Chatroom
 

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Bad Astronomy and Universe Today Forum > Space and Astronomy > Astronomical Observing, Equipment and Accessories
Register FAQ Members List Calendar Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 04-January-2003, 05:53 PM
Tom Tom is offline
Senior Member
 
Join Date: Oct 2001
Location: Gonzales, LA
Posts: 170
Send a message via AIM to Tom Send a message via Skype™ to Tom
Default

http://www.compgeeks.com/details.asp?invtId=78-4500

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

Wonder how they decided on that particular disclaimer?
Reply With Quote
  #2 (permalink)  
Old 04-January-2003, 06:46 PM
Sum0 Sum0 is offline
Member
 
Join Date: Aug 2002
Location: Norwich, UK
Posts: 67
Default

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...
__________________
"I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
Reply With Quote
  #3 (permalink)  
Old 04-January-2003, 07:39 PM
Hale_Bopp Hale_Bopp is offline
Senior Member
 
Join Date: Oct 2001
Location: Tucson, Arizona
Posts: 614
Default

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
Reply With Quote
  #4 (permalink)  
Old 04-January-2003, 08:32 PM
Smaug Smaug is offline
Senior Member
 
Join Date: Oct 2002
Location: Las Vegas
Posts: 209
Send a message via AIM to Smaug
Default

Quote:
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.
Reply With Quote
  #5 (permalink)  
Old 04-January-2003, 09:38 PM
Glom's Avatar
Glom Glom is offline
Senior Member
 
Join Date: Sep 2002
Location: University of Birmingham
Posts: 6,649
Send a message via MSN to Glom
Default

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).
Reply With Quote
  #6 (permalink)  
Old 04-January-2003, 11:12 PM
Kelfazin's Avatar
Kelfazin Kelfazin is offline
Senior Member
 
Join Date: Mar 2002
Location: Phoenix, Arizona
Posts: 1,412
Default

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?
Reply With Quote
  #7 (permalink)  
Old 04-January-2003, 11:50 PM
Kaptain K's Avatar
Kaptain K Kaptain K is offline
Senior Member
 
Join Date: Oct 2001
Location: Elgin, Tx
Posts: 7,537
Default

Quote:
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.
__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson
Reply With Quote
  #8 (permalink)  
Old 05-January-2003, 01:53 AM
nebularain's Avatar
nebularain nebularain is offline
Senior Member
 
Join Date: May 2002
Location: Central MD
Posts: 2,049
Default

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!
Reply With Quote
  #9 (permalink)  
Old 05-January-2003, 02:21 AM
Tom Tom is offline
Senior Member
 
Join Date: Oct 2001
Location: Gonzales, LA
Posts: 170
Send a message via AIM to Tom Send a message via Skype™ to Tom
Default

Quote:
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.
Reply With Quote
  #10 (permalink)  
Old 05-January-2003, 04:44 AM
Dickenmeyer Dickenmeyer is offline
Senior Member
 
Join Date: Jan 2003
Location: McCordsville, IN
Posts: 331
Default

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...
__________________
If you can't dazzle 'em with dexterity, baffle 'em with BS.
Reply With Quote
  #11 (permalink)  
Old 06-January-2003, 07:55 PM
aurorae aurorae is offline
Senior Member
 
Join Date: Oct 2001
Posts: 321
Default

Quote:
On 2003-01-04 19:50, Kaptain K wrote:
Quote:
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.

Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT. The time now is 06:20 AM.


Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
LinkBacks Enabled by vBSEO 3.0.0
©  2006 Bad Astronomy and Universe Today