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A dilemma

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#1 Senex Bibax

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Posted 30 December 2019 - 11:28 AM

I currently have four telescopes, and really don't want to own more than I can use:

  • Sears 6339-A 76 mm * 1200 mm
  • Sears 6333 60 mm * 900 mm
  • Sears 6309 60 mm * 700 mm
  • Celestron C-90 f/11 (older 1980's version)

I have an opportunity to acquire a classic white tube Tasco Lunagrosso 4.5" * 900 mm reflector (Circle-T) with EQ mount and tripod for $40 CAD. If I go for it, I would need to divest myself of one of the other scopes. Hence the dilemma - which one would I sell?

  • The big 6339-A is out of the question - it is a keeper.
  • The 6333 is a complete kit, with the original box and accessories. It also has given excellent views so far, with a 1.25" conversion.
  • The 6309 seems to be surplus. I am considering using it as a guide scope for the 6339-A but I don't have any other use for it if I keep the 6333, which is a better scope all around.
  • The C-90 is a true grab-and-go, and has given good views, has the largest aperture of my current scopes and I have a 1.5" adapter. The helical body focusing is a PITA, though.

I am leaning towards two options, but I am having trouble deciding:

  • Sell the C-90 and buy the Lunagrosso. Has the bonus that I would come out ahead $$.
  • Do nothing and stick with the scopes I currently own.

Any thoughts? Would you choose the Lunagrosso over the C-90? Should I not bother with the 6309 as a guide scope for the 6339-A?



#2 Defenderslideguitar

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Posted 30 December 2019 - 11:58 AM

if you cannot keep them  and I myself have just recently tried to do the one comes in  one must go out policy..... then I say you are right to send the 6309 to a new home.  The 6339 is out of the question of course.... so how much guiding do you do anyway? other scopes can fill that role  even other guiding apparatus  so  I think intuitively you are aiming in the right direction.  I cannot speak to the C-90  as I have never used one   good luck   btw   these are the problems to have in life   which scope to sell when I buy yet another.....smile.gif


Edited by Defenderslideguitar, 30 December 2019 - 11:59 AM.


#3 ccwemyss

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Posted 30 December 2019 - 12:06 PM

How would you use the 6309 as a guide scope? The 6339 mount isn't really suitable for astrophotography, and the extra weight/moment arm of the 6309 is likely to make it shake more. If you are thinking of it as a super-finder, using a wide field eyepiece to help zero in on objects that slip out of the view of the 6339 at high power or to hop around among close objects, then that could be useful. Since they are painted matching colors, it would also look nice. 

 

If you trade the C90 for the newt, you'll be giving up grab and go. With the 6309 piggyback on the 6339, your most portable scope will be the 6333. But I know what you mean about focusing the C90, especially if the grease has gotten stiff. 

 

I'm not familiar with the quality of the Towa optics in the Tasco, but they could be worse than the C90. Others here probably have experience with them. You're gaining about 25mm of aperture, which is significant, but only if the quality lets you take advantage of it. I would recommend getting the Tasco and doing a side-by-side comparison with the C90 (and the 6339) and then decide which to keep. One option is to resell the Tasco if it doesn't compare well or turns out to be more hassle than you want to deal with. 

 

Personally, if I were looking to upgrade from a C90 to larger aperture, I'd be on the lookout for a classic C5. 

 

Chip W. 


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#4 Pete W

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Posted 30 December 2019 - 12:10 PM

The guide scope option is interesting, but if the plan is to use the 6339a OTA, guidescope and finderscope on the native 6339a EQ mount, I'm thinking that extra mass would be pushing the EQ mount to the limit.  I've finally remedied the wobbles and slop in my 6339a mount and it works well with the OTA, but it is still at the upper limits of acceptable jiggles, particularly when focusing and in the wind.  


Edited by Pete W, 30 December 2019 - 05:36 PM.

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#5 deepwoods1

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Posted 30 December 2019 - 12:32 PM

I would keep all and see how your observing style turns out. You may decide the newt is redundant. Or a 60 is as well. That being said, I have way too many scopes due to the niches they fill. Good luck! Clear and steady skies.....



#6 Terra Nova

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Posted 30 December 2019 - 12:38 PM

Several years ago I had what I considered to be good C90. It was one of the early orange ones. I also had (and still have) several 60mm achromatic refractors (F11 to F15). I found the C90 views to be quite similar to theirs. (My Questar gives a view quite similar to my former 3” F16 Unitron, but the C90 was noticeably down a peg in performance.) In reducing my total number of telescopes I sold the C90, because it’s performance overlapped noticeably with my 60mm scopes, and I had a Questar which I intended to keep, that was similar in size but far better in performance. 

 

Now, in your case, it would seem to me that you have really three scopes competing for the same niche and one needs to go. Your choices are between the Sears 6333 60 mm x 900 mm,  the Sears 6309 60 mm x 700 mm, and the Celestron C-90 f/11. Reducing this to the two most similar you have the Sears 6309 60 mm x 700 mm, and the Celestron C-90 f/11, both F11, both portable, grab and go scopes. 

 

My recommendation, sell the Sears 60mm F11, keep the C90, and buy the 114mm F11 Newtonian.


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#7 Garyth64

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Posted 30 December 2019 - 03:14 PM

Senex,

 

Keep them all and buy the  reflector.  After you look thru the reflector, only then will you know if it is worth keeping.

 

I know you've seen this picture of my 6339a and my 6309 together on a CG5 mount.   There it is quite stable.

 

Guide scope 2.jpg

 

I believe you said you like the way it looked, and you wanted to the same thing.  But as others have mentioned this combo would not be good on the 6339a mount.

 

I didn't use the 6309 as a guide scope. I put it with the 6339a for an outreach event.  The 6309 shows some very good views and I wanted people to see the difference with a medium power eyepiece on Saturn eg on the 6309, against a high power eyepiece on the 6339a.  I would have people looking thru one and then the other.

 

It looks like you did a good job on those scopes.


Edited by Garyth64, 30 December 2019 - 03:16 PM.


#8 Senex Bibax

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Posted 30 December 2019 - 04:59 PM

Thanks everyone for the advice. I think I will stick with my current four scopes for now, and use them some more to fully understand their strengths and weaknesses. The Tasco reflector interests me because I have read good things about them on this forum, it is cheap and it has been on sale for a couple of weeks now, but they are common enough that another one will come along if I change my mind in the future. 



#9 Jon Isaacs

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Posted 30 December 2019 - 06:09 PM

I'd buy the Newtonian and store the C-90 inside thev114 mm OTA..  :)

 

Realistically, I'd buy the Newtonian, keep 5 scopes for a while and just time determine which stays and which goes. You really can't make a well reasoned decision without actually having tried them all out.

 

That said, I think the Circle T Towa mounts that came with these scopes was undersized. If You want a top notch 4.5 inch F/8, I'd be looking for a C-4.5.. It's Vixen on the very nice Polaris mount.

 

4525703-c4point5 CN.jpg
 
Jon

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#10 clamchip

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Posted 30 December 2019 - 07:59 PM

That's a pretty good deal a 4-1/2 inch newt with a eq mount $40

Its a inch more aperture than your current largest the C90

I would buy the newt and see how it stacks up against the refractors

and the Mak.

The inch more aperture is very welcome. The newt is completely

apochromatic and you just might fall head-over-heals in love with that.

Doing gymnastics for best ep position  is a unfun thing about newts, but

it's worth it. A newt is really the only affordable way to get aperture. 

Pretty soon you will want a 6 inch f/8, and then settle on a 8 inch f/7 as

the most perfect instrument.

Quoiting John Dobson:

"To Understand the universe we must be able to see the universe."

 

Robert


Edited by clamchip, 30 December 2019 - 09:31 PM.

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#11 Terra Nova

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Posted 01 January 2020 - 03:37 PM

 

I'd buy the Newtonian and store the C-90 inside thev114 mm OTA..  smile.gif

 

Realistically, I'd buy the Newtonian, keep 5 scopes for a while and just time determine which stays and which goes. You really can't make a well reasoned decision without actually having tried them all out.

 

That said, I think the Circle T Towa mounts that came with these scopes was undersized. If You want a top notch 4.5 inch F/8, I'd be looking for a C-4.5.. It's Vixen on the very nice Polaris mount.

 

 
 
Jon

 

I completely agree. I had the Meade Towa version on the Towa GEM as well as the Celestron Vixen version on the Vixen Polaris mount. There were leagues of difference between these two mounts, the Polaris being far superior. As far as the OTAs themselves, the Meade Towa was a bit nicer IMO (especially once I converted the focuser to 1.25”), the optics were indistinguishable and both quite good. They were really nice little telescopes, a lot of fun to use really. Ergonomically they were both much better than the Edmund 4.25” F10 I also formerly had. I have since given them all away. One can only have so many telescopes, at least if they are to be used and enjoyed. Anyway, here’s my old Meade Towa 114mm F8 Newtonian on my Vixen Porta II mount. It was a nice, easy to use combination.

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#12 GreyDay

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Posted 01 January 2020 - 05:44 PM

personally i wouldnt buy the newt, i'd sell the C90 and buy a 4" refractor.   A brief explaination why:

 

the 6339 at 76mm should perform pretty much the same as the C90 (my SW102Mak is equal to my 80mm refractor in performance) so the only real reason to keep the C90 is portability.

 

you have said you don't mind giving up the C90 for the less portable Newt, But... the 4.5" newt won't perform as well as, or cool down as quickly as a 4" refractor.(wait for the central obstruction arguement).

 

having tried newts maks and fracs side by side on a SkyTee2 i can honestly say that central obstruction does make a difference of around 20% loss on newts and maks. i'm not bashing newts, i own a SW200p but last year i only used it twice due to size and cool down.

 

At $40 it's worth buying and trying the Tasco, my opinion is just that... an opinion.... and everybody should have one :)


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#13 Senex Bibax

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Posted 26 March 2020 - 08:30 AM

I never did buy the Tasco reflector when it was originally posted. Now it has been relisted on Kijiji for $20.00. But social distancing....

 

Before the COVID-19 outbreak I was in discussions about buying a newer Tasco Lunagrosso (red tube) for $40.00, including EQ mount, what looked like a Meade 1.25" focusser upgrade AND a Telrad. All on hold for now.


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