refractor choice?

hi all,
after living previously with a 5" f/12 d+g, i am considering a new refractor, but perhaps a somewhat shorter one. it's a case of 5" or bust. i'm done with expensive 3" and 4"refractors, wonderful as they are. my price point includes meade's old 127ed or possibly i could stretch for an orion 120ed. the longer focal length of the meade is attractive, but i don't know how color correction compares on these scopes. i'd love to see some spot diagrams for these, but i guess they probably are not out there.

i'd appreciate any thoughts.
thanks,
glenn
another possibility might be a 6" rumak, but that's another story.

Hi Glenn,

I have owned many APOs including two of the Meade ED APO series, a 127mm and a 178mm. Both were excellent performers once collimated and centered. The 127mm never presented any issues, the 178 had a trip or two to Meade before it was right but once it was it was super! If you go with a Meade 127MM ED APO make sure it has the newer lens cell that allows centering the rear element. Here is a note from a few years back when I had the 127mm and a wonderful MN76:


26 December 2002

Cold and clear (for this area) night with a seemingly steady atmosphere. Took the 5" Meade APO and 7" MN76 out and placed them into the van for an hours cool-down. By the time I was ready to set them up, the sky had become unusually steady.

My first target was Saturn. Given the nearly identical focal lengths ( the Meade at 45" v the MN at 42") I decided to start with 7mm Pentax SMC orthos (lucky to have a pair on hand!). The Meade was turning in a rock solid, highly detailed image. Four moons were clearly defined as was Cassinis all the way around the ring. The outer ring was distinctly darker than either the B ring or the Crepe ring. Saturn's globe was a pastel olivine green with a darker band half way between the ring and the pole. From the band up to the pole the color darkened quite a bit. The pole and Cassinis were touching leading to a "hat-like" effect. The Crepe ring was quite obvious against the globe. Contrast was very good with the sky nearly black behind the image of Saturn. Being able to view from a seated position was a treat and made for a comfortable session.

Turning to the MN76 there was a pronounced increase in image brightness. Saturn was sharply defined and if anything, Cassinis was even darker and clearer-especially in the very front of the ring- than it had been in the Meade. The image was inverted relative to the Meade which made direct comparisons a bit tough. The moons were brighter as was the globe. All of the features mentioned in the Meade were seen easier in the MN76. Not sharper, the Meade held a steadier and possibly sharper image but the MN was just a world brighter which made everything easier to see. There was a bit of fluctuation in image sharpness- the image would go in and out of being razor sharp. This was not notices nearly as much in the Meade. Color more pleasing in the Meade, richer. The MN seems to overwhelm with light.

Switching to the 4mm Brandon-an old version I picked up recently- pushed the power to about what the conditions could hold. The Meade (285x) presented a good image but was starting to dim. The MN76 (266x) was sharp as a tack and I was able to glimpse-I think- Eckne's minima at least twice during moments of extremely calm seeing. I could not do this with the Meade. The 6mm Pentax SMC ortho was the best image in the Meade. Stunningly clear and detailed. The 4mm softened things up in the Meade more than in the MN76.

Jupiter was just coming into calm air around midnight. Back to the 7mm SMCs in both scopes. The Meade image was the best I have ever seen it turn in. Much like the evening Shoemaker-Levy hit Jupiter a few years back. Wonderfully detailed with the Great-Used-To-Be-Red Spot prominently displayed. Several bands present including two disjointed in the south equatorial region.

The MN was brighter but the Meade was better at showing low contrast features in the cloud bands. The background was a bit darker in the Meade as well. Again, things were easier to see in the MN due to the advantage in light gathering but the APO (really semi-APO as there was a bit of color showing) had higher contrast in the image.

Turning to 6mm eyepieces I tried the SMC v UO orthos. In both scopes the SMC was brighter then the UO and gave sharper and clearer planetary detail. The UO was excellent, the SMC better yet. Sharpness was a push in both scopes when using the same eyepiece.

Next I tried M42 paying particular attention to the Trapezium. Using the 6mm SMC ortho the APO pulled all six stars pretty easily. Interestingly, switching to the UO 6mm made it harder to see the two faint stars and I found I was using averted vision in it but not in the SMC. The MN with the 6mm SMC was brighter and all six stars were easy whether the UO or SMC was in the focuser. The APO surrounded the brighter stars with crisp diffraction rings. The MN was just about there but not as good as the APO. The star images were "tighter" in the APO but it was a small difference.

CONCLUSION:

I know these are different enough that the comparison was stacked in favor of the MN but I was curious to try it anyway. The Meade had just had the new lens cell installed and been cleaned and collimated . The contest was really close- it is a matter of personal preference given the MN's brighter images. The Meade is a more convenient scope to use, gives a bit more contrast and is ever-so-slightly sharper. Sitting is a major advantage in comfort. The MN suffers from a crappy focuser and the need to stand frequently-at least on the G-11. I could live happily with either...



All said and done, I would vote strongly in favor of an older Meade 127ED. Get a good one and it will last you a lifetime!