Re: 600gto for astrophotography

Bob Luffel <bluffel@...>

Sounds like you have it well in hand already.

I use a Celestron (vixen) 80mm f/11 and ST4 with my 155EDF.
At f/11 I generally have had no problem finding suitable guidestars within
the field. I like to have a bright enough star so I can keep the ST4 exposures
at or below 1 second. Assuming that your 60mm guidescope is f/11 it should
work just as well, just at a shorter focal length (but with the 130 f/6 you
will have a similar guidescope/mainscope focal length relationship).

Enjoy the manual guiding! I used to be more of a 'purist' and manually
guided, but I got used to auto guiding surprisingly fast :-) (still, the
set up time and hassles are the same for autoguiding and manual guiding).
What the ST4 really bought me is the ability to do something (like observe)
while taking an exposure. That is what my Traveler gets used a lot for (as
a second scope to use while the 155 is humming away).

Oh yeah, one more thing I learned. Stick with simple guidescope rings, they
work well. I once tried a Tak TGM-2 guidescope stage (basically a teegul
mount). It flexed like crazy and was actually a pain to use (lots of shift
in the axis' when adjusting).


Hi Bob,

I bought that 60mm GS from AP three years ago for the SDF and 130. With a
Tak 5mm Guide eyepiece, I'm at 140x, which does begin to get dim for
guiding. I'll try to keep within the FOV AMAP, good tip. The 140x works out
to be about 5x the focal length in inches with the 130f6, so it looks like I
should use 200+ with the 155f7. May have to upgrade as you say.

For all you ST4 users, isn't the 60mm GS adequate for autoguiding for 155f7?
Eventually I'll have to get one, but I want to experience the pain of manual
guiding for now anyway.

Thanks, Stephen

A 60mm guidescope can certainly work for manual guiding, though my
has been 80mm. I prefer to select a guidestar that is within the
field of the image, to minimize the chances of field rotation (good polar
alignment is important). An 80mm just gives you a brighter selection of
at a high enough magnification (200X or higher) to make guiding easier.

In any case, a 60mm guidescope is pretty cheap and you can always upgrade

Bob Luffel

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