PIER-14 IC1396 - Elephant's Trunk - Narrowband

Hi Richard, 

As I write it's still got 20 minutes to go downloading the smaller one. 

Well I hope you at least have the weekend off. I'm excited too.  Hopefully that nasty bit of interference is no longer present. Mind you how Peter manages to almost completely eradicate such things in images is a marvel. His latest picture of M51 is another good example. Keep that fire extinguisher handy when you do start.

You probably have mentioned it already somewhere, but what app do you use for the calibration and linear post processing. I use PixInsight which has so much in it, which is great but with so many options then at my age if it's a process I haven't used in the past week it's back to consulting any notes I may have taken. Oh for my recollection powers of my younger days.   Should rename myself as old_memory perhaps. 

Look forward to seeing something soonish. 

Cheers, 

Ray 

Ray,

I use Pixinsight (well I try), and I know what you mean. look at a variety of tutorials and descriptions of workflow, and they are all different. I keep trying different things, which does not lead to consistency. Must try harder!

I seem to get on much better with colour cameras. The process of getting a first image you can work from seems to be much easier. Here's a recent example https://stargazerslounge.com/topic/370963-heart-and-soul/. But that is part of the reason to use Roboscopes. I have never really been able to collect good enough narrowband at home to check whether my processing is up to it. Hopefully, I will now find out that I can produce an acceptable narrowband image.

In the meantime, I am processing the LBN 878 set in the background, while I grind out a report that is due by the end of today.

Richard, 

Thanks for the link to that image. I've seen many an excellent image taken using that lens and yours is no exception. A real bargain that lens compared to an equivalent scope I imagine, apart from having no really fine focusing capability. Were you able to use it at f2.8 or stop it down a bit? No need for an instant response, you get that report out! 

Regards, 

Ray 

The report is boring, so interruptions are gratefully seized on ;-)

I stopped it down a touch using a step-down ring on the front. probably to about f3.5 (I have never worked it out). I have a 3-D printed set of rings and focuser for the lens, which makes it pretty easy. I check focus every session using a Bahtinov mask, but rarely have to adjust.

And of course, guiding is easy!

A man of many talents. That step down ring was a great idea. I'd mistakenly thought that the lens had a manual aperture ring. A real pain these days when they're controlled by electronics in the camera.

The download finished, now attempting the larger one, M63. Goodness knows what that will uncompress to in size. 

Cheers for now. 

Ray 

66.5GB ;-).

That 8TB drive ain't gonna last long!

Actually after thinking about it you're not wrong. It will at least double in size after calibration, unless you delete the light frames afterwards. So that would be in the order of 1/8th of a TB minimum. That's a maximum of sixty four similar images, that's insane. A couple of decades ago, terabyte drives were really only needed by large corporations. Thank goodness the prices have tumbled since. 

Well they double in size when you go from FITS to XISF in Pixinsight.

I have just done a trial process on the R subs. Need to repeat as it turned out I have the wrong Flat :-(.

There were 5.57GB of raw FITS, 1.36GB of which I rejected because of cloud or poor centring. Processed the remaining 4.21 GB with WBPP (to have a look see) and ended up with a folder of 31.1GB with all the intermediate files. 25.5GB new processed files - say a factor of 5.

So yeah, we are going to have to have a fairly ruthless deletion strategy. If I get the same rejection rate of raw subs and then expansion on processing. I will end up with 130+GB files for that one image. So your 8TB will give you perhaps 60 frames. Our queue is already a third of that!

By the way, I don't know what I clicked on when I asked for the properties, but the unpacked raw data is 22GB, not whatever crazy number I said.

Richard, your datasetset #94 will be available to download later on today
it's uploading to the temp folder as we speak