Meade 127ED 5" APO vs c8 Review
By: Vlad Fedosov
I have always been intrigued with a good refractor. Perhaps it was because my first scope as a kid was a 60mm refractor, perhaps it is the fact that I have some of my most memorable views of both deep sky objects(DSO) and planets with my previous TeleVue TV-85 and NP-101. Having recently owned APO refractors in the 3-4” size, when I had the chance to purchase a 5” Meade ED-127 I jumped on the opportunity! The ED127 is an older f/9 ED(FPL-51 equivalent) doublet design with a 1140mm focal length. These where sold in the 1990's and early 2000's when I was in my late teen years just getting into astronomy. One of these large refractors was always a dream scope of mine(the 178ED in particular was like a fantasy, a fantasy you know would likely never come true)!
Having the 5” APO setup for a session of some late summer planetary observing I decided to also bring out my 8” SCT that I had just perfected the collimation on the previous few nights. I thought it would be fun to compare the views that both scopes provide of the planets! Each scope was set up about 2 hours before I started to observe so they should have been fully cooled down. The scopes were set up in my mag 4 backyard, with the moon out. Both seeing and transparency that night were average for the northwest(with our average seeing being not very good at all☹).
First up was Saturn. I started with the SCT with the 18mm Ortho which produces about 111x. The planet and the rings were there but were boiling over a bit with the normally not so great seeing we get here in the Northwest. Switching over to the refractor that had a 10mm Ortho producing 114x, I was greeted with a much more pleasing image to the eye. The turbulence was still there but the image was still sharper and definitely more contrasty. Going between the two scopes I noted that the view in the c8 was quite a bit brighter but it was definitely not nearly as sharp due to the atmosphere. Bumping the power up to 190x with 6mm Ortho in the reflector I was greeted with a much more detailed view of Saturn. The Cassini division was there, as well as some of the banding on the disk of the planet. The view was still turbulent but was a good view especially under moments of better seeing. I was now curious to see what the c8 would do at a higher magnification. I bumped up the power to 200x with the 10mm Ortho. What I saw was quite disappointing after the view in the refractor. There was Saturn, larger, but just a boiling over mess. I observed the view for a few minutes and continued to try and adjust the focuser to make it sharper. It was all in vain, as I could not get a satisfying image at this higher magnification. I switched back to observing Saturn with the refractor until Mars cleared the trees to the east.
With Mars finally rose above the trees I was excited to point both scopes at the red planet! Mars was just a few weeks past opposition and the planet-wide dust storm had mostly lifted. First up was the c8. The view of mars at 200x was nice and bright, but seeing was still mediocre so the planet was not giving up very much in the way of detail. I could see a bit of darkening towards the south where the polar cap was but nothing major was visible. I next turned to the 5” APO. The view was immediately noted as being a bit dimmer than the c8. While the planet was still unsteady at 190x the dark Martian surface details were a bit easier to pick up. I next decided to try out by Binotron binoviewer with a pair of 18mm Orthos. At the medium power switch setting which produces somewhere around 200x I was greeted with a view of the red planet that was definitely much more enjoyable to watch. I was easily able to pick up the basic structure of the dark regions as well as the polar cap. The color correction on the 127ED is about what I have seen in FPL-51 doublets. Saturn showed zero color. Mars displayed a minimal about of color that was noticeable at 200x but did not affect the view. Brighter stars like Vega did display a minor amount of secondary color at powers above about 150x. Overall excellent optics, but if you are a purest and need 100% APO views you will want to look at a premium triplet.
In conclusion I decided to point both scopes at a few DSO.
m57, and m13 where the two objects that I used to compare the scopes. There was
little surprise that the c8 did better than the 127ED. M13, in particular, was
much brighter and more resolved in the c8. I would say that the versatility of a
c8 is hard to beat. Small size, lightweight, good views for most any object.
However, if you live in an area that has seeing that is mediocre and you are
primarily a planetary or double star observer a 5” APO is a very potent tool in
the serious observers toolbox! These older Meade ED scopes will always have a place in my heart(and in the case of my 178ED a VERY permanent place in my scope collection). They are just a super cool looking scope at the long f/9 focal ratio, and if you get a good unit some very well color corrected optics even by todays standard.