Lee_P

Star trails around the North Celestial Pole. Taken from Bristol city centre, with no light pollution filter. The brightest line is Polaris -- close to the North Celestial Pole, but as this telescope view shows, not directly over it. * 21 April 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G (turned off after initial slewing) * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 180 x 120 seconds ------------------------------------------------------------ Total integration time: 6 hours ------------------------------------------------------------ By Lee Pullen

Thanks, I guess the FRA400's larger aperture helps.

Just updating this thread with some more example photos... * January 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Software: AutoStakkert!3, RegiStax 6, Lightroom, Photoshop * ASIAIR PRO * 500 frames --- The Soul Nebula * January 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight and Lightroom * ASIAIR PRO * 72 x 300 seconds Total integration time: 6 hours --- The Pacman Nebula * Jan - Feb 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight and Lightroom * ASIAIR PRO * 90 x 300 seconds Total integration time: 7 hours 30 minutes --- The Orion Nebula * February 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight and Lightroom * ASIAIR PRO * 89 x 300 seconds Total integration time: 7 hours 25 minutes --- The Pinwheel Galaxy and Friends * March 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: IDAS D1 Light Pollution Suppression * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 600 x 120 seconds Total integration time: 20 hours --- Nova Cas 2021 * 20 March 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 15 x 120 seconds Total integration time: 30 minutes --- M3 * March and April 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 300 x 120 seconds Total integration time: 10 hours --- Vesta * 29 March - 2 April 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom, ezgif.com * ASIAIR PRO --- Markarian's Chain * April 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 300 x 120 seconds Total integration time: 10 hours --- The Iris Nebula * April 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom * ASIAIR PRO * 615 x 120 seconds Total integration time: 20.5 hours

Sure! AF EXP: 2s for no filter / light pollution filter. 5s if I'm using the L-eXtreme. Step Size: 30 Autorun settings: every 1H, before Autorun start, after Auto Meridian flipped. For the more general settings... Fine (Slow) Step: 10 Coarse (Fine) Step: 30 Max Step Limit: 60000 Backlash: 0 Is that all the info you're after?

Sorry for what's probably a dumb question, but I tried setting DrizzlerIntegration to 1.5 today, but couldn't. The scale option only allows for integers. What am I doing wrong?

Congrats, can't wait to see what you do with it 😃

Thanks, that's really interesting. For future images I'll try 1.5 drizzle -- maybe that's a sweet spot.

Sure, I've uploaded a non-drizzled version: https://drive.google.com/drive/folders/1wB3May69oEWniF8hikueUkSS-TJvjMKC I'd be interested to hear your thoughts on the difference. My no doubt overly-simplistic reasoning was that a drizzled version would give me the option of a closer crop on the galaxy.

Thanks, this is really useful. Arcsinh stretch is a new one to me, I'll research it further 😃

That's absolute gold, thank you so much!

Thanks, that's all very helpful! I think I'm falling down with the DBE step; I can't get it to look quite as good as you or Dave have. I'd be very grateful if you could maybe post a screenshot of how you did DBE?

Thanks, this is a great help! Can I ask exactly how you removed the light pollution? Did you use DBE, and if so, what were your settings?

Hi SGLers, I’m hoping a PixInsight guru can help me. I’m a PI beginner, but am having fun learning. My question is about the level of noise in my images. After integrating and performing an STF stretch, the resulting image always looks quite smooth. But it doesn’t take long at all – just a DBE really, maybe then a gentle stretch – for the image to become really noisy. And then a lot of my editing is centred on battling that noise. My camera is an ASI2600MC-Pro, which I cool to -10. For a recent experiment, I gathered 20 hours of data from 120s subs. With that much integration time, and the low-noise camera, I was hoping for lower noise than I actually got. (I am shooting from Bortle 8, however). So my question is: are my expectations wrong, and actually the amount of noise I have is what’s to be expected? Or, have I messed something up in pre-processing or integration? In case it’s useful, I ran SCRIPT -> ImageAnalysis -> Noise Evaluation on the image straight out of integration and got the following: Ch | noise | count(%) | layers | ---+-----------+-----------+--------+ 0 | 2.626e-01 | 18.39 | 4 | 1 | 1.037e-01 | 12.01 | 4 | 2 | 1.636e-01 | 11.10 | 4 | ---+-----------+-----------+--------+ I’ve also uploaded the file (1.16Gb) for anyone kind enough to help investigate further: https://drive.google.com/drive/folders/1wB3May69oEWniF8hikueUkSS-TJvjMKC?usp=sharing Thanks! -Lee

Thanks for the heads-up, there was a brief gap in the clouds last night and I think I got it!

I started processing your data, but early on ascertained what the issue is. I took all your Light frames and ran them through PixInsight’s SubFrameSelector tool. This is a way of measuring the quality of Lights. Each Light was given a FWHM measurement: the lower the number, the better quality of the Light. That flagged up the problem. Your 18 Feb data is very good quality, but most of what you obtained on the other nights is much lower in quality, and would likely only serve to degrade your final stacked image. I think this screenshot shows what I’m talking about quite clearly: Your 18 Feb Lights are excellent, so your kit and skills are capable of it. I think you had low-level cloud on the other nights, which would explain the readings. So, the reason I didn’t continue editing your data is that my next step would have been to axe any Lights that didn’t make the grade, which would be almost everything taken after 18 Feb. Meaning I’d have been left editing the original data! I hope that makes sense and is helpful. Aim for four or more hours of data as good as your 18 Feb efforts and you’ll be able to produce a stunning image As an additional note for the future, I recommend trying to organise your data in a simpler way. My preference would be to have one folder containing all the Lights (all with the same ISO and exposure length); one set of Bias frames; one set of Dark frames; one set of Flat frames. I appreciate that this works well for me because I’m using a cooled astrocam, which makes using matching calibration frames easier. Let me know if I can help further or if you'd like me to elaborate on any of the points -Lee

Great video, thanks for making it

Okey dokey, just let me know when they're all uploaded

I'll have another crack at it. I'd like to do the stacking as well though, from the original light frames. Could you upload all of those, as you did with your first attempt?

That's tough... I think I prefer the original, sharper versions. The details just seem more defined. But the noise in your latest HOS is masked well. 🤔

Those are great! I always like seeing images taken from light polluted skies -- it's amazing how much data can still be pulled out. I've actually just finished the Rosette from my own Bortle 8 location, using Skipper Billy's old Orion Sirius EQ-G mount 😁 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * 450 x 120 seconds (total 15 hours)

I could have been clearer in my comment, but I was referring to the development of dual and tri-band filters. I image from a city. Back when I was using mono that was really the only sensible choice. But now OSC (plus filter) is a valid option -- it's what I'm using and am getting what I consider to be very satisfactory results. Hence, the gap between mono and OSC has narrowed recently, thanks to filters like the L-eXtreme.

Here's another photo with the Askar FRA400, ASI2600MC-Pro, and Optolong L-eXtreme. This is proving to be a great combination even from my light-polluted city centre. * February 2021 * Bristol, UK (Bortle 8 ) * Telescope: Askar FRA400 f/5.6 Quintuplet APO Astrograph * Camera: ZWO ASI 2600MC-PRO * Filter: Optolong L-eXtreme * Mount: Orion Sirius EQ-G * Guide: William Optics 32mm; ZWO ASI 120MM Mini * Software: PixInsight, Photoshop, Lightroom, Topaz DeNoise AI * 450 x 12 seconds ------------------------------------------------------------ Total integration time: 15 hours

Dithering is a good shout, if you're able to. Ideally all your exposure lengths should be the same, so maybe you want to start again with longer lights. The exposure time for your darks should match your lights. If you take a good set of flat frames then they should be good to calibrate lights taken over imaging sessions spanning multiple nights, especially if you can keep your camera attached to the telescope (i.e. not shifting the dust around, or changing the camera's orientation).

Hi from a fellow Bortle 8 imager! I’m learning PixInsight, so used that to have a crack at your data. I teased out more detail in the spiral arms, but there’s a lot of noise. I could have smoothed that out a bit, but left it in as it might help you to see it. Basically, you need to improve the signal to noise ratio by taking many more lights, and maybe using a light-pollution filter as well. Adding in flats would help with the editing too. A more experienced imager would be able to do more with your current data, but I think the key message – more data needed – would still stand 😊 -Lee

Congrats, this is great! Really impressive for just an hour as well. Focussing is tough, especially using a filter like the L-eXtreme. If you've got the cash spare, I really recommend looking into an electronic autofocusser -- great for getting perfect initial focus, and also for automatic adjustments over a night when focus shifts due to temperature changes.