Another NGC 2460

[tomato]

Images of this galaxy are like buses, you don't see one for ages then two turn up one after another.😉

My current target doesn't currently rise above the murk until around 11 pm so when I saw @wimvb's excellent wide and deep image of this target I realised it is well placed from my location to image in the early part of the night.

This is 8.47 hrs made up of 123x 2mins Lum with the Esprit 150/ASI178, and 131 x 2mins with the Esprit 150/ASI678c, down sampled x2 then processed in PI and Affinity photo.

You can see why Wim put 30 hrs in on this one, 8.5 hrs shows the extensive spiral arms, but only just. I'll try and take this one out to 20 hrs+ as an interesting comparison.

Edited March 2 by tomato
Typo corrected

[geeklee]

33 minutes ago, tomato said:

You can see why Wim put 30 hrs in on this one, 8.5 hrs shows the extensive spiral arms, but only just. I'll try and take this one out to 20 hrs+ as an interesting comparison.

It's interesting to see the differences even despite differing skies/conditions and integration.  Good luck on the longer term version - with the dual Esprit, it might come soon enough!

[WolfieGlos]

Wow, that must be a faint one if those arms are only just showing up after that time.

Good work, look forward to seeing how you progress with this one. If your forecast is anything like mine then good luck getting clear skies too!

[wimvb]

Nice! How dark are your skies? Officially  I'm in a Bortle 5 zone, but with all the snow, it seems brighter than that. I'm looking forward to your 20 hours version. I still plan to add Ha to my image. 10 hours might do it, but probably more.

2 hours ago, WolfieGlos said:

Wow, that must be a faint one if those arms are only just showing up after that time.

Believe you me, it is.

[tomato]

10 hours ago, WolfieGlos said:

Wow, that must be a faint one if those arms are only just showing up after that time.

Good work, look forward to seeing how you progress with this one. If your forecast is anything like mine then good luck getting clear skies too!

It will be a challenge. There were some breaks in the cloud last night and as the moon is now starting to intrude I went out to try and get some more subs. I captured 12 minutes worth…

[tomato]

7 hours ago, wimvb said:

Nice! How dark are your skies? Officially  I'm in a Bortle 5 zone, but with all the snow, it seems brighter than that. I'm looking forward to your 20 hours version. I still plan to add Ha to my image. 10 hours might do it, but probably more.

Believe you me, it is.

I’m in a Bortle 5/6 location, poor horizons to the East and West, and lots of neighbours with intermittent security lights, although they are only really a problem for visual work. I do like targets that stay above 70 degrees altitude all night.

[ollypenrice]

A tantalizing galaxy that will never let you rest!

lly

[WolfieGlos]

5 hours ago, tomato said:

It will be a challenge. There were some breaks in the cloud last night and as the moon is now starting to intrude I went out to try and get some more subs. I captured 12 minutes worth…

I bet it's making that remote hosting even more desirable 😉

[tomato]

4 hours ago, WolfieGlos said:

I bet it's making that remote hosting even more desirable 😉

Indeed, I haven’t forgotten about it but after frying my RisingCam camera in January, I need to allocate some of my Q1 astro budget to the repair.😒

[tomato]

I did promise to take this one out to 20+ hours of integration to see what the spiral arms would look like, but blimey, it's hard going with the lack of clear nights. This one is 17.57 hrs of integration albeit about a third of that captured under a full moon. I have tried to minimise the noise reduction so any discernible structure in the spiral arms is still visible. This is presented at native resolution (0.47" per pixel), I tried a x2 down sample to improve the SNR but it just made the detail in the core more difficult to retain without improving the spiral arms significantly.

This target is always well placed for me so I can return to it but I would like to try and image something new.

 

[wimvb]

Keep it up, you're getting there. 😉

I haven't had more than a clear night since I did my version. I spent that night collecting 10 hours H-alpha data, which turned out to be a waste of time. So no need to go that route.

[gorann]

Yes as Wim says keep it up, but I do understand if you want to aim at something different for a while. Galaxies usually do not go away. By the way In your original post I think you invented a new ASI camera model.

[wimvb]

1 hour ago, gorann said:

By the way In your original post I think you invented a new ASI camera model.

And since @tomato has edited the original post, now we'll never know what that invention was. 😉

[tomato]

17 minutes ago, wimvb said:

And since @tomato has edited the original post, now we'll never know what that invention was. 😉

It had a built in cloud gun but it doesn’t seem to be working.

[gorann]

5 minutes ago, tomato said:

It had a built in cloud gun but it doesn’t seem to be working.

So you are using cameras without cooling. Interesting. It seems to work quite well for you.

[tomato]

The ASI 178s have retro fitted Peltier coolers, which basically stabilise the sensor temp so the calibration with dark frames is more consistent. These are essential as even a 2 minute sub generates significant  amp glow.

The ASI 678 has no amp glow so I am using it uncooled with a 2 minute exposure time, this seems to generate useable data.

[tomato]

Of course the other way of revealing faint spiral arms and tidal interactions is to convert to black and white, invert the image and apply a radical stretch. There might be traces of IFN there, or more likely my uneven background.

[wimvb]

7 hours ago, tomato said:

There might be traces of IFN there, or more likely my uneven background.

Let’s call it IFN, otherwise we both have an uneven background.

8 hours ago, gorann said:

So you are using cameras without cooling. Interesting. It seems to work quite well for you.

According to an old entry on the zwo website, the ASI178 had the worst amp glow of all their models. The ASI174, which I used, was the second worst. With the new amp glow free models, maybe cooling isn’t necessary any more.

[Tomatobro]

as NGC2460 is known as the little whirlpool I did a comparison size wise using my ED72 portable rig between it and M51.

NGC2460 is the tiny Fuzz right in the middle of the image. Smaller than the core of M51

 

 

Edited March 3 by Tomatobro
wrong image of M51

[wimvb]

7 hours ago, Tomatobro said:

as NGC2460 is known as the little whirlpool I did a comparison size wise using my ED72 portable rig between it and M51.

NGC2460 is the tiny Fuzz right in the middle of the image. Smaller than the core of M51

Nice! Ngc 2460 looks smaller. But if you take into account the faint spirals, not that much smaller. I combined my ngc 2460 with an older image of M51. Stretched both about the same (but had to adjust the dark level of M51 somewhat), and added HDR transformations to both images equally to get this. (Same scope, same imaging scale)

(M51 2 hrs 24 min, ngc 2460 16 hrs 21 min)

If you also take into account that ngc 2460 is about three times further away, then they compare like this

(Btw, ngc 2460 is upside down)

Edited March 3 by wimvb

[Tomatobro]

Agree about the actual  size. It was more about the apparent size and the reason for the need for long exposures. A bit off topic but I promised my astro club I would help with outreach this year so put together a rig that would do live stacking. I have been experimenting with suitable targets to know what would work and what would not. Last night I had about 15 minutes before clouds rolled in after finishing M51 so I thought why not do a comparison between the two objects just to see the difference.

 

[Elp]

23 hours ago, wimvb said:

With the new amp glow free models, maybe cooling isn’t necessary any more.

Depends on your ambient temperature. I've been using uncooled cameras for years for DSO imaging, in the final image the difference between cooled and uncooled is small (as we all use NR on the final images anyway).

I've used 485mc, 183mm and 294mc, in fact I can compare the 183 as I have a cooled one too, in a raw image the uncooled is clearly more noisy, but after processing you don't really notice it. The only real difference I've found in use is when youre using the uncooled as a main camera, plate solving will detect more stars due to the noise.

I suppose it may make a difference if you're trying to image very very faint stuff, but for main target signal you can save money by using uncooled in a cool imaging environment. Look at it this way, if people have been using DSLRs for years producing excellent results, what's the issue with using uncooled astro cameras.

[tomato]

Right, I'm at 24 hrs of integration, and calling it a day (or should that be night?) at that. I have again gone easy on the noise reduction to try and preserve some detail in the spiral arms, there is perhaps the very faintest of hints of a tidal tail between NGC 2460 and IC2209 so it was a worthwhile exercise. It has been nice to image a target high in the sky with steady guiding at the start of each session recently, but there are now a lot of tempting galaxy targets starting to get into good positions.

[WolfieGlos]

That's some dedication and wow, 24 hours and the spiral arms are still that faint?

I'd be disheartened and also call it a night (day?)

Maybe one to return to at various times to pick up more data in the future, or a collab with others.

[tomato]

Thanks, I'm a bit underwhelmed if I'm honest. Wim is welcome to the data, as it was his wonderful image that inspired me to spend this much time on it, but I wouldn't want to turn his silk purse into a sow's ear.