I would agree that a 102 (4") scope would be great to have and possibly down the road, this would be the instrument that I would have if or when I am not travelling for work. This is why I gravitated to the AT92. It is as close as I could find to a 4" aperture while keeping the weight and length within certain limits. It is a bit longer than my cases can accommodate and could possibly exceed TSA or CBSA carry on size limits. It is a very nice scope though!
Thank you for your advice.
This was what I was thinking. I didn't want to find myself 'wanting' for something. I am hoping that the refractor that I decide on will be my primary instrument for several years to come.
I do realize the 'happy' part is impossible to answer even for me. I appreciate your thoughts!
There have been a lot of good recommendations and I think all the scopes mentioned are good options depending on what you want to do, and your expectations of performance. Sounds like a critical component of your decision making is portability. Airline measurements sort of set the upper limits on what you can do, as you rightly state. As I said, the 80 mm EDT has been a very nice performer for me. It has been surprisingly good on the moon and planets. I had a very nice session on the forth, where I was able to see quite a bit of detail at 170X on Jupiter. This included being able to see the red spot distinctly separated from its equatorial band, barges in the other equatorial band, polar cloud bands and the faintest hint of whorls and texture in the light region between the equatorial cloud bands. Saturn looked nice and crisp. I could clearly make out the Cassini division in the rings, and some cloud bands on the planet proper. At 170X and lower, the only spurious color I saw on any solar system object (the moon) was clearly due to atmospheric dispersion. For imaging you can see an example of M42 in one of my galleries that was taken with this scope. There is a small bit of color around the bright stars. If it bugs you, you can try using a UV/IR cut filter to minimize that. I also find that the scope works with with my plossl and orthoscopic eyepieces as well as my wider field Televue EPs.
A few folks have suggested considering several different 4 inch doublets. The AT 102 ED's are getting really good feedback. I do not have one of those, but I do have a TV102 doublet, that performs similarly visually to what I described for my 80 mm EDT, but with the advantage of more aperture. I have pushed that to 250X on the moon many times with excellent results. However it does show a similar amount of color when imaging as the 80 mm EDT. I have no doubt that the AT Doublets would be solid performers and worth your while if they meet your travel requirements.
I agree with the others that the AT92 is primarily optimized for imaging with a Focal ratio of F5.5. What this means to me, is that for visual use you might encounter a couple challenges. In particular, usually with such fast scopes there is a certain amount of field curvature that distorts things at the edges. Most imagers use a field flattener to correct for this. For visual use this means you are likely going to have a better experience with more expensive eyepieces, like the Televue Naglers, Ethos, Delos, etc... as opposed to less expensive designs like Plossls, orthoscopics, etc.... Secondly, because of that fast focal ratio, you have to go down to really small focal length eyepieces and/or use a barlow/powermate. That said, my brief experiences with my friends AT92 and my collection of TV eyepieces suggest it can be an excellent visual performer. the down side is that I could just about pay for the 92 if I sold 3 of my TV eps and a Powermate:-). Of course if you already have a collection of the green and black beauties( or similar), then this is not an issue.
The other factor in this is that as you get into this you are going to eventually want to see what more aperture gives you. My first refractor was an 80 mm Doublet. It was a fine scope, with excellent optics. I sold it because at the time, my eyepiece collection was limited and I could not get out of it what I wanted, and I was not imaging as much. Having come full circle, I am imaging more and I have a MUCH better lineup of EP's that can take advantage of the shorter focal length(even an F6 is still short). I have to agree with everyone that a 4 inch refractor is really a good place to start as a beginner if it meets your travel criteria. It is a good combination of aperture and portability. I love my 4 inch refractor. It grabs enough light to make bright DSO's interesting even in my orange/red zone. It will not pass the Carry on test, but it is easily transportable in a car. It is small enough to use on a relatively light weight Alt Az mount like a twighlight 1 or 2 or similar. The AT 102 is a bit shorter at F7,(my 4 inch is an F8.8) which will make it even more portable, although it might show a little bit more color.
Anyway, those are my experiences. Hope this helps with your decision making. One last thing I would say is that if the refractor bug really bites you, this first one will likely not be your last.:-).