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Ed Ting's Orion 120 Review

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#226 bobhen

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Posted 01 October 2020 - 02:37 PM

IMO refractors get a lot more credit for being short cooldown scopes than they deserve. Small scopes cool down quickly. Most of the reflectors/SCTs that take so much longer to cool do so because, well, they're drastically larger telescopes. Of course a 10" SCT takes far longer to cool than a 4" refractor. It also takes a lot longer to cool down than a 4" SCT.

I think the point is that a 4” doublet refractor will also acclimate quicker than a 4” SCT.

 

The refractor’s objective is exposed to the outside air whereas the SCT has its primary enclosed in a tin can.

 

Bob



#227 bobhen

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Posted 01 October 2020 - 02:45 PM

Even with the 120mm, I'd do the following for cooling: simply invert the tube so the objective faces downward to the ground and remove the diagonal so the heat in the tube rises and vents out the open focuser. I do the same thing with my Antares 6" F6.5 refractor. Ditto for SCc.

There’s really no need to invert the tube. By the time the lens has acclimated the air in the tube and the tube walls will already have acclimated. Inverting the tube just allows warm air coming off the objective to rise up the tube until the lens has cooled. Just remove the dew shield and set the scope outside.

 

Getting the lens acclimated in the goal; once that is accomplished all is good.

 

Bob



#228 RLK1

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Posted 01 October 2020 - 02:50 PM

There’s really no need to invert the tube. By the time the lens has acclimated the air in the tube and the tube walls will already have acclimated. Inverting the tube just allows warm air coming off the objective to rise up the tube until the lens has cooled. Just remove the dew shield and set the scope outside.

 

Getting the lens acclimated in the goal; once that is accomplished all is good.

 

Bob

I disagree, the cooling time is faster with the warm air out of the tube sooner. 



#229 Mitrovarr

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Posted 01 October 2020 - 03:32 PM

I think the point is that a 4” doublet refractor will also acclimate quicker than a 4” SCT.

The refractor’s objective is exposed to the outside air whereas the SCT has its primary enclosed in a tin can.

Bob


My point was that the difference is overestimated because it's almost always a larger mirror scope vs. smaller refractor.

I'm sure a 4" short-ish refractor (not sure about a long one, my F/15 is a slow cooler) would cool down faster than a 4" SCT. However, the 4" SCT will still cool down pretty quickly.

#230 LDW47

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Posted 01 October 2020 - 07:13 PM

I am not a fan of these.  Poor star colors, bad field curvature, below par on limiting magnitude, and poor contrast. Throw in a focuser designed half a century ago... (Do a side by side with the 102ED if you want to see the difference in limiting magnitude.  The 120ED is still teasing out tiny pinpoints after the ST120 has run out of encircled energy.)

 

While more expensive, something the AT 106 is a far better instrument. Yes, it costs much more, but used these can be had for $800 in pristine condition.

Even a used Orion or Stellarvue 11O are much better than the ST120. They have flatter fields, and as a bonus, with a T2 binoviewer, you can reach focus without a Barlos.    

And when you are done with the used AT 106 or 110ED, if you have taken care of it, you can sell it for what you paid for it.  So, you use it for a year free

 

I see people put upgrades on these too, and I think to myself "Why are they investing in a telescope that does not do anything with authority when they could be buying excellence for a few hundred dollars more?"

 

Just me, but I have owned several fast achromats and none of them could match slightly smaller ED or APO telescopes.

But the views are so wide, so spacious, so clear, all n all so wonderful that many great astronomers can’t resist them for next to nothing costs ! I have owned both achros and apos and the achros are neck n neck maybe even winning out in some cases but I still have an 80mm Equinox just to say I have one and it is no slouch either ! Its a flip of a coin thing !


Edited by LDW47, 01 October 2020 - 08:54 PM.

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#231 Jetfuel

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Posted 03 October 2020 - 12:36 AM

The way I look at cool down in a general sense is that for a similar volume, the light path goes through the refractor once, newt...twice and a mak/SCT 3 times.  So the latter has to be much more thermally stable. I understand there are more factors involved.


Edited by Jetfuel, 03 October 2020 - 12:36 AM.


#232 LDW47

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Posted 22 October 2020 - 09:10 PM

Rather than start a new thread I just thought I would say that Ed Ting continues to add to his series of YouTube reviews ! Keep checking periodically !



#233 RLK1

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Posted 23 October 2020 - 02:44 PM

I've looked at the Ed Ting video on the Orion 120mm numerous times and I'm in a nit picky mood today so I've got some additional comments on the imaging comparo he does in the video. Before I begin, I'll preface my comments with the disclaimer that you can't equate optical quality by means of imaging and I'm not taking anything away from the excellent apo in the comparo. Additionally, as Ed point out, youtube compression of the images factors in here as well. That said, I gotta disagree with Ed on a couple of things he says. First, on the images of the dumbbell nebula, he states the stars are different in the apo with some sort of unique character to them. In contrast, he says there's a "sameness"in the stars as seen in the 120 achro image. I disagree because if you look at the double star at approximately the 2 o'clock position in both images, the stars immediately adjacent to those double stars appear brighter in the 120 than they do in the apo view. In the image of the North American nebula, Ed says the stars in the stowaway image are smaller and there are more of them despite the lessor aperture. I'm not about to get into counting the stars in the images but I looked at the stars in the darkest and dimmest areas in the images that I could easily compare and it appears to me the areas are similar but, ultimately, I'll take Ed's word for it. What is more obvious, however, is that the "beak" in the pelican nebula is missing in the stowaway image and clearly evident in the 120 image. So, if anything, the image in the 120 is demonstrating something the image in the apo is not. 



#234 FlyingV74

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Posted 28 October 2020 - 10:43 PM

I’m a noob. I stumbled onto Ed Ting’s channel a few weeks ago. I enjoy the low budget video production combined with the high budget scopes that are scattered throughout. You can tell where his passions lie.

Regarding the review vs. demo argument......A noob like me could care less about a bunch of objective data. It is rather meaningless. But a comparison of an expensive scope vs. this one is invaluable! Still doesn’t mean I’m gonna buy it. But the subjective comparitive data that Ed provided is much more useful to the target audience of this scope. If you want hard core objective data, I think that if your at looking at a $250 scope, you are looking in the wrong place. Just my noob opinion.
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#235 LDW47

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Posted 29 October 2020 - 07:32 AM

I’m a noob. I stumbled onto Ed Ting’s channel a few weeks ago. I enjoy the low budget video production combined with the high budget scopes that are scattered throughout. You can tell where his passions lie.

Regarding the review vs. demo argument......A noob like me could care less about a bunch of objective data. It is rather meaningless. But a comparison of an expensive scope vs. this one is invaluable! Still doesn’t mean I’m gonna buy it. But the subjective comparitive data that Ed provided is much more useful to the target audience of this scope. If you want hard core objective data, I think that if your at looking at a $250 scope, you are looking in the wrong place. Just my noob opinion.

Well said and hits the nail right on the head ! Clear Skizes !



#236 shivaram

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Posted 01 November 2020 - 10:36 PM

There seem to be two version of the 120mm ST... Which is the better one or are both the same with a different color tube???

 

https://www.telescop...mbly/p/9836.uts

 

and

 

https://www.telescop...2160/p/9005.uts

(minus mount & tripod)

 

 

Looks like Ed's video talks about the latter.

 

Which one is good??


Edited by shivaram, 01 November 2020 - 10:36 PM.


#237 tony_spina

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Posted 01 November 2020 - 11:07 PM

Same scope,  different color


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#238 shivaram

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Posted 02 November 2020 - 11:20 PM

Thank you Tony



#239 NYJohn S

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Posted 21 November 2020 - 02:45 PM

Finally got around to watching the video. When he gets to the imaging setup Ed mentions some changes he made to she scope like the longer dovetail. If you look closely the focuser has been replaced with a 2 speed. Not sure if the stock focuser couldn't handle the weight of a DSLR or he just wanted to upgrade. Seems strange he doesn't mention it.

 

Does anyone know if the dew shield comes off on these? I came across one that needs cleaning. It's a long reach to the front objective.



#240 Jeff B

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Posted 21 November 2020 - 04:21 PM

Finally got around to watching the video. When he gets to the imaging setup Ed mentions some changes he made to she scope like the longer dovetail. If you look closely the focuser has been replaced with a 2 speed. Not sure if the stock focuser couldn't handle the weight of a DSLR or he just wanted to upgrade. Seems strange he doesn't mention it.

 

Does anyone know if the dew shield comes off on these? I came across one that needs cleaning. It's a long reach to the front objective.

Yes, they "slide" off but they can be tight and those need to be wiggled off.

 

Jeff


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#241 tony_spina

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Posted 21 November 2020 - 04:27 PM

Yes, they "slide" off but they can be tight and those need to be wiggled off.

 

Jeff

Correct on the dew shield, and the lens cell screws off


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#242 NYJohn S

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Posted 21 November 2020 - 04:33 PM

Thanks Jeff & Tony. This one is extremely tight and I didn’t want to break anything if it was fixed.

#243 tony_spina

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Posted 21 November 2020 - 07:09 PM

If you have a strap wrench it will help


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#244 kazi

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Posted 23 November 2020 - 12:55 PM

I was suspicious that the original focuser cut in the light path reducing the aperture. I've done the flaslight test: put a flaslight on the eyepiece with a 2" diagonal, and a "mm grid"paper on the objective end. The diameter of the illuminated area was about 110mm, when the focuser racked in. The focuser fully extended the diameter was approx 120mm, but because of the tilt of the focuser one side was still cutted down. So i think the original focuser needs to be replaced.




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