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+--- Thread: IC 443 Won't Calculate an Exposure or SNR (/showthread.php?tid=2944)
IC 443 Won't Calculate an Exposure or SNR - portopa - 2023-11-10
I imaged Jellyfish supernova remnant IC 443 for 11 hours last January from Casa Grande, AZ. I got 114 5-min images, and it all went very well.
I tried to go back and model that night in SkyTools so see what it would have recommended, and how its projected SNs would align with my actual collections (my ground truth).
But for some reason the system cannot reach any SN at all:
- Filters can't reach a target SNR in a New Imaging Project / Exposure Goals tab
- As shown in attached, Exposure Calculator shows no detectable signal.
Am doing something wrong, or is the database perhaps missing some info required to do the SN calculations?
Thanks.
Paul
See attached
RE: IC 443 Won't Calculate an Exposure or SNR - theskyhound - 2023-11-10
Hello,
If you look on the left side of the dialog, under "Target Object data" you will see the following values: SBr(V) = 99.9, SBr® = 99.9, Total = 99.9. These values indicate that there is no data for this object. Unfortunately, not every object has the data required for the calculations. I am actively working on that, but its a big job, especially for a relatively faint emission line object such as this one.
RE: IC 443 Won't Calculate an Exposure or SNR - portopa - 2023-11-10
That makes sense; I'll watch out for the 99.9s. Glad it wasn't something I was doing wrong. I'll try with some other object -- got plenty.
Thanks.
Paul