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View Full Version : My telescope is broken! ::giggle:: ::snort::



Tom
2003-Jan-04, 06:53 PM
http://www.compgeeks.com/details.asp?invtId=78-4500

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NOTE: This is an astronomical telescope. As such, images will appear upside-down. We will not accept returns for this reason.
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Wonder how they decided on that particular disclaimer?

Sum0
2003-Jan-04, 07:46 PM
I like the other "product requirement"...
* Clear line of sight
Ah, so this isn't the Chandra X-ray telescope that can see through buildings...

Hale_Bopp
2003-Jan-04, 08:39 PM
Personally, I want to see the 675x magnification through a 4.5 inch telescope!

They really hammer that upside down image thing, don't they? You would think they would push the "optional image erecting prism" as an add on.

Rob

Smaug
2003-Jan-04, 09:32 PM
On 2003-01-04 15:39, Hale_Bopp wrote:
Personally, I want to see the 675x magnification through a 4.5 inch telescope!

Rob


Heh, yeah I wish I could get that kind of magnification with my 6 inch.

Glom
2003-Jan-04, 10:38 PM
675x4.5-inch(114.3mm) reflector

According to Terence Dickinson and Alan Dyer of The Backyard Astronomer's Guard, trying to sell a telescope on the basis of its magnification is a sign of a 'Christmas-trash scope'. In fact, they say, "We've seen models advertised as providing 675x! All are sure signs that the telescope is just a junky toy in disguise." In fact, according to the BAG, the highest usable power for a 5 inch telescope is 200x. I wish I'd known that before I bought my 4.5 inch scope. I can use my 4mm lens to observe at 125x, which gives fairly okay views, but when I add a 3x Barlow lens to get 375x, the image is all fuzzy.

4mm, 12mm and 20mm eyepieces

I didn't get a 12mm, but I did get the other two. The 20mm was Huygenian and the 4mm was Ramsden. I found out from reading the BAG, that these are crappy eyepieces. They don't actually say what sort of eyepieces you'll be getting. If this was being targetted at amateurs who knew what they were talking about, they would probably say.

1.25-inch format eyepieces

That's okay. It 0.965 inch you have to worry about. That's a symptom of CTS.

Professional primary mirror

Yeah, but what kind? Spherical or paraboloidal? An unknowing buyer will not understand these terms but they will understand professional and be led into thinking it's good.

5x24mm finderscope

That can be misleading. According to the BAG, many finders are advertised like this but end up being stopped down inside to about 10mm. But I can't see a good picture of the finderscope to decide if this is one of them.

NOTE: This is an astronomical telescope. As such, images will appear. . .
. . .upside-down. We will not accept returns for this reason.

Any amateur astronomer who had read into the business before going out to buy a telescope would already know this. It smacks of targetting unwitting parents, who know nothing about it, trying to get their kid a new telescope for Christmas (ie a CTS).

Kelfazin
2003-Jan-05, 12:12 AM
Hey, while we're on the topic, what's the max mag i can get with an 8" f/6? According to Discover Telescope (from whom I bought my scope) it's 255x...this accurate?

Kaptain K
2003-Jan-05, 12:50 AM
On 2003-01-04 19:12, Kelfazin wrote:
Hey, while we're on the topic, what's the max mag i can get with an 8" f/6? According to Discover Telescope (from whom I bought my scope) it's 255x...this accurate?

The basic "rule of thumb" is 50X/inch of aperture. So, figure 400X for an 8 inch scope.

nebularain
2003-Jan-05, 02:53 AM
Regarding: NOTE: This is an astronomical telescope. As such, images will appear upside-down. We will not accept returns for this reason.

I'm betting they added this because several people [i]already have /i] tried to return their scopes for this very reason!

Tom
2003-Jan-05, 03:21 AM
I'm betting they added this because several people already have tried to return their scopes for this very reason!


Yah, I'm sure voyeurism isn't as much fun when you have to hang upside down like a bat to see the neighbors right side up.

Dickenmeyer
2003-Jan-05, 05:44 AM
But if I plug my FM receiver and a set of rabbit ears into it will I have a radio telescope? That would be cool...

aurorae
2003-Jan-06, 08:55 PM
On 2003-01-04 19:50, Kaptain K wrote:


On 2003-01-04 19:12, Kelfazin wrote:
Hey, while we're on the topic, what's the max mag i can get with an 8" f/6? According to Discover Telescope (from whom I bought my scope) it's 255x...this accurate?

The basic "rule of thumb" is 50X/inch of aperture. So, figure 400X for an 8 inch scope.


Perhaps the number from Discover was the magnification through the smallest eyepiece that was supplied with the telescope?

Let's see, an 8 inch at f/6 would have a focal length of about 1200 mm (if my math is correct), so 255x would be with a 4 or 5 mm eyepiece. So maybe my math wasn't exact, and they figured the max mag with a 4mm eyepiece.

But the Kaptain is correct that most folks figure 50x per inch of aperture as a rough limit. However, the clarity of view not only depends on the quality of the optics (mirrors and eyepieces) but also on the seeing at that particular time. Some nights are much better than others.