OAG and Binning

[Starwiz]

I recently went over to OAG using an ASI120mc for the guide camera.  Not the best camera for this sort of work, I know, but it's what I have available at the moment.

The scope is a SW200P on NEQ6 with an ASI1600mm-Pro as the main camera.

So, my question is, would using 2x2 binning with this scope/ guide camera combination have any significant adverse effect on guiding?

I'm thinking of doing this to increase the apparent sensitivity.

Thanks

John

[wimvb]

With a mono ccd camera, binning will bring the noise down and change the sampling scale (arcsecs/pixel). With a mono cmos camera, you change the sampling scale, but there is less gain in signal to noise ratio. But there is some, so it's still a good thing to do. With a colour camera, it's a bit more complicated because if you bin, you average over the colour pixels. There's probably still some noise advantage, but not as much as with a mono cmos/ccd. There's really only one way to find out if it makes a difference: try it. But do the test in a patch of sky where there are few guide stars; you'll probably get clearer results.

[tomato]

I use a ASI120 mini on an OAG for guiding a dual rig, binning 2x2 did no harm and may have improved the guiding but unfortunately I unscientifically made a couple of other changes to the guiding at the same time.

[Robindonne]

Im all ears for this experiment!!

[alacant]

12 hours ago, Starwiz said:

2x2 binning

Hi

Hands on with a SW 250p down to a 130pds with everything in between tells me that binning our t7m (120mini clone) and zwo120mm mini oag gets us a decent calibration and guide star every time. Found out the hard way before I knew about binning;)

Sorry, can't speak for the 120 colour but as @wimvb suggests, try it. My money is on a binning success.

Cheers and look forward to decent stars every time.

[wimvb]

1 hour ago, tomato said:

 

I use a ASI120 mini on an OAG

 

The mini is a mono cmos, which is more straightforward than the colour version. I too used the asi120 (Mono) binned past season, and had fewer ”star lost” events.

[rickwayne]

Also have a 120MC; if I don't hear from you first I'll try it and report back. Easiest quantitative test would just be the S/N reported by PHD2, if you're using that.

[vlaiv]

I regularly bin my color guide camera with OAG since "base" sampling rate is somewhere around 0.48"/px and I don't need that much resolution for my guide system.

 

[Ken82]

I always bin 2x2 on my asi 174 when using my 11”edgehd and OAG. 
 

By using 2x2 binning and longer exposures this has the effect of limiting the seeing conditions. Otherwise you will find you will be “chasing the seeing”

 

[Starwiz]

Thanks for the replies all.  When I get another clear night, I'll run some experiments and report back the findings.

John

[Kiwi_Brad]

Looking to switch over to my OAG on SW130 and ASI120mm has anyone got an update on this. I have very good dark skies and good seeing so would binning be better or am I better spreading the guide stars over more pixels or am I totally wrong with everything I said… cheers. 

[michael8554]

Hi Brad

650mm FL and 3.75um pixels gives a image scale of 1.19arcsecs/pixel.

Binning would up that to 2.38, IMO a more sensible value.

But depends on the guidestar shape.

Many setups have less than ideal star shapes.

PHD2 seems to cope, but worth testing both Bins on the same night in case Binning makes guiding worse :-<

Michael

[Kiwi_Brad]

8 hours ago, michael8554 said:

Hi Brad

650mm FL and 3.75um pixels gives a image scale of 1.19arcsecs/pixel.

Binning would up that to 2.38, IMO a more sensible value.

But depends on the guidestar shape.

Many setups have less than ideal star shapes.

PHD2 seems to cope, but worth testing both Bins on the same night in case Binning makes guiding worse :-<

Michael

Great thanks Michael. 
 

if anyone has any experience or updates from the above conversation I would like to hear how it went. 
 

Thanks