Second attempt at Astro photos, the aperture was 1.2 and the next half step before f2, could someone please let me know what the value of the half stop is?

The Cloud or nedula, i have no idea what it is called in the centre, it looks like crab defending it self. The second shot has a satelitte tracking through it, this was not planned to much, but i am reasonably happy with the results.

Lastly can you stack frames on a MAC, I checked Deepskytracker and all I could see were exe. files available to download?

Tthanks

[gmans]

(more pleasant than 4am

It is the most pleasent part of the day. When you aren't asleep. The 300 are you stacking images or tracking or both?

[hjw]

I do both, I have the O-GPS1 for tracking and than stack about 20 pictures of 10 seconds each. I am new to this too and I am still experimenting with conditions. I think at 300mm the O-GPS1 has found its limits. I had a picture somewhere where a shooting star went through and at 300mm you could see the steps where the GPS moved the mirror. I will post it when I find it again. Here is my best attempt of a deep sky object so far. It is the lagoon nebula (M8) and the Trifid nebula (M20) in the same shot.
Cheers
(Pentax K-30, O-GPS1, 55-300 DAL, ISO1600, 20x10sec)

[gmans]

I do both, I have the O-GPS1 for tracking and than stack about 20 pictures of 10 seconds each. I am new to this too and I am still experimenting with conditions. I think at 300mm the O-GPS1 has found its limits. I had a picture somewhere where a shooting star went through and at 300mm you could see the steps where the GPS moved the mirror. I will post it when I find it again. Here is my best attempt of a deep sky object so far. It is the lagoon nebula (M8) and the Trifid nebula (M20) in the same shot.
Cheers
(Pentax K-30, O-GPS1, 55-300 DAL, ISO1600, 20x10sec)

Good job on the nebula. it is good to know that the O-gps1 can track a 300mm, that is a 10 second exposure max at your latitude, I suppose the closer you are to the equator the less effective it is. Cheers

[hjw]

Hi gmans,

I finally got a chance to have a shot at the magallenic clouds. The large cloud is coming above the trees just after midnight now. I was really keen to do it every since I saw your post. Anyway, I took 20 images at 10sec and 10 images at 20 sec exposure (ISO6400; ~150mm focal length) + 5 dark frames each and stacked them.

Cheers
HJW

Attached Images

 

[gmans]

Cool, stacking is the way to go. Is this all the exposures in one stack? What aperture did you use?

[hjw]

Cool, stacking is the way to go. Is this all the exposures in one stack? What aperture did you use?

Yes, that's all the 30 images in one stack and I still didn't have as much light as I would have wished for. The lens was fully open - I think it's f/4.5 at 150mm.
Cheers

[gmans]

Should try tweak the exposure in Post Processing or you already have?

[hjw]

I did some post processing, but I think I still have too much light pollution. To give you an idea about the process I attach some images along the way. All are resampled to 25%. The first image is a single 20sec exposure shot. The second is the result of the stacking. The last is then the final processed image. I am still playing with conditions to get the whole process optimised. We'll have another clear night today - so there is hope .

[gmans]

Good luck tonight, Nothing for me, it is overcast up here. you might find this interesting it was copied from another thread.How-To: Picking a Great Lens for Milky Way Photography How-To: Picking a Great Lens for Milky Way Photography http://petapixel.com/2014/01/29/picking-great-lens-milky-way-photography/

[bossa]

Second attempt at Astro photos, the aperture was 1.2 and the next half step before f2, could someone please let me know what the value of the half stop is?

The Cloud or nedula, i have no idea what it is called in the centre, it looks like crab defending it self. The second shot has a satelitte tracking through it, this was not planned to much, but i am reasonably happy with the results.

Lastly can you stack frames on a MAC, I checked Deepskytracker and all I could see were exe. files available to download?

Tthanks

That "nebula" is The Large Magellanic Cloud. A satellite galaxy orbiting The Milky Way. The bright region to the lower left of the vertical bar structure is The Tarantula Nebula (30 Doradus) and is one of the most amazing nebulae in the known universe.

http://en.wikipedia.org/wiki/Tarantula_Nebula

[hjw]

There you go... learnt something new . The Tarantula nebula looks like a very interesting target. I am playing with the idea to get a lot more serious about this. There is a equitorial mount (Skywatcher HEQ5) on my list for Santa. I reckon the tarantula nebula would make a very nice target indeed. And I thought it was an over-exposed star .
Cheers
HJW

[Sagitta]

I do both, I have the O-GPS1 for tracking and than stack about 20 pictures of 10 seconds each. I am new to this too and I am still experimenting with conditions. I think at 300mm the O-GPS1 has found its limits.

I think when you start getting up towards 300mm you need both an extremely stable mount plus luck of the draw in not having anything to throw off the O-GPS's tracking in the surrounding geography.

I went out a couple nights ago with the camera mounted on my tripod and do what I would I couldn't avoid trailing, even at short 10/20/30 second exposures. I suspect its because my location sits where a mill used to be and the ground is pretty much thin soil over an insane amount of iron slag.

When I went out a few weeks ago and realized I'd forgotten my tripod mount I was forced to use a rock and my hat to prop the camera up with and I pulled off this shot at 300mm and 60 seconds (basically the max duration for the tracker, pulled back by 10 seconds).

[hjw]

I will get Orion around December to February in a reasonable position and I am looking forward to the encounter! I am actually more interested in whether I will be able to capture the flame nebula.

[gmans]

That "nebula" is The Large Magellanic Cloud. A satellite galaxy orbiting The Milky Way. The bright region to the lower left of the vertical bar structure is The Tarantula Nebula (30 Doradus) and is one of the most amazing nebulae in the known universe.

Tarantula Nebula - Wikipedia, the free encyclopedia

Thanks Bossa, the link is great I knew the name ( recently installed Stellaruim) but never see photo's of it, incredible is right. Cheers

[ajzimmerman]

What is the process of shooting the images you are going to stack? Is it similar to bracking, but with huge disparities in exposure? Do you do something like a 5 sec, 10 sec, 15 sec, 20 sec, etc?
I was confused about the difference between the dark flat files and the dark files...what constitutes dark..etc...