjustment features deliver an enhanced on-screen view that is equivalent to near doubling the 'scope's aperture for visual use. And because the maximum exposure time is only 5 seconds you don't need to guide the 'scope or even have a tracking mount – simply nudge the mount's RA control frome time to time as needed to keep the target more-or-less centred in view.


One complaint. The non-adjustable 6x30 finder that I received was of poor quality. Since no one else has mentioned a problem with the finder I assume that I got a Friday afternoon job. But replacing it with a decent Orion right-angle illuminated reticle 50mm finder was not too expensive and makes locating objects a pleasure. It adds a little weight but nothing that my SW EQ3 mount can't handle.


Hope this helps, David

[rjbokleman]

DavidJ, yes that does help. I didn't realize that folks used CCD camera's on this scope. It just expands the possibilities.

A lot of people have been telling me to look at an Orion XT6 or XT8 as my first scope, but I really need the portability since my backyard isn't suited for the best viewing. (Light pollution and trees in 3 out of 4 directions.)

I think the XT6/8 have been reviewed favorably, but getting them too and from a darker location might be a challenge.

I need something light and very portable. This scope, for it's aperture and price, would gather more light than an 80mm refractor.

I'm going to place my order tomorrow before the current sales run end.