Celestia Forums

I have a 6-Inch reflector that I got about a year and a half ago and it has roughly a magnification of 400x tops. Is this classed as a medium sized or small telescope? And I also have a problem getting a non fuzzy image of jupiter or any big planets with any eye peice but the one that has the lowest power. Is it because I live in an area where there is too much light from the city that causes things to look fuzzy? Or is it a cheap telescope?

Although it's small as reflectors go, 6" is larger than most refractors. It's usually considered a good size for people to start with.

Without knowing the anything about the quality of the mirror or of the eyepieces, it's hard to say anything specific. Unfortunately, inexpensive telescopes and eyepieces do tend to be of poorer quality than you might expect. Also, you might be expecting more of your 'scope than it's capable of.

I'd suggest you try contacting a local amateur astronomy group. They're bound to have someone who can help you judge the quality of the optics.

However, do remember that professional photographs of planets are usually taken with very large telescopes. Most amateur telescopes can't be compared with them. Also, light pollution and atmospheric disturbance (e.g. hot air rising over cities, and warm air rising from your telescope's mirror) both can degrade what you see.

You might take a look at some of the amateur astronomy web forums. You might be surprised at just how "fuzzy" pictures can be.

Raccoon wrote:I have a 6-Inch reflector that I got about a year and a half ago and it has roughly a magnification of 400x tops. Is this classed as a medium sized or small telescope? And I also have a problem getting a non fuzzy image of jupiter or any big planets with any eye peice but the one that has the lowest power. Is it because I live in an area where there is too much light from the city that causes things to look fuzzy? Or is it a cheap telescope?

I have been with telescopes of varying sizes throughout my life, starting as a child, building my first one. Since a number of years (> 10), I own a Celestron 8 inch Schmidt-Cassegrain telescope. Being a physicist, I even measured the (very shallow) Schmidt plate using laser interferometry etc. The result was that Celestron had to replace my optics THREE TIMES (free of charge) before it met their specifications

So I am certainly capable to give you expert advice as much as this is possible without examining your telescope. Looking with my ID=t00fri in the forum's search engine together with "telescope", for example, you might find plenty of further respective posts by myself that might be useful for you.

Since (cheap) Newtonian reflectors have a tendencey of being misaligned, I'd suggest you first try and examine whether the fuzzyness is due to misalignment or due to bad optics.

So, focus in a steady, clear night on a bright star in the center of your field. Check whether you can see any assymmetrical light "tails" emanating from the star.

If yes => your scope needs realignment first!
If no, => proceed:

Next you carefully defocus the eyepiece repeatedly in BOTH directions away from the focal plane. You then will see that your (defocussed) star increases in size with a series of dark rings and bright zones.

The very sensitive test on the quality of your optics is that the two defocussed star discs (intra-focal & extra-focal) must look PRECISELY IDENTICAL as to the zonal patterns. E.g., if the disc has a low-contrast and fuzzy border on one side and a sharpely delimited one on the other, your optics surely has significant /spherical/ aberration.

Next you must check whether the extra and intra-focal star discs remain EXACTLY ROUND. If they become elliptical towards the focal plane, then you have the very damaging so-called "astigmatism" error.

Go and have a look how these issues look in your telescope before we proceed.

Oh yes, I need to know what precisely your optical system is? A single (parabolic) mirror =Newtonian system with an open front near the eyepiece, or a Schmidt-Cassegrain telescope that is pretty short (< 50 cm) and has a frontal glass plate with a small central mirror?

Good luck,
Bye Fridger

selden wrote:Although it's small as reflectors go, 6" is larger than most refractors. It's usually considered a good size for people to start with.

Without knowing the anything about the quality of the mirror or of the eyepieces, it's hard to say anything specific. Unfortunately, inexpensive telescopes and eyepieces do tend to be of poorer quality than you might expect. Also, you might be expecting more of your 'scope than it's capable of.

I'd suggest you try contacting a local amateur astronomy group. They're bound to have someone who can help you judge the quality of the optics.

However, do remember that professional photographs of planets are usually taken with very large telescopes. Most amateur telescopes can't be compared with them. Also, light pollution and atmospheric disturbance (e.g. hot air rising over cities, and warm air rising from your telescope's mirror) both can degrade what you see.

You might take a look at some of the amateur astronomy web forums. You might be surprised at just how "fuzzy" pictures can be.

True, we are only human, we're not gods with zooming powers. Well, not yet anyways.

I myself have an ancient 5" Edu-science refractor with 300X max zoom. It is worthy of the gods though, it has such a high quality mirror, so you can pick off the smallest crater on the moon. And the tripod is so rickety you can barely keep it steady. I should get a new tripod.