Whatbird.com

Anyone here have experience using a telescope for birding? Celestron? Orion? TeleVue? What's the furthest distance they can reach in the real world?

They can reach as far as a spotting scope, but that's not going to be your problem. You'll find that you need an erecting prism so everything is backwards in the eyepiece (as an amateur astronomer I find this convention quite annoying--that the default is backwards) and the other issue is how close the object can be and still focus on it. Lastly, they are typically bigger (and heavier). Having said that, I've used a 70mm telescope to take pictures of birds, so there is nothing inherently wrong with trying it out.

Thanks Robert. And I apologize for being so brief.

The review I read at BVD [http://www.betterviewdesired.com/Catadioptric-or-Mirror-Scopes.php] claims that Catadioptric scopes beat even the high end Swarovski's hands down at ultra-long range bird identification. It highly recommends 5" (125 mm) mirror telescopes for this purpose. And I was thinking, if 5" does well, wouldn't 6" do better, 8" even better than that?

If NASA can read a license plate from space, and if price is no object, is there ANYTHING out there that I can use to sort though a flock of peeps on a sandbar 5000 feet away? So that I can pick the Least from the Semi-palmateds?

The short answer should be, yes, there is something that can allow you to differentiate individual feathers at 5000' and if price (and weight) are of no concern then I'm certain we can figure something out.

I find the review you posted to be quite thorough and well-written except I found the title a bit misleading. I think it should be Catadioptric (or mirror) Scopes since they are the same, not in competition, but that's just the editor in me.

Questars and TeleVues are always excellent, but can they do what you want? The article says the Questar 90mm can resolve 1.31 arcseconds. I guess we're going to have to do some math! I will post another note here soon with that calculation.

Maksutov-Cassegrain designs are generally excellent bang for the buck. My 70mm is a Mak, the Questar is a Mak, the new Celestron C90 is a Mak. The reason is that it is a simple yet robust design. Frankly I'm amazed that there are still Schmidt-Cassegrains on the market but I think time will tell. A good pair of astronomical binoculars might be a good option--binos are generally much easier to use, but (very large ones are) harder to carry.

I think you need to tell us whether you intend to carry your solution around with you because size and weight may be the deciding factor if price is not.

I think you're asking an interesting question and am anxious to work on it!

Robert 

Quick answer on resolution: One arcsecond resolution will allow you to see a dime at 2.3 miles so 1.3 arcseconds on the 90mm Questar, for instance, "should" be sufficient--note that this is approximately equal to the theoretical limit of a 90mm aperture and so it is only actually achieved in very high quality scopes. Nothing beats a field test for answering a question like this though.

My main requirements (beyond bird identification) are:

1. It must fit in the trunk of my car (my rear seat folds down for even more room).

2. No single component should weigh more than 35 pounds or so, since anything more than that is likely to throw my back out.

I plan on driving to my favorite observation point, take the telescope out of the trunk, and set it up within a few feet of the car. I already have a regular spotting scope that I carry afield. So I don't have to worry about carrying the thing very far. In fact, I can pull the car up to the observation point, unload the trunk, then go park the car.

Price, at this point, is not a concern.