Is this telescope any good?

In My Humble Opinion
1

Calling all the astronomy types here…

I’ve found the following telescope for sale on Ebay and need advice on whether it’s worth getting or not.

Link

The details are:
* Tasco 375x Astro 112mm Reflector
* Model 302911 375x Astronomical reflector
* Magnification: 25x 75x 125x 375x
* Objective Aperture: 112mm
* Focal Length: 500mm
* Mount: Full Equatorial with Altitude Azimuth and Hour circles
* Trackers: 2x manual flexible controls
* Eyepieces: 20mm, 4mm Huygenian type.
* Full size adjustable wooden tripod
* 3x Barlow Lens
* 5x25 Finderscope
* Accessory bracket to hold 5 x optics
* Can be adapted to fit standard SLR cameras by using an optional camera adapter tube (#6660) and a T-mount.
* Galaxsee Skywatch Software CD-ROM
* Star Maps, Moon Maps and Astro guide
* 10 years Manufacturers warranty

Are there any extras I should consider getting straight away? I’ve seen someone mention the Huygenian eyepieces aren’t very good.

Thanks in advance,

Tuco.

2

Sorry, its pretty bad. A bunch of cheap accessories are thrown in to make it seem more attractive.

Tasco pretty much sucks.

3

It’s cheap, but you’re getting what you pay for. The aperture is small, and the finderscope is uselessly small. You’ll never, ever get 375x magnification from that scope. It’ll be a blur.

If this is your first scope you don’t see super high quality stuff or expensive eyepeices. But you do need more aperture, of you’ll be disappointed with the view, and you definitely need a better finderscope.

4

How about this unit? Seems pretty affordable.

Purchase ETX-70AT Astro Telescope w/Autostar Controller and Tripod:

5

Kinda small and short. For very low magnifications it is ‘sorta OK’. Most of the folks on the sci.astro.amateur group don’t think much of it.

6

Furthermore, I can assure that the mirror in there is a spherical, not a parabolic. When you have a focal lenght as short as the one listed (500mm) that’s pretty much an image killer.

7

Here is the technical rundown, assuming everything is extremely good quality:

112mm (4.5 inch) aperture, 500mm focal length = f stop of f/4.45. This makes it a “fast” scope, for wide “rich field” viewing.

Based on the aperture, your maximum resolution will be 1 arcsecond.
Your magnification limit will be x220. To figure out what eyepiece that is, divide the focal length by the desired magnification, to get the eyepiece size.

You can figure that its performance in terms of magnitude, the brightness or faintness of objects you will see will be average to poor, even worse if you live in the city or suburbs.

Your scope will not be too great for seeing faint objects - nebulas and galaxies, because of the small aperture. It will also not be good for planets, because of the short focal length.

Since it is a fast scope, focusing will be touchy, and there will be greater demands on the need for a nearly perfect mirror. Slower scopes are more forgiving.

I have a 4.5 inch scope, with a focal length of 900mm (f/8). For a bginner, it is OK, but I also have several Plossl eyepieces and filters, and I never try for maximum magnification.

Your tripod is probably not very solid. Beef it up to control vibration, or get a better set of legs.

Finally. Toss those Huygens eyepieces in a drawer and leave them there. Get a few decent Plossls, as they are a good general purpose eyepiece. I suggest 40 or 32mm, 25mm, and a 15 mm.

8

Thanks for the replies, you’ll be glad to hear I won’t be getting that one (due to advice from here and another board), though I will be looking at a decent one in the near future (fingers crossed).

9

If you want “the most scope for the dollar”, look at the Orion and Discovery Newtonian (reflector) scopes, on a Dobsonian mount. For a beginner, a 6 incher might be good enough, or even an 8 inch. And, get some decent eyepieces.

10

Trouble is, he’s in England and shipping costs would be a bitch.

11

There has to be something equal over there, maybe he can check in some of the l astronomy magazines, or locate a local club that knows a source. An alternative would be to build one, but that is not something for a beginner to try. By the way, any department store scope such as a Tasco will definitely have a spherical mirror. A parabolic would carry a premium cost.