M33 Triangulum - 100% PixInsight processing.

[VPR]

Hi to all and hope everyone is staying safe,

In the past, I was never satisfied with color processing done in PixInsight . To troubleshoot, decided to change the steps in PI to see if that made a difference.

This image is processed entirely in PI (with different steps). No other software was used even for finishing work. Resampling the image at 18% for posting was not the best ..... but oh well.

Data was gathered in the backyard – Bortle 8 here in Irvine, CA.
- TEC140 (980mm FL) with separate guide scope (500mm FL – PHD2 with SSG) - riding on a G11 Losmandy.
- ZWO 1600MC OSC camera (had the wrong offset and ch balance settings in SharpCap – thought this was causing poor color).
- 20sec subs, 576 total (54 bad subs) = 2.9hrs of 20s integration.
- 30sec subs, 893 total (125 bad subs) = 6.4hrs of 30s integration.
- Therefore total integration time = 9.3hrs on the 1600MC at -20deg.
- SharpCap Pro / 30 flats / 30 darks.

My conclusion is that the Scope is good, Camera is good, SharpCap is good .... but my PI processing was NOT good. Changing PI processing steps made all the difference for color . Being able to do all the work in PixInsight is a bonus.

Hope this helps anyone having similar concern .... will be happy to answer any questions.
V.P

[Menno555]

Nice detailed capture!
Only a bit too dark? I do not know PI but I think that if you have it bit less dark, there will be even more details visible.

Menno

[VPR]

Hi Menno,

Good observation. I think I know where the problem is – wrong offset was in use during data collection. When I collected the data the offset was 5 (SharpCap calls it ‘Brightness’ for ZWO cameras! ). Subsequent tests have shown this needs to be much higher for the gain and temp used.

I have currently set this to 50 (as long as the gain is < 139 @ -20deg). Just starting to image with the new settings. At least I don’t need to worry about color when using PixInsight.

A little late to the party ..... but oh well .

V.P

[Menno555]

Ah yes. Over here I use actually only 2 values for Brightness with my Zwo: for short exposures like 30 seconds indeed 50 and for longer exposures like >180 sec I use 5. This with a Gain of <150.
But with processing a lot of things can be "saved". In Photoshop I can get a lot of things back with Curves. I know PI has that too, don't know how it works there though.

Menno