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Problem with Celestron travelscope 70


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Hello all,

I have just bought a Celestron Travelscope 70 to start with my "baby steps" in the astrogazing field and I am experiencing the following problems:

  1. The finderscope is always blurry. I tried to re-adjust the focus but I could never get a clear image of anything. Last night, when I tried it on the moon, I just got a bright yellow circle...
  2. I also got everything blurred with the main scope. I tried both the 10 and 20 eyepieces, but I could not get a clear shot of anything. Also, I tried it on the moon, but I also got the aforementioned blurred and bright yellow circle. I tried the focus handle on every position, but I got nothing.
  3. The 45° erect image diagonal was missing from the package. Does it make any difference to the performance of the main scope?

Since that particular scope can also be used for terrestrial observations (e.g. birds etc), I find it really difficult to believe that everything is broken :P. I must be doing something wrong...

Thank you in advance for your help!

P.S. I hope to resolve the issue soon, since this is my first attempt on the field and I don't want it to go south from the first step... 

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Hi, and welcome to the forum.

I assume you bought the scope used? If not certainly get back to the retailer, and if so then I would ask the seller why they sold it with parts missing.

The diagonal is normally needed to allow the scope to focus properly, and this seems to be the problem you are having, so first step is find the diagonal I would say.

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Thank you Stu for your quick reply!

I have already asked for the diagonal piece and I will try it out.

My first and most weird question is about the finderscope. Why can't it focus on anything? It does not make any sense at all...

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It is basically like the below image:

dGhVC.jpg

 

Just a bright blur. I tried to edit the focus, but there was no difference on either the finderscope or the main scope.

Edited by ntsalis
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Sometimes the atmosphere is so turbulent you won't get focus, and if the target is low in the sky this can to create an view difficult to focus.

But right now you are missing a diagonal so focus will not be possible. There is a focal distance required from the front glass elements to where the focus occurs and this is currently behind where your eye peice can sit as you are missing a diagonal.

Not sure what is going on with the finder unless it too is missing a bit hence the request to see a picture of your finder.

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The finder on those is a 5x24mm I seem to recall. It's not an achromat lens and it may even be stopped down to a smaller aperture by an aperture ring just behined the finder objective lens.

That said it should at least come to some sort of focus. I think the eyepiece end can be screwed in and out to reach focus on those finders ?. Rather like the one I've pictured below.

finder.jpg.c427df32ff6e3ab9fb908ebde16753db.jpg

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You are right, but it should work at least for terrestrial objects.

Also, the main scope does not include any mirrors, so it all comes down to the eyepieces.

Any more ideas on why both the finder and the scope are blurred at any direction?

I have read something about the temperature inside/outside, but I cannot recall.

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8 minutes ago, ntsalis said:

You are right, but it should work at least for terrestrial objects.

Also, the main scope does not include any mirrors, so it all comes down to the eyepieces.

Any more ideas on why both the finder and the scope are blurred at any direction?

I have read something about the temperature inside/outside, but I cannot recall.

If the telescope is missing its diagonal then the focuser drawer tube needs to be extended further by a similar distance out to compensate. The finders focus probably just needs adjusting. Some designs allow the front element to be moved forwards or backwards, not sure if this one does. Don't expect crystal clear views through the finder, it is just a simple refractor telescope.

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Thank you both for the valuable feedback.

There is no difference when using it during the day, for neither scopes. It is again blurred.

@cornelius: Of course I am not expecting a crystal clear view from the finder, but I would expect something visible at least

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30 minutes ago, ntsalis said:

Thank you both for the valuable feedback.

There is no difference when using it during the day, for neither scopes. It is again blurred.

@cornelius: Of course I am not expecting a crystal clear view from the finder, but I would expect something visible at least

In your shoes, I would troubleshoot the main telescope issue first - which means getting that diagonal.

Did you buy it new or used?

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So guys, problem solved!

1) The finder was faulty, so it was replaced.

2) Once I added the diagonal piece (that was missing) everything was perfect!

Overall it is a nice scope, but it is quite limited, due to the fact that it is a 70mm one. Is there any addition to enhance magnification? Maybe a smaller eyepiece? For instance, I could see Jupiter and its moons and Saturn (a sense of its rings), but I would really appreciate something better :)

Any suggestions will be more than welcome!

Edited by ntsalis
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Different (better quality) eyepieces  would improve the performance, and shorter focal length eyepieces or a Barlow lens will increase the magnification,  but don't expect too much. As the name suggests, the 70mm Travelscope is meant to be portable, and it is best used for wide fields of view and low magnification.  As it happens, I have a 70mm vintage telescope that performs very well (for its aperture) at high magnifications, but putting together its equivalent today (with mount) could cost quite a lot of money.  I spent around £200 on a mount for this long scope. 

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The Travelscope 70 is an F/5.8 achromat refractor so it's mainly designed for low to medium power observing. Using short focal length eyepieces will give more magnification but the view is unlikely to be crisp and clear over around 60x-70x and the chromatic aberration that the scope produces (in common with other scopes of similar spec) will become more and more apparent.

 

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I think it all comes down to the following things:

  1. scope itself
  2. eyepieces you use
  3. the mount and
  4. good environmental conditions

I have decided (for now) to keep the travel scope and maybe add a 6mm eyepiece for a better view of some planets.

Regarding nebulas and galaxies, you can easily use a 25mm eyepiece, right? As far as I understand, it is not about focus, but rather the environmental conditions and the scope's strength. 

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Hi  everyone,   I  have owned a Celestron Travelscope for about two years, and I thoroughly agree with all the previous comments. Another sure way of improving the performance of this scope is to mount it on a much sturdier tripod, the one supplied is little more than useless for the purpose, as vibrations are a major factor in spoiling your view of the heavens. Also I think you have to accept the limitations of this scope for astronomy, it will however, give lovely low power views of the moon, especially using the 20mm eyepiece supplied.  I personally would not waste time or money on a 6mm eyepiece, use the 20mm supplied to enjoy widefield views of stars clusters, the milky way and the brighter deep sky objects. If your interest is sparked you could later invest in a bigger and better scope, if you want to get a decent image of the major planets I would suggest at least 100mm in aperture.    Good luck and do not despair.    Chris.

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