Guidescope tips needed! Anyone used a startravel 80?

[IanL]

While I've nothing against Astrotortilla it is perfectly straighforward to find your object without it. Just re-synch your mount on a nearby star, if your GoTo is not all that accurate, and send the mount to the RA and Dec of the target as framed up beforehand in a planetarium software. This could hardly be much more simple.

Olly

Well in my case it has made my life a lot easier; my rig has serious cone error (over a degree and a half)  which I am loath to fix since I have pretty much zero flexure between the guidescope and the imaging scope.  I don't want to strip it down to fix the cone error (even assuming I can) and then find it flapping about.  My initial goto is usually so far off target that the alignment star is way off-chip.  Using AT I just don't have to worry about it at all.  Maybe I'm just lazy, but since I started using it I have saved 15-30 minutes of faffing about at the start of the night.

[Mr Bergman]

Hi all,

Some feedback from earlier discussion regarding equipment. I got a QHY5L+adapter for my 9x50 finderguider, but due weather I actually didn't get so many chances to try my equipment until yesterday. Windy conditions BUT a fairly good result for my first autoguiding testrun. A very nice feeling to see it work. This would have been a gigantic project hadn't it been for all you nice people in here giving me tips and advice! Thank you all.

Now to some technicalities; Used phd, and I must say I'm impressed. Let my guidestars be slightly out of focus ( actually couldnt get them really tight..), which I presume made it easier for phd to guide correctly? I turned the focus ring as tight as possible and screwed the qhy adapter all the way in. How much out of focus is optimal for guding?

I also set min motion to 0.05 due magnification of my guidesystem, and a calibrationstep of 2000ms. And it worked like a charm. Do you recognize these settings using same equipment,?

Best regards,

Erik

[NickMorris]

The focuser on the ST-80 is poor at best and usually a big source of flexure.  When I used my ST-80, I used to tighten up the focus tension screw underneath the focuser with a pair of pliers as hard as I could to stop the focus drawer tube flexing......

OAG all the way if I was you and don't bother with standalone if it was me.....

good luck

Nick

[IanL]

Now to some technicalities; Used phd, and I must say I'm impressed. Let my guidestars be slightly out of focus ( actually couldnt get them really tight..), which I presume made it easier for phd to guide correctly? I turned the focus ring as tight as possible and screwed the qhy adapter all the way in. How much out of focus is optimal for guding?

Well you should start with the best focus you can manage with your equipment.  The most important thing to have is a good SNR for the guide star so that PHD can lock on to it and track it reliably.  Too low an SNR and you will start getting 'star lost' errors flashing up in PHD.  De-focussing slightly might help improve guide accuracy but is only necessary if you have a large disparity in pixel scale between the imager and the guider; you certainly shouldn't defocus as a priorty - a high SNR is the first priority.  (Of course SNR also depends on the brightness of the guide star, so good focus is more important on faint ones).

Ultimately if it is working okay for now, don't worry about it too much.  If you start getting star lost errors or similar then you might look at focus as the first issue.

[Mr Bergman]

Nick - I did never buy the st80. I chose 9x50 instead. Thx anyways.

Ian - ok, thx, it works now slightly defocussed, but I'll try to get more focus next time. However, due large field of view with 9x50 makes it easy finding bright stars for now...

[Mr Bergman]

Aha....I need to remove the locking ring and then screw the lens back on the 9x50...the adaptor from modern astronomy isn't sufficient for maximum focus.