29 replies to this topic

[JCobb]

So, I’ve been trying to find a refractor that is 125-130mm ED f7-f9 DOUBLET (preferably closer to f7-7.5)
I found the at102ed (4”) $649
https://astronomics....ed&_ss=e&_v=1.0
And the at125edl (5”) $1849
https://astronomics....m-f-7-8-doublet

As far as I can tell there isn’t an at125ed and the at125edl is simply outside of what I am comfortable spending.

My question is, is there scope old or new that would be equivalent to a hypothetical at125ed that would land in price somewhere between those two?

Edited by JCobb, 02 October 2024 - 01:12 PM.

[Monel76]

SVBony SV550 122, it's an apochromatic triplet now on sale at 1299$

[Mike Q]

I have the AT 102EDL and to this day i have regretted not going bigger.  Like you I stayed in my budget, if i had it to do again I would go bigger.  Its only money and you cant take it with you 

[deSitter]

You are better off with f/8-9. Like mirrors, figuring gets harder in a non-linear way as the steeply curved ED elements get faster.

 

There are many choices new and old in the f/8-9 range. No more difficult to mount and handle than f/7.

 

-drl

[Echolight]

A 6 inch dob ought to do. 

[Echolight]

Here's the best deal going on a telescope right now.

https://telescopes.n...BiABEgJTAPD_BwE

 

Thanks to the large trunnions, the base on this one is smaller than all the others.

 

If I was starting over with astronomy right now, I'd buy this exact model right now and not think twice.

 

The ES Firstlight, in my opinion, is the best solid tube non premium dob available. The rings and large trunnions offer the ability to balance the scope and put the eyepiece at the most comfortable position unlike any of the others.

Edited by Echolight, 02 October 2024 - 07:22 AM.

[Jethro7]

As far as I can tell there isn’t an at125ed and the at125edl is simply outside of what I am comfortable spending.

My question is, is there scope old or new that would be equivalent to a hypothetical at125ed that would land in price somewhere between those two?

Hello JCobb,

Here is one listed on the CN Classifieds.

https://www.cloudyni...ro-tech-125edl/

 

HAPPY SKIES AND KEEP LOOKING UP Jethro

 

P.S. BTW, Astrotech scopes are consistently good and perform past their price points.

Edited by Jethro7, 02 October 2024 - 07:19 AM.

[approjects]

So, I’ve been trying to find a refractor that is 125-130mm ED f7-f9 (preferably closer to f7-7.5)
I found the at102ed (4”) $649
https://astronomics....ed&_ss=e&_v=1.0
And the at125edl (5”) $1849
https://astronomics....m-f-7-8-doublet

As far as I can tell there isn’t an at125ed and the at125edl is simply outside of what I am comfortable spending.

My question is, is there scope old or new that would be equivalent to a hypothetical at125ed that would land in price somewhere between those two?

Wait, then buy that larger aperture. You won't regret it. Buying a smaller aperture for now, then spending again for a larger aperture will be worse. That 5-inch is a good size, not too large that it requires a whole another category of mounts, and not too small for deep sky either.

[deSitter]

Personal recommendation - the old Meade 127ED f/9 scope - these show up used for less than a grand. My copy is fantastic - showed albedo features on Ganymede! Handles 300x like a champ.

 

-drl

[SeattleScott]

Synta 120mm ED doublets at F7.5 come to mind. Typically around $1,500 new, less on sale or used.

Edit: never mind, apparently these run $2,500 now. I guess I’m behind the times.

Apos get kind of exponentially more expensive as aperture increases so there is going to be a major price difference between 4” and 5”. That said, the 125EDL has better glass and is a triplet, so it will have excellent control of CA where the smaller doublet won’t be able to eliminate CA. So that’s part of why the 5” is three times as expensive.

Edited by SeattleScott, 02 October 2024 - 09:17 AM.

[dnrmilspec]

Let me ask the single most important question when buying a large(ish) refractor.  What mount do you currently have, or what is your budget for the scope with the mount? 

 

Do you want us to limit ourselves to refractors or would you consider another kind of scope.  For example, you could get an 6" SCT with a goto mount for your in-between price.  Or, as some have said, a bigger Dobsonian mounted Newtonian scope. 

[vtornado]

Skywatcher 120 ED used can be found for around $1000.00  They are fine telescopes for both color correction and figure.  Slightly smaller than a true 5 inch.  Orion had a rebrand of this telescope and those can be found even cheaper, however not many come up for sale.

 

As far as mounting I would use a CG5 class mount for a 120 ED doublet. 

[Refractor6]

Skywatcher 120 ED used can be found for around $1000.00  They are fine telescopes for both color correction and figure.  Slightly smaller than a true 5 inch.  Orion had a rebrand of this telescope and those can be found even cheaper, however not many come up for sale.

 

As far as mounting I would use a CG5 class mount for a 120 ED doublet. 

  The other nice thing about the 120 f/7.5 is its light weight OTA. After setting up my 152 f/8 refractor on most nights then switching to the 120 f/7.5 it feels like nothing in comparison. As noted you don't need a heavy mount for visual use with this scope.

 

 Amazed at how prices have changed. Back in 2007 I got a used Skywatcher Pro-Series 120 f/7.5  with a nice hard aluminum case, 9x50 finder, good quality 2" diagonal,  2" focuser upgrade and wider solid tube rings/dovetail bar upgrade for just over a grand. New ones are now over 3k Canadian nearly bare bones......crazy!

 

 Photo from back then added.....

Edited by Refractor6, 02 October 2024 - 12:40 PM.

[sevenofnine]

Maybe split the difference? By all accounts on this forum, it's a very good refractor 

 

https://astronomics....46cafc40c&_ss=c.

[JCobb]

SVBony SV550 122, it's an apochromatic triplet now on sale at 1299$

Trying to find a doublet, forgot to put that in my initial post.

Edited by JCobb, 02 October 2024 - 01:13 PM.

[JCobb]

Wait, then buy that larger aperture. You won't regret it. Buying a smaller aperture for now, then spending again for a larger aperture will be worse. That 5-inch is a good size, not too large that it requires a whole another category of mounts, and not too small for deep sky either.

Trying to buy a 5” the 4” was just to reference the type of scope I was looking for (just bigger). I also realized after I woke up that I had forgotten to state specifically that I wanted it to be a doublet.

[JCobb]

You are better off with f/8-9. Like mirrors, figuring gets harder in a non-linear way as the steeply curved ED elements get faster.

There are many choices new and old in the f/8-9 range. No more difficult to mount and handle than f/7.

-drl

Any examples of 5“ ED doublets in this range?

[Refractor6]

 Not a 5" but a 4"  ED doublet that's a good price:

 

 

https://www.cloudyni...th-accessories/

 

 

Had one these before I moved up to the 120 in the series....great optics!

 

   Updated...... The original add for the other 100ED got pulled and found this other one instead up above...better deal with more stuff and a better focuser.

Edited by Refractor6, 02 October 2024 - 05:47 PM.

[Oldfracguy]

I was going to suggest it, but I see other informed CN members have already done so: a used Sky-Watcher 120ED Evostar, or an old Orion ED120 (same OTA, different paint scheme).  There is one still available in the CN Classifieds.

 

The 120ED Evostar is better optically than a hypothetical AT125ED would be, and is much lighter.  The one I used to have only weighed 13.4 lbs. with a finder scope, diagonal and eyepiece installed.  That's only a pound or so heavier than an AT102ED ready for visual use.

Edited by Oldfracguy, 03 October 2024 - 11:54 PM.

[Freezout]

This one is between 4 and 5 and has a big discount.

It's a generic type doublet, please note that I have no experience with it, I just made a fast search on the site of Astroshop.

Astroshop is a major established supplier in Europe, TS also.

 

https://www.astrosho...ine-ota/p,52233

[Tony Flanders]

Just out of curiosity, why do you want a 5-inch ED refractor? It seems like an odd choice for a beginner.

Given a choice between owning only a 4-inch refractor and only a 5-inch refractor, I would pick the 4-incher in a heartbeat. It just seems more versatile.

Of course that assumes that I also own another telescope with reasonably large aperture -- anywhere from 8 inches on up. But that would be either a reflector or a catadioptric; 8-inch refractors aren't very practical.

[deSitter]

Any examples of 5“ ED doublets in this range?

I would look for a used Meade 127ED. Because of pervasive Meade bashing and the fact that the flagship of the ED line, the 178ED, had mechanical problems that compromised its optics, you can find these scopes for not much $$$. The design is excellent, conceived by a famous optical engineer. The 102ED and 127ED are consistently excellent performers. I will never sell mine. I had it on Jupiter once at 300x and noticed what appeared to be detail on Ganymede! "That can't be right." I made a mental note of the time, and when I later ran a simulation on my computer, I had in fact seen albedo features on the satellite. The scope is very easy to mount and a medium-duty mount like the Great Polaris, LXD75 etc is plenty strong to carry it.

 

-drl

[CollinofAlabama]

I'm with Tony Flanders here.  In fact, I'll go farther and say get the AT102ED for $650, then pick up the Explore Scientific 8" dob package on sale now for $460.  So that's $1100 for two different telescopes and experiences.  Your problem, however, will be the mount.  If you're good with an equatorial, the CG-4 would work and can be had for less than $400 online at a number of vendors, but I'm not a fan of equatorial mounts, and the SkyWatcher AZ-5 head is a little wimpy for the AT102ED.  Might work, but it'd be maxed out and I've not tried the two, the AT80ED more its speed.  BTW, an 8" dob will take anybody's 5" refractor on the planets -- seen it at the eyepiece.  Just better -- period.  Good luck

[vtornado]

If you're good with an equatorial, the CG-4 would work and can be had for less than $400 online at a number of vendors, but I'm not a fan of equatorial mounts,

 

With a few hand tools and 15 minutes the mount can be made to run in Alt-Az, by setting the declination to 90.  There is a plate that needs to be removed.  I can't recall if a tongue needs to be filed down to clear the mount body ???  If it does it's a quick job with a hand file.

Edited by vtornado, 04 October 2024 - 11:12 AM.

[Oldfracguy]

If you're good with an equatorial, the CG-4 would work and can be had for less than $400 online at a number of vendors, but I'm not a fan of equatorial mounts,

 

With a few hand tools and 15 minutes the mount can be made to run in Alt-Az, by setting the declination to 90.  There is a plate that needs to be removed.  I can't recall if a tongue needs to be filed down to clear the mount body ???  If it does it's a quick job with a hand file.

The tongue stays, but the top of the bracket the tongue rests atop needs to be filed down a little, or a notch created:

 

 

 

so the bracket will fit back on with the polar axis rotated all the way over to the 90° position, pointing straight up:

 

 

 

 

Edited by Oldfracguy, 04 October 2024 - 03:12 PM.