M51 'The Question Mark Galaxy', 2019-03-24 Manche France

[The Thing]

The daft name was the one N.I.N.A's object browser put into the Sequence name, I had searched for M51, as ya do... I thoroughly recommend N.I.N.A. as a capture app. I am using Version 1.8 RC006.

22 x 250s Gain 120 Offset 4 Temp -15c, 10x5.8s Flats, 10 Dark Flats, 10 Darks, 0 Bias

This seems to be the recipe for success with my camera. I again used SharpCap Pro Smart Histogram feature to work out the exposure and it looks like it was spot on. It suggested 70 subs but I only got 27 subs before the Moon started to rise and it turned out the camera hadn't cooled for the first 5 so I left them out of the stack.

The sky wasn't ideal last night but not bad, streetlights were on for 80% of the subs (23:00 they go off). Guiding was very good, less than 1". The post-processing in Star Tools has made the background of the image a bit dark for my taste, but you can still see loads of tiny weeny galaxies in between the stars. A satellite trail survived as well, one of many in the short session, a very busy portion of the sky.


Telescope aperture and focal ratio:   TS1506UNC f4, TS Komakorr
Camera and filters used:   ZWO ASI294MC Pro, Baader Neodymnium 1.25" filter
Processing applied:   DSS 4.x, Startools
Filesize:   1425 KiB
Date added:   Mar 25, 2019
Dimensions:   3954 x 2632 pixels


Click for the full size image, I've only trimmed 90px off each side to cover stacking artifacts.

[ApophisAstros]

it turned out the camera hadn't cooled for the first 5 so I left them out of the stack.

That couldn't happen in APT as it warns you the camera isn't cooled to the right temp when you start a plan.
Still come out great though , nice one.
Surely its M51 the whirlpool galaxy though?
Messier 52 (M52) is a bright open cluster located in the northern constellation Cassiopeia.
Roger

[The Thing]

Well spotted! M51. Brain storm due to getting a decent image at last.

You can turn that on in APT, or off. Someone on NINAs forum brought up the cooling issue today as it happens so a check may be added sometime soon.

[Carole]

That's come out well, but as you say the background a little dark.  Never used Star tools so not sure why it has done this, do you not have control over what happens with star tools or is is just scripts?

Carole

[The Thing]

Thanks Carole and Roger.

StarTools needs a different mindset and I'm not sure how to exert fine control in some of the tools. I know it can be done as as I've seen some excellent results. Must try harder or stick to one bit of software...

[JohnP]

Very nice Duncan. Loving all the feint background galaxies. Nicely processed - just hint of a few gradients particularly across bottom and a little top right but the full size image looks great.

Congrats & well done on the capture,  John

[The Thing]

Thanks John.

Star Tools Wipe function isn't the greatest, sometimes it works perfectly and sometimes not, I'm just using ST as a quick and dirty tool with a lack of understanding on my part. Now I'm getting good data I'll use the longer more involved PixInsight route.

[JohnP]

Well I have to say your processing & acquisition skills have certainly improved loads over last years - you are making the most of your dark skies (at least after 11pm) - posting some great pics.  John

[Carole]

Interesting to note, that even with OSC, you seem to get colour fringing on one side of the stars, particularly in red.  I get similar (sometimes) with my mono camera and it makes processing quite difficult at times. 

Do you have an explanation for this? Is it down to the telescope?

This is not a criticism, just an observation and something I am curious about.

Carole

[The Thing]

Interesting to note, that even with OSC, you seem to get colour fringing on one side of the stars,

Do you have an explanation for this? Is it down to the telescope?

Carole

Mark posted something recently about this, he has noticed it with his Tak.  I recall he came to the conclusion from the way it affects stars in different parts of the image that it's atmospheric dispersion of the different wavelengths. If I was a glutton for punishment I might try my ADCorrector on deep sky images :} Star Tools has a star fixing tool which can overcome this, basically by generating replacement stars. A bit much really. I think if I had software binned the image it might have ameliorated the effect.

[RobertM]

Nice one Duncan !  It looks like you have tamed the beast from the east.  I think Mark is right about dispersion but you'd need to compare images from different elevations to prove it.

It looks like you have a satellite trail through one of those subs, stacking has removed most of it but there's still a faint line there.

So many faint galaxies...

Robert

[The Thing]

 Thanks Robert.

Dark skies are a treat and this weather certainly helps. I moan about the street lights but we only have 5 within a mile of us  .

[NoelC]

Great stuff, look at all those galaxies!

Well done Duncan.
Noel

[MarkS]

Nicely done Duncan!

I've never heard it called the Question Mark.

Mark

[The Thing]

Well, we all question Mark when we have imaging issues! At last I'm getting colour in my colour pictures... I'm trying to do the Hercules Galaxy Cluster at the moment but more data required and its looking a bit green ;/