Orion Nebula

[Alan Clark]

1004 exposures of 1 second each at 500mm. As I do not have a driven mount I had to keep the exposures short to prevent motion blur. Stacked in AstroPixelProcessor.

• 1004 sec

 

[DaveC Oz]

Great shots. I have just acquired a sky tracker but I'm still getting the hang of it. Really nice colours, especially for a stacked shot.

 

[Unframed Dave]

Cracker!

 

[FowlersFreeTime]

Amazing!

 

[Jabo]

Beautiful capture !

 

[Alan Clark]

This is the same subject but with a tracker mount, and a much longer exposure of 94 minutes total , 10 seconds each.

• 5660 sec

 

[alexpler]

Just wow.

 

[MyDogsOwner]

Great work! I got an Ioptron Tracker last Fall for my IR Converted X-T2, but haven't tried it out yet. I've been curious how the A7R's would work with the noise, or if just stacking moire images would help with that. May I ask which camera and lens did you use?

 

[Alan Clark]

I used an A7iii camera with a Tamron 150-500 lens at 500mm. The mount is a Sky-watcher Star Adventurer GTi. There was a lot of noise despite stacking many images, but the denoise tool in ON1 reduced it considerably.

 

[evacguy]

Wow Alan, both images are fantastic. The untracked one is really good given it’s not tracked. What Bortle sky were you in? What sort of workflow do you have for your post? Do you have any problems with polar alignment? Do you use any tools to help?

 

[Angus Cameron]

I used an A7iii camera with a Tamron 150-500 lens at 500mm. The mount is a Sky-watcher Star Adventurer GTi. There was a lot of noise despite stacking many images, but the denoise tool in ON1 reduced it considerably.

The images are stunning. If you don't mind me asking, have you had the camera modified for Astro? If so what way did you go? I have an A7R II that I'm considering having modified. I've tackled a few Milky Way shots so far but I'm keen to try DSO. There has been little chance to get out as there has hardly been a night with a clear sky since getting a tracker.

 

[Alan Clark]

Wow Alan, both images are fantastic. The untracked one is really good given it’s not tracked. What Bortle sky were you in? What sort of workflow do you have for your post? Do you have any problems with polar alignment? Do you use any tools to help?

My sky is Bortle 7, so pretty bad. For polar alignment I obviously have the mount adjusted to my latitude and place the tripod on a level surface, and I use the compass app on my phone to find North. I don't use the pole finder in the mount. This is accurate enough for my purposes, although with a 500mm lens it might be a good idea to check that the stars have not moved far within the frame after 30 to 60 minutes. For wider angle shots the drift is negligible.
I process the images in AstroPixelProcessor then use ON1 to produce the final result.

 

[Alan Clark]

The images are stunning. If you don't mind me asking, have you had the camera modified for Astro? If so what way did you go? I have an A7R II that I'm considering having modified. I've tackled a few Milky Way shots so far but I'm keen to try DSO. There has been little chance to get out as there has hardly been a night with a clear sky since getting a tracker.

The camera is unmodified. I do have an A7R which has been converted to full spectrum, which I use for IR photography, but I have not tried it with astrophotography - it will be interesting to try it one day. The light pollution should be reduced significantly in 850nm infrared!

 

[evacguy]

My sky is Bortle 7, so pretty bad. For polar alignment I obviously have the mount adjusted to my latitude and place the tripod on a level surface, and I use the compass app on my phone to find North. I don't use the pole finder in the mount. This is accurate enough for my purposes, although with a 500mm lens it might be a good idea to check that the stars have not moved far within the frame after 30 to 60 minutes. For wider angle shots the drift is negligible.
I process the images in AstroPixelProcessor then use ON1 to produce the final result.

Thanks for info. I'm surprised you only use a phone compass to align with the North Star, I always thought that wouldn't be sufficient - especially at 500mm. Your long esposure image of Orion (10 s shots) is pretty impressive, especially as you don't use the pole finder to align the mount. Very little elongation on your stars. Was the 10 s exposure your maximum to avoid star trailing? If so, you think it would be worth trying the polar alignment to achieve longer exposures, or is it too difficult. Did you have to reframe often during the 90 min exposure? And Bortle 7, even more impressive. I guess you didn't use any filters to reduce the noise pollution? Do you use a Bahtinov Mask to assit in focusing?

 

[Alan Clark]

Thanks for info. I'm surprised you only use a phone compass to align with the North Star, I always thought that wouldn't be sufficient - especially at 500mm. Your long esposure image of Orion (10 s shots) is pretty impressive, especially as you don't use the pole finder to align the mount. Very little elongation on your stars. Was the 10 s exposure your maximum to avoid star trailing? If so, you think it would be worth trying the polar alignment to achieve longer exposures, or is it too difficult. Did you have to reframe often during the 90 min exposure? And Bortle 7, even more impressive. I guess you didn't use any filters to reduce the noise pollution? Do you use a Bahtinov Mask to assit in focusing?

The choice of 10 seconds was partly about reducing star trails, and also so that light pollution isn't too strong. It was shot at 12,800 ISO, which was probably not the best choice, apparently 1600 would be better as it reduces the noise.
I think it would be a good idea if I took more care with polar alignment with long focal lengths, this would allow longer exposures and no need to reframe, although the polarscope is a bit tricky to use. I did get quite a lot of drift on another target which would have benefited from reframing.
I use the focus magnifier to focus, which I have assigned to a custom button.
I have not used a light pollution filter.
I still have a lot to learn. Apparently an unmodified Sony A7 series camera is not very sensitive to the Hydrogen alpha line, so my full spectrum camera would be much better in that respect for nebulae. An H-alpha filter would also reduce light pollution considerably and can give good mono images, so that is something else for me to consider.