Telescope Reviews: When to use which and why... please.

OK, let's start with some basics. Your scope has a 5" aperture and a 1250mm focal length. A rule of thumb is that your maximum useful magnification is about 50 times your aperture which for you is about 250x. Keep in mind that more often than not the useful magnification will be limited by atmoshperic conditions so a more common maximum for you scope might be in the 150x to 200x range.

The magnification you can get from an eyepieces is equal to the scope's focal length divided by the eyepiece's focal length. So for your eyepieces:

Celestron 5mm = 250x
Baader 8mm = 156x
Baader 13mm = 96x
Baader 21mm = 60x
Meade 32mm = 39x

With this information, you can now get a better idea of what to use the eyepieces for. The first thing to notice is that the 5mm is right at the limit of you scope's magnification. Most nights you won't get much out of it. You'll probably see the same thing that you'd see in the Baader 8mm, just larger - but no more detail. This is known as empty magnification.

In most cases, when you GoTo and object with your scope, you'll want to use a lower power EP in the 40-75x range to locate your object since it may not be right in the middle after a GoTo operation. Then you'll ramp up to the magnification that lets you see it best. This is different for different objects since they are different sizes.

With planets, you'll probably want to use your highest useable EP which will likely be the 8mm at 156x. You can try the 5mm, but the Baader is a better quality and will probably show more detail.

Globular clusters need low magnifications to find, but respond well to higher magnifications if you have enough aperture to keep them bright. Note that higher magnifications mean less light. You'll probably end up viewing them at 100 to 150x

Galaxies are mostly small, but they are also dim. So while you'll want to go to a higher mag, you'll be limited by how much light you can see. Andromeda is an exception and is SO large that you'll need one of the lower mags, probably the 60x or 39x to fit it in the eyepiece.

Nebulae are all over the map. Some are huge and need low power, others are small and need higher power. Again, many of them are quite dim so you might be limited here just like the Galaxies.

I hope this helps!

-Dan

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Scopes: Celestron NexStar 8, Orion EON 72mm ED/APO on Astroview mount (EQ3)
Eyepieces: Celestron 40mm, 25mm, Baader Hyperion 13mm, 8mm, 5mm
Other: Telrad, 2x Barlow, 0.63x Focal Reducer, Dew-not strips, DewBuster controller