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View Full Version : Junk telescope will not work



2001-Nov-25, 01:08 AM
Ok, here is the deal. I own a Tasco telescope that cost about 100 dollars. I live in Maine. I left it outside for an hour before trying it. And guess what? It did not work. I do live in a smal city with street lights around however I was well away from them. I found a spot that was dark enough. Atleast in my opinion. Then again, I know nothing about astronomy. Any help would be great.

Lisa
2001-Nov-25, 04:58 AM
Can you be a little more specific? What exactly didn't work? Can't see anything? Can't focus?
Lisa

Trish
2001-Nov-25, 07:27 AM
Also, what magnification are you using with your eyepiece? What size is the telescope? 2", 4"?

David Hall
2001-Nov-25, 09:05 AM
My friend owns a couple of cheap junk telescopes. They aren't good for very much, but they do have their uses. And when you're strapped for cash, they're better than nothing. But you have to realize what you're dealing with and not expect too much.

He likes to use one of them for solar observing. He uses it to project an image on a sheet of carboard to see sunspots.
they're also not too bad to get views of the larger planets, Jupiter and Saturn. But you aren't going to get much detail. You aren't going to see much in the way of galaxies, nebula or such.

If you're having problems, maybe you're trying to see something it's not capable of catching. Or maybe you have a physical problem with the scope itself. The mirror or eypiece may be out of alignment. Or the mirror was fogged up or something (though an hour outside should have equalized tempratures).

I'm afraid as the others have said that we'd need more info to diagnose your problem.

Lisa
2001-Nov-25, 09:13 AM
David is right, alignment can be a huge problem. You should have seen my husband and I trying to set up our scope. Let's just call it "Two complete morons without a clue" and let it go at that. We finally got the hang of it. Good thing. We have a tendency of tossing the thing in the car and going places.
And setting up the spotting scope! I'm afraid that will never be accomplished to our satisfaction.
Lisa

Torsten
2001-Nov-25, 05:21 PM
The first scope we bought and which we still have, was a 60 mm 30x-90x zoom spotting scope. It was designed for terrestrial viewing and has the prisms inside it for righting the image. Anyway, it's a real bear for astronomical viewing due to its narrow field of view and lack of a finder scope, and could rightly be classed as a junk scope. It turns out that the ETX we bought later is much better for both terrestrial and astronomical viewing, so we hardly use the old one anymore.

But I learned a few things using the old scope. The first one was to use it during the day to learn just how well it focusses, how sensitive it is to vibration, and so on. The other was that since it lacks a finder scope, it was necessary to find a way to get it pointed in the right part of the sky at higher magnification, because with its narrow field of view I really had to hunt for objects. So I simply taped a couple of thumbtacks in appropriate spots on either end of the optical tube to serve as a sort of "iron sights". The position of these tacks was calibrated on a distant object in daylight of course.

The best use I have had of this scope however, is as David pointed out, for solar observing. I fashioned a cone out of a large piece of black construction paper and taped a piece of white paper to the wide end to serve as a projection screen. The narrow end is open and fits snuggly onto the eyepiece. A section of the cone was cut out to enable seeing the screen. The projected image of the sun is about 10-12 cm in diameter. This scope stands ready to use in the corner of a room and I can get a view of the sun in a matter of seconds. If it looks interesting, I can then take out the ETX and solar filter for a really good view.

Anyway, the point of all this is that you can have fun with and get utility from those junk telescopes, it's just that they don't make it very convenient and you have to be crafty.

2001-Nov-26, 09:22 PM
It is a 4 mm mag eyepiece. I tried to focus the scope in daylight and everything came out fuzzy. Thank you for all the reply.

Torsten
2001-Nov-26, 10:31 PM
Hmmmm. The 4mm eyepiece may have a lot to do with it. I'm going to guess that your scope is a 60 mm refractor. If your telescope has a focal length between 700 and 900 mm, this translates into a magnification of 700/4=175 to 900/4=225 when using this eyepiece. It's a general rule of thumb that useful maximum magnification is about 2x per mm of aperture for such a scope. So you're probably "overpowering" it. 4 mm eyepieces have notoriously poor eye relief as well. You probably just about have to jamb your eyeball against the glass to see anything. And if the eyepiece has a .965" diameter barrel, rather than a 1.25" barrel, it's even worse because these tend to give a narrow field of view. So try a longer focal length eyepiece if one was provided and see how it works.

And don't despair. There's more advice regarding your scope here:

http://www.seeviewo.org/seeview/beginners/articles/tascosc.htm

as well as a number of other beginner sites. (I chose to show you this one because they don't completely disparage the Tasco scope /phpBB/images/smiles/icon_smile.gif )

2001-Nov-26, 10:46 PM
Thanks for the info Torsten. I will see if I have a 2mm.

2001-Nov-26, 10:50 PM
By the way. The scope say it has a overall power of 525. Does that mean anything?

David Simmons
2001-Nov-27, 01:38 AM
On 2001-11-26 17:50, Jimi Hendrix wrote:
By the way. The scope say it has a overall power of 525. Does that mean anything?


The first, and I think the worst, mistake that beginning telescope users make is to try to overmagnify the image. I know I did.

For example, I discovered that for my first, 4" mirror, which had a focal length of about 30" my best viewing was with a 10 mm eyepiece giving a magnification of about 75. If the viewing was really good, and I live on the desert, I could go to 8 mm and on occasion 6 mm.

The first thing I did was to slap the 4 mm eyepiece in and I couldn't see anything. I soon learned to start at low magnification and gradually increase, usually stopping at about 10 mm.

I soon gave my 4 mm eyepiece to by sister's 4 year old as a toy.

Kaptain K
2001-Nov-27, 10:59 AM
I will see if I have a 2mm.
That would make the situation worse. What you need is a longer focal length eyepiece. Start with one in the 20 - 25 mm range. Magnification is WAY over rated. The advantage of a telescope is light gathering power. 60 mm is 12 times the diameter of the fully dilated eye (5 mm), which gives 144 (12*2) times as much light, so you can see much fainter objects and objects you can see will be much brighter.

By the way. The scope say it has a overall power of 525. Does that mean anything?
Pure, unadulterated advertising hype. The laws of physics limit the maximum magnification to about 50X/inch (or 2X/mm) even with perfect optics. Above that, you are merely magnifying aberations due to diffraction.

_________________
TANSTAAFL!

<font size=-1>[ This Message was edited by: Kaptain K on 2001-11-27 06:00 ]</font>

aurorae
2001-Nov-27, 05:05 PM
Typically, the 4mm eyepiece on these trashco scopes are really cheap Huygens designs, with a miniscule field of view. So even assuming you could get something to focus, it would be almost impossible to get it in the eyepiece. Especially with the shaky mount.

Would it be possible to return the scope and get your hundred dollars back? If you save your money until you get about $300 (well, $200 is possible but $300 is a lot better) then you would have a real telescope that would be usable.

2001-Nov-27, 06:14 PM
That really really SUCKS. LOL. So what you guys are saying is that I got screwed. It is too late for me to take the scope back because it was bought about 5, 6 years ago. Oh well. I will learn from this mistake next time.

Hale_Bopp
2001-Nov-27, 07:27 PM
Don't worry about it...I'll bet about 80% of the people on this board had a first telescope just like yours weather they will admit it or not /phpBB/images/smiles/icon_smile.gif

Mine wasn't a Tasco...I can't remember the brand, but it was a 60mm, "280x" refractor. I lived in a northern climate and even would set it up inside and look out through our patio doors, just to add another layer of distortion to the image! Hey, it might have produced lousy images, but when your age is still in the single digits, you don't have very high standards!

Rob

David Simmons
2001-Nov-27, 08:06 PM
On 2001-11-27 13:14, Jimi Hendrix wrote:
That really really SUCKS. LOL. So what you guys are saying is that I got screwed. It is too late for me to take the scope back because it was bought about 5, 6 years ago. Oh well. I will learn from this mistake next time.


Don't give up yet. My first scope was an inexpensive (polite word for cheap) Criterion 4".

Try starting, as was suggested in an earlier post, with a 25 or 30 mm eyepiece. Make sure the telescope is aligned. To do that, look into the eyepiece hole with the eyepiece removed and center the image of the diagonal in the mirror using the adjusting screws on the back of the main mirror mount.

2001-Nov-27, 09:12 PM
Thanks again for the info guys. But I can't seem to find 25mm to 30mm eye pieces. I guess I lost them. I think I am going to cut my loses and find another scope to buy. Any suggestions???

And, by the way. I am not the real Jimi Hendrix.

aurorae
2001-Nov-27, 09:13 PM
On 2001-11-27 15:06, David Simmons wrote:
Don't give up yet. My first scope was an inexpensive (polite word for cheap) Criterion 4".

Try starting, as was suggested in an earlier post, with a 25 or 30 mm eyepiece. Make sure the telescope is aligned. To do that, look into the eyepiece hole with the eyepiece removed and center the image of the diagonal in the mirror using the adjusting screws on the back of the main mirror mount.


The Criterions of yesteryear were a lot better than the Tasco refractors of today.

I think he has a 60mm refractor, so the advice on adjusting the secondary mirror doesn't apply. Because a refractor doesn't have one.

In addition to using the low power eyepiece (20mm or so), make sure that the tripod is as tight as you can make it (tighten all the screws) to reduce wobble.

Also, you might want to think about building an alt-az mount for it. I remember seeing plans and pics on the web someplace where someone did that very thing. (trundles off to look)

Here is one that is a little more advanced than what I was thinking:
http://home.att.net/~dale.keller/atm/refractors/keller5/keller5.htm

Here is a great collection of beginner info:
http://observers.org/beginner/

aurorae
2001-Nov-27, 09:16 PM
On 2001-11-27 16:12, Jimi Hendrix wrote:
Thanks again for the info guys. But I can't seem to find 25mm to 30mm eye pieces. I guess I lost them. I think I am going to cut my loses and find another scope to buy. Any suggestions???

And, by the way. I am not the real Jimi Hendrix.


I thought you seemed a little too lively. /phpBB/images/smiles/icon_smile.gif

Try this web page first:
http://observers.org/beginner/j.r.f.beginner.html

It is one of several really good beginner advice pages on the web.

Then come back with more specific questions.

It's hard to give specific advice on telescopes, because there is such a wide range of technology and prices. It's really about you, not about the scope. So you need to figure out what you are going to do with it, how you are going to use it, what limitations and preferences you have.

Anyway, read an FAQ and then post again.



<font size=-1>[ This Message was edited by: aurorae on 2001-11-27 16:23 ]</font>

Argos
2001-Nov-28, 10:10 AM
On 2001-11-27 14:27, Hale_Bopp wrote:
Don't worry about it...I'll bet about 80% of the people on this board had a first telescope just like yours weather they will admit it or not /phpBB/images/smiles/icon_smile.gif


My first was a dreadful 20 mm galilean scope. But It got me to discover the Moon. Now it lies right here in front of me, comfortably retired. It is a souvenir of a time of romance and discovery. I like it very much.

Eleapt
2002-Aug-14, 11:15 PM
Quote:
--------------------------------------------------------------------------------


On 2001-11-27 14:27, Hale_Bopp wrote:
Don't worry about it...I'll bet about 80% of the people on this board had a first telescope just like yours weather they will admit it or not

I guess, I should condider myself very fortunate indeed to having started with a
10 inch dobsonian.

Chip
2002-Aug-14, 11:39 PM
On 2001-11-27 16:12, Jimi Hendrix wrote:
"And, by the way. I am not the real Jimi Hendrix."

Ah too bad! I was just about to compliment you on how cool your "Electric Ladyland" album sounds.
Anyway, another problem with cheap telescopes is that a lot of them come with really terrible tripods. The worst are those with wobbly wooden ones locked down with crude "wing nuts." Even a cheap scope can seem to work better if its mounted on a solid base. (Dobsonians are excellent designs for avoiding wobbly images.) Mead and Celestron are but two top brands, and they come with excellent tripods and lots of great accessories and eyepieces. Check out their website via http://www.google.com.

JimB
2002-Aug-15, 02:03 PM
You can buy replacement eyepieces if you've lost the others. All brands are interchangable if the diameter of the eyepiece barrel is the same. A 0.96-in is common on inexpensive scopes and there are a few for this size. The 1.25-in eyepieces are much better and have hundreds of options. This mail-order site has lots of options:
http://www.telescope.com
I'm sure a 25mm (low power) would help you get a good daytime view and a good view of the moon.

Check out this site, too.
http://www.scopereviews.com/begin.html
Tons of good information and reviews of many different scopes.

Where do you live? Is there an astronomy store nearby or a club?
Clear Skys

David Hall
2002-Aug-15, 02:37 PM
Uh, I hope you all realize that this thread is over half a year old. Jimi doesn't seem to have popped his head around here for a quite a while.

Well, I suppose it's still good info for other readers. And who knows, maybe Mr. Hendrix is still lurking around out there. /phpBB/images/smiles/icon_confused.gif