Tripod isn’t an issue already have decent tripod from photography interests. I assume scopes fit on Std tripod mount.
Hi,
first of all, welcome to Birdforum!
Yes, modern scopes usually have the standard 1/4" mount to attach a tri- or monopod directly or more commonly a QR plate. Some also come with a special foot that fits one type of tripod head directly w/o attaching a plate (but can also attach a plate in case you want to use a different head).
As for whether your existing tripod/head combo will be good for use with a scope, that depends on a number of factors:
- the magnifications with spottings scopes (often 20-60x) are quite a bit larger than even a supertele (600mm/59mm =12x), so vibrations are much more visible. A scope setup will need a more sturdy support than a camera and lens of equal weight.
- the common three way head often used for photography is not too great for use with a scope - most prefer to use a so called video- or fluid head. For very small and light scopes, a small ballhead might also do the trick.
- zoom vs. fixed EP - classic zoom EPs with a 3x zoom range (e.g. for the common 20-60x magnification) tend to offer a quite narrow true and apparent field of view at the low magnification end (where you would like to have a wide true field for scanning). It is often a good idea to have a low mag wide angle fixed EP offering 20-30x magnification along with those - some users also use a 30x wide EP as their only magnification.
Some manufacturers have developed so called wide angle zooms with a 2x zoom range (e.g. 30-60x) and a wide true field at the low mag end. With those a fixed wide EP for scanning is not necessary.
Back in the days zoom EPs tended to deliver significantly worse sharpness and transmission than fixed EPs but with modern designs that is not much of an issue.
- which scope to buy - that is a difficult question - first size: 50 and 55mm models are usually bought as a lightweight option for long hikes to use together with a full size scope (often of the same make so EPs can be switched around). Intermediate size 60-70mm can be all you need if you don't need the high magnifications in bad light conditions. Full size scopes around 80mm the few expensive and heavy models around 100mm are what you want if you are going to need high magnification in all light conditions and don't plan to do long hikes.
- used or new - I'd say for a full size scope and EP your lower two price brackets pretty much mandate going used. A usable intermediate size might be found in the second bracket new with some shopping around. Usable 50mm scopes and EP can be found starting at 500 quid or even below but I'd not recommend those unless you plan to get a full size one later...
- in general, I would not buy a scope without being able to test it before buying or a no questions asked return policy from a reputable store. Sample variation does unfortunately happen even for alpha brands, so be prepared to test your scope before (or soon after if you can return) buying it.
A minimum requirement is the ability to deliver a nice and sharp image at the maximum magnification (with the default zoom EP) on a cool and cloudy day (to minimize effect of bad seeing aka heat haze). Also it should be fairly easy to find a distinct point of best focus - as opposed to a wider range of least fuzziness which indicates less than optimal optics.
- distortion (as in Angular Magnification Distortion or AMD) is a property of the eyepiece and usually dictated by the eyepiece design or in some cases even introduced on purpose by the designer.
What you want to test your scope for are aberrations with the most common ones being Spherical Aberration or SA, Astigmatism (vulgo stig) and Coma - but there many more so called higher order aberrations known. The sum of all aberrations in an instrument can be expressed as a so called Strehl value with 1.0 being defined as a fictional perfect and aberration free example and 0.8 (often called diffraction limited) being acceptable and at least with astro scopes what many manufacturers will assure to deliver.
- For a proper (especially quantitative) evaluation of the aberrations present in an instrument you normally need some specialized equipment (like Ronchi screens, collimators, optical flats or even a full blown interferometer setup along with a computer and analysis software) along with the know-how to use them for different optical tests.
One exception being the star test (either with a real star or an artificial one - a very small illuminated pinhole at sufficient range) which gives the interested amateur the possibility to quickly identify the different aberrations and get a rough idea how strong they are.
A thorough if a bit math-heavy introduction can be found online under
https://www.telescope-optics.net/star_testing_telescope.htm - don't be afraid of the math in the first half, the interesting part are the sample images in the second half). Or get the standard textbook "Star Testing Astronomical Telescopes" by H.R. Suiter (lately often out of print).
TLDR - point your scope at a bright star, zoom to maximum magnification, focus to best focus and then defocus ever so slightly for the same amount in both directions. What you want to see are identical patterns of well defined concentric circles - sth that amost never occurs. Ellipses with their major axis flipping by 90 degrees when going from inside of focus to outside indicate astigmatism, non-concentric circles indicate coma and a fuzzy disc as opposed to well defined circles on one side of focus indicates spherical aberration or SA.
Joachim
