Having got an adapter modified to mount a filter, last night looked promising so I set up and had a crack at some data covering the Lagoon and Trifid nebulae. I still need to tweak my sensor spacing but aside from that I am pretty happy with how the setup performs now.
38 X 5 min shots using an Evostar 72mm scope with 0.85 reducer/corrector and the ASI294MC Pro camera. Integrated in Astro Pixel Processor and a bit of a polish in Photoshop. More data to come if I get another clear night. I think with nebulosity going out of the frame I might have to do a 2 panel mosaic here if time and weather permit.
Last edited by The_bluester; 01-08-2019 at 08:22 PM.
Took me a bit of figuring as to why they look so different. Rowland's and mine are flipped vertically with respect to each other, maybe Rowland has a diagonal in the imaging train? Mine is all straight through with a refractor.
Mine looses a bit in the compression too, even the full size jpg version looks a lot crisper let alone the uncompressed tif. I have never really liked the 200kb file size thing for that reason, I have not got the knack of getting the files under that limit without them loosing a lot. I will pop it on Astrobin when I get home and link that. I did not have a chance to do it this morning, this is literally from data that I was still shooting at 10:30 last night. As things turned out I should have left it run as I could have got about another 30 subs before the roof of the house or clouds stopped it.
The processing program flipped my image and I meant to flip it back -but didn't.
I took a screenshot of a section which generates a good likeness of the original with a small file size. convert png to jpg at 89% compression in ImageMagick display.
I thought IIS would spoil it. But it did OK. Not sure if that helps.
Thanks, I am pretty happy with it for an initial crack with a change to the imaging train, yours looks to show more faint nebulosity, I might try stretching it a bit harder. I am in the middle of shooting flats now as I had no chance to last night so I will do another version with all the best subs I have (45 now not 38) and see how that goes.
Size reduction wise I am just using the old "Save for web" in Photoshop.
I am thinking of doing another panel above it if the weather permits. I am interested to see how far the emission area extends that goes off the top of the image as it is framed.
A certain amount of luminosity is recovered with the AutoDev and Heal modules in StarTools. But I use my own processes to create master frames for small image sets and use these in Siril. With lots of data I do all processing Siril.
My image had a lot of read noise. Heal lifts the pixel values to that of surrounding pixels which tends to expose otherwise lost detail. OK for wide field.
That is one thing that the cams like my ASI294 seem to be good for, low read noise. I can see some noise in the dark areas sub by sub if I zoom right in and examine sub after sub but it averages down quite nicely. It is certainly a lot less noise than seems to be common in a lot of CCD subs I have seen but they generally have the advantage of being able to use longer exposures to increase the SNR. I am yet to experiment with longer subs again now that I know I was loosing a lot of good information to UV-IR issues. Fitting that filter has improved everything from background brightness to automated focus quality. It would be nice with an OSC if you could tell SGP to focus using the green channel only to get the best average position not impacted by chromatic error in the case of cheaper APO (Arguably) scopes like mine.
I am hoping to use it to start a mosaic to put it all in context. A panel above to capture the nebulosity that is going off image, and two to the left as it is shown here to include a bit of the milky way. The weather has to cooperate for that though.
So, time and weather have prevented me getting the data I wanted, so I did a three panel mosaic around the area to capture the nebulosity that was headed out of frame top and bottom.
This one has been quite fun to do. Hopefully next year I can make a bit 9 panel job of it to put it more in context, but my current processing PC would melt!
