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Star travel 120mm...just how good?


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Mulling a couple of idea`s over, found myself thinking the ST120 could be an interesting frac, i guess its a bit shoddy on planets fair on Luna and pretty good on Sol white light, but how good on deep sky, does it still have rack an pinion focuser?

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yer it still has a R/P focuser, i find mine good on sol, moon, but when i use for DS i do mono because of the CA, narrowband is good too, i really do rate st120 as a good scope Jules if you can put up with a bit of CA. good luck  charl.

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Good for DSOs.  Quite portable, CA not a problem other than for bright objects.  (And even then you can mask the aperture.)  And I love the 4-to-5 degrees of field you get.

I really like it.  And now I've got Stellarium on a decent lappy, I can see exactly what I'm looking at and star hop around with ease.

Doug.

 

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They are great Jules. I bought one, the Helios version, when I got back into Astro in the 90s and it was a great DSO bagger. Loads of faint fuzzies were within its grasp, very portable especially on the eq3 I had with it. A planetary and lunar scope it is not, it will give reasonable images but the CA due to the short focus achro doublet is obvious but that doesn't matter on DSOs.

Get one mate

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I had one that I mounted on an AZ4 (which was more than adequate).  It's a great wide-field deep sky visual scope (obviously there's a limit to what 4" can give you in the UK) and I also used it for white light solar, which suited it very nicely.  Planets never brought out its best, nor did lunar but it wasn't shoddy by any means.  I know these things shouldn't matter but it also looked really nice in the diamond black and white livery.

I part exchanged mine and every so often I have a pang of regret about doing that.

Paul

 

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I rate mine as it is very useable. White light, grab and go, Terrestrial spotter, plenty of aperture for the night sky. Yes it shows CA but it has to be expected. It also suffers a little on edge performance, again to be expected. It does though sit well on an AZ4 and can be carried outside mounted with one hand if your fit. Not the smallest scopes but does make for a good grab and go none the less.

I have to say I am not all that bothered about CA and a filter will easily keep me happy looking at the brighter stuff. I'd also point out I use faster newts so edge performance doesn't grab my attention for long either not that it is all that distracting anyway and it is one of those things where your looking for faults rather than just enjoying the views.

All said I doubt it would offer you much over the scopes you already have Jules but if you just fancied a change or to have one to try for a bit I'd say go for it.

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I found mine really nice for deep sky, but for me at least I found the CA washed out any contrast in the Moon and planets. 

For imaging, there used to be a guy who posted on SGL called Stan26, he did wonders with the slightly smaller ST102, but I suspect a lot was down to his skill in Photoshop.

If I was going for a short achro again, it would probably be something like this, or the 102 f/5.9 version:

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127s-635-refractor-ota.html

p.s. as I was copying the link, my wife said that's a nice looking telescope :)

 

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15 minutes ago, Chris Lock said:

 

For imaging, there used to be a guy who posted on SGL called Stan26, he did wonders with the slightly smaller ST102, but I suspect a lot was down to his skill in Photoshop.

 

I think the st102 is slightly better on CA than the 120.

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12 minutes ago, Chris Lock said:

I found mine really nice for deep sky, but for me at least I found the CA washed out any contrast in the Moon and planets. 

For imaging, there used to be a guy who posted on SGL called Stan26, he did wonders with the slightly smaller ST102, but I suspect a lot was down to his skill in Photoshop.

If I was going for a short achro again, it would probably be something like this, or the 102 f/5.9 version:

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-ar-127s-635-refractor-ota.html

p.s. as I was copying the link, my wife said that's a nice looking telescope :)

 

That's an excellent alternative that Chris has suggested.  I have the AR127L (which coincidentally I part-exed my ST120 with him for) and they are tremendously good value for money: great build quality and some really innovative features.  I would say they're the Skoda of telescopes; in the old days that would hvae been an insult but nowadays it's definitley a complement!

Oh, and Chris' wife is right - they are nice.

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23 minutes ago, xtreemchaos said:

ive the AR127l Paul and love it to bits ive had it over 10 years and with my 200p there the 2 id never part with oh and my ed80 as well  :icon_biggrin:, i find the st120 easyer to handle when shooting out my obsyroom window. charl.

I love your gaggle of scopes, Charl!!

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1 hour ago, Dave Lloyd said:

I think the st102 is slightly better on CA than the 120.

Thats right. As the aperture increases, and while the focal ratio stays the same, the CA that an achromat shows also increases.

This chart shows this relationship quite well:

 

 

CA-ratio-chart-achro.jpg

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Knowing the kinds of targets you enjoy Jules, I really can't see the 120 f5 being the right move for you, sorry to be blunt! I'm sure it's an excellent deep sky scope, but the CA on the moon and planets is bound to have an impact on detail you can see, and other abberations are likely to be present too in such a fast objective.

Other than that, my lips are sealed :)

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1 hour ago, Dave Lloyd said:

I think the st102 is slightly better on CA than the 120.

Very true Dave, this is a good point :) Apeture really really effects chromatic aberration which is a real shame.

Sorry, I can't seem to delete the chart, I see John already linked it.

 

CA-ratio-chart-achro.jpg

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Thanks for all the replies so far, im thinking of selling my 80mm travel scope and getting the 120, as i have to use the 80mm on AZ4 i just as well have a 120 sat on it, more aperture at dark sites

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