M101, The Pinwheel Galaxy | April 3rd 2019

[MalVeauX]

Heya,

I had a fairly clear night the other night so I managed to point my setup at M101 and gather some data. I'm always in awe thinking how this light is 21 million years old and everything is probably so different there now. I'm not much of a DSO imager, as I mostly image solar system bodies (99% narrowband solar...). My system works for both though apparently.

Lights 45 x 240s @ ISO1600

Bias x 35

Flats x 20

C8 Edge + 0.7x Focal Reducer + Canon T4i APS-C (unmodified)

ST80 + ASI174MM Guiding

Orion Sirius (HEQ5)

Very best,

[Xiga]

Very nice Marty ? Glad you got your flats problem sorted too! 

I also have a HEQ5-Pro mount (with belt-mod) and a C8 (non-Edge though). You have a pier whereas i am using the standard tripod, so it's really interesting to see what a guide graph can look like with this mount carrying this amount of weight under optimal conditions (and you're not even using an OAG!). I tried using my C8 for the first time last week, but unsurprisingly the guiding performance wasn't great. 

A pier is out of the question for me, but i'm now wondering if a much beefier tripod could potentially open up the possibility of doing longer FL imaging with the HEQ5-Pro. Hmm...? 

Great image btw! I know you're new to DSO imaging, so maybe if you posted the (now properly calibrated) stack, then maybe a more experienced DSO imager could have a go and show you what your data is capable of? 

[MalVeauX]

Thanks, I think that focus is soft, as temperature dropped quickly over the 3 hours I imaged. Mounts definitely behave differently on piers than tripods. A very beefy tripod would likely improve overall performance, like those portable piers. One thing I know for sure, weight matters, and light weight stuff behaves differently from heavy stuff when it comes to this kind of thing. I was at 0.63"/pixel resolution with this setup and the seeing was pretty good (Florida) so I was appropriately sampled I think, but my focus was off unfortunately I think. I am considering attempting with smaller pixels, but even though with good seeing, going to 0.35"/pixel might prove to be not possible with this setup on my mount (with an IMX183 sensor). I'm considering adding a 2.4um pixel camera of some kind to my setup for full solar disc imaging and native F10 imaging (lunar surface mostly) at various wavelengths, and it happens to also be good for DSO with smaller options under good seeing. I think my C8 is too much for the IMX183 sensor on my current mount, but maybe my next mount will be able to handle it (considering a CGX-L maybe in the future). I don't really have a good DSO camera, nothing cooled, so just a dSLR or a small sensor camera like the 224MC, so considering eventually adding an ASI183MM Pro one day, but not any time soon since I do DSO the least.

Good point! I'm uploading the data now to the cloud. The latest stacks will have UPDATE in their file name. If anyone feels like playing with the data, the bad data and the updated good stacks are available at this link:

https://drive.google.com/drive/folders/1D-joV_wCO871FSaoSwyUaxASOm9tBU3o?usp=sharing

Very best,

[Xiga]

On 07/04/2019 at 01:12, MalVeauX said:

Thanks, I think that focus is soft, as temperature dropped quickly over the 3 hours I imaged. Mounts definitely behave differently on piers than tripods. A very beefy tripod would likely improve overall performance, like those portable piers. One thing I know for sure, weight matters, and light weight stuff behaves differently from heavy stuff when it comes to this kind of thing. I was at 0.63"/pixel resolution with this setup and the seeing was pretty good (Florida) so I was appropriately sampled I think, but my focus was off unfortunately I think. I am considering attempting with smaller pixels, but even though with good seeing, going to 0.35"/pixel might prove to be not possible with this setup on my mount (with an IMX183 sensor). I'm considering adding a 2.4um pixel camera of some kind to my setup for full solar disc imaging and native F10 imaging (lunar surface mostly) at various wavelengths, and it happens to also be good for DSO with smaller options under good seeing. I think my C8 is too much for the IMX183 sensor on my current mount, but maybe my next mount will be able to handle it (considering a CGX-L maybe in the future). I don't really have a good DSO camera, nothing cooled, so just a dSLR or a small sensor camera like the 224MC, so considering eventually adding an ASI183MM Pro one day, but not any time soon since I do DSO the least.

Good point! I'm uploading the data now to the cloud. The latest stacks will have UPDATE in their file name. If anyone feels like playing with the data, the bad data and the updated good stacks are available at this link:

https://drive.google.com/drive/folders/1D-joV_wCO871FSaoSwyUaxASOm9tBU3o?usp=sharing

Very best,

Hi Marty

I ran your data through APP to remove the gradient (< 5 mins). Then gave it about 30 mins in PS. This was what i ended up with. I think you are right about the soft focus, and as you already know, you need to up your dithering substantially, as there was a lot of walking noise. The colour is lacking in magenta, but that's likely just because your camera isn't modified. 

Thanks for sharing the data!