Upgrade My 'Scope!

[dick_dangerous]

Hi All,

I've had my ST80 for a couple of months now, and even had a few decent nights on which to take it out for a spin. But I realise that to use the scope to it's full advantage I need to upgrade my eyepieces.

I'm planning on buying an LP filter for it which seemed like a sound investment living under the glare of London lights, but what eyepiece would be a good starting point? The supplied eyepieces are a 25mm, a 10mm and a 2x Barlow lens. I was thinking of getting a 4mm or even 2.5mm for planets, but was worried about the short focal length of the scope. Alternatively I thought I might start with an even wider angle lens, like a 32mm or a 40mm. Was wondering if anyone had any thoughts or wisdom they could share on what might work nicely with what I've got.

Many thanks,

DD

[ronin]

Have a 70mm f/5 and find that a 4mm TMB clone is acceptable but smaller then that anything is a waste of time, the 3.2mm was bought to try and it is no real use.

The best eyepiece I use for "magnification" is the BST Explorer 5mm, it gives a fair image. An f/5 achro isn't really the best for magnification, the evostar 90mm achro would have been a somewhat better selection.

[rowan46]

I use a f6 80mm triplet as my scope. To be honest planets are not its forte and even the best eyepieces are not going to give you great views of planets, So I would suggest go towards wider targets. It doesn't have the apparture for much of a view on faint fuzzies so look for something that can maximise the wide field stuff and milky way. you don't need wider eyepieces I would suggest wider field of view something like the es82 range. I have a maxvision 24 which is quite nice for blasting stars out of the murk but I wouldn't go bigger and then a progression down to the es 4.7 82 degree which is probably the top end of your scopes magnification. you will need to go up quite a bit in eyepiece price at that fast a focal ratio. As for a filter I am not so sure its a good idea at such a small apparture but that may be just my opinion

[Stargazer_00]

I'd probably look to get a 120ish mak instead of eyepieces so you had a good portable widefield scope and also a good high magnification scope for lunar and planets. the st80 I owned didn't give me much more then open clusters and lovely wide views. I compared it to binoculars in the type of experience it provided but through changing eyepieces it allowed more versatility. quite useless on planets but okay for casual moon.

The highest magnification you can squeeze from them is about 120x to 150x bit that will be a very small exit pupil so grainy and dim. They operate best around 50x to 80x but show many degrees true field due to the very short focal length.

I think a small mak is a better investment to be honest. you'll get alot more or of the sky worth 2 complimentary scopes than the st80 and better eyepieces. eyepieces can't remove the inherent limitations of the small frac.Then buying eyepieces for the scopes will give 2 different results for one purchase. For instance an 8mm in an st80 is 50x but in a 1500mm focal length mak it'd give you something closer to 180x

[dick_dangerous]

Interesting advice, thanks! I'm considering upgrading the 'scope, but it's all a matter of what can be lugged on my poor weak shoulders to the park. While the ST80 is undoubtedly highly limiting, it's also fairly light! I reckon I could probably manage an ST102 but any bigger than that and I stand no chance without a car.

I think a small mak is a better investment to be honest. you'll get alot more or of the sky worth 2 complimentary scopes than the st80 and better eyepieces. eyepieces can't remove the inherent limitations of the small frac.Then buying eyepieces for the scopes will give 2 different results for one purchase. For instance an 8mm in an st80 is 50x but in a 1500mm focal length mak it'd give you something closer to 180x

This was my gut feeling of what I'd need if I was going to check out some planets. I was thinking of going for a 90mm Mak on the logic that it will fit on my mount. I know that the EQ1 isn't the sturdiest thing in the world but anything bigger would be chunkier to carry.

Thanks as always!

DD

[rowan46]

I have to carry my gear at the moment i have an 80 apo but I am looking at a celestron c6 ota but a c5 scope only weighs 2 75 kg and that is significantly better on planets than my apo and much better than a mak 90 http://www.firstlightoptics.com/optical-tube-assemblies/celestron-c5-spotter-spotting-scope.html

[Stargazer_00]

hi dd.

I definitely wouldn't buy an st102 if you had an st80 as it's so similar. a 90 mak would work but a 102 mak would be better and silk light. The 5 inch sct above is another good choice as sct are much much lighter than maks. But then you are talking mounts. chances are your st80 is on a camera tripod? mine used to work so well on one. I think a mak 90 would work on one too so that might be the wisest choice for your circumstances. Be interested to see what direction you go I recall the hell you had getting the st80 so that is a keeper im sure

[dick_dangerous]

Thanks for the advice - I won't be parting company with the ST80 in a hurry. I have it on an EQ1 mount. Possibly I should have gone for an Alt-Azimuth because of the lack of a counter-weight but I'm used to an Equatorial. In terms of cost, both a 90 Mak and a 102 Mak are within my price range. I'd go for a 102 but I don't think the mount would be up to it. Perhaps I'm wrong?

I've also considered buying a Heritage 130 because of it's army of devoted adherents and portability!

DD

[rwilkey]

The ST80 is a short-tube rich-field telescope and not really suitable for planetary use. If you want planets and other detailed objects I would suggest a 90mm or 100mm long-tube refractor rather than spending on ep's that will not technically satisfy you, it's about doing what's best for you in the long run and getting what you want out of astronomy.

[rowan46]

I don't think your mount is up to a long focal length 90 or 100mm refractor but Robin is right a wide field refractor isn't the best tool for the job. A 90mm mak doesn't really have the apparture to provide much resolving power but its probably going to be a little more usable than a sub 2mm eyepiece

[dick_dangerous]

The ST80 is a short-tube rich-field telescope and not really suitable for planetary use. If you want planets and other detailed objects I would suggest a 90mm or 100mm long-tube refractor rather than spending on ep's that will not technically satisfy you, it's about doing what's best for you in the long run and getting what you want out of astronomy.

That in a nutshell is my problem because I'm more interested in DSOs than planets, but any 'scope I buy needs to be extremely portable because I don't have a car and I don't have a garden. So I have to make the best use of what's practical for me! I'm considering investing in a Heritage, but I'm not sure I want to swap the ST80 for it because a} it's a lovely little telescope and b} my big worry with the Heritage was the fact it's so low off the ground. If I have to start carting tables around then it removes all the advantages of portability. But I've also heard it fits in a 25L backpack which would make it far more portable. I'm warming to the idea of buying one to complement the ST80...

DD