2024-01-31, 08:43 PM
(This post was last modified: 2024-01-31, 08:46 PM by theskyhound.)
Your filters look fine.
I'll try again to explain the issue with various HII objects.
SkyTools is designed to provide optimal imaging recommendations for narrow band filters based on available emission line data. For many targets, such as M27, this data is available, allowing for accurate exposure optimization. However, in the case of IC 410, the emission line data is not yet available, and the software must estimate based on less reliable broadband color data. This means that while SkyTools can still provide guidance for IC 410, the recommendations are based on estimations and might not be as accurate as for other targets with complete data. If there is a possible problem with your setup, we need to eliminate the possibility that it arises from the lack of data. The upcoming update will add more nebulae with accurate emission line data. See my previous explanation for how you can check to see if the emission line data is estimated (try opening the Object Info for IC 410).
Some calculations are affected more than others if the emission line data is estimated. Exposure times for narrow band filters are what is most affected, so the results of the SPB for narrow band filters, and your exposure goals might be a little suspect. The best period of time during the night to image, even in narrow band filters, is the least affected and can be relied upon.
Regarding number 3, someone said something similar here just a few weeks ago, so it is a common concern. But it is not a valid concern. Once you understand how to use the software to give you what you need/want, you will see that there is no assumption built in about how long you can image something. This is something that *you* decide. Tools like the SPB are designed to help you make that very decision.
Since you are most familiar with the SPB at this point, let me explain how it is best used. You decide what your goal is at the top, under Mode. If you express your goal as a total exposure time, enter the maximum amount of time that you think you will be able to spend on the target. It will then tell you what the quality of your images will be in each filter and for the final composite, in terms of SNR. Be sure to understand what the SNR values represent.
The other approach is to specify the minimum quality that you want in your final composite image, again in terms of SNR, and again, it is important to understand what the values represent. I like to use an SNR of 20 to represent the minimum acceptable quality of the final image. So when you specify a minimum quality of SNR=20, it will tell you how much exposure time is required to reach that SNR.
You are not being dictated to about this. Its advisory. Its telling you what you can expect in the time you have available for the project, and for each set of filters. The best results float to the top in the table, but you can scroll down to see other options. Either pick an option that you deem is doable, or select a different target. If you select a different target, that's not SkyTools fault. It's just telling you what you can reasonably expect so that you can make the call. What I understand doesn't come into play.
Moving on to scheduling: if you only have one project then you risk either getting crappy data by imaging your project when you shouldn't be, or wasting time under a clear sky. This is why it is a good idea to have multiple projects, so it can make the best use of your time available. Again, this has nothing to do with being in Chile. You tailor things to fit your own expectations. But if your target is setting after 11 PM, why not have a project that can start at 11?
I'll try again to explain the issue with various HII objects.
SkyTools is designed to provide optimal imaging recommendations for narrow band filters based on available emission line data. For many targets, such as M27, this data is available, allowing for accurate exposure optimization. However, in the case of IC 410, the emission line data is not yet available, and the software must estimate based on less reliable broadband color data. This means that while SkyTools can still provide guidance for IC 410, the recommendations are based on estimations and might not be as accurate as for other targets with complete data. If there is a possible problem with your setup, we need to eliminate the possibility that it arises from the lack of data. The upcoming update will add more nebulae with accurate emission line data. See my previous explanation for how you can check to see if the emission line data is estimated (try opening the Object Info for IC 410).
Some calculations are affected more than others if the emission line data is estimated. Exposure times for narrow band filters are what is most affected, so the results of the SPB for narrow band filters, and your exposure goals might be a little suspect. The best period of time during the night to image, even in narrow band filters, is the least affected and can be relied upon.
Regarding number 3, someone said something similar here just a few weeks ago, so it is a common concern. But it is not a valid concern. Once you understand how to use the software to give you what you need/want, you will see that there is no assumption built in about how long you can image something. This is something that *you* decide. Tools like the SPB are designed to help you make that very decision.
Since you are most familiar with the SPB at this point, let me explain how it is best used. You decide what your goal is at the top, under Mode. If you express your goal as a total exposure time, enter the maximum amount of time that you think you will be able to spend on the target. It will then tell you what the quality of your images will be in each filter and for the final composite, in terms of SNR. Be sure to understand what the SNR values represent.
The other approach is to specify the minimum quality that you want in your final composite image, again in terms of SNR, and again, it is important to understand what the values represent. I like to use an SNR of 20 to represent the minimum acceptable quality of the final image. So when you specify a minimum quality of SNR=20, it will tell you how much exposure time is required to reach that SNR.
You are not being dictated to about this. Its advisory. Its telling you what you can expect in the time you have available for the project, and for each set of filters. The best results float to the top in the table, but you can scroll down to see other options. Either pick an option that you deem is doable, or select a different target. If you select a different target, that's not SkyTools fault. It's just telling you what you can reasonably expect so that you can make the call. What I understand doesn't come into play.
Moving on to scheduling: if you only have one project then you risk either getting crappy data by imaging your project when you shouldn't be, or wasting time under a clear sky. This is why it is a good idea to have multiple projects, so it can make the best use of your time available. Again, this has nothing to do with being in Chile. You tailor things to fit your own expectations. But if your target is setting after 11 PM, why not have a project that can start at 11?
Clear skies,
Greg
Head Dude at Skyhound
Greg
Head Dude at Skyhound