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My first real which scope thread.

Moonshane

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Moonshane

Moonshane

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I have been having a couple of discussions about a scope to fill a gap (in truth there's no gap but hey).

My current scopes are:

16" dob

12" dob

These are not part of the considerations but listed to show I have faint stuff covered.

Also:

6"f11 dob on tracking mount. Takes a while to cool but superb.

120mm f5 achromat mainly for white light solar and low power wide field at night

100mm pst mod not going anywhere

80 mm f11 achromat

My wish is far a grab and go scope for planets, moon and doubles. I cannot stand CA and the 80 has very little but I miss the aperture of the other Scopes.

So something with no CA, aperture of 100_120mm which cooks quickly is what I am after. I store Scopes indoors and have good eyepieces.

If I sold a few bits I could raise maybe 500.

Any suggestions?

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dweller25

dweller25

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This is just what I have done - a g&g for the planets with no CA that cools quickly.......

I ended up with a 4" F/8 Apo on a Skywatcher AZ4 mount on 2" (CG5) steel legs. It does low power wide field to high power planetary.

For your £500 target a SW 100ED would be perfect - I used to have one and they are very well corrected for CA - but not as good as a triplet.

I almost went with a C6 but cool down would be an issue

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jetstream

jetstream

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Would this not show a little CA still on eg Jupiter?

Yes. Well my 120ED does anyway and I think I'm not supposed to mention this.... I did on another forum and it didn't go over very well :grin:  My Baader/Zeiss prism also aggravates the CA on Jupiter, unless an extended cooldown is given- and I mean extended...

My 90mm SV APO triplet shows zero CA and takes mag well, but this size scope may not give you the resolution you need, 500 pounds buys a nice used one though.

I see slight CA on the moon too, but this was explained to me as " you must be looking off axis though the EP", "it must be atmospheric", "you have a poor one" etc.... These SW fracs are excellent, taking very high mag, but to my eyes they show slight CA. There, I just killed my re-sale! :sad:

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bish

bish

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Sorry I'm no help but  this is quite funny.  You've only got 6 scopes and really need another one.  I'm the same (although I need several more)  - I think it's an astronomy thing (or is it a bloke thing?).  Good luck in your search!

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dweller25

dweller25

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Sorry I'm no help but  this is quite funny.  You've only got 6 scopes and really need another one.  I'm the same (although I need several more)  - I think it's an astronomy thing (or is it a bloke thing?).  Good luck in your search!

Get the rope boys, We got us a multi-scope hater!!! :grin: :grin: :grin:

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Caldwell14

Caldwell14

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Yes. Well my 120ED does anyway and I think I'm not supposed to mention this.... I did on another forum and it didn't go over very well :grin:  My Baader/Zeiss prism also aggravates the CA on Jupiter, unless an extended cooldown is given- and I mean extended...

My 90mm SV APO triplet shows zero CA and takes mag well, but this size scope may not give you the resolution you need, 500 pounds buys a nice used one though.

I see slight CA on the moon too, but this was explained to me as " you must be looking off axis though the EP", "it must be atmospheric", "you have a poor one" etc.... These SW fracs are excellent, taking very high mag, but to my eyes they show slight CA. There, I just killed my re-sale! :sad:

I have owned both ED100 and the ED120. The 100 wins hands down on the CA front. It has to be said the miniscule CA in the 120 is far preferable to diffraction spikes on any Newton (Nasty horrible things)

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jetstream

jetstream

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I love the views the 120ED gives and use it frequently - it is an amazing star splitter among other things. The CA is very small, but if a person is really "bugged" by this phenomena they may not like this scope. The APO triplet has no false color that I can see and its good to hear the 100ED will show even less than the 120mm, these are very good scopes. Absolutely amazing in white light and soon in Ha ( I hope).

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russ.will

russ.will

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I'm not bothered by CA in moderate amounts, but I must say, I've been fairly blown away by the planetary views in my first SCT. I was expecting it to be so, but cool down doesn't seem to be much of a issue, even at 8". Maybe I was forgetting that SCTs have a much thinner corrector plate than Maks.

It would certainly add a different string to your bow and it is non too shabby on DSOs either, which gives it a multi-purpose justification. As it stands, I can't see what a long 100-120mm ED scope would give you over your planetary Newt.

Russell

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rowan46

rowan46

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the celestron c5 spotter comes to mind it cools quicker than the 127 mak and its a bit lighter it holds collimation well no ca yes at f10 its narrow but stick a focal reducer and you have  an f7ish 800mm scope which appears ti widen it a little i find it better on planets than my 80x480 triplet also better on all but the wider dso;s i will be at  sglx if you want a look

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Qualia

Qualia

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Visually, I imagine a 4" ED frac and a 5" Mak will give roughly the same results. The Mak will take a little while to cool but is very compact and rugged. It would also sit nicely on something like an AZ4.

However, a Mak's cooling time does get in the way of it being truely a grab and go; more like grab, wait 30 minutes and then go :smiley: . In that case, something like a 4" ED refractor would be more suitable, but, again, it might need a bigger mount and depending on its focal length will be more susceptible to vibrations from the wind etc and isn't nearly so compact for those grab for trips and holiday ventures. 

In that case a small 80mm APO is extremely quick to setup, fast to cool down and is also something that packs small and is suitable for trips away. The FL is short enough to get those gorgeous double cluster or whole Rosette views and with the Moon and Jupiter and many double stars, there doesn't appear to be a compromise on the performance.

Sure, we know on paper that light grasp goes as the square of the aperture, so you get half as much light again in the 100mm over the 80mm. But in reality at the eyepiece, it is quite hard to know how the view is affected by this. I mean, when I compare my little 76mm APO to the 100mm achro, the latter scope doesn't allow me to see more. Indeed, I feel the little APO performs better on brighter objects; they are crisper, cleaner, more contrasty and sharper and unless I'm ogling Sirius at higher powers, there's not a hint of CA to my eye. Another thing the 76 does very well on is double stars and clusters, they're stunning.

I'm not sure now if this a ramble about aperture, quality of glass or the optimum grab n go 4" to 6" scope :grin: I've confused myself :p  So, what I think I want to say is that if you get a chance, Shane try to see if you can use/borrow/check out these different options open to you. Each will give a different but equally gorgeous perspective and experience of the night sky.

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gary777

gary777

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Right now I am more or less inbetween scopes, just picked up a 102mm Orion/Skymax until I get someting a little better. I must say the optics are quite good for being made in China, it only weighs about 5lbs, but yes there is cool down time, I got my ota used for around 112#

If that 500 is burning a hole in your pocket, a 80/480 triplet is pretty hard to beat for what you want to do, but even a used one will be a bit more than 500. No color is going to cost you if you want a refractor.

Gary

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Moonshane

Moonshane

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All these comments have all been running round my head for a bit. Maybe best to do nothing except save up and see what comes up - and pounce.

Using whatever on a giro iii btw. Should have mentioned that! And that I am not remotely interested in imaging

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Stu

Stu

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Hi Shane,

It's a really tricky one isn't it?!

Don't forget that the 100ED is f9 (vs f7.5 for the 80 and 120), so combined with the fpl-53 doublet I reckon it would perform very well in terms of CA.

A 4" scope will give cracking views and will cut through poor seeing well too.

You've got the f11 for when you want a bit of aperture, so maybe give the 4" a whirl?

I will try to get that test done on the 80m before it disappears!!

Stu

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