Polaris IFN (v2)

[AbsolutelyN]

This is second attempt at Polaris with Sigma 105 1.4 and 2600mc on a star adventurer. This time I went with 2min exposures and managed a longer integration time, almost 7 hours. 

Setup in action here - 

 

Edited April 13, 2021 by AbsolutelyN

[symmetal]

Great image. Lovely detail in the wispy bits without the background being noisy. I think wide angle shots suit this feature better than the narrower angles I've tried. 🙂

Alan

[kirkster501]

Hi mate, how do you connect the Sigma 105 to the ASI please?  Via a Canon adapter? I understand you can only control the aperture of the Sigma lens from a DSLR - there is no manual ability to control the aperture?  So how to wet it?

Fabulous image by the way!

[AbsolutelyN]

1 minute ago, symmetal said:

Great image. Lovely detail in the wispy bits without the background being noisy. I think wide angle shots suit this feature better than the narrower angles I've tried. 🙂

Alan

Thanks Alan. I really like narrower field of view here but they need much more exposure so harder to do. I also find it's not very easy to plate solve and guide in this area. The area is utterly fascinating though, just the starless version shows some quite amazing structures to explore.

[AbsolutelyN]

20 minutes ago, kirkster501 said:

Hi mate, how do you connect the Sigma 105 to the ASI please?  Via a Canon adapter? I understand you can only control the aperture of the Sigma lens from a DSLR - there is no manual ability to control the aperture?  So how to wet it?

Fabulous image by the way!

I'm using the Astromechanics EOS adapter. I've had issues connecting and controlling to the thing but when you get it working it's superb. This image for example was refocussed once every 2 hours automatically in SGP. It's just like using any scope autofocusser in SGP and you can even set the aperture when you connect to it. 

Without the adaptor you can change aperture on a Sigma lens by attaching it to a canon body, setting aperture, press depth of field preview and remove the lens whilst its pressed. 

Edited April 13, 2021 by AbsolutelyN

[michael.h.f.wilkinson]

Very impressive image. I have been tempted by this lens, I must say, but I hadn't seen any astronomical results

[AbsolutelyN]

6 minutes ago, michael.h.f.wilkinson said:

Very impressive image. I have been tempted by this lens, I must say, but I hadn't seen any astronomical results

It's a fantastic lens, though from reviews I hoped for better coma 

[michael.h.f.wilkinson]

2 minutes ago, AbsolutelyN said:

It's a fantastic lens, though from reviews I hoped for better coma 

What aperture did you use?

[AbsolutelyN]

1 minute ago, michael.h.f.wilkinson said:

What aperture did you use?

F/1.4 as I can barely tell the difference between f/1.4 and f/2 ... and seems pointless to got to f/2.8 as you could get a cheaper lens 🙂

[michael.h.f.wilkinson]

Just now, AbsolutelyN said:

F/1.4 as I can barely tell the difference between f/1.4 and f/2 ... and seems pointless to got to f/2.8 as you could get a cheaper lens 🙂

Thanks! Temptation levels have just increased

[kirkster501]

What are the individual subs like please?  Trying to judge the coma without the stacking that can remove some of it.

[AbsolutelyN]

9 minutes ago, kirkster501 said:

What are the individual subs like please?  Trying to judge the coma without the stacking that can remove some of it.

This is about as good as I've managed so far. Bit better stacked as you say. 

Edited April 13, 2021 by AbsolutelyN

[michael.h.f.wilkinson]

11 minutes ago, AbsolutelyN said:

This is about as good as I've managed so far. Bit better stacked as you say. 

Impressive! Clearly better than my 50-100 mm F/1.8

[AbsolutelyN]

11 minutes ago, michael.h.f.wilkinson said:

Impressive! Clearly better than my 50-100 mm F/1.8

I was a little disappointed at first as unrealistically expected perfection given only using aps-c and not full frame but having worked on the spacing to get it like this I'm finding it perfectly ok and very usable. 

Edited April 13, 2021 by AbsolutelyN

[AbsolutelyN]

4 minutes ago, AbsolutelyN said:

I was disappointed at first as unrealistically expected perfection given only aps-c and not full frame but having worked on the spacing to get it like this I'm finding it perfectly ok and very usable

This is a corner from full frame 6d

[clarkpm4242]

Love this image!!

Paul

PS ...and now I know how to set the aperture when I connect my Canon lens to the ASI2600 

[symmetal]

6 hours ago, AbsolutelyN said:

I really like narrower field of view here but they need much more exposure so harder to do.

That's probably why my 5.25 hours at f6.3 was a bit disappointing. I'd need well over 20 hours to get something decent. 😬

Alan

[AbsolutelyN]

10 hours ago, symmetal said:

That's probably why my 5.25 hours at f6.3 was a bit disappointing. I'd need well over 20 hours to get something decent. 😬

Alan

At 400mm I needed 15 hours (from bortle 5) to get good detail in the IFN and that's at f/2 so I find fast lenses and scopes are the only real way to access it with UK weather.   

Edited April 14, 2021 by AbsolutelyN

[kirkster501]

16 hours ago, AbsolutelyN said:

I'm using the Astromechanics EOS adapter. I've had issues connecting and controlling to the thing but when you get it working it's superb. This image for example was refocussed once every 2 hours automatically in SGP. It's just like using any scope autofocusser in SGP and you can even set the aperture when you connect to it. 

Without the adaptor you can change aperture on a Sigma lens by attaching it to a canon body, setting aperture, press depth of field preview and remove the lens whilst its pressed. 

Yes I am schooled in SGP focus on my wide field 135mm lens rig and the motor and belt rig I set up.  Does this EoS adapter  you describe also control the focus as well without resorting to such measures? What issues did you encounter?

[AbsolutelyN]

11 minutes ago, kirkster501 said:

Yes I am schooled in SGP focus on my wide field 135mm lens rig and the motor and belt rig I set up.  Does this EoS adapter  you describe also control the focus as well without resorting to such measures? What issues did you encounter?

Yes it controls focus and aperture. Focus control seems as good as my sesto senso to me, very fine adjustments possible. You can only set aperture when you connect in SGP so you've have to disconnect and change a setting and reconnect if you wanted to change aperture. 

The main issue was power but I don't think you'd have this problem as you have an observatory. I'm running it at the end of a 20m USB cable and there is no power left in the USB cable to power the adapter which draws power from USB. I've fixed it by installing a powered USB hub. 
Another issue was it being inconsistent at connecting. Again this could be because of my setup as it always works fine from a short cable direct into laptop. 
Finally if you add too many spacers it seems to hit a hard infinity despite still being able to manually get the image in focus. 

Overall brilliant bit of kit though and much more compact than a belt driven solution - https://www.firstlightoptics.com/adapters/astromechanics-ascom-aps-c-m42-to-canon-lens-controller-mark-ii.html

Edited April 14, 2021 by AbsolutelyN

[kirkster501]

Thanks.  I will investigate.

[vineyard]

17 minutes ago, AbsolutelyN said:

Overall brilliant bit of kit though and much more compact than a belt driven solution - https://www.firstlightoptics.com/adapters/astromechanics-ascom-aps-c-m42-to-canon-lens-controller-mark-ii.html

Sorry to intrude but that does look a clever piece of kit.  I'm guessing it would not work with old manual prime lenses which don't have those electronic contacts?  And that is a beautiful photo of the IFN!

[AbsolutelyN]

1 minute ago, vineyard said:

Sorry to intrude but that does look a clever piece of kit.  I'm guessing it would not work with old manual prime lenses which don't have those electronic contacts?  And that is a beautiful photo of the IFN!

It will only work on Canon AF lenses - they have a list of lenses its been tested with here:

https://astromechanics.org/downloads/ascom_ef/en/manual/lens_test.pdf