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what's a good telescope to pair w/ a 120 mm apo?

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#1 jfoley68

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Posted 29 September 2013 - 10:37 PM

Dear Folks,

I have a very nice Orion EON 120 mm (f/7.5) apochromatic refractor, which I have found to be a great all around scope for my purposes. But I'm interested in using it in conjunction with a second telescope, mounted together a double-headed Explore Scientific Twilight II mount.

So, what's a good "companion" scope for a 120 mm apo?

I'm still a newbie compared to many on this site, but I like a wide variety of visual observing, especially lunar, planetary, and star clusters. With my apo (and my light pollution levels) deep sky observing (faint fuzzies) has been a bit limited. Maybe I can fix that with a second scope?

So, what do you suggest?

I know some people like a "Mak and Frac" combination, putting a fairly fast widefield refractor on one side, and a high-power Mak on the other.

I also see the wisdom in pairing the refractor with a nice big reflector (8" or so), to have the "best of both worlds" optical designs.

What does the collective wisdom of Cloudy Nights suggest? ;-)

Thanks!

Jon
Saint Paul, MN

#2 jfoley68

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Posted 29 September 2013 - 11:23 PM

I should mention again that I would like to mount these two scopes *side-by-side* on the same ES Twilight II mount.

The mount has two Vixen style saddles, and can handle about 20-30 pounds on each side. I plan to put the refractor on one side, and something else on the other, and have them pointing exactly (with some minor adjustments) in the same direction.

#3 kfiscus

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Posted 29 September 2013 - 11:26 PM

I had a rig sorta like this when I started out in 1980. Two 4" scopes of different focal lengths acting as counterweights for each other on a 2" galvanized pipe GEM.

I realize that your two scopes would be on the same side of the mount.

#4 Jon Isaacs

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Posted 30 September 2013 - 12:18 AM

I should mention again that I would like to mount these two scopes *side-by-side* on the same ES Twilight II mount.

The mount has two Vixen style saddles, and can handle about 20-30 pounds on each side. I plan to put the refractor on one side, and something else on the other, and have them pointing exactly (with some minor adjustments) in the same direction.


I like to setup two scopes but on different mounts... The ES mount limits the size of the scope you can actually use and without slo-motion controls, tracking at high magnifications is going to be a problem. Hand tracking works nicely with a Dob, you have a long lever on a super solid mount...

Jon

#5 SeattleScott

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Posted 30 September 2013 - 04:39 AM

You would not want to pair a reflector and refractor on the same mount unless the object was for you to view through the top of the reflector tube while your small child viewed through the bottom of the refractor tube. Stick to SCT or Mak which also view through the bottom of the tube. Maks are great for planets but so is your refractor so I would go SCT.

#6 Tony Flanders

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Posted 30 September 2013 - 06:09 AM

I have a very nice Orion EON 120 mm (f/7.5) apochromatic refractor, which I have found to be a great all around scope for my purposes. But I'm interested in using it in conjunction with a second telescope, mounted together a double-headed Explore Scientific Twilight II mount.


I guess the question is what you're trying to accomplish, other than have the warm fuzzy feeling that there are two scopes on your mount.

A 120-mm f/7.5 achromat is pretty much of a generalist scope, so I don't think anything in the same size class will really complement it. How about two copies of the same scope, operating at different magnifications?

If you really want better views, get an 8- or 10-inch Dob. But obviously that won't work on the same mount.

#7 GOLGO13

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Posted 30 September 2013 - 07:07 AM

That's a heck of a scope...so congrats!

My opinion would be either go a good amount bigger or a good amount smaller (or both eventually). An 80mm apo (or even the sweet 72mm I have) would be a nice wide field grab and go. But aperture limited of course.

An 8-10 inch dob (I'd lean toward the 10 since you have the 120mm) would give you the deep sky grasp which your current scope would lack.

So if you are interested in zooming in on deep space objects the 10 inch dob. If you are interested in a small travel scope which to sweep the milky way at low power, a small fast (F6ish) 66-80mm apo would be nice.


EDIT: I see...you want something for your other side of your mount. Then I'd certainly consider the wide field 80mm apo. I don't see any point going similar to your 120mm in another design. That's about as good as you can get in the 5 inch range. A 6 inch MAK won't be as good as your 120mm in my opinion.

#8 csrlice12

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Posted 30 September 2013 - 07:26 AM

Get the BAD....(BigA**Dob). Preferrably a 10" or 12" (depends upon health/transportation). Don't put it on your mount, leave it as a dob.

#9 lamplight

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Posted 30 September 2013 - 07:47 AM

Two dobs. Or a small APO ?

#10 Gert K A

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Posted 30 September 2013 - 09:04 AM

I have to go with Tony on this one
I simply could not wrap my head around pairing this nice scope up with anything
unless you needed a guide or camera beside it

#11 Jarad

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Posted 30 September 2013 - 11:58 AM

A 120mm apo is pretty nice scope. There won't be much of anything else in the same aperture range that will do much that it won't. A 6" mak will have very similar performance at high power, but lose the low power.

If you really want to mount something on the same mount, I would go with something for wider field - maybe a 4.5" f4 starblast, or a shorttube 80 f5.

But my recommendation would be to go the other direction, and get a medium-large dob, 10" or larger. That will bring in a lot more light than the 4.7" apo and let you see DSO's you can't in the smaller scope.

Jarad

#12 T1R2

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Posted 30 September 2013 - 12:22 PM

usually one gets a mid-size refractor on a alt/az for ease of use, I wouldn't put anything next to it, its already capable of wide field views, and if you put a SCT next to it you probably will not use the sct much because the stars will look much better in the refractor

#13 Mark Costello

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Posted 30 September 2013 - 12:32 PM

A C9.25 might be a good scope to have riding shotgun. The optical tube assembly weighs about 20 lb. All success in picking a winner....

#14 orion61

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Posted 30 September 2013 - 07:04 PM

I love my Meade 7" 180mm F15 Mak.. Beautiful scope.

#15 SeattleScott

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Posted 01 October 2013 - 12:08 AM

I have to side with Mark on the 9.25" SCT. It is similar to the frac in terms of portability. This combination would give nearly the light grasp of the 10" Dob everyone is recommending with wider FOV because of the frac and less collimation problems. The Pleiades would rock in this scope with the 3 deg FOV and refractor pinpoint stars. The 180mm Mak wouldn't be a bad way to go either, more portable and higher contrast than the SCT but not as much resolving power.

That being said I personally would go with a 10" reflector as it would provide the resolution, good contrast and reasonably wide FOV all in one scope that takes less setup time, especially if you get a Dob. But you already have the frac and wanted to know what to pair it with.

#16 Qwickdraw

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Posted 01 October 2013 - 05:43 AM

I would suggest making a day/night setup and get a HA double stacked pressure tuned solar scope.

#17 jfoley68

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Posted 02 October 2013 - 08:03 PM

Thanks, everyone, for the great advice!

#18 Paco_Grande

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Posted 02 October 2013 - 08:15 PM

I love my Meade 7" 180mm F15 Mak.. Beautiful scope.


That was my sense, too. Orion has a nice one. A bit pricey, but they do appear in classifieds now and again.

#19 dr.who

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Posted 03 October 2013 - 06:24 PM

This is an interesting question. The APO gives you about the equivalent to a 6-7" SCT so you would want to get at least 2" over that top number for any kind of WOW effect if I remember it right... So that would be a 9.25" or higher SCT or similar sized Newt.

If you want similar views to the edge as you get with the APO you will want the Edge series from Celestron in SCT's. Not sure what to do in terms of Newt's... I would go big with an 11" Edge SCT! It's at 30 lbs so at the top end. Either that or a 9.25" Edge at 20 lbs.

That combination would give you an interesting and varied perspective on the object you are looking at. One wide but less "bright" and one narrow but "brighter"

#20 jfoley68

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Posted 06 October 2013 - 10:23 PM

Thanks, everyone, for the great advice!

I decided to pair the 120 mm f/7.5 EON apo scope with a smaller 80 mm f/6 apo EON scope. I'm going to use the 80 mm with a wide angle eyepiece (24 mm pan) and the 120 with higher power eyepieces. Should be a great combination!

The only trouble is that the 80 mm scope is a lot lighter than the 120, and the Explore Scientific Twilight II mount works best if both sides are roughly the same weight. Can I add some weights to the 80 mm scope somehow?

Thanks again!

#21 SeattleScott

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Posted 06 October 2013 - 10:43 PM

And I thought the Eon 120was a wide field scope. I guess the more the merrier. An 8" SCT would have 3x the light grasp and be around the same weight as your Eon. I guess I don't quite see the logic of pairing two of the same telescope type but others are recommending it, so what do I know?

#22 Lamb0

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Posted 11 October 2013 - 05:31 AM

Can I add some weights to the 80 mm scope somehow?



:hmmmm: Sure, just use a 21mm Ethos (2.25lbs) or a 31mm TermiNagler (2.2lbs) with the 80mm f/6 for a bit of gravitas. With an ocular of modest weight in the 120mm the differential would only be 5lbs... and/or perhaps the 80mm can be extended further to the outside, (ask ES). That's a husky little mount! :sumo:






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