53 replies to this topic

[sojourneyer]

Hello All,

I have a post about 4" Refractors for purchase consideration but many of the suggestions for me were too much over the top (eg veterans who have been into astronomy for yonks)

 

Thus this posting

 

I would like to know what people think of the Omni AZ 102.  Both the standard and the XLT versions.

 

Specifically

how do you like the scope

its pros and cons

what changes have you made to your scope (eg mount, focuser, etc)

 

I WOULD ONLY LIKE TO HEAR FROM OWNERS PLEASE. 

 

Also in your comments please tell us what  version Omni you have-- for example, 102 XLT f/9

 

thank you

 

[jeffreym]

I have the Omni XLT AZ102 f/6.5.  I picked this up thinking it would make a good starter scope but also to compare it to some other 102mm refractors I had.

 

At about $200 the price is reasonable.

Easy to use ALT-AZ  mount with infinite slow motion controls.  The mount could be stronger but for the weight, it is about as good as it can be.  It's fine. 

The optics of the scope are impressive for a crown/flint doublet.  I have compared mine to the following 102mm scopes:  102 Tak, 102 Stellarvue Access,  Explore Scientific EDT102CF, Explore Scientific AR102, Meade 102 Infinity, Celestron 102 spotting scope (f/5).  I think my OMNI was equal to the EDT102CF except for the CA.  The Tak and the SV were clearly better optics but at 6x to 12x the price the views were maybe 10% improved.

I put a GSO dual speed fucuser on it but took it off as it was not necessary and made the thing a lot heavier. 

I did add tube rings in place of the stock dovetail so I could adjust the balance better for heavier eyepieces.

I have a Twilite 1 mount that I prefer over the Omni mount so I do use that more.

I have the OMNI XLT AZ130 (reflector) as well and that one stays on the OMNI mount it came with because that entire setup is just so light weight and easy to move around.

I have sold the EDT, the AR, the Infinity, and the f/5.  My OMNI will not be leaving any time soon.

I am clearly satisfied with mine.

Have fun,

Jeff

[sojourneyer]

Jeff, thank you for input was very good I appreciate it.

 

One other fellow replaced the mount/tripod With a vixen porta two

 He also installed a crayford 2 "focuser.

Celestron told me the optics on the XLT about 5% better than the standard 101 AZ

I will not be using a camera so do you think the current mount would suffice? Also is the mount/ tripod

made of metal or plastic?

 

 Again thank you 

[jeffreym]

The factory mount is fine as delivered if you don't use heavy eyepieces.  Just be sensitive to the weight you add. 

 

The mount is cast aluminum.  There are some plastic covers.  The tripod has a cast aluminum mounting plate with extruded aluminum legs.  The weakest link is the plastic locking brackets on the tripod legs.  They work fine just be careful around them and there is no need to over-tighten them. The thumb screws attach at a point that should be better reinforced.  I had my tripod lowered all the way putting the thumb screw near the ground, I stepped on one.  The screw and bracket snapped right off.  Obviously, the thing was not designed to be stepped on.  Celestron replaced the leg immediately.  I now keep the tripod legs extended 6". . .

 

Again, I would not add the two speed focuser.  The slight increase in performance is not worth the added weight.  I already had the Twilight 1 mount (about the same as the Porta 2)  which is 3x the mount as the OMNI.  Of course I like that better, anyone would.  But, the out-of-the-box kit is easily usable for a 1000 objects without adding anything.

 

Now with that said, I would add a 1.25" 99% dielectric mirror diagonal (I use the factory, CI diagonal for star hopping and for most viewing and switch to the mirror diagonal when viewing details like double stars or specific moon craters) and two eyepieces (Explore Scientific, 82 degree 14mm and 6.7mm).  I use the 6.7 to view double stars.

 

Hope this helps.

Jeff

Edited by jeffreym, 20 December 2019 - 06:38 AM.

[bobhen]

Not an owner but I did see the 102 AZ on the floor at my local astro shop.

 

The build quality looked very nice for the price. As others have said, I would add a nice diagonal right off the bat. Other than that, don’t add anything until you spend some time with the scope and figure out what you want/need. You’ll save money by not jumping ahead on accessories.

 

I have the faster Celestron 102mm F5 refractor that I have been enjoying for 16 years and the 102 AZ should deliver even better image quality.

 

I also have the 102mm F9.8 Celestron refractor OTA, which uses the same lens as the Omni XLT. The longer XLT will be slightly better on the moon and planets but will have a narrower field of view and of course will be longer.

 

If portability and deep sky objects are high on your list then the 102 AZ would be a strong consideration.

 

If you can deal with the larger and slightly more complicated setup of the 102 F9.8 and the moon and planets are more of a priority then the longer XLT would be a strong consideration.

 

Note that both scopes will do deep sky and the moon and planets, just one scope “slightly” better than the other.

 

If I were making the choice, I would pick the 102 AZ. Its portability and ease of use make it attractive. The 4” lens will be really wonderful for deep sky viewing and will do fine for the moon and planets and be more conducive to travel and daytime viewing. If later you become a lunar /planetary enthusiast, you can get something even better than the longer Omni XLT version. The money you save on the AZ you can put toward eyepieces, etc.

 

You won’t go wrong with any of these 4” Omni refractors. I usually recommend a 4” refractor over a 4.5” to 6” Newtonian/Dobsonian.

 

Bob

Edited by bobhen, 20 December 2019 - 07:47 AM.

[Jon Isaacs]

A friend loaned me a Omni 102 AZ for about a month.

 

For the price, it's a good enough scope. The mount is overloaded but usable.

 

The RACI diagonal only has 14 mm of clear aperture and I would replace it with an inexpensive star diagonal.

 

I'm not sure which eyepieces ship with the current version of this scope. If they're Hygenians like many entry level Celestrons they should be replaced immediately. They're Afov is about 30° and they're a poor choice for a scope this fast.. plus at least the eye lens is plastic.

 

In terms of recommendations, a 6 inch F/8 Dob is a more capable instrument, more light gathering, better resolution, no chromatic aberration. Mechanically the mount is stable without vibration. 

 

Jon

[Riccardo_italy]

Do whatever you want with your money, but an ED is light years better than an achro of the same focal lenght.

 

Look, I had a 100mm achromatic refractor, and it was one of the best available in the market (TAL100RS). The Celestron is of lower quality and, most important, faster (f6.5 instead of f10). I would never suggest, as a single scope, a fast achromatic refractor.

 

Finally, this is a mass produced bundle, with cheap accessories (nothing comparable with the eyepieces I suggest you in the other topic). You will regret if you choose the Celestron. Too many people buy cheap bundles and then quit the hobby.

Edited by Riccardo_italy, 20 December 2019 - 08:56 AM.

[Jon Isaacs]

Do whatever you want with your money, but an ED is light years better than an achro of the same focal lenght.

 

Look, I had a 100mm achromatic refractor, and it was one of the best available in the market (TAL100RS). The Celestron is of lower quality and, most important, faster (f6.5 instead of f10). I would never suggest, as a single scope, a fast achromatic refractor.

 

Finally, this is a mass produced bundle, with cheap accessories (nothing comparable with the eyepieces I suggest you in the other topic). You will regret if you choose the Celestron. Too many people buy cheap bundles and then quit the hobby.

 

Just as many if not more buy expensive bundles and then quit astronomy.  The Celestron Omni 102 AZ is far, far better than my first scope.. $5 at a garage sale, one 2 element eyepiece, no finder. 

 

The critical factor is not the telescope,  it's the individual. Amateur astronomy requires patience, persistence, curiosity, you can't buy that.. 

 

Sure a 4 inch apo is better optically but there's always a bigger, better telescope. Making the most of what you have, that's what it's all about.

 

Last night I spent about a hour with my 80 mm F/5 achromat. I had had my 120 mm apo out but decided I wanted a change of pace. I had some wonderful views and enjoyed the time with it..

 

My sister is a professor of modern history at the Università di Pisa. (This is true)  I think she told me she was looking through the archives and found a manuscript where Galileo said he almost gave up because he felt he needed an FPL-53 triplet instead of his crude singlet. (This is not true but makes a point.)

 

This 102 mm F/6.5 achromat is good enough.. If the first views don't thrill you, if they don't light a spark that turns into an undeniable passion, nothing will..

 

I've had friends whose first look through a telescope was a night under dark skies with my 25 inch. They enjoyed it but that's as far as it went.. it's not about the telescope.

 

Jon

[jeffreym]

One more thing, the kit comes with a very good 25mm plossl eyepiece and Celestron's Premium StarPointer Pro finder that projects a dual-circle reticle instead of a simple red dot.  No need to replace these.

 

I LOVED the CI diagonal that came with my 102 AZ.  I have lots of diagonals from $15 to $750 and have compared them plenty.  I use what I like and given all the choices I have, I used the CI so much I wore out the eyepiece set screw.  I recommend getting a good mirror diagonal but don't discount the view through the CI that comes with the kit.  Use it and then decide for yourself.

 

Jeff

[Jon Isaacs]

One more thing, the kit comes with a very good 25mm plossl eyepiece and Celestron's Premium StarPointer Pro finder that projects a dual-circle reticle instead of a simple red dot.  No need to replace these.

 

I LOVED the CI diagonal that came with my 102 AZ.  I have lots of diagonals from $15 to $750 and have compared them plenty.  I use what I like and given all the choices I have, I used the CI so much I wore out the eyepiece set screw.  I recommend getting a good mirror diagonal but don't discount the view through the CI that comes with the kit.  Use it and then decide for yourself.

 

Jeff

 

The main trouble with the correct image diagonal is the clear aperture. I measured it at 14 mm. 

 

Also, from what I am seeing, these scopes current ship with a 20 mm and 10 mm of unspecified types. 

 

Jon

[jeffreym]

The main trouble with the correct image diagonal is the clear aperture. I measured it at 14 mm. 

 

Also, from what I am seeing, these scopes current ship with a 20 mm and 10 mm of unspecified types. 

 

Jon

Well, I am able to see Mag 12+ stars with the CI and the theoretical limit for the scope is mag 12.7.  Switching diagonals in the field, other than flipping the image, changes very little.  It does change.  Looking with premium diagonals is a wonder and well worth the additional $300 (or $750).  However, within the context of this scope and anyone just starting out, my personal experience shows poor seeing/poor transparency/light pollution are almost always the limiting factor, not the diagonal.

 

I just checked all the major sellers and they all show the 25mm plossl only.  However, it's good to know that some packages could be different and to understand what is included.

 

Thanks,

Jeff

[aeajr]

Hello All,

I have a post about 4" Refractors for purchase consideration but many of the suggestions for me were too much over the top (eg veterans who have been into astronomy for yonks)

 

Thus this posting

 

I would like to know what people think of the Omni AZ 102.  Both the standard and the XLT versions.

 

Specifically

how do you like the scope

its pros and cons

what changes have you made to your scope (eg mount, focuser, etc)

 

I WOULD ONLY LIKE TO HEAR FROM OWNERS PLEASE. 

 

Also in your comments please tell us what  version Omni you have-- for example, 102 XLT f/9

 

thank you

Note that he only wants to hear from owners. 

[aeajr]

The main trouble with the correct image diagonal is the clear aperture. I measured it at 14 mm. 

 

Also, from what I am seeing, these scopes current ship with a 20 mm and 10 mm of unspecified types. 

 

Jon

Jon,

 

When using a Plossl eyepiece, would this likely vignette the view?  The scope comes with a 25 mm Plossl eyepiece.

 

Why does this 14 mm aperture matter?  I think the OP may not understand the significance of your comment.  

 

Where would this start to become an issue?  Would it be AFOV or focal length related?

 

One can buy other diagonals for as little as $25 so improving this may not be a significant expense if it needs to be addressed at all.

 

For the benefit of the OP:

 

Understanding Telescope Eyepieces- There are recommendations, based on budget, but the meat of the article is about understanding the issues when selecting eyepieces.

https://telescopicwa...ope-eyepieces/ 

[sojourneyer]

One more thing, the kit comes with a very good 25mm plossl eyepiece and Celestron's Premium StarPointer Pro finder that projects a dual-circle reticle instead of a simple red dot.  No need to replace these.

 

I LOVED the CI diagonal that came with my 102 AZ.  I have lots of diagonals from $15 to $750 and have compared them plenty.  I use what I like and given all the choices I have, I used the CI so much I wore out the eyepiece set screw.  I recommend getting a good mirror diagonal but don't discount the view through the CI that comes with the kit.  Use it and then decide for yourself.

 

Jeff

I point of correction for all.  The 102 XLT comes with the 25mm Plossl; however ,the 102 AZ comes with a 10 mm and 20 mm Kellners I believe ( I am certain of the two eyepieces but not the type of eyepiece)

Edited by sojourneyer, 20 December 2019 - 11:56 AM.

[Binojunky]

I picked one up last year from Amazon ca, this is what I found, the short dovetail was removed due to balance issues, the holes were plugged with two short grub screws and rings and a longer dovetail fitted, the 1.25" reducer was a very tight fit in the 2" focuser, that was replaced with an identical one I had that seems a bit easier than the original. The mount is a bit jiggly but is usable, the 

Star Trek style red dot is fine, the eyepieces are usable, the diagonal was replaced with better quality ones (1.25 & 2"). 

For the price I paid I,m happy with it, quick to set up its like an ST80 on steroids and has given me lots of enjoyment, D.

[sojourneyer]

I picked one up last year from Amazon ca, this is what I found, the short dovetail was removed due to balance issues, the holes were plugged with two short grub screws and rings and a longer dovetail fitted, the 1.25" reducer was a very tight fit in the 2" focuser, that was replaced with an identical one I had that seems a bit easier than the original. The mount is a bit jiggly but is usable, the 

Star Trek style red dot is fine, the eyepieces are usable, the diagonal was replaced with better quality ones (1.25 & 2"). 

For the price I paid I,m happy with it, quick to set up its like an ST80 on steroids and has given me lots of enjoyment, D.

Binoman...I am a bit confused. Are you saying that the Amazon scope came with those changes or you made them? 

 

What unit are you referring to ?

 

thanks

[tony_spina]

I had the Omni XLT 102AZ.   Purchased for $159 on Amazon a couple of years back. It is a very good scope. At that old sales price a great deal.

 

The optics on mine was very good. Yes it had CA but it did provide great lunar views at 150x. Saturn was also good at 150x with clear and sharp views of the Cassini division and shades of color on the planet.  Jupiter was also good with several bands clearly seen.  The CA was more evident on Jupiter. But a simple #8 yellow filter helps cut it down

 

What folks don't talk about is SA. Spherical Aberrations.   This scope has very good figure, much better than the Meade 102AZ

 

The scope is also very good for bright GSOs

 

Build quality is also very good. All metal with the exception of the focus knobs.   The mount is above average compared to what other manufacturers provide in this price range it can be tweaked to make it better, but what will improve it is to put rings on the OTA to better balance the scope

 

The diagonal is ok for terrestrial views but a simple SVBONY 1.25 diagonal for $20 is a great improvement 

 

We gave this to a family friend with modifications.   He uses it a lot

 

[Jon Isaacs]

Well, I am able to see Mag 12+ stars with the CI and the theoretical limit for the scope is mag 12.7.  Switching diagonals in the field, other than flipping the image, changes very little.  It does change.  Looking with premium diagonals is a wonder and well worth the additional $300 (or $750).  However, within the context of this scope and anyone just starting out, my personal experience shows poor seeing/poor transparency/light pollution are almost always the limiting factor, not the diagonal.

 

I just checked all the major sellers and they all show the 25mm plossl only.  However, it's good to know that some packages could be different and to understand what is included.

 

Thanks,

Jeff

 

Just be clear:

 

The 14 mm clear aperture causes vignetting with eyepieces that offer a wider field of view.  A 32 mm or a 26 mm Plossl. Vignetting is a darkening or even a fully black outer region near the edge of the field.

 

I am not suggesting investing in a premium diagonal but a $35 star diagonal would provide full illumination. At higher magnifications, the CI diagonal will cause a spike on double stars that affects the image. A star diagonal will eliminate this.

 

Most often with scopes like this, the scope itself is a solid performer.  The accessories and the mount are the weak points. The mount might be substantially improved by replacing the exiting tripod legs with legs fashioned from 2x2s or 2x3s. I did not try that with this mount but it's been effective with other similar mounts. 

 

Jon

[CChristakis]

I have the Omni 102AZ F6.5.   Its a fun scope to use and I have equally used it as much as my 8" Dob.   It also serves as my solar telescope with a Lunt Solar Wedge.   I mainly use it as my Grab-N-Go for short quick sessions.   Even though the scope suffers from CA, I still will use it on the moon and bright planets.  

I paid about $180 for it on Amazon about three years ago.   I used it as is for 6 months and then I slowly started to upgrade things.    I replaced the Diagonal with a 1.25" GSO Dielectric Diagonal but now have a 2" Orion Dielectric.   I also added tube rings to make the scope more stable on the mount.   Last year I purchased a Skywatcher AZ GTI mount.    At this point I probably wont' sink any more money into the scope and down the road will replace it with a better refractor.

I would say it has served me well.

Pros:  Inexpensive, Good Optics for the money, Versatile, Portable and Nice Widefield
Cons: Cheap Diagonal, Not that great but usable stock mount, Chromatic Aberation but acceptable for me.
 

[aeajr]

sojourneyer,

 

I don't know what you know so, just to be clear, several people have made reference to CA.   To be sure you understand, CA is chromatic aberration.  This is normal in all achromatic refractors and is more pronounced in lower focal ratio scopes.  So this is not unique to this scope. 

 

CA is a tendency to show a false color ring around the edge of bright objects.  Some people find this very objectionable, and some, like me, just ignore it.    Your smileage will vary. 

 

Refractors fall into:

• Achromatic (typically has two aperture lens elements of different glass)
• Achromats with ED Glass (reduces as much as 90% of CA)
• APOs or Apochromats which virtually eliminates the CA which is a characteristic of refractors (usually 3 aperture lens elements)

As you progress down the list the price of the OTA goes up significantly.   The Omni 102 is a Achromat as are most beginner refractor telescope packages. 

 

I have two achromats.   I have been looking at an ED refractor as an upgrade.  APOs are typically used for astrophotography but are also fine for visual use. 

 

Different types of Telescopes
https://telescopicwa...-of-telescopes/

Edited by aeajr, 20 December 2019 - 01:55 PM.

[sojourneyer]

I have the Omni 102AZ F6.5.   Its a fun scope to use and I have equally used it as much as my 8" Dob.   It also serves as my solar telescope with a Lunt Solar Wedge.   I mainly use it as my Grab-N-Go for short quick sessions.   Even though the scope suffers from CA, I still will use it on the moon and bright planets.  

I paid about $180 for it on Amazon about three years ago.   I used it as is for 6 months and then I slowly started to upgrade things.    I replaced the Diagonal with a 1.25" GSO Dielectric Diagonal but now have a 2" Orion Dielectric.   I also added tube rings to make the scope more stable on the mount.   Last year I purchased a Skywatcher AZ GTI mount.    At this point I probably wont' sink any more money into the scope and down the road will replace it with a better refractor.

I would say it has served me well.

Pros:  Inexpensive, Good Optics for the money, Versatile, Portable and Nice Widefield
Cons: Cheap Diagonal, Not that great but usable stock mount, Chromatic Aberation but acceptable for me.
 

Great review CChristakis

[sojourneyer]

Thanks for the discussion on types of objective lenses.

I suppose an achromat is the same as achromatic?

 

The chromatic aberration should not bother me I believe as I will be viewing from 30X to 125X at a max and even with the latter for a short span of time..

[Redbetter]

Well, I am able to see Mag 12+ stars with the CI and the theoretical limit for the scope is mag 12.7.  Switching diagonals in the field, other than flipping the image, changes very little.  It does change.  Looking with premium diagonals is a wonder and well worth the additional $300 (or $750).  However, within the context of this scope and anyone just starting out, my personal experience shows poor seeing/poor transparency/light pollution are almost always the limiting factor, not the diagonal.

 

Jeff,

 

The limiting magnitudes listed for scopes are rather low for an experienced observer without eye issues in dark sky. With a 4" refractor I can reach the high 14's on calibrated stars and I have reached 13.7 with a 60mm ED. 

 

Premium diagonals that expensive are overkill in my estimation/experience,  spending ~$100 on a 99% dielectric is more than sufficient.  I prefer them as the alignment of the housings and mirrors seems to be better than the average 1.25".  The difficulty I find with 1.25" diagonals is that the $35 to $50 ones often have poorly made housings with seriously skewed eyepiece holder/nosepiece and/or mirror mounting issues.  I have had to go all the way up to $70 for a heftier mirror diagonal to get around that (or to use $150 Tak prisms.)

 

Note that the very narrow ~14mm clear aperture of some RACI's (and even some other better RACI's that are 20-21mm) will not impact the center of the field illumination.  The center is still fully illuminated but the edges will be more vignetted even if not easily detected visually at night, and will likely be undetectable with small field stops.  Therefore, in the center of the field one should be able to see to the limitation of the scope's aperture...  Except that reaching the full capability of the scope requires a crisp image at high power, and RACI's tend to have some aberration at such magnification.  This might knock off a few tenths, and it makes resolving very close double stars or planetary detail more difficult/confusing. 

[sojourneyer]

Jeff,

 

The limiting magnitudes listed for scopes are rather low for an experienced observer without eye issues in dark sky. With a 4" refractor I can reach the high 14's on calibrated stars and I have reached 13.7 with a 60mm ED. 

 

Premium diagonals that expensive are overkill in my estimation/experience,  spending ~$100 on a 99% dielectric is more than sufficient.  I prefer them as the alignment of the housings and mirrors seems to be better than the average 1.25".  The difficulty I find with 1.25" diagonals is that the $35 to $50 ones often have poorly made housings with seriously skewed eyepiece holder/nosepiece and/or mirror mounting issues.  I have had to go all the way up to $70 for a heftier mirror diagonal to get around that (or to use $150 Tak prisms.)

 

Note that the very narrow ~14mm clear aperture of some RACI's (and even some other better RACI's that are 20-21mm) will not impact the center of the field illumination.  The center is still fully illuminated but the edges will be more vignetted even if not easily detected visually at night, and will likely be undetectable with small field stops.  Therefore, in the center of the field one should be able to see to the limitation of the scope's aperture...  Except that reaching the full capability of the scope requires a crisp image at high power, and RACI's tend to have some aberration at such magnification.  This might knock off a few tenths, and it makes resolving very close double stars or planetary detail more difficult/confusing. 

The subject dealt with Celestron Omni 102 AZ scopes

Specifically

how do you like the scope

its pros and cons

what changes have you made to your scope (eg mount, focuser, etc)

I WOULD ONLY LIKE TO HEAR FROM OWNERS PLEASE.

 

Not on diagonals 3X the price of a beginners scope..

Thanks

[markdaleanderson]

I purchased the 102 AZ for a lightweight travel scope that I can leave in my vehicle.  I will take it to Florida in three weeks because of my other scopes size and weight.  I did an extensive side by side with my ES AR102.  The Celestron held its own and for the price has exceptional optics.  However, mechanically the AR102 wins hands down.  The focuser is a very stiff 2 inch rack and pinion.  At some point I will clean out the old grease and replace it with lithium grease.  I put a 2 inch diagonal on the scope and took it off pretty quick.  You can balance the scope with a longer dovetail and 2 inch accessories but the vibrations are unacceptable even at low power.  If you use 1 1/4 inch accessories it's not too bad.  For the price, it is a fantastic deal.  The OTA is worth the cost.  I plan on doing the Messiers with it and should know a lot more by the time I am finished.  Also, you can upgrade the scope a lot if you so desire.

 

Hope that helped.