Quote:
Originally Posted by gotduss
I just saw the moon. You were very helpful, thank you so much. Is it possible to see the moon's craters with a 20mm or should I use a different eyepiece (12.5mm)?  |
Hi Gauthier,
From what I can gather, your telescope is
114 aperture
900 focal length
f/8
and you have eyepieces H20 H12.5 and SR4
Short answer to you question is Yes. You should be able to make out craters on the moon with the H20. And this is usually the best eyepiece to start with. Once centred in the eyepiece you can switch to higher magnification if required.
Magnification is calculated by focal length (900 in your case) divided by eyepiece number.
So without the barlow or erecting tube (both which increase magnification -3 times and 1.5 times respectively) your eyepieces should give you magnifications of:
H20 = 45x
H12.5 = 72x
SR4 = 225x
The theoretical best usable magnification is twice your aperture.
So 114x2 = 228x
But you will need good conditions to be able to focus clearly even for that.
So the reported 675 zoom claimed is advertising BS. and will provide nothing more than a BIG, but fuzzy blob.
Also, the higher the magnification, the quicker the target will appear to move through the eyepiece field of view. So another reason to start with the smaller magnification.
Enjoy your scope, you may find the limitations prompting you towards a bigger and better scope and (more especially) better mount, quite quickly once you get hooked.
Tip. Moon is better viewed when smaller. ie not Full moon. More detail of craters can be found along "The Terminator" the line between bright and dark part of the moon.
Next: Point at the middle "star" in the sword of orion. (some people call the handle of the teapot) for a nice bright Nebula.
Feel free to ask more questions
Welcome to IcenSpace
