M104 - The Sombrero

[Dave882]

I made an attempt at m104 on Saturday night but the seeing was soo bad (round stars but guiding consistently around 1”) I just couldn’t do it justice. Last night was a different story- with good guiding around 0.4-0.5 all night. The detail just popped and who knew there were so many tiny fuzzies in the background!

Refocused half way through but the re-framing was off so had to do a crop. Attached is the small cropped and rotated version.

C14 / eq8
Asi2600mc no filter
OAG & asi290mm
90x2min subs
ASIAIR PRO / AAP

Here the bigger one too (https://1drv.ms/u/s!ArpSiLT3VkGHiPIxoek-NjXp2z8E3w?e=P4W7fG)

[Anth10]

Super shot Dave!

[Stephane]

Superb! I'm seriously considering getting that camera, and your images aren't helping to dissuade me! Well done.

[AdamJL]

Oh wow, that's amazing. The large version blows me away. So much detail!

[PKay]

A very nice hat Dave.

Well done :thumbsup:

[Dave882]

Thanks folks very much appreciate the comments.

The c14 /2600mc combo presents quite a challenge but when the conditions and mount are agreeable it has the capability to give quite incredible detail. Basically I’ve worked out I need to be guiding at or below 0.45 rms to get a tidy image. I’m still learning the image processing side of things but have found APP to be extremely user friendly and quite powerful to fix my major problem: gradients from light pollution and poor calibration files. It doesn’t have the additional processing available in startools and PI but I’ve found this is a good start for me (2weeks into my trial) and I’m pulling out far less hair.

[Graman]

That is an amazing shot...so much depth and detail! Well done...

I can never forget the first time I glimpsed at M104 around this time last year from Bortle 2 skies near Hunter Valley. Just my 8 inch SCT, but could make out the centre laneway clearly.

Was totally blown away by the fact that the exact photon that was hitting my retina on that night left the galaxy over ~30 million years ago...

30 freaking Million years ago...:eyepop: our human race hadn't even evolved back then...

GR

[Dave882]

Thanks GR. I know the feeling!! And that’s why I still love getting the eyepieces out when I can get somewhere dark. There’s just something about seeing these ancient beauties with the naked eye… but I have to admit that from the suburbs it’s usually through a camera these days. Cheers

[Nikolas]

Lovely shot!!

[Dave882]

Thanks Nik

[Startrek]

That’s a super Sombrero from your Bortle 7 location
In regard to imaging galaxies, I reckon with enough data and good seeing the 2600MC gives mono cameras a run for their money
Well done !!
Martin

[AstroViking]

What everyone else has said - lovely work.

I'm very tempted to go back and have another shot at it now.

[ahmed_haider]

David that is just amazing! This one of the few objects that look 3 dimensional in good images, and your image is one of the best i've seen! Bravo mate!

[gb44]

Certainly a magnificent piece of work. The tips are appreciated as my attempts have been failures.
Why no filter? I used to know this....

[Dave882]

Thanks Ahmed & Glenn- much appreciated. Yes, the Sombrero is a beautiful target and I agree has that 3d appearance once the dust lanes are resolved. That’s the hard part I guess, getting a good night of seeing and getting the guiding good enough to squeeze the best resolution out of the scope. Bear in mind I’m imaging at just over 0.3”/pixel, but when guiding or sky conditions are not ideal I don’t get anywhere near that resolution.

The asi2600mc has a built in uv/ir filter in the sensor window hence no need to add another filter to the mix. If you’re camera doesn’t have this then it’s usually advised to use one in the image train. The best results for galaxies are always in dark sky and no filter, although in my case in the suburbs I’ll settle for a moonless night!

[Stephane]

Hi David, you might consider binning 2x2. Binning improves your signal to noise ratio at the cost of resolution. However, if after binning you’re resolution is still less than half of your seeing, you haven’t actually sacrificed any resolution.

Either way, this image is superb!

[Dave882]

Thanks Stephane- yes this is something I’m in the process of trialling to see what works best. The complicated thing is that the data changes with the sky conditions / guiding so it’s hard to make a hard and fast rule. I’ve received some recommendations to bin between 1.5-3x in post processing depending on the data. According to astronomy.tools the ideal pixel size for Good Seeing (1-2" FWHM) seeing is: 0.33 - 1" / pixel, so not far off at all. I’m interested as to how you decide or do you just do the same thing every time?

For example the last 2 nights I’ve been playing round with the c14 at native f11 fl3900: Monday was some of the best guiding I’ve ever done averaging between 0.35-0.45rms. And then last night it was double that! Obviously the detail will be different.

I might do a side-by-side comparison of this m104 and see what happens…
Cheers

[gb44]

That multistar guiding in PhD2 is also of big assistance, but in my case it doesnt always activate. Its frustrating as I dont know why that happens.
GlennB

[Stephane]

Dave, I’m certainly no expert and some folk here can give some much better advice on this topic. From what I’ve read though, you need to consider the seeing for the night in question. If your resolution is at a third of seeing, then bin 1.5; if your resolution is a quarter or less, then bin 2.

If you’re worried about binning and following nights having excellent seeing conditions where you wouldn’t wish to bin, you could either consider not binning at all, or you could set up multiple targets that you image depending on your seeing.

I think at 0.3 though you could definitely consider binning even under excellent seeing. Binning 1.5 will take your resolution to 0.45. So seeing would have to be better than 0.9ish to even start losing out on resolution.

Resolution is a fascinating topic, and I too would be interested to hear what others might have to say as I am still new to this hobby. For example, does deconvolution really “undo” some of the blur from seeing? What effect could that potentially have on decisions to bin?

[Startrek]

Stephane,
I software Bin using Startools, keeps it simple
And use Deconvolution if necessary

Refer to the links if your interested

https://www.startools.org/modules/bin
https://www.startools.org/modules/sv-decon

Using Ascom to drive the 2600MC doesn’t give you a hardware binning option, default is Bin 1

Cheers
Martin

[Stephane]

Martin, thanks for passing on those links. Binning during the processing phase is quite a nice feature by Startools.

[ahmed_haider]

Hi David,
Just a random question......do you have the hyperstar for your C14?
I'm planning to get the starizona nexus for my own F4 newtonian soon.....well as soon as I can cough up ~750AUD for it :)
Ahmed

[RDB]

hi
The Sombrero Galaxy is a favourite of mine..you have captured it very well.
Cheers
Ron:)

[Dave882]

Thanks very much Ron. Yes a very nice target indeed!

Hi Ahmed- yeh I’ve got a Hyperstar but to tell you the truth I actually prefer things at longer fl and seeing all that juicy detail! I use the Hyperstar for some fun with targets that need a wider fov so quite handy to have still.