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What are two main properties that astronomers use to classify stars ?

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How many stars are there

"Astronomers estimate there are about 100 thousand million stars in the Milky Way alone. Outside that, there are millions upon millions of other galaxies also!"

Source: How many stars are there in the Universe

Hope that helps!

Mar 05, 2014 | Computers & Internet


What are those SMALL letters with numbers on the star chart?

Those are OBJECTS in the sky that you can try to find and observe!

"M" objects- this is the Charles Messier catalog containing over 100 sky objects he discovered in the 17th century!

"NGC" objects- this is the New General Catalog by J.L.E.Dreyer produced in the late 1800s and early 1900s. It has over 7000 sky objects that you can observe. Some of these are very dim and only possible to see in larger telescopes or from a dark sky observing site.

"IC" - this is the later Index Catalog produced by Dreyer Same web site

There are dozens of other sky catalogs! My computer GOTO telescope lists 30,000 objects in it's internal database.

Here is a very good star chart:

And here is a free monthly star chart:

I would also recommend that you download the free planetarium software Stellarium, install it on your computer, put in your location; and it will show you the sky for any time or date. The graphics of the sky on this free program are VERY good.

Another good FREE computer star chart is Cartes du Ciel. The free download is available here:

Clear Skies!


on Jan 02, 2010 | Optics

1 Answer

My land scope is showing the pictures up side down does anyone know how to fix this issue this is a brand new bushnell scope

This is an astronomical telescope-- all astronomical telescopes show upside down and or reversed images. It's completely normal.

For terrestrial viewing you must buy an "erecting prism diagonal" similar to these:

Jul 15, 2011 | Bushnell 675x5 EQ Reflector Telescope

1 Answer

Image is upside down

Yes, nothing is wrong. All astronomical telescopes show upside down images. For terrestrial viewing you can buy and erecting diagonal like this one:

Sep 10, 2010 | Tasco Galaxsee 45-060675 Telescope

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I have a tasco galaxsee 45-114375 and misplaced my manua. l My image is upside down, how can I change that?

All astronomical telescopes have upside down images. It's perfectly normal.

You can buy an "erecting prism" for terrestrial viewing.

Here is one:

The manual will only have assembly instructions. It will not tell you how to use the scope or how to find objects in the night sky. Read my TIPS on my profile page-- a free monthly star chart is available here:

Aug 14, 2010 | Tasco Galaxsee 46114375 (375 x 114mm)...

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I was given a 12TE-5 Tasco telescope without any manual and I would like to know how to assemble and use

Look at the picture on this web site:

This is a classic Japan made Tasco refractor.

Very simple to assemble-- just by looking at the picture above.

Then read my TIP -- frequently asked questions- on my profile page.

Buy a good astronomy book like:

Turn left at Orion



Both available on

Mar 28, 2010 | Tasco Astronomical 302675 Telescope

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The view through my telescope is upside down. Why?

All astronomical telescopes show upside down images. There is no up or down in space.

You can buy an erecting prism from this supplier and others.

Astro-telescopes don't have this because it adds more glass between you and the sky object. These are only used for terrestrial viewing.

Nov 18, 2009 | Tasco Astronomical 302675 Telescope

1 Answer

How does a telescope used, and can we see a star through it even if the star is really really far?

Put the eyepiece with the largest number written on it into the telescope. Go outside during the day and practice focusing on a distant object.

Stars ALWAYS look like -------------- stars no matter what telescope you use. They are all too far away to see as a "disk" , always just points of light.

The closest star is Proxima Centauri at 4.2 light years away.

That is about 25 TRILLION miles!

Oct 30, 2009 | Tasco Astronomical 302675 Telescope

1 Answer

Image upside down

Hi, this is a common "problem" for astronomical telescopes. Same with my Meade 3" refractor and spotter. It is actually a design 'feature' not broken.

The issue is that most astronomical telescopes naturally show images upside down, or some combination of upside down and left-right.
(Astronomers usually don't care, because space has no up or down.)
It is just the way optics work when lenses or mirrors bounce and bend light. (And since the professional astronomer wants the most light and most direct image, they usually don't want extra devices just to make it right-side up.)

Reason that binoculars don't do that , is they employ special internal prisms to get the image back right-side up.

Easiest solution for astronomical telescope is to buy what is called a "star-diagonal" or "image-erector prism". These will usually make the image look normal for us earth-based folks.

I do not know what exact type your Meade 227 telescope is, but the spotter scope is most likely a simple refractor. So it MAY be possible to install a star diagonal onto it. Or might not. Depends on the exact spotter scope design.
Another option may be able to buy a replacement spotter scope that is designed for correcting image orientation.

Aug 10, 2009 | Meade DS-2114 ATS (325 x 114mm) Telescope

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