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Forum: Post Your Photos! 10-10-2018, 07:45 PM  
Nature Colors of the Adirondacks
Posted By SunValley
Replies: 8
Views: 611
From a quick trip through the Adirondacks last Monday.

Lower Cascade Lake

West branch Ausable River at High Falls Gorge
Forum: Pentax K-5 06-19-2018, 09:11 AM  
K-5 For Astrophotography
Posted By Eric Seavey
Replies: 1,105
Views: 301,118
I had the IR-cut filter and anti aliasing filter removed a couple months back, and now have a capable astronomy camera with a bare sensor. I think it was about $250 conversion at spencer's camera, and is now a capable atro-photography camera.

The Eagle Nebula with the Pillars of Creation in the center I shot 90 lights and 30 darks at 45-second exposures and ISO 400 with my Skywatcher Maksutov-Newtonian 190.
The Lagoon/Trifid Nebulas with Webb's Cross in the top right corner I shot 90 lights and 30 darks at 30-sec exposures and ISO 400 with my Takahashi FSQ106ED.
Forum: Pentax K-5 05-11-2017, 05:03 PM  
K-5 For Astrophotography
Posted By Eric Seavey
Replies: 1,105
Views: 301,118
Another shot using my K-5 camera. Prime focus on a Skywatcher MN190 telescope. Enjoy!

Cigar Galaxy (Messier 82) and Bode's Galaxy (Messier 81)
Forum: Pentax K-5 04-06-2017, 01:33 PM  
K-5 For Astrophotography
Posted By geo444
Replies: 1,105
Views: 301,118
First, sincere congratulations Pete_XL ! :cool:
I was very sad to spend the rest of my life being the only one to do Astrophotography with the K-5 at ISO 80 ! :(
K-5 For Astrophotography - Page 4 -
6 Astrophotos taken in a well lit city at seaside (lots of turbulence) at ISO 80
No Dark Frames, No Bias Maps (Offset Frames) subtracted !

Not so Unbelievable : the K-5 DR measured at ISO 80 is ~the same~ as the Nikon D600 DR at ISO 100
The (Very) Long Exposure from the K-5 at ISO 80 are the Cleanest RAW files I ever shot !
A 1000 sec Exposure from the K-5 at ISO 80 as is... then Pushed 6 Stops :
PK5Lv 5 6 - Astro - Photo Gallery - Cloudy Nights

This is because the first génération of Digital Astrophotographers mostly used Canon Eos xxD CMos Cameras
Their CMos sensors showed Huge Amount of Noise at Base ISO -vs- almost No Noise at ISO 1600
1st Proof here : each Test = 5 subs stacked ISO 100 vs ISO 1600 Same Night & Sky :
M42 : Eos 20d : 100 iso vs 1600 iso - Nebulae - astronomy photos
2nd Proof : Canon CMos are NOT ISOless = you CanNot Push an ISO 100 Raw File :
Test Astro 100 iso vs 1600 iso 30 seconds - Nebulae - astronomy photos

More on the Huge Difference from a Canon CMos to... the Sony Exmor CMos in the K-5 :
K-5 For Astrophotography - Page 2 -
Canon Eos 20d and 5d at ISO 1600 : Members - Astronomy photos
Pentax K-5 at ISO 80 : Members - Astronomy photos
geo444: Galleries: Digital Photography Review : Digital Photography Review

... see you soon... at ISO 80 ? ;)
Forum: Post Your Photos! 03-27-2017, 02:12 PM  
Night Black Hole Generator + few others
Posted By MJKoski
Replies: 8
Views: 738
Astro season is nearing its end here. Still, new moon opens up few possibilities.

Black Hole Generator

Starlight Beacon

Frozen in Time
Forum: Post Your Photos! 03-27-2017, 10:53 PM  
Landscape Aurora Australis March 27th
Posted By following.eric
Replies: 12
Views: 842
Shot on the night of March 27th. A big showing from the Aurora Australis. My third time getting to see it. But this time it was on another level. Although you can see the colours with you naked eye, I could see the beams and you could tell when it was erupting, you could see the beams dancing over the mountains and I kept firing the shutter. I did another time lapse but have not put it together yet.

This was a three shot Pano from the K-50 and Sigma, proving to be a great combo of lens and price for what I shot. Edited lightly in lightroom. This is pretty much what the jpegs looked like in the back of the camera while shooting.

Aurora by Eric Ducourneau, on Flickr
Forum: Pentax K-1 06-20-2016, 06:09 PM  
Posted By SunValley
Replies: 7
Views: 1,371
I have a K-30 and the o-gps1 unit but I suspect the K-1 astrotracer is pretty much the same. I've been using it for over two years now and really enjoy working with it with lenses from 16 to 105 mm when I can get from 40 s to over 3 min worth of precise tracking. I've had success with the 200 mm at 30-40 s. My 400mm won't give me more than 10 s. (It's hard to calibrate with such a lens!). Some have reported much longer tracking though. As Adam pointed precise calibration is key, especially with 100 mm +. Here's a link to the official Pentax calibration page. The footnotes are very interesting. You can browse the o-gps1 flickr group for some examples. Here are a couple of mine.

10 X 40 s iso 800 with a Sigma 105 mm f/2.8

Pano of five images, 2 min exposure each with a M28/2.8 lens

Clear skies!
Forum: Pentax SLR Lens Discussion 04-24-2016, 07:13 PM  
SMC-(M,A,F) 50mm 1.7 comparison - Crunch time
Posted By swanlefitte
Replies: 5
Views: 1,085
The F lens completely flipped a horse around.
Forum: Post Your Photos! 12-23-2015, 05:12 PM  
Night Moon via Sigma 150-500 K3II
Posted By Kath
Replies: 6
Views: 1,067
Wanted to highlight the Sigma 150-500's capabilities when paired with the K3II, which makes cropping a real pleasure. I'm enjoying this lens more and more since coupling it with the K3 sensor. Focal length 440mm.

Forum: Post Your Photos! 12-20-2015, 06:50 AM  
Night Horsehead and Flame - not only Canon can......
Posted By Kerrowdown
Replies: 28
Views: 2,171
To whom do you refer I wonder... :rolleyes:

In answer to your question... in my case that'll be the taxman. :(

It's a doddle compared to all that techy stuff your doing to those stunning images. :cool:
Forum: Pentax K-3 11-16-2015, 01:44 PM  
K-3 astrophotography first session
Posted By y0chang
Replies: 126
Views: 35,728

M31, andromeda galaxy. K3 w/ O-GPS-1 astrotracer, DA 50-135mm, F4 ISO 1600 6 shots stacked around 20 secs at 135mm.
Forum: Post Your Photos! 10-03-2015, 10:49 PM  
Night Super Moon Super Resolution on 100mm
Posted By jeffshaddix
Replies: 8
Views: 2,037
That blood super moon was fun wasn't it? :)

I don't have a lens longer than my Pentax D-FA 100mm 2.8 Macro, so I had fun with my new photoshop cc subscription. :)

For my own recollection later, and If anyone cares about the process I used:
1) Tale your 16 consecutive shots each 15 seconds apart @ F/4, 1sec, ISO1000. Do the same with the lens cap on.
2) In photoshop, pull in the 16 "dark" shots with the lens cap as layers, create a smart object out of all the layers, then set the stack mode to median. This gives a nice dark bias frame to get rid of sensor bias.
3) Then pull in the 16 "light" shots without the cap as layers, and do the same smart object->median trick. Since the stars move, they won't appear in the median. The moon will though, so duplicate the layer and set the stack mode to minimum to get rid of it.
4) Then combine the two layers using a layer mask - the median one is preferred, with the minimum one only over the moon area.
5) Then copy the dark bias frame and merged it into this frame using the "subtract" blending mode in order to remove the bias.
6) Then Blur->Gaussian 100px. Heal the spot over where the moon was to make it smooth. Now we have an atmospherics frame with all the reflected light from the city.
7) Then take the atmospherics frame and dark bias frame and "added" them using the linear dodge blending mode, and merged into a single "offset" frame.
8) Now make 16 copies of the offset frame and "subtract-merge" them into each of the 16 "light" shots - we now have pseudo-calibrated images (flat field seems negligible on the 100mm macro at f/4)
9) Crop out a section of the image that contains the moon across all layers, then save it as a different PSD.
10) Follow the guide here to do super resolution: A Practical Guide to Creating Superresolution Photos with Photoshop
10a) Some notes: auto-align wouldn't work, i had to register them all into place manually (nudging helps). I also found the smart sharpen gaussian mode better suited than lens blur as in the guide, followed by another small amount of unsharp mask.
11) Cool now we have our moon - select it with the magic wand until you get the whole thing. Then expand the selection 5 pixels or so, invert selection, feather selection 2px, and hit delete to clear out everything but your moon.
12) Back in the original PSD, it's time to align the stars - again auto-align doesn't work. I found aligning in the center, then distortion-type transform from two corners seemed to work (the star movement isn't linear across the scene). Don't worry about the moon not lining up, it doesn't move the same speed as the stars.
13) Once you've arduously registered the star fields, convert to smart object->median. Rasterize and heal out the moon. Now you've got a star field worth enhancing.
14) Add adjustment layers with curves, exposure, hue/saturation, and channel mixer until you get your stars where you want them without much noise (blue channel had the most noise for me).
15) Copy and paste your super-resolved super moon onto the spot where the you healed out the other moon (yes it'll be twice as big, but that's OK right?) :)
16) Export as TIFF, then bring it into lightroom for any final touches.

Yeah that was probably too complicated for me to do for this 100mm shot, but it was fun to learn how to do it. :)

The single frame starfield, single frame moon, and post super-res moon are posted below too so you can see the difference it made.

Do any of you have suggestions on what I could have done better? I'm fairly new to astro imaging. If I had done it again, I would have taken 32 shots instead of 16. Then I wouldn't have had to worry about the extra minimum stack mode frame due to slow moon movement. I also do wish photoshop had an auto-align that worked on starfields - is there a good plugin to do such a thing?
Forum: Pentax K-5 10-01-2015, 12:12 PM  
K-5 For Astrophotography
Posted By bofh
Replies: 1,105
Views: 301,118
No one did a shoot of the moon during the eclipse? :confused:

So I took this one:

Forum: Pentax K-5 11-06-2014, 06:04 AM  
K5 & O-GPS1 for astrophotography: Pix and experiences from Namibia
Posted By stephp
Replies: 119
Views: 81,199
Recent pics with my new Sigma APO DG 300/2.8

Messier 31: 15 images (20secs, ISO1600, f/2.8) stacked with DeepSkyStacker

Messier 45: 32 images (20secs, ISO1600, f/2.8) stacked with DeepSkyStacker

My deep sky collection (thanks to the O-GPS1 unit) : Accueil / Albums / Astrophoto | PhotosSteph
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