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AstroView 120ST EQ....good or bad.!

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#1 newtoskies

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Posted 28 November 2012 - 05:40 PM

Hi all

I posted a thread in the newbie board on buying a cheap refractor. My budget was to be around $300 but after lots of good advice and help I have decided to raise the budget to a max of $500.
What I want/need is a scope that is short tube, 90-120mm, a decent mount / tripod. I am thinking maybe later doing very limited planitary AP with this Refractor.

I was thinking the Omni 102 or this one Astroview 120ST EQ
This is on the high end of my budget. I have a 6" dob for DSO's and sharper images of planets. Thing is that sometimes, especially when it's this cold, my back hurts too much. I want/need a scope that I can use most of the time standing.
So my question is this, is the Orion 120ST a good scope. I know the mount is not the greatest. This will not be my primary viewing scope.

Thanks for any help.

#2 magnus

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Posted 28 November 2012 - 06:14 PM

Good scope..everything is relative in this world. I find my S-W 120ST good for widefield observing and brighter DSO observing. I can also push it to 160X for limited binary observing and planetary if you can stand the CA. So yes I think it`s an adequate refractor condsidering the price.I use mine on a Vixen Porta mount. But keep in mind it`s not an ED or APO. Far from it!

Good Luck,
Magnus 57N.

#3 orlyandico

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Posted 28 November 2012 - 06:19 PM

if you don't mind used... you can find an Orion 100ED for $400.

and there are manual EQ mounts out there for $100 - $150.

I'd rather spent $550 for an ED refractor and manual mount, than $500 for a 120mm achromat even on a motorized mount... the manual mount can be upgraded to motorized later, but the achromat can't be upgraded to ED or APO..

#4 Jon Isaacs

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Posted 28 November 2012 - 06:19 PM

I am thinking maybe later doing very limited planitary AP with this Refractor.



These scopes are primarily low power, wide field scopes, a 120mm F/5 has a lot of chromatic aberration that significantly affects the planetary views. Your 6 inch Dobsonian is going to much better on the planets.

Jon

#5 newtoskies

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Posted 28 November 2012 - 06:27 PM

Like I said, I'm still very new t this and know nothing about refractors. So Ed and APO is all greek to me.I'll check the Orio site for Ed scope then.

#6 Locoman

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Posted 28 November 2012 - 06:51 PM

I like my ST120 a lot. It's not a planetary scope. The nice thing about it is the short tube so on lighter mounts like the Porta ll its more stable than longer tubes. Once in a while they show up in the classifieds and they don't last long there.

#7 newtoskies

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Posted 28 November 2012 - 06:59 PM

I am not too worried about using this one on planets, my 6" dob is good for that. I enjoy clusters and that is where I will most likely use this, when I do use my Dob.
Starting to get bumbed as I thought I finally boiled it down to one or two scopes.

Used scopes don't last long and on CL they are all pretty much *BLEEP* or over priced.

#8 Locoman

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Posted 28 November 2012 - 08:11 PM

If standing is important then a refractor on a EQ or AZ mount and tripod would require a lot of bending over and getting on your knees if you don't want to sit in a chair.

#9 dlapoint

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Posted 28 November 2012 - 09:58 PM

Look into an ed80 on an az3 mount to start. Fits the bill.

#10 Sky Muse

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Posted 28 November 2012 - 10:28 PM

This would be ideal...

http://www.buydig.co...roogle&omid=...

...and it comes with the CG-4 mount. I just received a CG-4 mount a day or two ago, and it's better than I had expected, in conjunction with my FS-102. Plus, you'd get the Celestron 4" f/9.8 achromat with "Starbright" coatings.

It's a no-brainer, for the amount allocated, and you'd have enough left over for the dual-axis motor drive set from Amazon.com.

Cheers,

Alan

#11 newtoskies

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Posted 28 November 2012 - 11:00 PM

Thanks for the link. I had seen that scope elsewhere but really didn't look into it.
I don't mind sitting, especially if the ep is eye level and I don't have to lean or twist very much. That is one of the problems at the moment with my dob, the finder scope. Once the cold weather sets in, my knees and back feel it the most.
I'll print this one out as well and add it the the rest of the ref. scopes to compare.

#12 Sky Muse

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Posted 29 November 2012 - 12:20 AM

There's also a 16" pier offered by Orion that will fit the CG-4 between the tripod head and the mount which will raise the refractor to clear the tripod when viewing at the zenith, adding even greater stability to the mount overall in addition to raising the eyepiece to a more comfortable position...

http://www.telescope...Orion-SkyVie...

However, it's black to match the "SkyView Pro" equatorial, but will fit the CG-4 in addition. I've ordered one and will need to paint it white to match my CG-4. I also have the polar scope for the CG-4, too...

http://www.highpoint...lar-Scope-fo...

...and for lining up the mount with Polaris for improved tracking, along with this...

http://www.amazon.co...ils_o01_s00_i00

The drive set comes with a four-D-cell battery pack for a total of 6v, but I'm going to try substituting a rechargeable 6v golf cart battery, as our auto battery charger has a 6v charging function.

I'm accessorising mine to the hilt with everything available for this model. :jump:

Cheers,

Alan

#13 Goodchild

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Posted 29 November 2012 - 09:43 AM

Rob,
I think the 120ST would fit your needs nicely. It's short and light and you wouldn't need to bend much to view from it. With a mount extension it would be even nicer.

I used to own a Celestron 102 f/5 and for the items you want to view it did a very good job. I only looked through a 120ST once but I was impressed with the added light throughput. In my opinion, I think it's a very good scope, especially for the money. It would work very well on a Voyager mount.

#14 Jon Isaacs

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Posted 29 November 2012 - 10:46 AM

Thing is that sometimes, especially when it's this cold, my back hurts too much.



What chair are you using? With a refractor or a reflector the eyepiece height changes from the horizon to the zenith so it is difficult to be comfortable while standing. A good quality, adjustable astronomy chair makes seated viewing comfortable.

Jon

#15 newtoskies

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Posted 29 November 2012 - 10:48 AM

As much as I would love to get a really good refractor, the budget just is not there. To be honest, I'm still not sure WHAT I want to do with it. Mainly to have a refractor to take breaks from the Dob and get some experience with other scopes.
Another scope that may be more in the budget is the Orion 'short tube' 80 mm EQ. It's a short tube which I like, weighs less than 16 lbs and won't take up much space. It goes for $300 on the Orion site. It's 400fl and f5.0.

#16 Sky Muse

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Posted 29 November 2012 - 11:55 AM

Rob,

The Orion AstroView 120ST w/equatorial you're considering, in addition to the Celestron Omni XLT 102 w/equatorial, comes with a black mount that is practically identical to the white Celestron CG-4 mount previously described, with very slight cosmetic differences. However, the tripod is of aluminum and not as sturdy, albeit lighter, than the steel tripod of the CG-4, though you wouldn't have to paint the extension to match, and it can be fitted with the Celestron dual-axis motor drive set in future, if desired.

The Celestron 4.02" achromat with its moderate f/9.8 ratio would be better suited for planets, binaries, open and globular clusters and brighter DSOs. It will also exhibit minimal false colour when viewing brighter objects, and may be used for imaging.

The Orion 4.7" achromat, with its fast f/5 ratio, is better suited for wide-field viewing of star fields, DSOs and astrophotography. Though, when viewing brighter objects, such as Jupiter, Venus, and brighter stars like Rigel, Vega and Sirius, the false colour will be considerable, perhaps correctable to a bearable level with a minus-violet filter. Also, to achieve higher magnifications, you'll need a focal amplifier, such as a 2x barlow.

In other words, among the mounts, it's a toss up; among the achromats, however, it will depend on your preferred observing and recreational interests, given the above.

Regardless of choice, don't be surprised if your new refractor eclipses your reflector in preference.

As a gentleman mentioned, the Astro-Tech "Voyager", from which I've upgraded to an equatorial, is an altazimuth mount and unsuitable for long-term observing and serious astrophotography. I'll keep my "Voyager", but for terrestrial use only, perhaps with a Maksutov reflector someday.

Cheers,

Alan

#17 Sky Muse

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Posted 29 November 2012 - 11:58 AM

Hear! Hear! I'm wanting one of those myself. :)

#18 Jon Isaacs

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Posted 29 November 2012 - 12:37 PM

The Orion 4.7" achromat, with its fast f/5 ratio, is better suited for wide-field viewing of star fields, DSOs and astrophotography.



It think it is a stretch to suggest that a 120mm F/5 achromat is well suited for astrophotography. Cameras capture a much wider spectrum than the human eye so the inability to focus focus the red and blue ends of the spectrum results in seriously bloated stars. In general, this where apo's shine, their ability to focus a broad spectrum of colors including those that the eye cannot see.

I also think it is important to address the statement "is an altazimuth mount and unsuitable for long-term observing." The fact is that manually tracked alt-az mounts are fine for serious long-term observing, particularly with scopes in this aperture class and particularly mounts with slow-motion controls. The most important things about a mount are whether it is stable and free from vibration and whether it is comfortable for viewing.

I have both a CG-5 ASGT and a Astroview sitting on a Vixen wooden tripod. They are fine mounts but I prefer the freedom to roam the skies and comfortable viewing that a good alt-az mount provides.

Jon Isaacs

#19 Sky Muse

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Posted 29 November 2012 - 01:47 PM

...well suited..."

I wrote, "...better suited...", and over the slower achromat, as an astrograph; regardless of chromatic abberration, in that both are achromats, thus debate.

"...this where apo's shine, their ability to focus a broad spectrum of colors including those that the eye cannot see."

The gentleman is considering a choice between two achromats, and given the funds allocated for said dilemma, it necessarily excludes the consideration of an apochromat, thus the generality.

"...manually tracked alt-az mounts...
...particularly mounts with slow-motion controls."

A manually-tracking altazimuth must always be accompanied by slow-motive controls if they are to be "fine for serious long-term observing". Redundancy noted, unless one was referring to the tiresome method of bumping the refractor itself to the left, then right, then up, then down, in the first instance, and within the same sentence even.

One would have to master the dexterity of a Ouija-board "mystic" to seriously anything with an altazimuth, when compared to the luxury of the consummate, motorised equatorial.

"...but I prefer the freedom to roam the skies and comfortable viewing that a good alt-az mount provides."

Precisely all that an altazimuth accomplishes, a roaming, as opposed to the singular, stray-free observances afforded by a motorised equatorial.

Cheers,

Alan

#20 waso29

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Posted 29 November 2012 - 02:41 PM

Unless you live under dark skies where the Milky Way is visible, I'd say skip the low-power wide-field 120ST short tube refractor.
I have owned two.
During the great recession, I was lucky to find used 120st for around $200.
They are great for scanning rich field starry skies.
Low power views are washed out in urban skies.
Basically slightly better views than a pair of binoculars.

You "run out of gas" viewing the moon and planets.
You'd get better lunar and planetary aP pics thru your 6in scope.

The EQ mount that comes with the setup is ok.
The motor is mounted awkwardly and gets in the way at certain viewing angles. With low power views of the scope, you really don't need tracking.

Overall, the 120st setup is a stepping stone.
Cheap way to learn about refractors and eq mounts.
You'll find out how much time is needed to setup the tripod, then the mount, then balancing the scope with counterweight.
Rotating the scope, viewing objects as it crosses the meridian, etc. I'd rather not during winter nights.
For me, it was not a keeper.

Have you considered raising the height of your dob?

If your budget allows, a used 80ed or 100ed on an alt-az mount like voyager/porta is better complement to your dob.
A nice cold weather grab-n-go setup.

Good luck.

#21 Jon Isaacs

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Posted 29 November 2012 - 03:18 PM

The gentleman is considering a choice between two achromats, and given the funds allocated for said dilemma, it necessarily excludes the consideration of an apochromat, thus the generality.



He is actually considering a number of choices and open to suggestion. A used ED-80 is within consideration. Any suggestion of using an 120mm F/5 achromat for astrophotography needs to point out that these scope are a poor choice because of the chromatic aberration and increased spectrum involved.

One would have to master the dexterity of a Ouija-board "mystic" to seriously anything with an altazimuth, when compared to the luxury of the consummate, motorised equatorial.



Humm...

I suspect that I have average dexterity, maybe a bit better than most. I have no trouble with manually tracking for long periods at the sorts of magnifications a 4 or 5 inch refractor is capable of. To my mind it is misleading to suggest that one would have to have the "dexterity of Ouija-board "mystic"" to use an alt-az mount for "serious observation." Tracking mounts are nice in this regard, if they are sturdy and track well, but a decent alt-az mount can be used effectively with a little practice to observe for long periods...

Bottom line: Both alt-az mounts and equatorial mounts are viable options.

Jon

#22 newtoskies

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Posted 29 November 2012 - 03:39 PM

As Jon has said, I am open to suggestions. I don't want to get into serious AP, just some quick images with a cheap digi camera and then an iphone., so not really AP.

This scope is just to get familiar with refractors and mounts. I mainly enjoy Clusters so that is what it will be used for, as well as maybe Jupiter. I don't want to spend a lot and end up not liking refractors, then being stuck with an expansive scope that rarely will get used. I love the Dob and will eventually go bigger with a 10". It won't hurt to have and use both types of scopes.
i am looking at somewhere between a 90 -120 scope that is in my budget and am checking for used as well. I know the EQ -1 and 2 are not the greatest mounts but it will be for learning and also not for long observing sessions, which I rarely ever have.

#23 Slow Astronomer

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Posted 29 November 2012 - 07:00 PM

I have the 120ST and love it for DSO work. $320 for the OTA from Orion. I use it on a ioptron Mini Tower. I wasn't impressed with the focuser so I replaced it with a JMI EV-1r (costs as much as the OTA). Does a fantastic job on DSO's and I'm impressed with the planetary performance also. Did a mini Mess(ier) the other night and had a blast looking at a bunch of M3x's as well as M45. The detail was incredible. The views of Jupiter the other night were tremendous using my TMB Planetary EPs. I am really in love with the OTA performance for the price. Outside of the stock focuser I think the OTA glass is tremendous for DSO's. Use a TV 24 Pan and 16 Nagler and you can cover some sky. Clear skies. :watching:

Dave

#24 coutleef

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Posted 29 November 2012 - 07:41 PM

The gentleman is considering a choice between two achromats, and given the funds allocated for said dilemma, it necessarily excludes the consideration of an apochromat, thus the generality.



He is actually considering a number of choices and open to suggestion. A used ED-80 is within consideration. Any suggestion of using an 120mm F/5 achromat for astrophotography needs to point out that these scope are a poor choice because of the chromatic aberration and increased spectrum involved.

One would have to master the dexterity of a Ouija-board "mystic" to seriously anything with an altazimuth, when compared to the luxury of the consummate, motorised equatorial.



Humm...

I suspect that I have average dexterity, maybe a bit better than most. I have no trouble with manually tracking for long periods at the sorts of magnifications a 4 or 5 inch refractor is capable of. To my mind it is misleading to suggest that one would have to have the "dexterity of Ouija-board "mystic"" to use an alt-az mount for "serious observation." Tracking mounts are nice in this regard, if they are sturdy and track well, but a decent alt-az mount can be used effectively with a little practice to observe for long periods...

Bottom line: Both alt-az mounts and equatorial mounts are viable options.

Jon


Absolutely right,

I think my dexterity in that regard is below average but it is quite easy to track wtih a refractor and the twilight mount (without fine tracking) at 200x, as well as with a dob.

#25 Sky Muse

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Posted 29 November 2012 - 11:46 PM

Splitting double stars is also enjoyable with a refractor.

The Orion EQ-2 is amazingly and exactly identical to the Parks equatorial I once had, combined with an 80mm f/11 achromat, both made in Japan at the time, in 1992. I fitted a single motor drive to track in right ascension. With it, I observed Venus from when it was still dark, early in the morning until almost noon, the sun high in the sky, the planet's surface like fine sandpaper, and still centered in the eyepiece, with only a few adjustments in declination during the entire time to correct errors in tracking. I'll never forget it, and the most enjoyable observing session of my life.

I was 27.

Thus, an EQ-2 would be a good match for an 80mm, 90mm, or perhaps even a fast-to-moderate four-inch. I never had a need for a motor for the declination, so you'd save money there, too.

Even though I prefer equatorials, I am purely a visual observer, with no interest in imaging whatsoever, and all for a hassle-free experience.

Cheers,

Alan






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