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is 4 inch enough for serious planet observing?

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#76 Muffin Research

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Posted 21 November 2020 - 05:42 AM

Certainly when getting into this hobby buying used makes lots of sense as you can buy considerably better performing gear and mechanics than what that budget would get you new.



#77 Astrojensen

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Posted 21 November 2020 - 06:19 AM

Certainly when getting into this hobby buying used makes lots of sense as you can buy considerably better performing gear and mechanics than what that budget would get you new.

On the other hand, if there's something wrong with the scope, you're often stuck with it, if it's bought used and for a beginner, who may not know how to handle the situation or properly identify the fault, that can mean a lot of cash simply thrown away. If you buy new, you can return it for a new sample or a refund. 

 

I would NOT recommend beginners to buy used gear, unless they can get help from a VERY EXPERIENCED amateur, in which case the situation is completely different.

 

 

Clear skies!

Thomas, Denmark


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#78 Echolight

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Posted 21 November 2020 - 07:00 AM

Europe prices:

 

100ED: https://www.astrosho...rrector/p,53999

=1000 euro

 

120ED: https://www.astrosho...o-ota/p,15058  

=1600 euro

 

150ED: https://www.astrosho...-ed-ota/p,59364

=2100 euro

 

 

Why i mention the 150? Because these threads devolop always in bigger aperture answers then the OP is asking...cool.gif

That's a high price on the 100ED. They frequently go on sale in the US for $750 USD. Or have in the past.



#79 Muffin Research

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Posted 21 November 2020 - 07:32 AM

On the other hand, if there's something wrong with the scope, you're often stuck with it, if it's bought used and for a beginner, who may not know how to handle the situation or properly identify the fault, that can mean a lot of cash simply thrown away. If you buy new, you can return it for a new sample or a refund. 

 

I would NOT recommend beginners to buy used gear, unless they can get help from a VERY EXPERIENCED amateur, in which case the situation is completely different.

 

 

Clear skies!

Thomas, Denmark

hmm not sure I agree, I find the astro community generally very friendly and helpful and quite precious with their gear, I went through a forum locally as well in buying my first scope secondhand, I mean there are just so much better deals to be made. 

I guess if you're buying a scope from someone who also just bought it to try it out,  sure I get what can happen, but in general if you buy from freaky astronomers there's good gear to be had.  



#80 michiel

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Posted 21 November 2020 - 09:18 AM

Yeahh. The scope arrived yesterday. Of course this means for the coming week only clouds and rain, amazing how a scope purchase can influence the weather. The scope is beautiful, it is a sort of matte white, a tiny bit broken white, not glossy or shiny. I was amazed how light it is, that must come from the aluminium tube. For me it looks tiny, compared to the 200mm F9 achro I had and sold a year ago. It also looks much less massive than the 152mm f5.9 achro I had. . I could only do some daylight observing.. from a window as it was slightly drizzling outside, the image was clear and sharp and I saw no trace nor hint of any chromatic aberation at 140x looking at a brick wall edge  and tiny leaves from a tree at 50 meters distance, this looks promising.102mm F11 ED TS refractir.jpg

 


Edited by michiel, 21 November 2020 - 09:20 AM.

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#81 Jeff B

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Posted 21 November 2020 - 10:33 AM

I buy nearly all my equipment used and that includes all the refractors I currently own as well as the my Dobs and binoculars.  There is an increased risk with buying used and the returning in 30 days just because I don't like the scope is not really an option.  You won't be buying anything from me. 

 

I can warranty that the scope as is described and will stand behind that but whether or not you like the scope, that's your deal.  I will find another buyer.  

 

But in this case, the issue is the fact that a 120mm ED costs more than $200-$300 more than a 100mm F/9 ED. I have seen Orion ED-100s for as low as $300, $500 is more realistic.  With 120EDs going for $1925 new, they are normally over $1200 used.  

 

I don't see comparing new 4 inch versus 120mm used.  If you are willing to buy used, compare them both used. 

 

Jon

Agreed!  And I would never do that to a buyer just because I did not like it.  I'm clear that any return would be for bad glass and it would be within 5 days of its arrival as I've the capacity to test.

 

Funny in that the range of prices for a used 100ED class scope is right around $400 to $500, or about $450 average.   Doing some research a while ago on CN and AM I found the range of prices for a used 120ED to be "all over the place" from $700 to over $1250.   And a lot of that depends on vintage and what's included, such as the case, diagonal and finder.  I see an ~$950 average, but if you're quick, I imagine you can snag a good sample for $900 USD.  I paid $800 for my older sample OTA.  

 

But I find buying used has its attractions, mostly cost.  So, I find it, in my own head, fair to compare what you get for your money between new and used, especially for the money, but also eyes wide open that you are buying used. 

 

Jeff


Edited by Jeff B, 21 November 2020 - 10:34 AM.

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#82 daquad

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Posted 21 November 2020 - 11:10 AM

Yeahh. The scope arrived yesterday. Of course this means for the coming week only clouds and rain, amazing how a scope purchase can influence the weather. The scope is beautiful, it is a sort of matte white, a tiny bit broken white, not glossy or shiny. I was amazed how light it is, that must come from the aluminium tube. For me it looks tiny, compared to the 200mm F9 achro I had and sold a year ago. It also looks much less massive than the 152mm f5.9 achro I had. . I could only do some daylight observing.. from a window as it was slightly drizzling outside, the image was clear and sharp and I saw no trace nor hint of any chromatic aberation at 140x looking at a brick wall edge  and tiny leaves from a tree at 50 meters distance, this looks promising.attachicon.gif102mm F11 ED TS refractir.jpg

The focuser end of the tube appears to be of smaller diameter than the rest of the tube.  Is this correct, or is it just an optical illusion?

 

Dom Q.



#83 Don Taylor

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Posted 21 November 2020 - 12:41 PM

Apparently some if the later TS 102F11ED scopes do have tne removable section in a smaller diameter. Same for the Kasai Trading Blanca version. My Altair has the full diameter removable section.

#84 gwlee

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Posted 22 November 2020 - 12:34 AM

After reading this thread, I'm wondering why I need a refractor, at all.  I want one, though, and I've been looking at the Astrotech refractors from 4" to 5.5"    If  I'm going to get better planetary views with my SCT and better deep sky views with a Dobsonian for 1/3rd the price, the only real reason to get a refractor, to me, would be for "grab and go" and even then it would be the 4" model.  Still, I want one and those Astrotech models seem so reasonably priced and the reviews are outstanding.  They have a 4" AT102EDiii for only $599.  That's crazy. 

 

Small refractors offer more portability, wider fields of view, and views that are as good as it gets within the limitations of their small aperture.

 

If you want to go deeper for DSOs or want more resolution for planets you want a bigger scope, which is going to be less expensive if it’s a reflector.

 

For $600 you can have a good quality 4” refractor without a mount or a good quality 10” reflector with a mount. Most of us start with one or the other, but eventually want both or a similar combination. Few of us need either.


Edited by gwlee, 22 November 2020 - 12:35 AM.


#85 michiel

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Posted 22 November 2020 - 04:08 AM

After reading this thread, I'm wondering why I need a refractor, at all.  I want one, though, and I've been looking at the Astrotech refractors from 4" to 5.5"    If  I'm going to get better planetary views with my SCT and better deep sky views with a Dobsonian for 1/3rd the price, the only real reason to get a refractor, to me, would be for "grab and go" and even then it would be the 4" model.  Still, I want one and those Astrotech models seem so reasonably priced and the reviews are outstanding.  They have a 4" AT102EDiii for only $599.  That's crazy. 

Just because its a refractor...lol.gif



#86 michiel

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Posted 22 November 2020 - 04:11 AM

Dom... indeed there is a smaller diameter part tube near the focuser. I am not sure i can remove it as Don suggested.... 


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#87 Astrojensen

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Posted 22 November 2020 - 06:56 AM

Dom... indeed there is a smaller diameter part tube near the focuser. I am not sure i can remove it as Don suggested.... 

It can be pretty firmly tightened. Mine was and needed a strong grip to turn the first time. I decided to replace it with a pair of Baader M68 extension tubes in the focuser instead, which is much more flexible and vastly easier to change as needed. 

 

gallery_55742_4772_251167.jpg

 

 

Clear skies!

Thomas, Denmark


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#88 Jon Isaacs

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Posted 22 November 2020 - 07:19 AM

Thanks Jon, bawling.gif I want my big Mac......     smile.gif

 

Maybe you should call your new scope:  Big Mac... :)

 

Jon


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#89 Daniel Mounsey

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Posted 22 November 2020 - 07:28 AM

A fun read this has been.


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#90 michiel

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Posted 22 November 2020 - 05:28 PM

Yes, it was fun, i triggered a lot of posts. Today was first light, well rather  first clouds. There was a lot of wind and clouds coming over but I had a few glimpes at the moon, very sharp, white no traces of CA not even at 180x, I am not (yet) a moon observer, but i saw details i had never spotted before. Jupiter and saturn were very low and i had to dodge trees houses and clouds to spot them but the image was sharp, albeit that the wind and clouds smeared uit subtle surface details, i saw cassini and the 4 moons showed different sizes, the focus snapped into view. Unluckely mars was just above a rooftop and i could not get a good stable look. Then clouds took over complètement. First impression  is that the scope perfoms beyond what i expected and i am looking forward to better seeing conditions. Very promising. 


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#91 Echolight

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Posted 22 November 2020 - 08:38 PM

That's great! I've been running my 6 inch f8 achromat up to 375x along the terminator lately. Details are fantastic. Crisp and clear.

 

It's usually slightly undermounted on a manual alt/az mount, so I haven't been doing much planetary studying with it lately. Also since Jupiter and Saturn are much lower than a few months ago. Still take a peak now and then.

 

Clusters and star fields are very much in play though. I love some clusters, but they often inflict aperture fever on me.


Edited by Echolight, 22 November 2020 - 08:48 PM.


#92 Traveler

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Posted 23 November 2020 - 01:14 AM

Hi Michiel, congrats with your nice scope.

 

Question, how well do you like your  tripod and mount when viewing with a 180x magnification?



#93 michiel

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Posted 23 November 2020 - 08:17 AM

Hi Michiel, congrats with your nice scope.

 

Question, how well do you like your  tripod and mount when viewing with a 180x magnification?

This is an old custom alt-D mount. It follows when you grab the tube, like a dob, but honestly it is not for high magnification viewing, above 100x it is not optimal. I have an EQ6 but often I am too lazy to take it out and align it, so for quick sessions, which are almost 90 % of my sessions, I just take the altazimuth mount. Laziness wins over vibrations.. grin.gif grin.gif



#94 daquad

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Posted 23 November 2020 - 09:43 AM

Dom... indeed there is a smaller diameter part tube near the focuser. I am not sure i can remove it as Don suggested.... 

Thanks for the info.  I once owned a Tasco 76.2 mm f/15 refractor with an extension tube that could slide forward for storage in the case.  Back then binoviewers were not in general use for refractors, but that scope would have been very binoviewer friendly.  

 

Dom Q.


Edited by daquad, 23 November 2020 - 09:44 AM.


#95 daquad

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Posted 23 November 2020 - 09:47 AM

It can be pretty firmly tightened. Mine was and needed a strong grip to turn the first time. I decided to replace it with a pair of Baader M68 extension tubes in the focuser instead, which is much more flexible and vastly easier to change as needed. 

 

gallery_55742_4772_251167.jpg

 

 

Clear skies!

Thomas, Denmark

Tomas, so your model did have a smaller diameter section that could simply be unscrewed from the main tube?  I was under the impression that the removeable section was held in place with three grub screws. 

 

Dom Q.



#96 Astrojensen

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Posted 23 November 2020 - 10:56 AM

Tomas, so your model did have a smaller diameter section that could simply be unscrewed from the main tube?  I was under the impression that the removeable section was held in place with three grub screws. 

 

Dom Q.

My version has the full diameter removable section. It's not held in place with grubb screws per se, meaning you don't remove the grubb screws to remove the section. It's threaded into the main tube, just like the version with the smaller diameter section, but it is partially assembled with screws. It's not a good design. Removing it altogether and replacing it with the two Baader M68 extension tubes cleaned up the functionality of the scope dramatically.

 

 

Clear skies!

Thomas, Denmark


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#97 daquad

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Posted 23 November 2020 - 11:30 AM

My version has the full diameter removable section. It's not held in place with grubb screws per se, meaning you don't remove the grubb screws to remove the section. It's threaded into the main tube, just like the version with the smaller diameter section, but it is partially assembled with screws. It's not a good design. Removing it altogether and replacing it with the two Baader M68 extension tubes cleaned up the functionality of the scope dramatically.

 

 

Clear skies!

Thomas, Denmark

Thanks, Tomas.  The modification you made to your scope gives it very clean lines.

 

Dom Q.



#98 RichA

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Posted 23 November 2020 - 09:05 PM

Whether a telescope of any given size is enough for serious observing depends more on the observer than the aperture... 

 

 

Clear skies!

Thomas, Denmark

To a degree, but lets not broad-brush it too much.  A novice looking through a 10 inch scope on a good night for about 30 minutes is going to see more than an experienced observer looking through a 4 inch scope.



#99 Ihtegla Sar

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Posted 23 November 2020 - 09:15 PM

To a degree, but lets not broad-brush it too much. A novice looking through a 10 inch scope on a good night for about 30 minutes is going to see more than an experienced observer looking through a 4 inch scope.


Not necessarily. A 4" is sufficient to see the SPC, NPH, and numerous albedo features on Mars. Yet, this past Mars season has seen numerous novice Mars viewers, some of whom had 10 or 12 inch reflectors, posting threads saying they couldn't see anything on Mars but a white disc, likely due to issues such as cooling, collimation, seeing, and viewing Mars too low in the sky, but experience observing subtle difference in contrast of Mars albedo featutes may also play a role.
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#100 N-1

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Posted 23 November 2020 - 09:50 PM

They might see more but nor necessarily observe more LET ALONE seriously observe more. There are many things well within reach of a 4" that will still competely escape the uninitiated.

To a degree, but lets not broad-brush it too much. A novice looking through a 10 inch scope on a good night for about 30 minutes is going to see more than an experienced observer looking through a 4 inch scope.


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