WBPP Bonus - 04Dec22 - Processing Flaming Star IC401

Roger Smith

Hi Adam,

No problem here, but just commenting that CMOS cameras have low read noise vs CCD, and it is being advised to take shorter subs, and more of them. In the IC401 data set the subs are only 120sec. Your processing in the captioned video took more than 24 hours to process the 700+ lights. Thank you for uploading only 481 lights to the FastTrack Data.

I went out yesterday and upgraded my laptop to 32GB ram. I copied almost all my other data off my 1TB SDD to an external HDD (took 2 hours) just to be able process IC401. I have to wait until I come home from work tomorrow to start the processing as it says it will take 16 hours (with only the 481 subs). Start at 6pm, finish at 10am. No that does not work!  If I choose interactive for Local Normalization, I may have to get up at 2am to do it. So I unticked it. As you can see there is a huge penalty for this data set. My camera is also ASI2600MC. So I would do this object differently:

In the header for lights it says the image capture (SWCREATE) was SharpCap. I assume then that SharpCap was used. That program has live stacking as well as single frame capturing. So if SharpCap were set up to livestack 10 x 60S subs, then save, the total number of files to process in PI would be 120/600= 1/5th. That reduction will save a huge amount to time to process, and the saved data will be reduced also. 

To do a 20x30S livestack the imaging setup guiding must be good enough for 600seconds without trailing, etc. Anyone doing narrowband should be able to have good tracking for 600S.  Sharpcap has dithering, with pause, and works well with PHD2. 

I have finished imaging with SharpCap of M31 using 20x30S = 600sec livestack subs. I have 58 subs. I am still processing it. My observation is that one 20x30S livestack sub is considerably less noisy than when I previously imaged M31 with normal 600S subs (different camera).. Also the livestack stars are sharper.  I have not completed my comparison as I am still processing. I am going to start over now that we have SPCC. I wish Juan and team would take a long holiday!

If the new M31 looks good, then I plan to set up (via sequence planner) SharpCap to take one 20x30S livestack followed immediately by 1 x 600S sub. Then dither. Repeat all for total 50 subs each. Process the two groups separately and compare. I do not know what object I will do, and it is not easy to get 10 hours data due to weather, pollution and humidity/fog.

I really appreciate that you keep on top of PI developments, and provide us with the latest updates. Other mainstream software, such as Photoshop do not update as often as PI. I think PS is too busy promoting and making big money, rather than upgrading. Certainly no one has as comprehensive tutorial or as technical tutorial as your Adam Block Studios. Thank you!

Roger

BlockHead

Hi Roger,

Thanks for all of the commentary. 

-the Blockhead

Roger Smith

HI Adam,

This was a very generous data set for us to process through WBPP. Thanks for your good connections. I like your new cursor that is easy to follow.

In the Bonus WBPP the most revealing thing to me was your comparison of the 180 images master and the 700 images master. I was expecting to see more faint stars in the 700 master, but they appeared the same. So the additional images results in primarily a noise reduction. Of course the less noisy image can process fainter nebula more aggressively as there us much less noise to be amplified. It is a tradeoff depending on the depth of the nebulosity you want to bring out.

My full processing of (only) 481 subs took 13 hours, whereas PI predicted to take 16 hours. My astrometric solution failed. I need to check that out and study (again) if I should do registration and integration again. 

Roger

BlockHead

Yes, that is a good observation and you are absolutely correct. 

People should look closely at the difference... more exposures usually means better S/N .. .not increased faint limits in a visual way. Faint stars (and nebula) will have better S/N... they are present- albeit noisy... even in a single image. 

-the Blockhead