M101 at just over 25h - Probably the last image of the season

[ONIKKINEN]

766 x 120s, around 50/50 split between UV/IR cut and an Antlia Triband RGB filter. Taken with an 8'' newtonian, TeleVue Paracorr, and a RisingCam IMX571 OSC camera.

Resampled to 75% of original resolution, so roughly 1'' per pixel.

The UV/IR cut filter data is all pretty good from better than average seeing nights and little or no Moonlight. The Triband data not so much, with some real uphill battle nights and 10+m/s winds and/or Moonlight. I think the UV/IR data is doing most of the heavy lifting here so not that big a deal. Imaged over 7 nights in total, 2 of which were in April 2023, 2 in February 2024, and 3 in March 2024. Haven't gotten a chance to image in April of this year mostly due to weather, and its looking like that is not going to change as the Moon is rising and the season closes in around 2 weeks so this will likely be the season closer for me. This year was significantly more windy than the 3 past years i have imaged, i think this might have been a 40+ hour image had the conditions been better but still shouldn't complain, its not like 25h is a short image.

Calibration and stacking in Siril, processing in PI and Photoshop. I used a 2 stack method for this one, with the first stack containing all the data and the second stack containing only the Antlia Triband data. The Triband only stack was used as an H-alpha enhancing layer in Photoshop which is a subtle but noticeable boost to the bright emission regions.

Feedback welcome

-Oskari

[WolfieGlos]

7 sessions in 3 months must be demoralising (I thought you had been quiet), but I'd say from this one image it was worth pursuing. The detail in that core is really nice, Ha isn't overdone for me, and the 25 hours shows across the whole image. It could even be one you return to with more data next season?

If not, it's one of the best Pinwheels I've seen.

Edited April 14 by WolfieGlos

[ONIKKINEN]

5 minutes ago, WolfieGlos said:

7 sessions in 3 months must be demoralising (I thought you had been quiet), but I'd say from this one image it was worth pursuing. The detail in that core is really nice, Ha isn't overdone for me, and the 25 hours shows across the whole image. It could even be one you return to with more data next season?

If not, it's one of the best Pinwheels I've seen.

Actually its 7 nights in a year since the first 2 nights were in 2023 🙃. Of course its not all the nights that i had in the 2023-2024 season, just the ones where M101 was nicely positioned (17 nights in total since august 2023).

My plan is to get a monochrome camera for galaxy season 2025, and yep i would be shooting actual Ha and luminance for this one to make the best possible image i could reasonably make. I think there is a chance that the project will go on in 2026 if next year's weather is equally bad since i would like to get a similar amount of luminance to the current RGB stack (so another 20+ hours...), but whats another year when the project already celebrated its first birthday.

[CCD-Freak]

Great work !!!  That has to be one of the best images of M101 I have ever seen. 

[900SL]

Very nice image Oskari. 

[tomato]

As M101 images go it’s up there with the best, deep and detailed.👍

I love the background galaxies too, like this barred spiral:

[ollypenrice]

Quality takes time. Nice one!

Olly

[ONIKKINEN]

Thanks all for the compliments!

5 hours ago, tomato said:

As M101 images go it’s up there with the best, deep and detailed.👍

I love the background galaxies too, like this barred spiral:

One of the best things about going for longer integrations i would say. The background just tends to spawn interesting objects out of thin air.

For example here is a quasar with a redshift of 4.170:

Unassuming little speck, however that speck has spent more than 12 billion years on its way here.

[callisto]

2 hours ago, ONIKKINEN said:

Thanks all for the compliments!

One of the best things about going for longer integrations i would say. The background just tends to spawn interesting objects out of thin air.

For example here is a quasar with a redshift of 4.170:

Unassuming little speck, however that speck has spent more than 12 billion years on its way here.

Amazing... that's why I love astronomy ☺️ 

Mark.

[ONIKKINEN]

1 hour ago, callisto said:

Amazing... that's why I love astronomy ☺️ 

Mark.

Sure is a humbling hobby. There are countless objects in the image that are not in any catalogue, and this is a very popular imaging target so its strange to find so many of them. Many of those faint fuzzy spots are older than the Earth, all in just a single degree of field of view.

[gorann]

That is a truly outstanding M101 Oskari! Why more data if you with what you have can produce such an image?

Up here in the north @wimvb and I have also concluded that we have taken our final images for the season due to moon and lack of astrodarkness. Good thing is that we avoid exposing our optics to the pollen season.

Edited April 17 by gorann

[ONIKKINEN]

46 minutes ago, gorann said:

That is a truly outstanding M101 Oskari! Why more data if you what you have can produce such an image?

Up here in the north @wimvb and I have also concluded that we have taken our final images for the season due to moon and lack of astrodarkness. Good thing is that we avoid exposing our optics to the pollen season.

Thank you!

There is always this thought at the back of my mind "what if it were better/deeper still". So i have no trouble justifying the hours to try and chase that. I do think there is room for improvement, particularly in Ha because the Triband + OSC combo is very inefficient at capturing it (wide 30 ish nm pass and only 1/4th of the sensor). I reckon just a few hours of proper mono Ha will beat the current triband data.

The luminance aspect i am not so sure about. Part of me is excited to see if new faint background galaxies emerge from the noise, or if more stellar detail can be resolved in the galaxy. If the image doesnt improve much, well thats a problem for future me.

[wimvb]

1 hour ago, ONIKKINEN said:

Part of me is excited to see if new faint background galaxies emerge from the noise,

There is a limit to that, set by your sky darkness. Going past some 22+ Mag/arcsec2 just isn’t feasible. But yours is an excellent image as is.

Edited April 17 by wimvb

[ONIKKINEN]

11 minutes ago, wimvb said:

There is a limit to that, set by your sky darkness. Going past some 22+ Mag/arcsec2 just isn’t feasible. But yours is an excellent image as is.

I think my magnitude record is in the 22 region, in my last year's 35h M81 image. Skies in the location i use are between 20.7 and 21.3 depending on whether we have snow or not so going much further than that might not be too realistic.