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Autoguiding with afocal projection?

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#1 Lord Beowulf

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Posted 27 March 2009 - 09:19 PM

This may not be the best location to ask, but has anyone tried this? I'm looking to improve guiding with my ST-80 when imaging at f/10 on my SCT, and figure that eyepiece projection would give me some magnification to allow the autoguider to have a higher resolution and better reaction to image shifts. Of course the related question here is if this is practical, who makes a 1.25" to 1.25" EP projection adapter that would allow me to connect my StarShoot autoguider? Thanks for any info/suggestions.

Beo

#2 WadeH237

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Posted 27 March 2009 - 09:36 PM

Most guide software is good enough at finding the centriod that your ST80 should work fine as a guide scope at 400mm.

If you really want more focal length, I would think that a barlow would be a better choice than trying to do afocal.

-Wade

#3 Lord Beowulf

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Posted 28 March 2009 - 03:10 AM

I would think that a barlow would be a better choice than trying to do afocal.

Ah! Good idea...Duh!

As far as the guide quality, with my current setup it's been ok, but the quality achieved using the SCT to guide the ST-80 was phenominal by comparison. Granted much of that has to do with the quality of the mount, but for really good guiding I would think that the higher the resolution the better, up to some limit where things break down and get noisy. I'm just not sure it's worth getting another f/10 OTA to use as a guide scope! At any rate, thanks for the suggestion, I'll have to give that a try.

Beo

#4 Dan G

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Posted 28 March 2009 - 09:48 AM

Beo -

What was your guide error +/- with the ST-80 vs the C8? When you say guide quality do you mean the deviation of the guide star was less or the quality of the image was better?

Dan in NY

#5 Lord Beowulf

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Posted 31 March 2009 - 01:08 AM

Hey Dan,

I really couldn't tell you the numbers, but with the C8 as the guide scope I've had some really good image results on the ST-80 even with my jury-rigged SE mount. So yes, I mean the quality of the image was better once I got PHD tweaked in, since the amount of guide star motion on the C8 results in only small variations on the ST-80.

Beo






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