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Guiding scope question

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Hello :p

Well totally new to this thing called guiding, I have a Evostar 120 (f10) refractor on a HEQ 5 syncan.

I have been using it for a year now and been taking a lots of photos but I want to be able to do longer exposures 3-5 minutes at least and with a Barlow 2-3x, up to date 90s are doable as is no Barlow, but about 70-80% goes in the bin with star trails and all.

So heres my plan :)

I heard allot of good words here about the SW Synguider, was thinking about getting a SW Startravel 102T to go whit that , mounted with aid of a SW Guidescope Mount.

Now to my question, will the scope and guider go along well and serve my intentions or I'm I about to do a big mistake here :D

Many thanks for advise/thoughts about this in advance :eek:

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I nearly got one of those, but ended up with a QHY5 instead. Very happy with it, as it was an absolute doddle to set up even on my tiny 50mm finderscope.

I have the computer outside anyway (for webcam imaging), so it wasn't a big deal to connect up the camera. It also made me think that I may as well also try out an EQDIR module with CdC - and I certainly won't be going back to the GoTo handset!

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The 4 inch is overkill and has a smaller FOV for finding guide stars. The ST80 is my idea of the perfect guidescope so I have two in regular use. I never need to adjust the guidescope to find a star so I do not use a guide scope carrier, I just bolt down the ST80s rigidly.

Why a barlow for DS imaging? At native f10 you are already very slow so the opposite of a Barlow, a focal reducer, would be a far better idea.


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Thanks for your thoughts and advise.

First off, I want a standalone solution meaning no laptop or the like (non available) and also one thing less to carry.

Why Barlow, well I have a thing for globular clusters and I would like to get a bit "closer" currently having a FOV of ruffly 1.2 degrees and 0.5 degrees would be near perfect, but much darker ofc. I my making a mistake that I would get more resolution that way, not even sure that the scope could handle it but thats what I got at the moment :D

A reduser would ofc also be nice for larger DSO's and are also on my list of items to ask Santa for :p

So 4" is over kill hm.. I'll look in to those ST80's then :)

Just thought that I could get more accurate guiding with higher resolution but if it is sufficient whit lesser then thats fine and most likly less expensive, no need to shot rabbits with bazookas ;D

From what I'v read about the synguider it could be tricky to get guide star on the center of the chip and that why I thought that I needed something to slightly adjust the whole thing.

Kind Regards


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No need to go beyond a focal length of 400mm with electronic autoguiders. I'm sure of that. Imaging globulars at f20 cannot be a good idea, though. I did M13 at a focal length of 980 (aperture 140, f7) and got the result below. SteveL used a Mak Newt at 2 metres (apertue 190 and using a Barlow or Powermate to take him from f5 to f10) and certainly out resolved my image by a long way. However, f10 is where you start at native and that's where I think you should stick. Besides, the guiding required at over 2 metres is not really on with an EQ6 even with autoguider. It can be done but not easily or reliably.

You might be right about needing to adjust the guidescope with the Synguider, I just don't know. I used cooled CCD cameras to guide and they are probably more sensitive. Try a specific question, maybe.

Have fun!



Edited by ollypenrice
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