73 replies to this topic

[chaoscosmos]

OK, I did it. New 120ED arriving next week.

 

I wouldn't pay higher than Amazon or BHPhoto's prices currently. If the OTA is truly awful as some seem to believe I can always return it, but I suspect it'll be good enough and I pretty much know what to expect from the optics.

 

I'll see if it's passable in stock form before doing any mods other than using a different dovetail. I'll be able to see if there's a visible difference using my Televue diagonal or the diagonal included in the package…. 

[A Y]

Congrats on the new scope! Another mod to consider is immediately replacing the visual back’s clamp with either a compression ring (http://www.scopestuff.com/ss_fas2.htm) or a Baader Clicklock (get the 2-inch M56 model: part no. 2956256). 
 

The included diagonal is surprisingly good. 

[RAKing]

The stock focuser on mine was terrible, but I knew it wasn't going to stay anyway.

 

The optics were excellent and that is what counted for me.

 

I hope it works well for you! 

 

Ron

[chaoscosmos]

Congrats on the new scope! Another mod to consider is immediately replacing the visual back’s clamp with either a compression ring (http://www.scopestuff.com/ss_fas2.htm) or a Baader Clicklock (get the 2-inch M56 model: part no. 2956256). 
 

The included diagonal is surprisingly good. 

Scope stuff looks to be out of stock but this looks like the same item: 

https://www.firstlig...actors-m56.html
 

I imagine Agena or others have the equivalent as well.

 

My TV 101 has a single set screw to hold the diagonal but perhaps that’s a different situation with a more precision back? The Baader Clicklock is more for holding photo gear, correct?

Edited by chaoscosmos, 16 September 2023 - 05:34 PM.

[A Y]

The stock clamp has 3 screws (I think) that press against the nosepiece directly, so they can dig little holes and mar the finish. The Scopestuff or FLO compression band clamps have a couple screws that push against a metal band that grabs the nosepiece around its entire circumference so it doesn’t mark it. I believe Televue has a compression band too. 
 

Clicklocks are great for visual and my impression is that they were designed primarily for that. Clicklocks do eat more backfocus so if you’re close to your focuser being fully retracted to bring an eyepiece to focus, you may not want one. 

Edited by A Y, 16 September 2023 - 06:29 PM.

[chaoscosmos]

The stock clamp has 3 screws (I think) that press against the nosepiece directly, so they can dig little holes and mar the finish. The Scopestuff or FLO compression band clamps have a couple screws that push against a metal band that grabs the nosepiece around its entire circumference so it doesn’t mark it. I believe Televue has a compression band too. 

I'm not sure if I'm visualizing this correctly. Are we talking about the end of the draw tube where a diagonal would be inserted, and the screws would mar the diagonal etc? At the end of the draw tube on the Telvue there is a brass ring lining the tube about an inch inside, but it's not what I usually think of as a compression ring. The diagonal if used has a close fit into the draw tube and is held by a precision fit, with a single set screw on the side.

[A Y]

I don't know about the older TV scopes, but on the NP101, the screws press against a brass band in an adapter at the end of the drawtube that compresses around the nosepiece of the diagonal, but I'll defer to you and others who have the scope.

[chaoscosmos]

Yes, then a change was made, apparently with the NP-101 or at some point after its release.

 

I’m reading comments the 120ED may be a little wobbly at that connection, so I understand why an after market compression ring makes sense. 

[chaoscosmos]

Congrats on the new scope! Another mod to consider is immediately replacing the visual back’s clamp with either a compression ring (http://www.scopestuff.com/ss_fas2.htm) or a Baader Clicklock (get the 2-inch M56 model: part no. 2956256). 

It may be best to wait to see if I’ll use the stock focuser before getting a compression ring or Clicklock. It seems an upgrade to a GSO focuser might eliminate the need for either of them?

 

Btw, after my purchase for the scope from Amazon was complete, their price increased $119. I think they lower prices to clear stock, then as units are sold the price goes up. 

[Lookitup]

It may be best to wait to see if I’ll use the stock focuser before getting a compression ring or Clicklock. It seems an upgrade to a GSO focuser might eliminate the need for either of them?

 

Btw, after my purchase for the scope from Amazon was complete, their price increased $119. I think they lower prices to clear stock, then as units are sold the price goes up. 

The EON focuser is available as an alternative. https://www.firstlig...refractors.html

CS Pete

[chaoscosmos]

The EON focuser is available as an alternative. https://www.firstlig...refractors.html

CS Pete

That looks like my old 120 EON focuser except that mine screwed on with a chrome ring. 
Agena’s GSO focuser weight is listed at 861 grams. I don’t see a weight given on this one.

 

I still have a defective copy of the screw on version made functional by converting it to single speed.

[RAKing]

That looks like my old 120 EON focuser except that mine screwed on with a chrome ring. 
Agena’s GSO focuser weight is listed at 861 grams. I don’t see a weight given on this one.

 

I still have a defective copy of the screw on version made functional by converting it to single speed.

 

The stock SW focuser weighs 1279 grams.

 

My FT2025, with the A20-288 adapter, weighs 1082 grams. 

 

I think the GSO might be a great choice.

 

Ron

[chaoscosmos]

The stock SW focuser weighs 1279 grams.

I wonder then if Agena's listed weight of 861 for the GSO focuser is accurate. That would make the stock focuser nearly a pound heavier. 

[Lookitup]

If accurate it will have the same optics as my ex Eon with several pounds less weight. 

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[chaoscosmos]

Scope arrived today and I have it mounted on the DM4 & DM4 tripod. It’s overcast here tho.

 

Not something I thought of, but with the stock finder being on the left, it lines up directly with the knob on the DM4 saddle that tightens up to hold the dovetail. It may be useable this way, but the obstruction creates an out of focus shadow at the center of the finder view. If I knew for sure the GSO focuser was superior to the stock, the finder mount location might be an additional reason to switch focusers. 
 

The stock focuser so far seems fine, just makes a barely audible rubbing sound that may be normal. I don’t think I like the feel of the large focus knobs, but maybe I’ll get used to it.

 

I’m a little unsure re the stock rings. It’s hard to tell when they’re exactly square to the OTA, and how much to tighten them is sort of a guess… My dog decided to take a nap right under the scope and I made her move, being that I’m just shy of being 100% sure the scope is secure.

Edited by chaoscosmos, 21 September 2023 - 10:39 PM.

[chaoscosmos]

Problem solved with the finder obstructed by the knob on the saddle… Just mounted the scope to the left of the tripod, which I thought would be awkward but turns out it really doesn’t matter. Once I started viewing, the focuser seemed fine, so no real need to change that… I may just get a compression ring and leave it at that; maybe rings, or not.

 

Viewed Jupiter with wispy clouds drifting around, so not fair to the scope, but I had to give it a go anyway… 

Edited by chaoscosmos, 22 September 2023 - 02:36 AM.

[RAKing]

I’m a little unsure re the stock rings. It’s hard to tell when they’re exactly square to the OTA, and how much to tighten them is sort of a guess… My dog decided to take a nap right under the scope and I made her move, being that I’m just shy of being 100% sure the scope is secure.

 

The easiest way to check this is to loosen the bolt holding the rings to the dovetail.  Then tighten the rings around the OTA first before you re-tighten the rings to the dovetail.

 

I changed to slightly longer bolts for the rings so I could thread a jam nut on top of the bolt.  After I went through the steps to get the rings square and tight, I opened the rings, pulled out the OTA, and tightened the jam nut.  Then I put the OTA back into the rings and all is well.

 

Enjoy your new scope!  

 

Ron

[chaoscosmos]

Out a few hours last night and realized the focuser certainly isn’t great. The main issue tho is that even with the DM4 being capable, the length of the scope on the mount is necessitating a settling time, causing a jittery image whether you’re dialing in rough or fine focus. I have the same issue with the TV101 w/ single speed rack & pinion focuser on the mount however, just not quite as severe.

 

In fact I’m not sure I’ve ever had a refractor not jiggle on an alt-az mount, whether it be DM4, DM6, or Gibraltar. 

 

I’ve seen comments on CN advocating moving the rings closer together, spreading them apart, using longer or shorter dovetails, etc. I’ve been avoiding tightening up the tension on the DM4, hoping to leave it where it’s set for the 101.

Edited by chaoscosmos, 24 September 2023 - 09:11 PM.

[Lookitup]

Curious that even the TV101 is not stable on your DM4. Used the same mount with Manfrotto CF tripod and Tak DF. Dampening time was under 1 sec. Once I mounted the SW ED 120 it was more like 4 sec. 

The SW became more stable and heavier with a 2.5" FT focuser. I was able to move the OTA forward, which brought the focuser closer to the mounting rings. Even with more weight there was less jiggle. Did you try using cork tiles under the tripod legs? On concrete it works wonders. CS Pete

[Sergio_2014]

Old thread I know, but I also bought a 120ED earlier this year. Got it for about 40% of the current price here. 2nd hand, owner had used it just a couple of times for bird watching (or so he said). After a terrifying couple of days having nightmares about how the tube could/must have been banged all over the place by the post service, the tube arrived in one piece, healthy. Well packaged in double box (previous owner was legend!), still the smell of brand new when the suitcase is opened. The first light left me quite happy: pinpoint stars, nice colors, no offending CA. Focuser was a bit loose, but since I already have a 80ED, I know how to deal with this. I have been using the original Crayford focuser for imaging with no problems (I think some people love to hate the Skywatcher Crayfords. Imo they're workable). Recently got the original 0.85 reducer/flattener from Skywatcher, thinking that even though I own a Starizona 0.65x FF/FR, maybe it was too much a reduction and could lead to CA?. I have not done a lot of imaging with this scope yet, though, as I've been kind of stuck with my tiny refractors for the last couple of years. In summary, I'm quite pleased with "my precious" 120ED. I intend to keep it.

[dgilbey]

A little off topic, but bear with me.

 

I just received a new Svbony SV 5500 122mm refractor today - I paid $AU1900. I'd always wanted a 120ED, but the price here in Australia has been ridiculous IMO - almost $AU3000.

 

'Just because' I checked current prices for the ED120 yesterday and several vendors had it in stock for $AU1999 - a cool thousand dollars off the old price.

 

Competition, don't you just love it?

 

And yes, it's cloudy tonight...

[Exnihilo]

I’ve ended up getting another Moonlite focuser, I’m going to try adapting it to my 120ED. 

[Exnihilo]

A little off topic, but bear with me.

 

I just received a new Svbony SV 5500 122mm refractor today - I paid $AU1900. I'd always wanted a 120ED, but the price here in Australia has been ridiculous IMO - almost $AU3000.

 

'Just because' I checked current prices for the ED120 yesterday and several vendors had it in stock for $AU1999 - a cool thousand dollars off the old price.

 

Competition, don't you just love it?

 

And yes, it's cloudy tonight...

I’d never pay the new price for either the 120ED or 150ED, not when scopes like the SV 5500 or the AT EDL scopes are available.   My SW 120/150 EDs were both obtained used.  

[civis]

I got SW 120ed recently for $1800, optics is surprisingly good, and even the focuser is not broken this time. Tested it so far on terrestrial objects only (it's cloudy of course) and even with 3.5mm eyepiece the image is sharp.

 

What are those 4 black screws for on the bottom of the green mounting plate?

Edited by civis, 21 April 2025 - 09:26 AM.