expectations with guiding

[coppernob]

dear all,

please can someone give an indication of how long the subs i am likely to achieve with good polar alignment of an ed80 scope on a eq5 pro synscan mount. I will be trying to guide with phd2 with a planetarycam on a 9x5o finderscope. Inwill be using an unmodded dslr as the imaging camera.I have been managing 1 minute unguided subs so far.

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[iksose7]

I would say at least 5-10 minutes. Only way to find out is to try it!

I am guiding my 115mm frac on a NEQ6 with a 50mm guidescope, its focal length is close to double the ED80 and i manage 10 minutes fine, not been brave enough to try anything longer yet though. I have never used a EQ5 though so couldnt be too sure how well it preforms.

Callum

[VikN46]

I use a similar set up, Equinox 80, EQ5, 9 x 50 finder/guider with QHY5 and when I used to use my DSLR I regularly managed 5 - 10 min subs but it depended a lot on seeing conditions and light pollution.

[Freddie]

If you can guide for 10 mins you can guide forever. Your sky conditions will however be the limit to the sub duration.

[ollypenrice]

How many arcseconds per pixel are you working at while imaging? As a minimum standard your guiding must keep your imaging scope within that range. So if you are imaging at, say, 2 arcsecs per pixel your guiding must keep errors at the imaging scope below 2 arcsecs per pixel. If it does not do this you will lose resolution. In reality it must guide, I think, better than this not to lose resolution but I'd start with that.

Olly

[Tommohawk]

If you can guide for 10 mins you can guide forever. Your sky conditions will however be the limit to the sub duration.

Agree with this - a related question might be: whats the longest sub thats useful? 

Most folk seem to think in terms of 5-10 minute subs, but it must surely depend on camera type. I use DSLR and 8 minute subs typically - but 8 minutes with a CCD should give more data than you can shake a stick at.

[Owmuchonomy]

Take in Olly's post above and then relate it to the output from PHD2 on your computer screen. For example, my main imaging set up works at 1.24" per pixel with an AA 102mm 'frac and a Canon 60D and the guiding output from PHD2 tells me (usually) I'm around just under 1" error. A comfort zone which is repeatable on my HEQ5 only really upset by poor seeing.

[Thalestris24]

Hi

I'm guiding at 4.3"/pix (finder guider) and imaging at 1.49"/pix (1100d) but my guiding graph gives me +/-2" to +/-4" variable error (< 1 arc sec / pix rms). The guide error seems to be largely due to my local seeing conditions which are quite poor. So I seem to lose resolution resulting in 'soft' images. I have acquired 900s and even 1200s subs but usually limit exposures to 600s max because of the lp. The image softness can be made less apparent by reducing the image size to 33% of actual. This is easy to do with dslr images which are big to start with. 

Louise

[coppernob]

Thanks everyone. arcseconds per pixel. Have to look that up

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[lensman57]

dear all, please can someone give an indication of how long the subs i am likely to achieve with good polar alignment of an ed80 scope on a eq5 pro synscan mount. I will be trying to guide with phd2 with a planetarycam on a 9x5o finderscope. Inwill be using an unmodded dslr as the imaging camera.I have been managing 1 minute unguided subs so far. Sent from my iPad using Tapatalk HD

I used to have an EQ5 SynScan guided with PHD and GPUSB. With good PA and balance I used to manage 900s subs with my SW 100ED DSPro @ F7.6  and a modded Canon 1100d ( 765mm FL -1.4 arcsec/pixel ).

A.G