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Looking for an upgrade, not sure what to do!

KevUU

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KevUU

KevUU

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I posted this under a more specific title in a different area, but I think it's become a more general question than the one I originally asked so I thought I'd open it out a bit...

Apologies for the repetition to those who have read the other post - and big thanks to those who responded too! So without further ado:

I really enjoy what I have right now which is an ST80 on a purely manually AZ. But, I want more aperture. What do I do?

I'd like to keep a purely organic, powerfree setup.

If that will be restrictive (isn't an EP change at x250 going to be impossible?) then I may have to begrudgingly look at tracking - although the dob mob seem to manage this problem okay.

But, I'm energy-limited so my feeling is that a 200mm dob would be an effort for me to move and to load into the car and so on. Just a guess from the specs and pics of them, as I've never seen let alone touched one.

Hence I've been thinking C8. There are many people on here who have had theirs for years and years and are still very happy.

But, a C8 SE won't do: I don't want goto - I spend my life with computers, I couldn't stand it.

So then there's the question of mount, and the tracking question as above.

:icon_scratch: :icon_scratch: :icon_scratch:

Unfortunately Bristol astro soc doesn't really have a members' club night, they have open-for-the-public-to-use-their-big-scope nights so it's not easy to try some stuff out.

I keep saying I want to get through a full season with my first scope before I upgrade, which would conveniently tie in with SGL8 when I could look around some options. But more and more I find myself pushing beyond the boundaries of my little scope. Yes, I has the fever and I has it bad! :grin:

Any thoughts or advice gratefully received.

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Capricorn

Capricorn

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TS do a 152mm f/5.9 achro refractor for about £680, maybe £660.

One possible problem with the C8 is the field of view, it is a lot less then the ST80 so you will find it more effort to locate anything. Also at the longer focal length come higher power and less field in the eyepiece so things disappear out of view faster. You are not going to admire Jupiter for 5-10 minutes. It will have gone out of view by then. Anything will move about 5x faster as the FoV is simply that much smaller, eyepiece being the same.

In your ST80 centre to edge is about 1.6 degrees (25mm plossl), we rotate at 0.25 deg per second so Jupiter remains in view for about 6 minutes. In a C8 with the same 25mm plossl you get 0.3 degree centrte to edge, so just over 1 minute. Shorter focal length eyepieces mean smaller fields of view and things really zip zcross.

That is I would say the reason for mounts suitable for C8 etc having motors most of the time. The simple convenience of actually being able to observe objects in the eyepiece.

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RikM

RikM

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SGL8 would be a great opportunity to have a look around a few different types of telescope and mounts, if you can wait that long :)

Changing eyepieces at 250x isn't difficult if you have a nice stable mount and a well balanced scope. A C8 is a very nice instrument but at over 2 metres focal length, I don't think I would put it on an EQ3-2. Cotswold AS have one on a tracking, but not GoTo, fork mount. I am not sure if these are still available though.

What sort of objects are you hoping to view? Normally, more aperture, no GoTo = 200P Dobsonian. A great all rounder and very easy to transport.

If you fancy a trip up the M5 to Shurdington on Jan 19th, we are having an observing evening for Stargazing Live and will have all sorts of scopes available to play with.

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KevUU

KevUU

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Hi Kev, the C8 is available as an OTA only, its about 3 KG lighter than a 200P, but around 3x the price. I would say that you would get away with a EQ3-2 mount with a C8 for visual astronomy.

Cheers Catweazel. I've seen a few OTAs around s/h for sub £400 but would need mounting, which was my original question but now wonder if I'm barking up the wrong tree... Head says wait for SGL 8 and play with stuff, impatience says get a C8 now!

Will have a look at EQ3-2 specs, ta.

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KevUU

KevUU

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Hmmm, hadn't looked at that. That'd be 2.25 x my current focal length instead of 5x, giving x30 with my current EPs. Ah, but I see it's 12kg for the OTA :shocked:

Yeah that is my concern - although inevitable if I want bigger and better, which is fine. But again, this must be manageable with a dob? And of course there are slo-mo controls for this reason. Just not sure if that's a realistic plan...

Someone mentioned the C8 Celestar before, which sounds like it would have been exactly what I'm after if only they still made it! Hohum.

Thanks Capricorn, that's more food for thought.

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John

John

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I've used an undriven Giro-style alt-azimuth mount (photo below with my ED120 on board) for a few years now. It has a high weight bearing capacity and you can put a counter weight on the other arm for tubes over around 8kg. It would take a C8 easily. The one I have is out of production now but the original Giro mounts are sold by Telescope House.

post-118-0-77316900-1355157795_thumb.jpg

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KevUU

KevUU

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SGL8 would be a great opportunity to have a look around a few different types of telescope and mounts, if you can wait that long :)

That's what I should do, sure ;)

Changing eyepieces at 250x isn't difficult if you have a nice stable mount and a well balanced scope.

I was hoping someone would say that - although there doesn't seem to be a consensus :undecided: TBH the more I think about it the more I'd like to avoid faffing with power tanks. Although, that assumes I can survive withotut a dew heater too, otherwise the equation changes again...

What sort of objects are you hoping to view? Normally, more aperture, no GoTo = 200P Dobsonian. A great all rounder and very easy to transport.

Yeah, and cheaper too. I'm just concerned about the ease of grabbing it and lugging into the garden, and how much I may have to move my chair around for different positions etc. As I say I have some energy limitations so I know that if it's not simple I'll find my self not doing it, which would be a real shame. Hence my extended deliberations...

If you fancy a trip up the M5 to Shurdington on Jan 19th, we are having an observing evening for Stargazing Live and will have all sorts of scopes available to play with.

You're only an hour away so it's possible, thanks.

Now you mention it I'm sure a friend at Bristol AS mentioned they have a star party at some point, but they don't seem to have info on t'web yet, I must ask for more info...

Thanks for the advice Rik :)

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KevUU

KevUU

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One possible problem with the C8 is the field of view, it is a lot less then the ST80 so you will find it more effort to locate anything.

I was figuring on a Telrad or similar, and either a RA finder or just use my ST80, which would mean I had a real widefield option there if I wanted it too. Of course the details of that are no doubt a whole other minefield!

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KevUU

KevUU

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I've used an undriven Giro-style alt-azimuth mount (photo below with my ED120 on board) for a few years now. It has a high weight bearing capacity and you can put a counter weight on the other arm for tubes over around 8kg. It would take a C8 easily. The one I have is out of production now but the original Giro mounts are sold by Telescope House.

Hmmm, looks interesting. I don't see any slo-mo controls, so does this rely on nudge-to like dobs? If so, how easy/comfortable do you find it to track?

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John

John

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Hmmm, looks interesting. I don't see any slo-mo controls, so does this rely on nudge-to like dobs? If so, how easy/comfortable do you find it to track?

Tracking is very smooth and easy and the friction of both axis is adjustable to a high degree. I regularly use 257x with the above scope and I've used over 300x with other scopes on the same mount. To be fair though i) I've always uses these sorts of mounts so I'm 100% at home with them now and ii) I use ultra-wide angle highly corrected eyepieces which makes tracking at high power easier because of the large field of view.

Any slight inconvenience is, to me, well worth not having to worry about any power cables etc or polar alignment :smiley:

If you would like slow motion controls then there is always the Skywatcher Skytee II mount which has them on both axis.

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RikM

RikM

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I was hoping someone would say that - although there doesn't seem to be a consensus :undecided: TBH the more I think about it the more I'd like to avoid faffing with power tanks. Although, that assumes I can survive withotut a dew heater too, otherwise the equation changes again...

I don't own a powertank. For visual observing I much prefer manual altaz to tracking mounts. I mostly use a 10" Dob and then a few different scopes on an AZ4 or Tele-Pod mount. Either a 6" Newt, a 5" f/9 Achromat, an ST80 or a Televue Pronto. None of these have slow-mo controls and I don't find it any bother even up to 300x. But, I have Rigel QuikFinders on all my scopes and, like John, I use premium wideangle eyepieces, which do help.

Yeah, and cheaper too. I'm just concerned about the ease of grabbing it and lugging into the garden, and how much I may have to move my chair around for different positions etc. As I say I have some energy limitations so I know that if it's not simple I'll find my self not doing it, which would be a real shame. Hence my extended deliberations...

I have an ironing stool, which I have set a little higher than a regular garden chair. I don't have to adjust it and just either sit up straight to reach the zenith or lean forwards a bit to see down to my horizon. I do have to pick it up and shift it when moving from a target on the East to a target in the West, for example. But you would have to do that no matter what scope you choose.

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scarp15

scarp15

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Someone mentioned the C8 Celestar before, which sounds like it would have been exactly what I'm after if only they still made it! Hohum.

I purchased mine second hand, keep a look out on the usual second hand sites, or advertise - as wanted, through Astro buy and Sell. sometimes they come up as a complete set up, or alternatively purchase the OTA and consider some of the non 12V currently available mount options as has been mentioned.

One of the features I like on the earlier models, is the single motor clockdrive, which is powered by a 9 volt battery in the same way that a telrad is, and seemingly lasts just as long. The Celestar is mounted on a wedge, it tracks in Right Ascension, is great for high magnification, especially when observing the planets. The slow motion controls are ergonomically placed to . The eariler models are all USA built and the quality of each component is excellent.

To be honest it was the only way I could afford to purchase a C8 at the time (about 5 years ago) and they can come up at a good price if you are prepared to travel to collect. There are other users of similar clock drive motor SCT's on the forum and they may yet contribute to the thread.

As has been mentioned, whatever combination of mount you go for, the C8 have many attributes and it is their portability that I enjoy especially when the car is loaded up (often to bursting point) with the scope, family and camping gear.

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KevUU

KevUU

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Any slight inconvenience is, to me, well worth not having to worry about any power cables etc or polar alignment :smiley:

Now you're talking my language :D

I don't want to *have* to spend lots on EPs, but I figure a decent 2" widefield to start and the rest could come later (if at all, and if you believe that...). I'll have more of a look at mount options, thanks for the pointers.

Cheers John :)

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KevUU

KevUU

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Thanks again Iain and Rik, I appreciate the further feedback :)

It sounds like I really have to get some hands-on time and see what works for me - and what doesn't. Hopefully I can get to an event in the new year, but failing all else I'll be that stereotypical guy called Kev walking around looking at everyone's kit at SGL8 :D

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