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Target Selection Tool: Img. Time
#11
Hi Phil,

I have already tried it with Frankfurt, Germany that comes with ST4, same result…

Maybe I should delete everything and start from scratch

CS

Markus
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#12
Frankfurt would be severely light polluted. I was thinking of Mesa Redonda or Texas Star Party, if you've kept those locations. They're further south & have very dark skies, so they might make a good test to be sure that you have things set up properly. Also since they're built in, they're easy for other users to run as a comparison. That way there's no need to share your Location.

Depending on how much customization you've done, I'd wait on the Uninstall/Reinstall until Greg suggests it.  Wink It could be something simple.

Just a suggestion,

Phil S.
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#13
What I can see looks good, but I was hoping to see if your lat/lon were entered correctly and that the time zone matched the longitude. It also precludes me from attempting to reproduce your results. The Img. Time is merely how long it spends about the airmass you have set. Maybe try changing the number (where it says 1.5) to something like 2 just to see what happens.
Clear skies,
Greg
Head Dude at Skyhound
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#14
Hello,
I have double checked my coordinates. I have corrected timezone setting to GMT+2. I have played around with the bortle settings. I have also tried to play around with the airmass constraints, but it doesn't help. I have created a new test location (not my home, but alike), so you can use it for testing
   

@edit: I tried several other things on my second computer with a fresh installation of ST4: same problem there, as well with the imaging systems, that come with ST4. With the C11 I get four entries with Img. Time of 24h, the others are marked with "---".

I have created some other locations out of the ST4 Location list (e.g. Frankfurt, Bonn): it's always the same problem. When selecting "Mesa Redonda" it looks good. So the problem seems to be in the locations.

Maybe you could create some of these locations in your ST4 installation (e.g. Europe --> Germany --> Bonn), to check if the problem is reproducable at your computer?
   

@edit2: I tried to increase Max X to 5 and now some targets are displayed with an Img time of 24 hours:
   

Thanks & CS
Markus
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#15
Its important to think about what the Img. Time column actually is. The purpose of this column is to tell you the maximum amount of time there will be to image the object on a single night. It looks at the time spent above the airmass you have set. But it also uses the best night of the year (see column). Using that night it also looks at how long the night is on that date (ignoring the moon). The airmass constraint is what usually matters but for your northern latitude, I believe the time between twilight is the limiting factor for summer objects.

So we should consider the possibility that it is actually working as intended, even though the results look off. This is all with the obstructed horizon turned off (please keep it off until we are sure things are working correctly).

I believe what may be happening is that the Messier list has a lot of summer Milky Way objects in it, which are best during your short nights. Many of these are extended objects that cover so many pixels (F/7?) that they are difficult to get a high SNR for, and are being filtered out because you can't image them in a useful way with the telescope and camera and filters that you are using. Those are the objects where the columns are blank.

I'd be interested to see what M42 looks like in your list. It should have a different Img. Time because it is a winter object. But before you check that be sure to disable the obstructed horizon and set the Max Airmass to a more reasonable number, like 2.0.

Maybe its time to show us your imaging system.
Clear skies,
Greg
Head Dude at Skyhound
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#16
Hello Greg,
thanks for the explanation of the Img. Time column, I think its meaning is mostly clear for me.

Here you can find M42, listed with "---" in all green columns (I have set Max X to 2 and Target SNR to 10):
   

In the Object Info of M42 you can find the following YearBar, as I understand it, this time span should be displayed in some way in the green columns (Date range):
   

I have saved my Imaging System to a STX file:
   

.stx   TS115f7 ASI2600MC.stx (Size: 15.39 KB / Downloads: 0)

The obstructed horizon is disabled (not defined for the "test location")

Thanks & CS
Markus
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#17
Marcus,

What happens if you set the Date to 2023 Dec 20 or some other time during the winter? Do the Img Times look better then? The Night Bar at the top of the Target List display indicates that M42 doesn't rise during the night during June so there wouldn't be any time to image now. Summer nights at 50°N don't get very dark.  Sad.

Phil S.
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#18
Hello Phil,
yes, in the moment it's not a good time for astrofotographie Sad 

I have set the date to 20th dec. 2023 and now there are several entries in the green columns and the Img Time column.

But I don't really understand, why the selected date has influence to the values in the green columns? The green columns should give the time span during the whole year where it is best to observ the objects. So a specific date you set on top of the form should have no influence to it? And the airmass is independent to the skies darkness, it depends only on the height of the object...

   

CS

Markus
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#19
it is really strange: I have changed back the date from december to the night 9./10. june 2023 and now the green columns are filled:
   
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#20
I don't do much imaging so I'm not too familiar with ST4 Imaging. I'm surprised that changing the date on the Target List tab to Winter & back to June seemed to correct the issue for all of the objects in the TL. Maybe it will provide a clue.

If you close & restart ST4i, do the Img Times look OK if the Date is set to Jun 10/11, for example? Can this date change serve as a temporary work-around?

Greg will get it figured out.

Phil S.
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