Portability counts - SW ST102 or ST120??

[steve_bham]

My preference is not to use them for visual, too. Barlowing up the 5mm might give you some indication of whether it was worth getting the 2.5mm though. My gut feeling is that you'd probably decide it's not worth it with the ST120.

James

Thanks for info, what do u think about the 4mm and 3.6mm eyepieces?

[JamesF]

I've not tried that range of eyepieces, to be honest. I'm just working on the basis that the shorter focal lengths of my set of BGOs didn't produce particuarly good views when barlowed in the ST120. I'm really not convinced it's worth going beyond 5mm.

James

[John]

Re: very short focal length eyepiece, my shortest is 3.5mm and I find that I'm beginning to see the floaters in my eye a bit with that one. I tried a 2.5mm for a while and found the floater issue seemed much worse !.

It may not be the same for everybody but I thought I ought to mention it.

[Tiago]

I intended to test the waters by Barlowing my 10 mm EP (well, if I had actually received it), and then perhaps get one specifically in that size for the odd planet / moon observing. I also concur that <5 mm sounds like pretty bad as far as eye relief goes. I've had enough of that with the 4mm EP on the Firstscope ...

[steve_bham]

Re: very short focal length eyepiece, my shortest is 3.5mm and I find that I'm beginning to see the floaters in my eye a bit with that one. I tried a 2.5mm for a while and found the floater issue seemed much worse !.

It may not be the same for everybody but I thought I ought to mention it.

Did think about floaters, ill check if I can see them in my 5 mm when it's clear

[JG777]

Some great info here, I have ordered an AZ 4 and am considering a ST120 and this thread was the only place on the net I could find out the length of the tube so thanks James F !

[steve_bham]

Just got my az4 mount for my ST 120mm refractor and its a perfect match. Had a chance to try it out Saturday night and it performance was first class.

[zedzed]

Has anyone got experience comparing the ST120 to the 200 dob, particularly on DSOs? I'm torn between the 200 dob (back garden only) or the ST120 (back garden, but I can take on holiday to north scotland for some real dark skies).

[JamesF]

Has anyone got experience comparing the ST120 to the 200 dob, particularly on DSOs? I'm torn between the 200 dob (back garden only) or the ST120 (back garden, but I can take on holiday to north scotland for some real dark skies).

The 200P has well over two and a half times the aperture area of the ST120. That's going to be hard for any scope to make up. I'd be trying really hard to work out how to fit the 200P in the car

James

[Stargazer_00]

I Have the st120 too. The az3 mount struggles with a 2 inch diagonal and 2 inch widefield ep. That's An extra 1.2 kg on the business end though. The optics are nice for dso for sure and the scope is light.

I'm going to upgrade to az4 with height extension if I can find it. I understand the heq5 extension pillar works.

Compared to the 250 dob I don't see it as 5x as weak as the math suggests.

[steve_bham]

The 200P has well over two and a half times the aperture area of the ST120. That's going to be hard for any scope to make up. I'd be trying really hard to work out how to fit the 200P in the car

James

The 200 dob will be the winner. But the 120mm refractor under very dark sky's will be amazing.

[damnut]

The 200p dob would be the winner, except for travelling with.. My ST120 went everywhere, from our favourite haunt Strathconon in the Highlands to south wales. Bullet proof, roof box, back seat or boot shrugged off snow, sand and dog slobber!!.

If you are going anywhere near the northern highlands, drop in on the HAS :- http://www.spacegazer.com/ they have a great obsy near Culloden

Cheers

[zedzed]

Thanks for the info guys. Leaning towards the ST120 .... now ... if only I could find someone near me selling one second hand I'd be all over it like a rash

[steve_bham]

Thanks for the info guys. Leaning towards the ST120 .... now ... if only I could find someone near me selling one second hand I'd be all over it like a rash

You won't be disappointed if you get one. A small scope that packs a punch really.

[Which Star is that]

With the focus tube fully wound in and dew shield in place, about 660mm. The ST102 is about 110mm shorter.

James

Is there any chance someone could measure an ST120 and let me know how long the tube is without any eyepieces/diagonals and with the dewshield retracted or removed (if it can be)? I am trying to work out if one can be fitted into an Airline carry on bag!

Rick

[JamesF]

Is there any chance someone could measure an ST120 and let me know how long the tube is without any eyepieces/diagonals and with the dewshield retracted or removed (if it can be)? I am trying to work out if one can be fitted into an Airline carry on bag!

I don't know how the dew shield comes off, but as it went on presumably it can be removed again. My smaller ST scopes have push-fit shields, but the ST120 is far more hefty and I wonder if it screws on instead. If you removed the 2" to 1.25" adapter from the focus tube and the dew shield then I reckon it would come down to 500mm. That's based on measuring the overall length including the dew shield, then subtracting the distance from the end of the shield to the ridge inside that I believe to be the end of the tube itself.

James

[Which Star is that]

I don't know how the dew shield comes off, but as it went on presumably it can be removed again. My smaller ST scopes have push-fit shields, but the ST120 is far more hefty and I wonder if it screws on instead. If you removed the 2" to 1.25" adapter from the focus tube and the dew shield then I reckon it would come down to 500mm. That's based on measuring the overall length including the dew shield, then subtracting the distance from the end of the shield to the ridge inside that I believe to be the end of the tube itself.

James

Thanks James - really quick reply!

It's just about on the limit then as the airline max is 20" (which I make 508mm!) so it looks like a no go as the case itself has to have some padding - although I suppose it could go diagonally in a wider case... Now how did that Pythagoras thing go!

It's be close!

Rick

[Which Star is that]

Actually - I just checked and I got that wrong! Airline limit is 22" (559mm) so should be OK :grin:

Rick

[JamesF]

And you could always remove the focuser, I guess

James

[Stargazer_00]

Removing the dewshield would expose the primary objective and you'd have no supplied means to protect it. You'd have to come up with something yourself. And even then you'd still have to put the dewshield somewhere. I guess it could go over the focuser end like a finger in a hula hoop.

[Which Star is that]

Removing the dewshield would expose the primary objective and you'd have no supplied means to protect it. You'd have to come up with something yourself. And even then you'd still have to put the dewshield somewhere. I guess it could go over the focuser end like a finger in a hula hoop.

Yes, my hope is that after unscrewing it I could slide it on backwards (so to speak). I have just had an accurate measurement from someone with a ST120 and a crawford 2 speed focuser upgrade (which I have been considering) and he says it measures 46cm, so with the dewsheild reversed and some kind of homemade lens protector I could be in business...