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Old 19-04-2010, 10:09 PM
ausemdg (Rob)
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New Meade LS 8 - ACF Vs Older 10"-12" LX200 Classic

Hi Guys

Being new to astronomy and with a budget of about $3,000, which telescope out of a new LS 8 Light Switch with the ACF lenses or one of the older 10" or 12" LX200 with the UHTC lenses would you suggest would provide the best images? I am looking at learning astrophotography.

Cheers

Rob
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Old 20-04-2010, 12:01 AM
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Adelastro1 (Wayne England)
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Hi Rob,

I only bought a UHTC 12in scope a month ago so I might not be the best qualified to comment, but when I was looking around and working out what I wanted I asked the same question. The answer I got was that the ACF feature is a bit gimmicky and there's very little if any difference to the quality of the optics with it. Basically it's been 'put on' newer models as a technology advance but also I guess because Celestron have a similar thing with theirs. If anyone knows different I'd be glad to hear too!

Just starting to get into photography with a scope myself so I thought a slightly older (and cheaper) scope would be a better starting point. Even if the newer ones are better, the older ones are still very very good.

I remember from my early days in astronomy that a scope is like a light bucket - the bigger you have the more light it collects. I stretched my budget to a 12in and I'm glad I did - dark sky views are amazing, but you need to have money left over for eyepieces, camera adaptors etc too if they don't come with the scope.

Are you a member of the Astronomical Society of SA? If not I would recommend it as the Society has many members that can help with this sort of thing. Check out their website too.

Wayne
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  #3  
Old 20-04-2010, 07:47 AM
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DavidTrap (David)
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I have an ACF LX-90. The difference is easily noticible, even to a beginner. There is significantly less distorsion around the edge of the field - "coma".

The price difference between the 8 inch LX-90 SCT and ACF models is about $200. Definitely worth it.

However, you need to consider the mount on which the scope is riding. I bought an LX-90, which I now realise it is inadequate for serious imaging. It's "OK" if you just want to piggyback a 400mm focal length refractor on top of the scope, but forget any attempts at long focal length imaging.

The minimum would be an LX-200 mount - much stronger and larger gears, "permanently" trainable periodic error correction (the LX-90 forgets every time you switch it off), longer forks to allow a camera to swing through the forks (an LX-90 is limited to restricted to <70 degrees declination - ie. you can't image around the polar regions).

I have never seen an LightSwitch mount, but cannot see how only half a fork would be superior to a full fork.

You could buy an older LX-200 and use a focal reducer/field flattener to overcome some of the coma problems of the SCT design - but I'd talk to others about this before you commit your money. Unfortunately you can't use the standard Meade Focal Reducer/Flattener on the ACF scopes so it is difficult to improve their field of view to image larger objects - still looking for an option there.

A 10 or 12 inch LX-200 will also need an ultrawedge for equatorial mounting - about $1000...

Happy to talk to you further if I can help - pm me.

Ta
David T
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Old 20-04-2010, 08:48 AM
casstony
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Hi Rob,
a schmidt cassegrain telescope(sct) is not the easiest instrument to start imaging with, and imaging is not the easiest way to get into astronomy. Had you thought about just going visual at first and easing into imaging?

The long focal length of the sct will more readily show errors in tracking/guiding; sct's have problems with cooling and won't show the best image unless they're at ambient temperature, and best focus changes with changing temperature; sct's have 'mirror flop' where the mirror moves slightly as the scope tracks accross the sky. That said, the sct is my favourite type of telescope, but an 80mm refractor on an equatorial mount would be easier for starting out in imaging.

So an alternative plan would be a 10" dob for visual, followed by an EQ6 mount and an ED80 refractor. After you gain experience the 10" tube could be put on the EQ6 for imaging.
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Old 20-04-2010, 09:03 AM
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renormalised (Carl)
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Hi Rob...welcome to IIS

Dave pretty much hit the nail on the head with what he wrote, however, if you want to do long exposure astrophotography with an LX 90 ACF, you can. You can get a wedge for the mount, just the same as you can get one for an LX200, but the LX200 drive system is more robust and has a few extra features. In any case, you can get yourself a camera like a GStar EX, Mallincam, DBK21-41, Watec or Stellarcam (low light video cameras) and use the LX90/LX200 in Alt-Az, as they take multiple short exposures in quick succession, which you can stack later on to produce an image.

The ACF models have considerably better off axis performance than the normal SCT...I know from experience, as I have an ACF myself. They are wonderful visual instruments and are very good for piccies as well

Your budget of $3000 has sort of limited you to the smaller apertures, even an older model LX200 in 10-12" would be worth more than $3000. You could try the IIS Classifieds, but I think you'll find they're still worth more than that.

If you want to get into piccies, for a start, you'd be better off getting a shorter f ratio apo refractor on an eq mount....an ED80 on a EQ6 mount would be good to start off with. They're easier to handle than a SCT plus they have a wider FoV (field of view) and shorter f ratios (f6-8 versus f10). It's also more portable. An Orion Eon ED80 + EQ6 mount will set you back about $2900...then you have to think about eyepieces, camera mounts and adapters, spacers etc etc etc. Astrophotography can be a rather expensive hobby, but one you can slip into over time as you buy extras for your scope. You also have to think about guiding your scope, so you'll need an autoguider (basically a CCD camera optimised for as such) and another, smaller guiding scope, or you could buy an off axis guider or a self guiding camera (which can get expensive). You can see where I'm going here. It's not cheap and you have a myriad of options to choose from, which can confuse newbies completely.

The best thing for you to do is to learn to crawl before you can walk. Get yourself a good scope for visual use first up, then move onto piccies at a later stage, once you've gotten to know the sky and have a bit of experience up your sleeve. That way, you'll be ready to move onto the more complicated areas of astronomy, such as astrophotography.

Last edited by renormalised; 20-04-2010 at 09:20 AM.
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  #6  
Old 20-04-2010, 11:37 AM
cohiba (Robert)
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Hi Guys
I would be intested to hear from anyone who has purchased a LS6 or LS8 I am looking for somthing portable as I have a caravan coming soon,and would like to take a small scope on my travels
I currently have a LX200R 12" and can not fault it but its a bit to big to shift around
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Old 20-04-2010, 11:47 AM
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GrampianStars (Rob)
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Wink

Quote:
Originally Posted by cohiba View Post
....I have a caravan coming soon,and would like to take a small scope on my travels
...
Whats wrong with the 80 APO you have, put it on an EQ6 pro mount
Very portable and stable.
Maybe upgrade and get the AP 105 EDFS or Tak TSA-102 Triplet

Last edited by GrampianStars; 20-04-2010 at 12:02 PM.
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Old 20-04-2010, 06:43 PM
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DavidTrap (David)
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Carl speaks wise words. Talk to others, join a club, have a look at what others are doing. I bought my scope based on my experiences with astrogear at high school and then joined a club. Had I done things in the proper order and joined a club first, I would have bought a German Equatorial Mount.

The advice from those with experience in my club is to learn to image at short focal lengths and work your way up to longer focal lengths. An 8 inch SCT with a 3.3 focal reducer would at best reduce to ~600mm focal length, but that meade focal reducer has a very small imaging circle - far smaller than a DSLR and most modern CCDs - you would only get a small circle in the middle of your imaging chip. It's not the same as imaging through an 80mm refractor with a 600mm focal length.

I have stopped imaging with my LX-90 (sold my wedge) and will move "back" to imaging at ~6-800mm focal length on a GEM. Assuming that goes well, I may defork the optical tube from my LX-90 and try that on the GEM.

I have seen some fair examples of imaging at 2000mm focal length through an LX-90 on the web - these people must have the patience of a Saint in my opinion. With my limited attempts, I only achieved elongated stars and really average graphs on the guiding software.

Carl's suggestion of video astronomy is an excellent idea - I've seen a few guys doing this through 8inch SCTs on Alt-Az mounts with great results.

If you want to let it be, astrophotography can be extremely expensive - much like standing in a cold shower tearing up $100 bills.

DT
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  #9  
Old 21-04-2010, 10:49 AM
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renormalised (Carl)
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Quote:
Originally Posted by cohiba View Post
Hi Guys
I would be intested to hear from anyone who has purchased a LS6 or LS8 I am looking for somthing portable as I have a caravan coming soon,and would like to take a small scope on my travels
I currently have a LX200R 12" and can not fault it but its a bit to big to shift around
One of the new LS models would make a great portable scope for use if you have a caravan. The LS6, especially. If you have anything of what ails ya' (arthritis, bad back, stuffed shoulders and neck etc etc), you'll find the smaller scopes a God send. Plus with the LS models, you have the added benefit of a camera attached to the scope which you can use to take piccies
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  #10  
Old 22-04-2010, 12:17 PM
ausemdg (Rob)
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Thanks for all the valuable advice. I have decided to join the SA Astronomical Society and try out some of their hire telescopes. Not only for experience but also to see which type I prefer.

I will continue to watch the IIS Classifieds Forum and any others I can find. Who knows I may come across a bargain somewhere.

Thanks again.

Cheers

Rob
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  #11  
Old 23-04-2010, 10:10 PM
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Adelastro1 (Wayne England)
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Great Rob! Maybe I should ask for a discount on my membership for finding a new member! haha. I might see you at the meetings and viewing nights..


Quote:
Originally Posted by ausemdg View Post
Thanks for all the valuable advice. I have decided to join the SA Astronomical Society and try out some of their hire telescopes. Not only for experience but also to see which type I prefer.

I will continue to watch the IIS Classifieds Forum and any others I can find. Who knows I may come across a bargain somewhere.

Thanks again.

Cheers

Rob
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  #12  
Old 01-02-2012, 08:22 PM
Brisbane (Joe)
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Ls-8 sct uht acf

Hi guys,
I purchased a LS-8 two years ago and can honestly say this is a great little scope as a second "grab & go" scope. The optics are brilliant but there have been some software issues with the earlier versions and had to reload a few times. Autostar III updates are currently at version 1.6a. The scope is portable and easy to set up. My 3k budget was well spent, now I'm looking for larger apertures having built a few Coulter Optical dob. scopes in my time - LX200 10" or 12" is where I'm heading. I would always try & keep the LS as a second backup scope, the scope talks to you while you are observing and if you're with friends, all the questions the may have re answered without having to look up stats. The 3.5inch LCD monitor is a bit of a distraction if not set to night mode but shows all the necessary data. A good portable camping scope.
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