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Unitron 3” vs Questar 3.5

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#1 Carlos_Padron

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Posted 11 July 2023 - 09:35 PM

Greetings friends, 

 

I’m curious what are the optical (visual) differences in these two systems (Questar vs Unitron 3” f16 achromat) for those that have observed through both. I’m mostly a Lunar and planetary observer (as well as an astrophotographer but this won’t be used for that).

 

I currently have a Unitron 142 equatorial and I consider it a great example of the type. My other scopes are a 1985 C8 and a Evostar 100ED APO.

 

Clear skies! 

 

Carlos

IMG 3450
IMG 3009
Clavius Crater Unitron 142
Unitron 1
6-11-23
6-11-23
After some front surface Cleaning

 

 


Edited by Carlos_Padron, 11 July 2023 - 10:41 PM.


#2 gstrumol

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Posted 11 July 2023 - 10:19 PM

hmm.gif 

 

Are you challenging the Questar folks to an image comparison?

 

popcorn.gif


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#3 Carlos_Padron

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Posted 11 July 2023 - 10:39 PM

No I’m interested in the visual differences. 



#4 Toddeo

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Posted 11 July 2023 - 10:52 PM

Well, one will show a view from a 3" scope, the other from a 3.5" scope!waytogo.gif


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#5 Carlos_Padron

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Posted 11 July 2023 - 10:55 PM

Not bad lol my gut tells me the views are more similar than different. Unfortunately haven’t had the chance to look through a Questar.


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#6 RMay

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Posted 11 July 2023 - 11:04 PM

I’ve been known to take an iPhone pic or two through my 3.5; here’s a 12 Pro close-coupled to the 16mm eyepiece of my 3.5 at 87.5X magnification. Single frame, no guiding. Perhaps an interesting comparison.

 

Ron

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  • 1F34F535-F464-453C-ABF9-4D2E3BBA8116.jpeg

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#7 Carlos_Padron

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Posted 11 July 2023 - 11:15 PM

Not bad Ron! I’ve seen how powerful the mak design can be. I have a pretty budget mak toy sarblue 60mm. It still walked all over the Celestron 127 Byrd jones a buddy of mine brought. We did a side by side comparison. No question which was better…


Edited by Carlos_Padron, 11 July 2023 - 11:16 PM.

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#8 R Botero

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Posted 12 July 2023 - 01:56 AM

I once owned both. I now have the Questar only. Although the Polarex (Unitron in Europe) was magnificent for solar work - I did plenty of imaging with it - it was very cumbersome to set up on short notice. The Questar on the other hand took no time. I have done no imaging with my Questar though.
Roberto

#9 R Botero

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Posted 12 July 2023 - 02:08 AM

Here's a 25 panel mosaic of the sun during the last solar cycle taken through the Polarex:

 

https://www.astrobin.com/54326/0/

 

cuQexzBs8ZBO_2560x0_bDM8psdn.jpg

 

NK6GHJLeQQU0_2560x0_bDM8psdn.jpg

 

 

 


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#10 Carlos_Padron

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Posted 12 July 2023 - 06:40 AM

Here's a 25 panel mosaic of the sun during the last solar cycle taken through the Polarex:

 

https://www.astrobin.com/54326/0/

 

cuQexzBs8ZBO_2560x0_bDM8psdn.jpg

 

NK6GHJLeQQU0_2560x0_bDM8psdn.jpg

How did you find the views between them? Nice H Alpha shot!


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#11 R Botero

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Posted 12 July 2023 - 06:51 AM

They weren't too dissimilar.  My Polarex sample had a very good lens - but not all of them have and you may get a lemon.  Questar on the other hand is guaranteed quality.  Magnification is similar given the focal lengths with the Questar a bit darker in terms of brightness.  You have more/easier to use options in the refractor with filters for solar observation.  Hydrogen alpha filters for the Questar don't really work as well as with refractors.  I prefer the Questar for lunar observation.

 

Roberto


Edited by R Botero, 12 July 2023 - 02:48 PM.

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#12 gstrumol

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Posted 12 July 2023 - 08:55 PM

How did you find the views between them? Nice H Alpha shot!

Both were taken with the same scope according to the info under the images, no?



#13 gstrumol

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Posted 12 July 2023 - 09:15 PM

If you just want to see lunar comparisons here are two images: one taken with the AT80EDL (80mm) refractor and the other with the Apex 90mm MCT (a 'poor man's Questar' wink.gif ):

 

at1.jpg

 

at2.jpg

 

I don't know if this helps answer your question.


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#14 Toddeo

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Posted 12 July 2023 - 09:46 PM

What? How many other scopes are involved in this crazy discussion ???confused1.gif


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#15 gstrumol

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Posted 12 July 2023 - 10:08 PM

What? How many other scopes are involved in this crazy discussion ???confused1.gif

It's total lunacy, I'd say! lol.gif

 

In my defense, the topic was comparing a 3" refractor to a 3.5" MCT, so I thought my examples were spot on! shrug.gif


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#16 Dave Trott

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Posted 24 July 2023 - 09:32 AM

The views may be nearly identical but the experience is vastly different. A small, compact bit of engineering perfection vs a long, heavy cumbersome hunk of engineering perfection. 


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#17 Carlos_Padron

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Posted 24 July 2023 - 01:22 PM

Hey Dave, glad you came across this thread. I’m a sub to your YT channel. Great stuff, and thanks for your thoughts on the matter. 

 

Carlos

The views may be nearly identical but the experience is vastly different. A small, compact bit of engineering perfection vs a long, heavy cumbersome hunk of engineering perfection. 


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#18 BarrySimon615

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Posted 27 July 2023 - 09:25 AM

Interesting topic that hits close to home.

 

Some 20 or so years ago, a friend that had (and still does have) a Unitron #142 3" f/16 refractor got the bug to give a 3.5 inch Questar a try.  He decided that he ultimately would only keep one telescope - either the Questar or his 3" Unitron so challenge #1 was to get a Questar vendor to commit to selling him a Questar with the proviso that should it show no real advantage in a head to head test vs his 3" Unitron it would be returned to the vendor for a full refund.  Anyway the first contacted vendor would not agree to these terms even after telling my friend that there would be no way that the Unitron would be able to best the Questar in a head to head challenge.  I guess he really did not have faith in the superiority of the Questar.

 

On to the next vendor, I believe it was Spectra, or a similar name, in California.  Now out of business.  The owner (Dan Gordon, I think) also believed that the Questar would come out on top and that my friend would be very happy with the Questar.  He was a bit hesitant to agree to the terms of the purchase and the test (Questar going back to the vendor if it could not clearly show some advantages over the Unitron) but ultimately he decided that his confidence in the superiority of the Questar made his risk as a vendor minimal.

 

So Joe eventually got a Questar to compare to his 3" Unitron, which he had purchased from me.  I already had another 3" Unitron as well as the 4" and the 2.4", all equatorially mounted.  Note that at the time of the test there was no "driven" advantage of one scope over the other in that both had simple right ascension drives.

 

On the night of the test I went to Joe's and brought my C-90 with me.  It would be interesting to compare the C-90 to the Questar, there being approximately an 8 to 10 fold price differential between the two scopes.

 

Over the course of the evening we looked at the Moon, Saturn and some double stars and indeed the comparison was close.  At f/16 the Unitron displayed little if any chromatic aberration, certainly nothing that was objectionable.  All targets looked good thru both the Unitron and the Questar.  Comparisons were very, very close.  Both scopes are classics and both look very nice when set up to be displayed when not in use.  The Questar has an advantage in being able to be packed up into a tighter package when not in use.  Although the Unitron is not a real problem in this regard.  We both felt that the Questar offered no real advantage over the Unitron, to the point at close to a $2000.00 outlay would be justifiable.  

 

The lowly Celestron C-90, while clearly inferior to the Questar was not that far behind in performance.  The Questar's performance was not 10 times better, which would have been in line with it's 10 times better price increase.

 

So the Questar went back, and Dan at Spectra was stunned, but he had agreed to the terms.  Joe, some 20 years later, is still happy with his Unitron.

 

Note - I had a second hand Questar briefly.  I quickly learned that the optics needed recoating.  With full disclosure I managed to sell it without too much of a loss.  I currently have a Questar 7 which I admittedly have only used once, being just a few weeks out from a right hip replacement.  The views were quite nice and it is a keeper.

 

I am posting a photo of the 3.5 Questar that I had briefly.  I have to admit that it is a stunning telescope to look at.

 

Barry Simon

Attached Thumbnails

  • Questar right rear with flash.jpg

Edited by BarrySimon615, 27 July 2023 - 11:17 AM.

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#19 Carlos_Padron

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Posted 27 July 2023 - 09:39 AM

Fantastic write-up Barry. Thanks for your input. 

 

Carlos 

Interesting topic that hits close to home.

 

Some 20 or so years ago, a friend that had (and still does have) a Unitron #142 3" f/16 refractor got the bug to give a 3.5 inch Questar a try.  He decided that he ultimately would only keep one telescope - either the Questar or his 3" Unitron so challenge #1 was to get a Questar vendor to commit to selling him a Questar with the proviso that should it show no real advantage in a head to head test vs his 3" Unitron it would be returned to the vendor for a full refund.  Anyway the first contacted vendor would not agree to these terms even after telling my friend that there would be no way that the Unitron would be able to best the Questar in a head to head challenge.  I guess he really did not have faith in the superiority of the Questar.

 

On to the next vendor, I believe it was Spectra, or a similar name, in California.  Now out of business.  The owner (Dan Gordon, I think) also believed that the Questar would come out on top and that my friend would be very happy with the Questar.  He was a bit hesitant to agree to the terms of the purchase and the test (Questar going back to the vendor if it could not clearly show some advantages over the Unitron) but ultimately he decided that his confidence in the superiority of the Questar made his risk as a vendor minimal.

 

So Joe eventually got Questar to compared to his 3" Unitron, which he had purchased from me.  I already had another 3" Unitron as well as the 4" and the 2.4", all equatorially mounted.  Note that at the time of the test there was no "driven" advantage of one scope over the other in that both had simple right ascension drives.

 

On the night of the test I went to Joe's and brought my C-90 with me.  It would be interesting to compare the C-90 to the Questar, there being approximately an 8 to 10 fold price differential between the two scopes.

 

Over the course of the evening we looked at the Moon, Saturn and some double stars and indeed the comparison was close.  At f/16 the Unitron displayed little if any chromatic aberration, certainly nothing that was objectionable.  All targets looked good thru both the Unitron and the Questar.  Comparisons were very, very close.  Both scopes are classics and both look very nice when set up to be displayed when not in use.  The Questar has an advantage in being able to be packed up into a tighter package when not in use.  Although the Unitron is not a real problem in this regard.  We both felt that the Questar offered no real advantage over the Unitron, to the point at close to a $2000.00 outlay would be justifiable.  

 

The lowly Celestron C-90, while clearly inferior to the Questar was not that far behind in performance.  The Questar's performance was not 10 times better, which would have been in line with it's 10 times better price increase.

 

So the Questar went back, and Dan at Spectra was stunned, but he had agreed to the terms.  Joe, some 20 years later, is still happy with his Unitron.

 

Note - I had a second hand Questar briefly.  I quickly learned that the optics needed recoating.  With full disclosure I managed to sell it without too much of a loss.  I currently have a Questar 7 which I admittedly have only used once, being just a few weeks out from a right hip replacement.  The views were quite nice and it is a keeper.

 

I am posting a photo of the 3.5 Questar that I had briefly.  I have to admit that it is a stunning telescope to look at.

 

Barry Simon



#20 Jae

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Posted 31 July 2023 - 02:19 PM

Interesting topic that hits close to home.

 

 

 

Over the course of the evening we looked at the Moon, Saturn and some double stars and indeed the comparison was close.  At f/16 the Unitron displayed little if any chromatic aberration, certainly nothing that was objectionable.  All targets looked good thru both the Unitron and the Questar.  Comparisons were very, very close.  Both scopes are classics and both look very nice when set up to be displayed when not in use.  The Questar has an advantage in being able to be packed up into a tighter package when not in use.  Although the Unitron is not a real problem in this regard.  We both felt that the Questar offered no real advantage over the Unitron, to the point at close to a $2000.00 outlay would be justifiable.  

 

I have to admit that it is a stunning telescope to look at.

 

 

 

This was my experience as well.  I used an Orion branded Towa 80mm f15 at the time of my comparison, which was at least as good as my Unitron 140, and Tasco 10TE.  I saw no real advantage to the Questar other than the compactness and stunning looks.   People tout the ergonomics but I've yet to have a bonding experience in that regard.



#21 Larry Geary

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Posted 10 August 2023 - 06:33 PM

 

Greetings friends, 

 

I’m curious what are the optical (visual) differences in these two systems (Questar vs Unitron 3” f16 achromat) for those that have observed through both. I’m mostly a Lunar and planetary observer (as well as an astrophotographer but this won’t be used for that).

 

I currently have a Unitron 142 equatorial and I consider it a great example of the type. My other scopes are a 1985 C8 and a Evostar 100ED APO.

 

Clear skies! 

 

Carlos

 

The 3.5" Questar will show a slightly brighter (but noticeable) image with slightly higher resolution compared to the 3" Unitron. The 3" Unitron will show slightly better contrast than the Questar. The Unitron may show chromatic aberration, while the Questar will not.


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#22 Larry Geary

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Posted 10 August 2023 - 06:38 PM

The views may be nearly identical but the experience is vastly different. A small, compact bit of engineering perfection vs a long, heavy cumbersome hunk of engineering perfection. 

 

The Unitron's mount is a piece of art. So is the Questar's mount, though they are very different from each other.



#23 Mapman

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Posted 08 September 2023 - 10:46 PM

I had a 4" Unitron and purchased a 3.5 Questar - views were comparable with some unobjectionable CA on the Unitron.  Portability, ease of set-up, and ease of use were Questar advantages. 

 

Years back, sold that Unitron to a friend who enjoyed same until he passed years later.  Owned my Questar for 50 years - always quick and easy to use. 

 

My eyesight remains 20-20 but floaters etc take away the visual pleasure - cameras next!


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#24 Alan Grant

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Posted 17 September 2023 - 11:15 PM

I did side by side comparisons with these two scopes since I've owned both.  As much as I wanted the Unitron to 'win', the Questar showed more detail on both the moon and planets.  Double stars, even.  


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#25 Erik Bakker

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Posted 18 September 2023 - 04:18 AM

I have a 3” f/12 Japanese achromat of ultra high quality and an essentially (apart from CA) perfect startest. A 3.5” Questar with Zerodur mirror and BB coatings showed a tiny bit more on Jupiter on a very calm night. With worse seeing, the long focus achromat without a central obstruction showed a sharper, stable image more often. 

 

When comparing my A-P EDF 130 f/6 with my Questar 7, I was surprised by how much cleaner, free from CA, the startest of the Questar was. An eyeopner with regards to the meaning of apochromatic for both scopes.




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