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4" refractor vs. 4" Mak

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#51 nickcodybarrett

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Posted 06 March 2018 - 10:08 PM

No these were user photos. http://www.obsession...es/20/index.php



#52 edwincjones

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Posted 08 March 2018 - 06:49 AM

I see it as a FOV issue

do you want the wider FOV lower mag  of a refractor for larger objects like clusters

or the smaller FOV high mag for detail for planetary 

 

question.gif

 

edj


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#53 Jon Isaacs

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Posted 08 March 2018 - 07:12 AM

 

 

You said that at just the right time. I was planning on selling my Avx 8" Newt but today I doubled the length on the tripod legs(something I've never done before) and it was an entirely new telescope. Turns out everything was just awkward. Now I'm completely comfortable. I'll probably just use it for EAA instead.

 

 

With my 8 inch F/5, I kept the legs short but rather than standing, I sat comfortably in an adjustable observing chair..  If you don't have one, it might be worth considering.  I use mine with every telescope I own, every night.

 

Jon

 

Well I checked and about the lowest the scope will go is just under my standing height. I wouldn't be able to use a chair. Note the stepping stool.

 

I find that odd.  My 8 inch F/5 on a CG-5 ASGT is very workable with a chair with the tripod legs not extended.  I saw the step stool.  I also saw that you had the tripod legs fully extended. 

 

 

 

 

There is an all purpose telescope. It's called a 20" obsession on an eq table.

Hardly! For one thing, that's not going to be a good astrophotography rig without major modifications. Standard Dobs aren't rigid enough for astrophotography, and generally don't have a very wide fully illuminated field.

More to the point, a 20-inch Dob is too big to observe many objects. Consider the Pleiades just as one example.

 

Well they may not be the best astrographs but the pictures on  obsessions website are still pretty good for me.

 

 

I had a 25 inch F/5 Obsession, currently I have a 22 inch F/4.4 Starsplitter.  A little heavier than a 20 inch F/5 Obsession but maybe a little shorter. 

 

These scopes are massive, require a real ladder for observing and are far from an all purpose telescope.  The second one from the left is the 22 inch.  

 

4 Dobs plus Jon.jpg
 
Jon

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#54 DonnieBe

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Posted 08 March 2018 - 09:47 AM

Jon, that’s a beautiful set of scopes you have there. Truly impressive, I could see myself owning something like you have there!!! Do you view from home, or do you transport them, or both?

#55 jgroub

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Posted 08 March 2018 - 11:47 AM

Jon, that’s a beautiful set of scopes you have there. Truly impressive, I could see myself owning something like you have there!!! Do you view from home, or do you transport them, or both?

Why thanks!  Yes, since they're so small, they're easily transportable, but I've since added a big brother to them, a C9.25 . . . 

 

Ohhhh, you mean the other Jon.  <slinks away in shame>


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#56 grif 678

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Posted 08 March 2018 - 11:47 AM

I have had both, both are good scopes, my achro was the Japan made C102, the top of the 4 inch achro's. But on nights that you just want to take a quick look, the 4 inch mak would be better, and it would be used more. The images in the achro may be a little sharper, but not enough difference to me to take the achro out for a quick look see. The 90 ETX would be a great choice also, I have one now, and it will perform excellently. Mine is on a unitron 114 altaz mount, the ultimate in light weight and ease of use, with excellent planetary and lunar view.



#57 Jon Isaacs

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Posted 08 March 2018 - 04:17 PM

Jon, that’s a beautiful set of scopes you have there. Truly impressive, I could see myself owning something like you have there!!! Do you view from home, or do you transport them, or both?

 

Donnie:

 

I took that photo during a transition period . I had purchased my 22 inch to replace the 25 inch and needed to take photos of the 25 inch for the Astromart ad.  I had to roll out the 22 inch to get to the 25 inch so I decided to take advantage of the photo op and roll out the 16 inch and the 12.5 inch as well.  The 25 inch did sell. 

 

The 22 inch lives in the high desert and only gets rolled in and out of the garage . The other two travel with us in our motor home on our trips around the southwest .

 

5608397-Scopes at Navajo National Monument.jpg
 
Jon

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#58 NEOhio

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Posted 08 March 2018 - 05:23 PM

Hi guys,

 

I'm currently debating with myself if I should get a 4" frac or mak as my grab-n-go. I don't know much about either because I'm primarily a reflector guy. I want it to cover the entire observing spectrum: Planetary, Lunar, DSO.

 

Just tell me: What would you buy

 

Thanks,

Nick

FWIW, I'm wondering if your comparison of a 4" refractor versus a 4" mak is the best comparison. If your main concern is portability I don't think it is. I have a 4" refractor and a 6SE, bought with the idea of the 4" refractor being grab-n-go and the 6SE being my goto scope. But I found the 6SE OTA on the TWI mount is actually far more portable than the 4" refractor on the TWI, simply due to compactness, and it rides better on the TWI as well. So unless price is an issue, maybe your comparison should be between a 4" refractor and a larger 5" or 6" cat of some sort (not sure if a mak would be ideal at that aperture). You may be able to get more portability and more aperture with the latter choice.



#59 DonnieBe

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Posted 08 March 2018 - 07:49 PM

 

Jon, that’s a beautiful set of scopes you have there. Truly impressive, I could see myself owning something like you have there!!! Do you view from home, or do you transport them, or both?

 

Donnie:

 

I took that photo during a transition period . I had purchased my 22 inch to replace the 25 inch and needed to take photos of the 25 inch for the Astromart ad.  I had to roll out the 22 inch to get to the 25 inch so I decided to take advantage of the photo op and roll out the 16 inch and the 12.5 inch as well.  The 25 inch did sell. 

 

The 22 inch lives in the high desert and only gets rolled in and out of the garage . The other two travel with us in our motor home on our trips around the southwest .

 

 
 
Jon

 

Man....... that’s the kind of problems I want lol!!!  Sounds amazing, I could see myself owning a Teeter Classic.  Way cool collection Jon 


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#60 hboswell

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Posted 08 March 2018 - 09:15 PM

 

 

 

For Planetary, Lunar, and DSO I'd go with  short Focal Length ED Refrator as the shorter F/L and ability to use longer 2" Eyepieces (to their fullest) is something the Mak isn't able to do.

The 4" ED will also cool faster although not a huge difference.

Oh I forgot to mention Achro. I cant afford an ed right now.

 

5" short tube newt.

 

Bingo.

 

A 130 mm F/5 with a decent mirror and a 2 inch focuser. No CA, much faster than the Mak or the refractor for EAA and very rugged.

 

I've owned several.. It's scary sometimes how good they can be. I remember one night under dark skies.. I was doing the low power, wide field thing with my NP-101 and swapped it out for a 130 mm, F/5 Newtonian with the 31 mm  Nagler and a paracorr. I wasn't giving up much with the $200 scope.

 

The closest thing there is to a poor man's 4 inch apo.

 

 

 

Jon

 

Have these improved over the years?  The last time I knew anyone with one was 20 or so years ago, and they weren't happy at all.  I'm interested because I'm looking for a scope to take on camping trips.

 

Harry



#61 nickcodybarrett

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Posted 08 March 2018 - 10:27 PM

 

 

 

You said that at just the right time. I was planning on selling my Avx 8" Newt but today I doubled the length on the tripod legs(something I've never done before) and it was an entirely new telescope. Turns out everything was just awkward. Now I'm completely comfortable. I'll probably just use it for EAA instead.

 

 

With my 8 inch F/5, I kept the legs short but rather than standing, I sat comfortably in an adjustable observing chair..  If you don't have one, it might be worth considering.  I use mine with every telescope I own, every night.

 

Jon

 

Well I checked and about the lowest the scope will go is just under my standing height. I wouldn't be able to use a chair. Note the stepping stool.

 

I find that odd.  My 8 inch F/5 on a CG-5 ASGT is very workable with a chair with the tripod legs not extended.  I saw the step stool.  I also saw that you had the tripod legs fully extended. 

 

 

 

 

There is an all purpose telescope. It's called a 20" obsession on an eq table.

Hardly! For one thing, that's not going to be a good astrophotography rig without major modifications. Standard Dobs aren't rigid enough for astrophotography, and generally don't have a very wide fully illuminated field.

More to the point, a 20-inch Dob is too big to observe many objects. Consider the Pleiades just as one example.

 

Well they may not be the best astrographs but the pictures on  obsessions website are still pretty good for me.

 

 

I had a 25 inch F/5 Obsession, currently I have a 22 inch F/4.4 Starsplitter.  A little heavier than a 20 inch F/5 Obsession but maybe a little shorter. 

 

These scopes are massive, require a real ladder for observing and are far from an all purpose telescope.  The second one from the left is the 22 inch.  

 

 
 
Jon

 

Used it last night. Lowest I went was the Orion Nebula and I fit right under the EP. I could use a chair but it would be no different for I'm just as comfortable.



#62 REC

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Posted 09 March 2018 - 11:58 AM

 

For Planetary, Lunar, and DSO I'd go with  short Focal Length ED Refrator as the shorter F/L and ability to use longer 2" Eyepieces (to their fullest) is something the Mak isn't able to do.

The 4" ED will also cool faster although not a huge difference.

Oh I forgot to mention Achro. I cant afford an ed right now.

 

I have a C102 F1000mm f/9.8 and there is very little AR color in it, don't bother me much. It gives me nice sharp stars and has become my main grab 'n Go scope. I have it on a nice AZ mount and use up to 150x cleanly.




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