magnifying lenses

[gannook]

Hello. I bought two barlow lenses for my new Vixen VMC 110L telescope - a celestron X-cel LX and a Vixen 2X. both do little more than provide a larger, more blurry view of things. I also want to buy a lens that flips the image for terrestrial viewing. I just don't want to keep buying junky things and sending them back. Better to pay a little more and have something of quality, I think. Any suggestions?

 

[Ricochet]

What eyepieces are you trying to use with the barlows and your telescope? Neither barlow sounds like junk and it is more likely that you were trying to exceed either the atmospheric conditions or capabilities of the scope. Also, for high power viewing you need to ensure that the scope has been given sufficient time to cool and is properly collimated. 

[gannook]

I only have a 25mm lens that came with the telescope, a Vixen  110L. Just trying to view things on the mountains behind my house.

[Charic]

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[gannook]

The view is fairly clear without the barlow. Maybe I'm using it incorrectly, but I don't see how. I just put it in the hole and then put in the lense. Frustrating. Is a zoom different than a barlow, and might that be a better option for me?

[Cosmic Geoff]

The 25mm lens is an unknown quantity (with other makes the kit eyepieces are generally not very good).  With this design of telescope (long focal ratio) you don't need Barlow lenses at all. You might be better advised to buy shorter focal length eyepieces of good quality to increase the magnification.

A powerful large aperture telescope like this is unlikely to deliver its best by day, especially if the sun is out, causing heat shimmer.

The star diagonal which you probably got with the scope will deliver the image erect but mirror-reversed.  If this is not what you want, you can get prism disgonals (45 degree or 90 degree angle) that will completely correct the image. Be careful to avoid confusion with prism star diagonals which just turn the light through 90 degrees.

Correction - I see this scope has a built-in flip mirror, which probably means you have fewer options for changing the diagonal.

[gannook]

Good info. thanks.

[vlaiv]

Do you refocus after inserting a barlow (which you inserted properly - it goes instead of eyepiece, and eyepiece goes in barlow)?

With scope FL of 1035mm and 25mm you will be getting ~x41 magnification, with x2 barlow - this would be raised to about x82 - nothing your scope can't handle with ease, and image should be sharp

[Peter Drew]

Your 25mm eyepiece will give roughly 40x magnification, the 2x Barlows, which are both good quality ones, will raise that to over 80x. Far too much maginfication for long range terrestrial viewing, 50x is generally accepted as the highest for good results on the average.

[Charic]

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[Charic]

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[Cornelius Varley]

1 hour ago, gannook said:

Hello. I bought two barlow lenses for my new Vixen VMC 110L telescope - a celestron X-cel LX and a Vixen 2X. both do little more than provide a larger, more blurry view of things. I also want to buy a lens that flips the image for terrestrial viewing. I just don't want to keep buying junky things and sending them back. Better to pay a little more and have something of quality, I think. Any suggestions?

 

Large blurry views suggest that you haven't focused the telescope properly. The Vixen 110 and similar cassegrain type telescopes have a wide focuser range that requires many turns of the focuser knob to get from one end of the mirrors movement to the other.

[Ricochet]

1 hour ago, Peter Drew said:

Your 25mm eyepiece will give roughly 40x magnification, the 2x Barlows, which are both good quality ones, will raise that to over 80x. Far too much maginfication for long range terrestrial viewing, 50x is generally accepted as the highest for good results on the average.

This matches what I've found. When I take my spotting scope out I typically take eyepieces giving 28x and 39x. In the heat of summer the additional heat haze can make the 39x unusable. 

[pete_gamby]

For terrestrial use, this Vixen diagonal works with the VMC110L and is comfortable to use on the straight through view port:

https://www.vixenoptics.com/Vixen-Erect-Image-Diagonal-p/8791.htm

Have you checked the image quality with the Barlows at short range (30 to 50 yards) to eliminate possible problems caused by atmospheric conditions?

The eyepiece supplied with the scope is a stock Plossl rather than one from Vixen's NPL line so it is not the best of this type of eyepiece. However, it should be able to handle 80x mag no problem.

The VMC110L can be collimated if there is an issue with focus of the scope at higher magnifications (see attachment) but generally they are pretty good out of the box from the factory.

HTH

Pete

VMC95_VMC110L_Collimation_Guide.pdf

[Louis D]

18 hours ago, gannook said:

I also want to buy a lens that flips the image for terrestrial viewing.

There are 90 degree and 45 degree amici prism diagonals.  I have both types and they work well enough for daytime viewing.  It comes down to what angle feels most comfortable to you while viewing.