pgc hunter
16-08-2015, 05:46 PM
After years of searching for my perfect do-it-all grab n go setup, I finally chanced upon a used Vixen R130sf 130mm F/5 Newtonian. After having tried many grab n go setups in the past, including:
127mm Mak on EQ5: This did not fit the the bill as cooldown was too long and the EQ does not constitute grab in go in my book, plus narrow FOV;
120mm F5 refractor on Alt-Az: Great for wide field sweeping but little else, too much CA and images go soft approaching 100x;
80mm F7.5 refractor on Alt-Az: Good optics, but not enough light gathering to make DSOs pop.
I've come to the conclusion that a smallish fast (not too fast!) newtonian on a lightweight Alt-Az would be as close to the "full package" as possible, providing short cool-down time, much better light gathering than those 80mm refractors, no CA so potential for higher power planetary all the while providing wide-field capability and still light enough to carry the full setup in on go. Was finding this 130mm Vixen complete with Moonlite focuser the answer to my prayers? Let's find out.
The Scope
Anyone that is familiar with the R130sf knows that the original focuser is a very cheap plastic job that cannot handle much without flexing. The previous owner has fitted this example with a Moonlite single-speed which is one major reason I jumped on this. I also bought a 40mm extension tube for visual (wanted a 50mm but was out of stock) which despite my initial concerns about not reaching focus and focuser intrusion into the light path, in the field these worries were unfounded. I mounted this scope on my existing Stellarvue M1 mount.
In the Field
The scope was already pretty well collimated so left well alone. Balancing it on the M1 mount proved tricky and I could not use my heavy LVW eyepieces without cranking down on the tension. As such I was restricted to the 3 eyepieces that came with the scope, 30mm, 20mm and 6.3mm plossls. To be fair though, my Vixen LVWs are grenades. Focusing at magnifications up to around 80-100x was alright, but beyond that vibrations became too much. The M1 is not quite up to the task of supporting this OTA although for lower power viewing, say under 100x, it is fine. However I do want to do some planetary aswell, and am considering the Bintel Skyview Alt-Az with its slow motion controls. I've heard it is a pretty solid mount.
The first beam of light to hit the primary came from Saturn. With the 20mm PL and 2x barlow at 65x, the view was satisfyingly crisp with 4 moons seen, Cassini Division was seen at the ring's ansae and a dusky belt on the globe. Not bad! With the 6.3mm plossl, 103x (I hate that tiny hole!) Saturn appeared pleasantly sharp with Cassini visible almost all the way around the rings, the light brown belt on the globe cleary visible as was the shadow of the globe on the rings, with sharp contrast between the dark shadow/background sky and the bright planet. The contrast in my opinion was very good and if anything, reminded me of my 8" dob. The mirror set in this Vixen is nearly spotless though which I think was showing at the eyepiece.
Barlowing the 6.3mm, I lost some sharpness, but it just seemed like something was holding the scope back. I noticed the mirror is held in place by clips so my first though, check out a bright star. An in-focus airy disk appeared slightly triangular which is a consequence of the mirror clips being too tight. So I'll have to take the mirror cell out and loosen them off, a simple fix.
Just did some widefield next. Using the 30mm plossl provided only 21x. With this eyepiece, objects like IC 2602, M7, M6, the Zeta Scorpii region, and both the Trifid and Lagoon Nebulae were nicely framed. Open clusters sparkled nicely, unlike in my 80mm which rendered them comparatively anemic. Star colours were quite rich, particulary with the 20mm plossl (32x), the carbon star near Beta Crucis was a nice ruddy hue and the red stars in NGC 3532, NGC 3766 and NGC 3293 contrasted nicely with the other bluish members while the clusters themselves were bright and pretty. This will certainly be a good scope for enjoying coloured stars, owing to the good contrast and aperture.
I also had a quick look at M57. It clearly appeared as a ring with the 20mm plossl and 2.5x Powermate (81x), brighter along its northern and southern edges. Zooming in on M4 at the same magnification showed good resolution with its "bar" structure visible.
Spent some time sweeping the Sagittarius Milky Way at 32x. Came across M17 which clearly showed its shape and with the UHC, could even make out some nebulosity extending from near the "tail" and looping back around. Some detail in the main part of the nebula itself was evident at 81x.
Conclusion
Overall I'm very happy with the scope and it pretty much fulfills my desire for a "do-it-all" package. Enough aperture to give DSOs justice, short enough for widefield and potentially a very good planetary rig aswell. I just have to address the mirror clips so performance will be even better. I am however planning on replacing the mount with the Bintel Alt-Az with the slow motion controls and maybe pick up a set of vibration suppression pads for higher power viewing (if I am still getting the shakes). The slow-mo controls will no doubt become handy. The M1 is just not up to the task of anything more than low power widefield.
All in all, this OTA provides bright views of DSO's, good contrast, wide-field, short cool down time and only mild coma as expected from an F/5. While Saturn was impressively crisp and contrasty at my tested magnification of 103x, I'll get a better idea of the true planetary performance once I address the mirror clips.
edit - pics or it didn't happen :P
127mm Mak on EQ5: This did not fit the the bill as cooldown was too long and the EQ does not constitute grab in go in my book, plus narrow FOV;
120mm F5 refractor on Alt-Az: Great for wide field sweeping but little else, too much CA and images go soft approaching 100x;
80mm F7.5 refractor on Alt-Az: Good optics, but not enough light gathering to make DSOs pop.
I've come to the conclusion that a smallish fast (not too fast!) newtonian on a lightweight Alt-Az would be as close to the "full package" as possible, providing short cool-down time, much better light gathering than those 80mm refractors, no CA so potential for higher power planetary all the while providing wide-field capability and still light enough to carry the full setup in on go. Was finding this 130mm Vixen complete with Moonlite focuser the answer to my prayers? Let's find out.
The Scope
Anyone that is familiar with the R130sf knows that the original focuser is a very cheap plastic job that cannot handle much without flexing. The previous owner has fitted this example with a Moonlite single-speed which is one major reason I jumped on this. I also bought a 40mm extension tube for visual (wanted a 50mm but was out of stock) which despite my initial concerns about not reaching focus and focuser intrusion into the light path, in the field these worries were unfounded. I mounted this scope on my existing Stellarvue M1 mount.
In the Field
The scope was already pretty well collimated so left well alone. Balancing it on the M1 mount proved tricky and I could not use my heavy LVW eyepieces without cranking down on the tension. As such I was restricted to the 3 eyepieces that came with the scope, 30mm, 20mm and 6.3mm plossls. To be fair though, my Vixen LVWs are grenades. Focusing at magnifications up to around 80-100x was alright, but beyond that vibrations became too much. The M1 is not quite up to the task of supporting this OTA although for lower power viewing, say under 100x, it is fine. However I do want to do some planetary aswell, and am considering the Bintel Skyview Alt-Az with its slow motion controls. I've heard it is a pretty solid mount.
The first beam of light to hit the primary came from Saturn. With the 20mm PL and 2x barlow at 65x, the view was satisfyingly crisp with 4 moons seen, Cassini Division was seen at the ring's ansae and a dusky belt on the globe. Not bad! With the 6.3mm plossl, 103x (I hate that tiny hole!) Saturn appeared pleasantly sharp with Cassini visible almost all the way around the rings, the light brown belt on the globe cleary visible as was the shadow of the globe on the rings, with sharp contrast between the dark shadow/background sky and the bright planet. The contrast in my opinion was very good and if anything, reminded me of my 8" dob. The mirror set in this Vixen is nearly spotless though which I think was showing at the eyepiece.
Barlowing the 6.3mm, I lost some sharpness, but it just seemed like something was holding the scope back. I noticed the mirror is held in place by clips so my first though, check out a bright star. An in-focus airy disk appeared slightly triangular which is a consequence of the mirror clips being too tight. So I'll have to take the mirror cell out and loosen them off, a simple fix.
Just did some widefield next. Using the 30mm plossl provided only 21x. With this eyepiece, objects like IC 2602, M7, M6, the Zeta Scorpii region, and both the Trifid and Lagoon Nebulae were nicely framed. Open clusters sparkled nicely, unlike in my 80mm which rendered them comparatively anemic. Star colours were quite rich, particulary with the 20mm plossl (32x), the carbon star near Beta Crucis was a nice ruddy hue and the red stars in NGC 3532, NGC 3766 and NGC 3293 contrasted nicely with the other bluish members while the clusters themselves were bright and pretty. This will certainly be a good scope for enjoying coloured stars, owing to the good contrast and aperture.
I also had a quick look at M57. It clearly appeared as a ring with the 20mm plossl and 2.5x Powermate (81x), brighter along its northern and southern edges. Zooming in on M4 at the same magnification showed good resolution with its "bar" structure visible.
Spent some time sweeping the Sagittarius Milky Way at 32x. Came across M17 which clearly showed its shape and with the UHC, could even make out some nebulosity extending from near the "tail" and looping back around. Some detail in the main part of the nebula itself was evident at 81x.
Conclusion
Overall I'm very happy with the scope and it pretty much fulfills my desire for a "do-it-all" package. Enough aperture to give DSOs justice, short enough for widefield and potentially a very good planetary rig aswell. I just have to address the mirror clips so performance will be even better. I am however planning on replacing the mount with the Bintel Alt-Az with the slow motion controls and maybe pick up a set of vibration suppression pads for higher power viewing (if I am still getting the shakes). The slow-mo controls will no doubt become handy. The M1 is just not up to the task of anything more than low power widefield.
All in all, this OTA provides bright views of DSO's, good contrast, wide-field, short cool down time and only mild coma as expected from an F/5. While Saturn was impressively crisp and contrasty at my tested magnification of 103x, I'll get a better idea of the true planetary performance once I address the mirror clips.
edit - pics or it didn't happen :P