Yearbar

[GregL]

                I am curious about what factors go into the computation of 'yearbar'? Looks like a great idea but with some objects I don't get any 'good' indications or what is produced seems odd. Case in point - M13. The daily visibility for this object shown in Daybar is pretty close to that computed in another product. (Daybar and Day-profile). But the annual calculations are wildly different (Yearbar and Year-profile). I dont understand why yearbar is showing visibility when other sources show it to be not visible?

thanks,

greg latiak

[theskyhound]

Hello,

It would seem that something is not working correctly. Without knowing more about your location and imaging system it is difficult to say what the problem is.

The YearBar calculation is not a simple matter of visibility. It is a complex calculation shows the length of time on each night (vertically) that the target object is deemed to be at its best (usually an IQ of A) during each night. The calculation considers everything: your location, imaging system, weather and seeing conditions, type of object, etc.

This is essentially the same calculation that appears in the yellow columns on the Target Selection tool for a specific night. So I would use the Target Selection tool to try to understand what is going wrong. Ensure that the Start, Duration and Q columns are enabled. Select a night. Look at those columns. Maybe post a screen capture of this (the Target Selection Tool with M13 highlighted) instead, because it contains a lot more info.

[GregL]

           

Here you go...

greg

[theskyhound]

Thanks. Can you increase the size of the Target Selection Tool image? It's just a bit too small to read.

[GregL]

   

Here we go. I shrank the window down as small as it would go so a screengrab was under your 500kb max upload size.

greg

[theskyhound]

Thanks Greg,

I think it is your weather settings. 10C at 80% humidity is pretty bad for imaging. Notice that the best quality is C or D for many of these targets. Usually this is higher, at A or B. Have you set the monthly weather for your location? That may help. And when you do, set it to a typical night that you actually observe on for each month (which hopefully is a little better).

What I think may be happening is that SkyTools looks for a typical "good night" in your weather settings for your location and then compares the SNR you can get on a specific night to that one. Perhaps there is a month where the humidity is much better than 80%. If so, the nights at 80% look pretty bad in comparison, and that is affecting your result.

[GregL]

I will try that and let you know.

g