What telescope to buy for a guidescope?

h0ughy (David) · #1 18-11-2005, 07:48 PM

Ok my plans keep changing by the minute, which i hate. As some of you know I have put together this setup http://www.iceinspace.com.au/forum/s...highlight=m500 .

I wish to add a guidescope in the middle, but I want my cake and eat it too. I want a widefield scope, with excellent build quality for a cheap price, portablity, but I want quality optics as well. I have an ST4 autoguider and I want to also take widefield photos thought it as well. the contenders are a Saxon 80ED and a Orion Express.

What do I do???? No I am not buying both!!

Striker (Tony) · #2 18-11-2005, 08:10 PM

I like the Saxon ED80....but looking at the size of your Mak maybe the Orion Express may sit a little better.

Is she going to sit on top as piggy back or side saddle....have you got the guide rings yet.

Whats the diff in price.?????

The ED80 has proven itself but I'm sure the express wouldn't be too far behind.

Robert_T · #3 18-11-2005, 08:29 PM

Hi Houghy, I can't comment on the saxon ed80, but I have the Zenithstar 80 which is same as the Orion Express. You might find the WO version just as cheap if you want a diagonal - I got eh ZS80, 2inch dielectric diagonal and a minus violet filter for $ 8 hundred and something from Frontier Optics. Very nice, beautiful build quality and lovely views. There a few pics taken through the Megrez 80 (much the same optics) on the ATS web-site that deom what can be achieved imaging through it too.

http://www.atscope.com.au/williamopt.html

enjoy your consideration/purchasing!

cheers,

h0ughy (David) · #4 18-11-2005, 08:43 PM

Quote:

Originally Posted by Striker

I like the Saxon ED80....but looking at the size of your Mak maybe the Orion Express may sit a little better.

Is she going to sit on top as piggy back or side saddle....have you got the guide rings yet.

Whats the diff in price.?????

The ED80 has proven itself but I'm sure the express wouldn't be too far behind.

side by side, the difference in price lets just say for argument they are the same price

h0ughy (David) · #5 18-11-2005, 08:46 PM

thanks Robert I will take that onboard to consider

RB (Andrew) · #6 18-11-2005, 08:49 PM

Orion Express

janoskiss (Steve H) · #7 18-11-2005, 09:16 PM

Andrew, Please explain...

RB (Andrew) · #8 18-11-2005, 10:07 PM

I just think it would make a nice wide field scope as well as a good guide scope for the ST4.
And going on the quality of the Orion 80ED I think the Express should do well.
I know the express is not as good as the ED80 but it's a faster scope and would make a good all round little scope.
If I didn't have the 80ED already I would consider the Express.
The price is ok too <$600.

Please forgive me, I was just being silly before, just trying to be funny as I pass some time while I process some avi's.

Cheers guys

[1ponders] (Paul) · #9 18-11-2005, 10:46 PM

h0ughy, if you're looking for a guidescope you don't want it being too much shorter in the FL than the mak. Maybe something that is about a half to a third the Fl so you can use a 2X or 3X barlow to bring it in comparison.

I asked in a post a long time ago what the shortest fl you could use for my old lx200. Theorectically with sub-pixel guiding I could have gotten down to a 300mm fl scope. Realistically though taking indeterminate seeing into account, at least half the fl would make life a lot easier for you when autoguiding.

HTH

CS

h0ughy (David) · #10 18-11-2005, 11:26 PM

Quote:

Originally Posted by [1ponders]

h0ughy, if you're looking for a guidescope you don't want it being too much shorter in the FL than the mak. Maybe something that is about a half to a third the Fl so you can use a 2X or 3X barlow to bring it in comparison.

.

HTH

CS

Paul, the fl of the Mak is f10, the express is f6, the eq80 is F7.5. I do have a 2 x 2" big barlow.

do you use a barlow with your scope for autoguiding?

[1ponders] (Paul) · #11 18-11-2005, 11:47 PM

Normally I do h0ughy. Depends on what scope combination I am using. If 8" meade and Focal reducer and my orion then yes I do with the orion.

Robby · #12 19-11-2005, 08:45 AM

Houghy,
For a guide scope you don't need to go as exocitic as an ED or semi-apo. A basic acromat will be fine. I use a Celestron ST80, which is also sold be many oher brands. Cost me $US90 on Astromart!! Cheap as chips.. Barlow it and you'll be laughing.
Although I should have probably brought an ED or apo cause now I have the desire to do some shots though the 80mm.... Bust for a bare bones guide scope you can't really beat it.
Cheers

Striker (Tony) · #13 19-11-2005, 09:07 AM

I would still go for an ED if you have the cash.....as you will probably want to do some widefield shots aswell......then you can use your Mak as the guide scope.

But like Robby said...if it is only for guiding a cheap Acho will do.

Houghy...you may confuse people saying the FL as the F ratio.

Ambermile · #14 19-11-2005, 10:28 AM

I think more important really is what you are going to put in the guidescope rather than what the guidescope is - as has been noted. Most any ST80 will guide, add a barlow if you must but the sub-pixel thing is a misnomer unless your imaging camera has a big chip/little pixels. You need to think anout the system as a whole rather than the individual parts H0ughy.

Personally... I'd go with a WO or one of the clones of these scopes - that way you get a decent build, decent optics, eye candy, and grab and go as well

Having said that, the ED80 genre are very nice, mid-FL range scopes that again, are good grab and go as well.

Arthur

ving (David) · #15 19-11-2005, 02:02 PM

plenty of st80s' on astromart

was considering one for a while there as a grab n' go

avandonk · #16 19-11-2005, 04:19 PM

Guidescopes and guiding a short guide.If you are guiding with a toucam say and Guidedog your guiding accuracy is sub pixel.Even if its not say one pixel about five micron.If the guidescope has a focal length of 300mm say,the accuracy is still better than one thousanths of a degree.The fallacy of needing a long focal length guidescope was due to the need for manual guiding and we humans are not good at it.The best bet get the biggest aperture never mind the quality and you will always find a guidestar.My 300mm F4 achromat guides a 2000mm telescope very well.
Bert

gbeal · #17 19-11-2005, 04:40 PM

Like Robby, I use an ST80 as a guidescope (actually a Celestron Nextar 80, but what the heck).
In as much as a dual instrument though, I reckon a better scope than the ST80.
If for guiding only then OK, but for grab and go as well, go the next level. OR try an ST80 first, they are cheap.

Ambermile · #18 19-11-2005, 10:12 PM

Well, we are all agreed then

Best thing is to have a read of this...

http://astro.neutral.org/articles/au...toguiding.html

and take it from there I think. Tom is a hands-on person who takes nothing "written" for granted and so pushes what he has to do what he needs. I like him and his attitude.

Arthur