M81 and M82 -- Bortle 8, OSC

[Lee_P]

20 hours of integration time on this. I probably should have nabbed some L-Ultimate data too, given how much h-alpha there is! Details under the image, and more info -- including comparing this Askar 130PHQ data with a previous attempt using an Askar FRA400 -- on my website.

* April 2023 (2 weeks)
* Bristol, UK (Bortle 8 )
* Telescope: Askar 130PHQ Flatfield Astrograph
* Camera: ZWO ASI 2600MC-PRO
* Mount: Sky-Watcher EQ6-R PRO
* Guide: William Optics 50mm Guidescope with 1.25″ RotoLock; ZWO ASI 120MM Mini
* Control: ASIAIR Plus
* Software: PixInsight, Lightroom
* Filters:
– No filter 600 x 120 seconds (20 hours)

Total integration time: 20 hours

By Lee Pullen

[tomato]

Nice result, is there a hint of IFN in there? I guess it will be hard to capture from a Bortle 8 location, even with 20 hrs integration.

[Lee_P]

4 hours ago, tomato said:

Nice result, is there a hint of IFN in there? I guess it will be hard to capture from a Bortle 8 location, even with 20 hrs integration.

Ha, I wish I'd caught some IFN! One day... 

[fullmoon]

Amazing photo!

[ONIKKINEN]

You definitely have some IFN!

The lower part will look like it connects to M81 as an extra spiral arm if given more time. But that might require a really unhealthy dedication to one image from Bortle 8. But still, IFN is IFN and you absolutely do have it here which is an accomplishment on its own from inner city conditions.

[Lee_P]

7 hours ago, ONIKKINEN said:

You definitely have some IFN!

The lower part will look like it connects to M81 as an extra spiral arm if given more time. But that might require a really unhealthy dedication to one image from Bortle 8. But still, IFN is IFN and you absolutely do have it here which is an accomplishment on its own from inner city conditions.

Oh wow, thanks ever so much. Looks like @tomato was right! I kinda assumed I'd never be able to capture that from my location.

[tomato]

IFN from a Bortle 8 location, that’s entertainment.👍

[imakebeer]

Fantastic image @Lee_P 👍

By coincidence I just posted yesterday my latest M81 / M82 pic, taken from a Bortle 5 area.

I'm pleased with the progress I'm making but I'm still some way behind your effort.

Can some of you experts help explain where the differences are coming from, and what changes might deliver the most bang for buck? E.g.

Integration time: 20hrs vs. 2.5hrs. This I can fix for free, with a bit of dedication on my part and maybe a bit of luck with clear skies.

Camera: ZWO ASI 2600MC-PRO vs. modified Canon 450D. I think both are OSC (right?). The ZWO has a slightly bigger sensor but not than double the pixels, and small pixels at that. But does this mean a big difference in images vs. the difference in cost?

Scope: Large diameter ED refractor vs. low cost reflector (SW150PDS in my case)? Again, there's a big difference in cost but does this necessarily translate into a big difference in images quality?

Post processing: I can practice for free. And Siril and GIMP certainly don't seem bad for free software, but maybe paid for software like PI and the various xXterminator tools offer that little bit more???

Thanks in advance for any tips you guys can offer 👍🔭

[tooth_dr]

Dont really want to clog up Lees thread on this, but here is my view on it.  PS also I am not an expert, but have some experience under my belt to give my opinion

 

1 hour ago, imakebeer said:

ZWO ASI 2600MC-PRO vs. modified Canon 450D

I have the 2600MC now but I used to shoot with a DSLR some time ago.   Unfortunately the comparison stops at the them both being OSC.  The cooling, the lower read noise, different architecture of chip design, better technology, better sensor, etc, make the 2600MC just an absolutely brilliant camera and a significant improvement over any DSLR.   You can still get a decent image with the DSLR, it will just require a lot more integration time and a heavy handed processing approach.  In the summer when the temps are warmer, you will also find a lot more noise in your subs.  But I think the two sensors are the same size, both crop size APS-C sensors?

 

57 minutes ago, imakebeer said:

Large diameter ED refractor vs. low cost reflector (SW150PDS in my case

I image with both a good quality refractor and a low cost reflector (SW250PX) depending on the time of year.  Bang for buck the reflectors are brilliant.  Sometimes the coma correctors/flatteners used with reflectors can introduce abherrations, and I find the stars are just that bit nicer in a refractor versus a reflector.

 

1 hour ago, imakebeer said:

Post processing:

I use Astro Pixel Process and Photoshop and PI.  I used to use DSS which is free for stacking.  I could never get onto GIMP.  The tools such as BXT and NXT are very useful, and I feel worth paying.  Do the free trials and see if they are worth it, that's free.

 

43 minutes ago, imakebeer said:

Integration time: 20hrs vs. 2.5hrs.

There are some many factors that influence required integration time, not least your own personal preference on how much time to dedicate to one target.  I'm in a darkish site, so I aim for 8 hours per target.  However it's often more like 25 hours.

 

 

[Lee_P]

3 hours ago, imakebeer said:

Fantastic image @Lee_P 👍

By coincidence I just posted yesterday my latest M81 / M82 pic, taken from a Bortle 5 area.

I'm pleased with the progress I'm making but I'm still some way behind your effort.

Can some of you experts help explain where the differences are coming from, and what changes might deliver the most bang for buck? E.g.

Integration time: 20hrs vs. 2.5hrs. This I can fix for free, with a bit of dedication on my part and maybe a bit of luck with clear skies.

Camera: ZWO ASI 2600MC-PRO vs. modified Canon 450D. I think both are OSC (right?). The ZWO has a slightly bigger sensor but not than double the pixels, and small pixels at that. But does this mean a big difference in images vs. the difference in cost?

Scope: Large diameter ED refractor vs. low cost reflector (SW150PDS in my case)? Again, there's a big difference in cost but does this necessarily translate into a big difference in images quality?

Post processing: I can practice for free. And Siril and GIMP certainly don't seem bad for free software, but maybe paid for software like PI and the various xXterminator tools offer that little bit more???

Thanks in advance for any tips you guys can offer 👍🔭

I agree with everything @tooth_dr said.

A cooled astrocam (OSC or mono) will be a big step up from a DSLR. I you want to splash some cash, that’s where I’d be looking. Your telescope is good, no need to change that.

Longer integration times will give you much better data to work with. I’ve written an article with tips about how to get long integration times. It’s not just about dedication and being lucky with the weather; there are kit choices that help. For example, having a cooled camera means you can use a library of calibration frames, which makes things much easier. An electronic autofocusser will keep you in focus all night long. And I’m not sure how you’re controlling your system, but a method of remote automation (I use an ASIAIR Plus) is highly recommended. If I can be forgiven for plugging another of my articles, you might like this one about top upgrades.

As for post-processing, this is as important as all the data acquisition that comes before it. I really like PixInsight and can recommend it, but everyone is different and some pieces of software “click” with people more than others. So, give it a fair try but if you hate it then don’t feel you need to stick with it.

The image you posted is very respectable and shows you’ve got a good grasp on the fundamentals. I don’t think you’re far off taking it to the next league!

[imakebeer]

Thanks for the tips @tooth_dr and @Lee_P , much appreciated.

I understand what you're saying about the benefits of a cooled astrocam w.r.t. noise - it's obvious now you say it!

I have more software on the list to trial, just need to find a relatively clear stretch when I can play before I press "go" on a 30 day trial.

[ONIKKINEN]

8 minutes ago, imakebeer said:

Thanks for the tips @tooth_dr and @Lee_P , much appreciated.

I understand what you're saying about the benefits of a cooled astrocam w.r.t. noise - it's obvious now you say it!

I have more software on the list to trial, just need to find a relatively clear stretch when I can play before I press "go" on a 30 day trial.

 

Honestly, Siril goes really far on its own. My 2 cents would be to stick with it + Gimp for now. Or maybe consider subscribing to Photoshop. At 12€/month its an absolute steal of a bargain and will take you more than 2 years to become "more expensive" than PixInsight which i think you might not be able to use efficiently at the moment as its quite challenging to use although here i inject my own bias in to the mix as i learned to use other tools before PI. Photoshop has many included plugins that are easy to use and can work well with astrophotos (like Camera raw, Smart sharpen, Unsharp mask, noise reduction, lightroom etc).

Siril has an amazing background extraction tool, simple and effective Photometric color calibration tool and easy to use stretching tools with a simple interface where you actually see what you are doing while you are doing it (as opposed to PixInsight). The newest version can also do non-blind deconvolution which will sharpen your images if there is anything to sharpen while attempting to not boost noise. You can also link Starnet++V2 to it and run it on linear images to create a starless and a stars only image to play with further in Gimp or Photoshop should you choose to do that.

I would say get to the bottom of the basic workflow: which includes well calibrated data, well stacked data with obvious outliers removed using the "plot" tab in Siril, background extraction, colour calibration and stretch. All are very easy to do in Siril and result in an "almost done" image!