The Meade 60 AZ-T Short Focus Telescope
This little scope is not being made at this time. I picked up one on eBay, with its little table top tripod missing, for a very reasonable price. My intent is to learn about it for helping beginners that might have a scope like it, and for use as a rich field scope.
The scope originally came with a nice carry bag (canvas case?) with a 45 degree, correct image diagonal; K25 and K9 eyepieces, a 2X Barlow Lens, lens cleaning cloth, and a table top tripod. Both eyepieces are in bullet type plastic containers. Over-all, it is a really nice little rig.
I do not have the tripod with mine, therefore I cannot comment about it. But, judging by the other items included, the tripod is most likely adequate to its task. There is a place inside the carry bag for this small tripod to be strapped in.
Using the scope in its intended terrestrial mode, with the original eyepieces, it is everything I expected, just maybe a little better in image quality. I can certainly see where this scope could be used by a youngster (of any age) to watch birds feeding their young, the activities around a wasp nest, or any other objects of interest in our normal daily world. For the person inquisitive about the daytime world around us, I think this scope is a very good option.
The scope is proving to be a success for astronomy, but there are a few issues to deal with. The most significant issue is that the scope is set up for viewing objects at relatively close range, requiring a longer racking of the focuser than with astronomy. The focuser itself is fairly short in its racking distance, probably due to the wide angle of its potential field of view. The erect image diagonal seems to have a shorter light path than a star diagonal. All of this adds up to put the focus position with a star diagonal and infinity focus very close to the end of the focuser travel. With just a regular eyepiece in the focuser, there is less than a quarter of an inch of travel left in the inward direction. The focuser cannot accommodate a 2X Barlow. I was able to use a Meade No 128 3X Shorty Barlow, but not any 2X that I own. Since I have very short focal length eyepieces that I can use, plus the fact that I have other telescopes that I would use for higher magnifications anyway, this is really not a problem.
This situation does point out that this scope is a special purpose instrument for terrestrial and wide angle viewing. It is not a planetary telescope, even though I could see the two large bands on Jupiter quite well and am pleased with what I could see on the Moon. The scope does not have the contrast of a longer focal length refractor, but will work in that capacity when looking at the Moon or planets is a secondary purpose.
On the evening of December 19, 2013, Jupiter was half way up in the east and Orion was in the SSE. The moon was about two days past full and sitting roughly between Jupiter and Orion, about two-thirds the way from Orion to Jupiter. Using my set of TMB Planetaries, the optimum view was with the 6 mm eyepiece.
On Orion, three stars in the Trapezium were visible with a 20 mm, 70 degree, University Optics eyepiece, but all four were in view with the TMB eyepieces from 9 down to 6 mm. At 5 mm, the fourth star disappeared, but resolution did not noticeably fall off. For most things, I am thinking that something around 60X is a good upper limit, even though the limit may be higher. With the 20 mm SWA, the true field of view is four degrees. This completely encompassed Orion’s Sword, with some nice artistic space on either end. There is some fall off in the image in the outer parts of the image, due to field curvature. I think most of this is related to the eyepiece and not the scope, but I do not have a good way to test the theory. In any event, that portion of the image is useful to me as framing space and good resolution is not really necessary.
For the Moon, the view with the 3.2 and 2.5 mm eyepieces were of about equal quality and reasonable for me with my vision. A really sharp-eyed observer might think differently. At these higher magnifications, the focus sensitivity became significant and I was wishing for a find focus knob. However, you get what you pay for. For my purposes, something around 120X is probably the limit. The biggest difference between this scope and a 700 mm focal length 60 mm refractor for lunar observing is less contrast and more flare with this one. I expect the 700 mm would also have a bit better resolution.
The socket for eyepieces in the focuser is a bit short, compared to a normal focuser, and standard eyepieces bottom out in the focuser. This leaves maybe an eighth of an inch of the eyepiece barrel exposed, but this does not seem to pose a problem either.
The focuser has a single set screw for holding a diagonal in place. For the lighter eyepieces this scope was designed to use, this is not a problem. Fiddling with all kinds of eyepieces, I found the set screw having trouble with heavier 1.25 inch eyepieces, such as my 26 mm, 5000 series Plossl and my three 1.25 inch Meade Ultra Wide Angle eyepieces. Since these eyepieces probably weigh at least three or four times as much as the eyepieces that came with the scope, I am not surprised at all that there was a tendency for the diagonal to rotate around in the focuser. Careful tightening of the set screw made this situation workable, but I am concerned about stripping out the plastic threads in the focuser with continued use of eyepieces that heavy.
My SWA, 70 degree eyepieces in 20, 15, and 10 mm seem to be a good compromise. They do not have the weight of the better eyepieces, but do have more field curvature showing itself. Since I do not have a big need for fine focus in the outer areas, these eyepieces will probably be the ones I leave with this scope.
As far as magnification goes, and using all the readily available eyepieces I had over several nights, the scope seems to have a reasonable range for most things from around 14 to 60X. This range keeps the size of the exit pupil reasonable for my eyes. The 20 mm SWA eyepiece gives a magnification of 17.5X a true field of view of four degrees, and an exit pupil of 3.4 mm. A 25 mm eyepiece with a 60 degree AFOV would be a little better, I think, if the weight issue with the focuser can be reasonably resolved. That would give the 14X, with a TFOV of about 4.3 degrees and a pupil size of 4.3 mm, which would be about optimum for my eyes. Naturally, younger eyes could use a longer focal length eyepiece, like a 32 mm 4-element Plossl to get a 4.5 deg TFOV at 11X and a pupil size of 5.5 mm.
Compared to an APO of similar focal ratio, I am sure this little scope does not measure up in terms of visual precision across the field. However, for me, what I am seeing with this scope is not objectionable. The difference in price between an APO and this scope fully off-sets the improvement in optical quality. I would rather keep the additional money for the APO in my pocket and simply enjoy what this little scope has to give.
I have sanded the inside of the dew shield and the objective retaining ring to create pseudo threads and spray painted the inside with flat black paint. I blackened the edges of the objective lenses with the flat side of a cone-tipped "Sharpie." I may look into a different focuser and may cut off the optical tube a little. I need to think about that for a while.
Other than the focuser travel and set screw grip with heavier eyepieces, I am quite satisfied and excited about this little scope for rich field observation, which I do not think it was actually designed to do. What I have done with my little tests definitely pushes the scope well beyond its intended purpose. The results are much better than I expected for my $22.50 and for a scope that was sold mostly as an introductory toy for children. I am quite happy with it.