This is the Horsehead Nebula in the Orion region with the Horsehead Nebula, Flame Nebula and some other minor ones.


Now the final result of test within a discussion in the Astrophotograpy Group that is about high iso, dynamic range and noise in astrophotos.
It should prove that there is an enourmous potentional in Pentax cameras in respect to amateur astrophotography.
Set up: K3 II with SMC Pentax-A 400 mm F1:5.6 @F1:6.3, 88 x ISO 400,15 x ISO 1600 and 91 x ISO 3200, 60 seconds exposure az ISO 400 and 1600, 30 s aat ISO 3200. Stacking with DeepSkyStacker with 2x drizzle activated. The Picture is uncropped. Postprocessing with Photoshop and Lightroom, some denoising with NIK dfine2.

[osv]

pic is private on flickr, can't see it

[Pete_XL]

pic is private on flickr, can't see it

Oops, thanks for the info, fixed it, should work now.

[osv]

nice pic, like the colors!

thx for the post

[slowpez]

Amazing shot.

[wtlwdwgn]

Excellent. Love the starburst.

[gtis]

Cracking shot you can really see the horse head
Neil

[Scootatheschool1990]

Nice shot! Not sure about the star though, Is that real or exaggerated?

[Ex Finn.]

Very nice image. Those diffraction spikes are pretty overwhelming however.

[bertwert]

Great photo!

[Pete_XL]

Nice shot! Not sure about the star though, Is that real or exaggerated?

It is the star Alnitak that shows the starburst. The starburst is a diffraction pattern resulting from optical effects at the aperture blades of the lens. It occurs at very bright pinpoint objects like the star Alnitak is.
It dominates the picture because the nebulae are quite dim and the exposure must be pushed up to the limit to make them visible.
I shot this pic with a "normal" 400 mm lens from the 80ies last century. In a picture made with a mirror telescope (that has no aperture blades) you would see 4 diffration "spikes" which result from the mounting of the front mirror.

[Pete_XL]

Exchanged the old (intermedioate result) picture against the final version of the test.
Pentax K3 II with SMC Pentax-A 400 mm F1:5.6. and Skywatcher Star Adventurer Mount.
Data:
F1:6.3
88 x 60s @ISO 400
15 x 60s @ISO 1600
91 x 30s @ ISO 3200
Stacked with DeepSkyStacker using 2xdrizzle.

[gtis]

Hi
I am getting a star adventure mount for Christmas are they easy to setup
To get 60s did you use the bulb setting on the camera
And did you use any darks in the final image
What's 2xdrizzle
Neil

[Pete_XL]

Hi
I am getting a star adventure mount for Christmas are they easy to setup

Yes they are- if you get the version packet with the polar wedge and the "L-bracket". As all depends on the quality of the polar alignment I would urgently recommend the App PS Align Pro to help with a quick and exact polar alignment. And a small light for scope illumination. Without the wedge I think no quick setup is possible, I would go crazy.

I need 1/4 h for setup on a tripod and 5 minutes if I mount it on a steel shaftI have installed on my balcony post. Between the wedge and the stand I have implemented a Feisol horizontal turntable (right word?) that helps a lot to adjust the azimuth of Polaris.

To get 60s did you use the bulb setting on the camera?

I use a wired timer remotecontrol in bulb mode of cam so I need not touch the system and am free to do what I want while the mount and camera are working autonomously then. the mount has its own built-in timer that can trigger the cam. It is fixed to 100 second exposure time. My But my remote gives me more flexibilty in exposure time setting.

And did you use any darks in the final image

In former times I used 1/3 darks when possible. Meanwhile I have the feeling to better make as much lights as possible than to shoot darks. If I have enough lights (>60 or so) the darks only cost time and the effect in noise reduction seems to me small in comparison to the noise reduction effect of stacking heaps of lights. Also if you have a lot of lights you probably have more sharp and undisturbed ones, selection of the best is important for the result. so no darks at the moment but I am sure others see that point totally different.

What's 2xdrizzle
Neil

Drizzle is a function in DeepSkyStacker to magnify a selected part of the picture by factor 2 or 3. Be carefull with drizzle. It crashes the program if you use selection windows bigger than the designated ones or if you forget to uncheck the drizzle option before you stack the normal window next time.
Pete

[Kerrowdown]

I need 1/4 h for setup on a tripod and 5 minutes if I mount it on a steel shaftI have installed on my balcony post. Between the wedge and the stand I have implemented a Feisol horizontal turntable (right word?) that helps a lot to adjust the azimuth of Polaris

Think I'll just stick to my "simple" street photography, I don't need a dictionary to do that.