Thread: Bintel BT-252
View Single Post
Old 06-07-2019, 07:33 PM
mental4astro's Avatar
mental4astro (Alexander)

mental4astro is offline
Join Date: Jun 2008
Location: sydney, australia
Posts: 4,628
Ok, we may need to review telescopes 101 a little...

a, Magnification = scope focal length eyepiece focal length.

b, Golden Rule : max magnification for a given scope = 50X per inch aperture

So, for your 10" scope, this is 500X

c, Max magnification on any given night is determined by the atmosphere, so even a 10" scope may be limited to only 150X because seeing conditions won't allow for more before the image begins to break down, regardless of the aperture of your scope. Most nights you we only be able to pull 150X. On good nights you can pull 250X (if your aperture allows). And you've hit the jackpot when you can max out your scope, whatever that may be.

Now, in your case, we first need to know what is your shortest focal length eyepiece is. Secondly, the plantes are always small in the eyepiece - you will never see them the size of a dinner plate.

From all of the above tech-talk, an amazing amount of detail can be seen at modest magnifications. It just takes a patient eye. Yes the object drifts across the field of view, but by now you would have figured out how to position the object in the eyepiece to maximize its drift time.

With your 10" dob, 250X will be a quite practical upper limit of magnification. The biggest challenge you will have is not the magnification but the smoothness of the action of the mount if it will allow you to easily chase the planet to restore it in the field of view. If the mount is tight or jerky it may make following the planets when using say 400X, very difficult or impossible. It's not just about magnification but also the practicalities of your scope. This is the one major short coming of your scope - the way the mount has been designed and made as a mass production instrument. Optically it is actually very good! But the mount is the compromise to keep its price down - it's not cheap, but compared to high end dobs it is inexpensive.

My dobs, I've built them all. I have no problem using 400X and following the planets is easy as the mounts have a silky smooth action, not jerky or stiff. You will need to adjust your mount so that it is as silky smooth as possible and maintains balance.

So lets us know what eyepieces you have, and lets take it from there


Last edited by mental4astro; 06-07-2019 at 08:59 PM.
Reply With Quote