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Forum: Pentax K-5 & K-5 II
11-12-2019, 12:13 PM
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Yes, as others have said, we're at solar minimum now. Also, we are coming off the lowest activity solar cycle in over 100 years, so the Sun has indeed been relatively lethargic for some time. The biggest peak in (some of) our lifetimes was around 1960.
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Forum: Pentax K-5 & K-5 II
11-12-2019, 10:29 AM
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Forum: Pentax K-5 & K-5 II
11-12-2019, 10:14 AM
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Adding to what photoptimist said about solar cycles, 75% of the days in 2019 have not had any sunspots. For comparison purposes, at solar maximum in 2012-13 every day had sunspots.
There's a new sunspot just rotating around to face Earth today.
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Forum: Pentax K-5 & K-5 II
11-12-2019, 10:09 AM
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This image does a great job of showing the difference in scale between these two heavenly bodies. Well done Eric.
I've collected some basic info about the planets from the NASA website. Here's a few facts about Mercury:
Distance from Sun of about 36 million miles (0.39 AU)*
Light time from the Sun - 2.8 minutes
Length of day - 59 Earth days
Length of year - 88 Earth days
Smallest planet - only slightly larger than Earth's Moon.
Surface gravity - 12.1 ft/s2 (0.378g)
Equatorial circumference - 9,525.1 miles
Equatorial Inclination - 0 degrees
*Mercury's highly eccentric, egg-shaped orbit takes the planet as close as 29 million miles and as far as 43 million miles from the Sun.
With a radius of 1,516 miles, Mercury is a little more than 1/3 the width of Earth. If Earth were the size of a nickel, Mercury would be about as big as a pea. (The Sun would be as big as a 7 foot diameter weather balloon.) Standing on Mercury's surface, the Sun would appear more than three times larger than it does on Earth, and the sunlight would be as much as 11 times brighter. Despite its proximity to the Sun, Mercury is not the hottest planet; that title belongs to nearby Venus.
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Forum: Pentax K-5 & K-5 II
11-12-2019, 09:13 AM
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The number of sunspots varies on a 11-year cycle. We're near the minimum right now so there are no spots.
See Solar cycle - Wikipedia for more.
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Forum: Pentax K-5 & K-5 II
11-12-2019, 08:57 AM
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Amazing!
Just curious -- I would have expected to see sun spots or other features on the surface (I don't know much about astronomy). Would you mind explaining briefly the absence in these images? Thanks.
- Craig
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Forum: Pentax K-5 & K-5 II
11-12-2019, 07:11 PM
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You've done a great job here. Thanks for sharing.
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Forum: Pentax K-5 & K-5 II
11-12-2019, 03:34 PM
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Forum: Pentax K-5 & K-5 II
11-12-2019, 01:19 PM
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Awesome, humbling and underwhelming, all in the same image. It's so easy to miss Mercury in the image, or to even assume it's just a spot on the sensor.
Beautiful shot, well done!
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Forum: Pentax K-5 & K-5 II
11-12-2019, 12:50 PM
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Forum: Pentax K-5 & K-5 II
11-12-2019, 10:49 AM
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Oh, that's a stunner!
Nice work.
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Forum: Pentax K-5 & K-5 II
04-18-2018, 05:07 AM
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.
To answer the "what else" question, I summarized :
- the Top-8 Cameras with lowest Detection-Threshold < 0,01% @ 0dB SNR, from DxOmark
same as in my previous post, ordered by Measured-ISO
- the Top-8 Cameras with lowest Noise-Levels in 5 min. Dark-Frames
from The Sensor Noise DB. – Brendan Davey Photography
ordered by their Noise-Mean-Value
Pentax K-1, the 95 Top Measured-ISO with a Detection-Threshold of 0,009% @ 0dB SNR
+ the 2nd Noise-Mean-Value just behind the Pentax K-5 in 5 min. Dark-Frames (+5ev)
The very Low Dark-Current levels of the Sony imx071 explain the Pentax K-5 Top position
= the 1st lowest Noise-Mean-Value in the 5 min. Dark-Frames (+5ev) test
the Dark-Current Chart is from the Zwo Astro imaging site :
https://astronomy-imaging-camera.com/products/asi-cooled-cameras/asi071mc-pro/
Same Sony sensor, at a $1700+ price !
Then the Asi071(K-5) compared to the Asi294 and Asi1600
= two Astro-Cams with 4:3 ~22,7mm diagonal sensors
High ISO settings are mandatory to lower the Exposure Time to 1 sec. or less
this to cancel the Atmospheric Turbulence effect with long FL.
the only way to operate with Lucky Imaging !
But finally, what do you lose from Base-ISO to ISO 10K :
- Dynamic Range value from 14 ev down to 7 !
- Tone Values from 16384 down to 128 !
- SNR to be Half the Base ISO SNR
- your RAW File Size doubles
- for the same final IQ, you'll have to Stack much more RAWs...
- with Dark-Frames !
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Forum: Pentax K-5 & K-5 II
04-13-2018, 11:44 AM
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.
You've had a good idea, gbeaton !... I already know Sensorgen.info, but...
it reminds me a nice way to understand how easily the K-5 detects very faint lights at ISO 80 !
Sensorgen calculations from DxOmark Full-SNR
Open the K-5 in DxOmark Database
- Open it in a New Tab at Measurements / Full-SNR tab...
- Open the Eos 7D & Eos 1D Mk IV at Measurements / Full-SNR in 2 more Tabs
the 3 Cameras Sensor I've compared in 2011
Everything you need to know about a Camera-Sensor's Behavior in Low-Light is here ;)
Let's Compare their Detection Threshold at -1) base ISO -2) ISO 1600
Base ISO Detection Threshold - PK-5 0,008% - C1DM4 0,036% - C7D 0,045% of Gray Scale
ISO 1600 Detection Threshold - C1DM4 0,097% - PK-5 0,109% - C7D 0,193% of Gray Scale
=> Pentax K-5 is far more Sensitive at Base ISO than a Good & Expensive Canon PRO cam.
Subtracting tens of Bias-Maps & Dark-Frames from the Eos CR2 files will lower their Noise
but they will Never Detect 0,008% Gray Details unless you Stack tens+tens of RAW files
while Pentax K-5 and its Very Low Noise only needs from 3 to 6 RAW files at ISO 80
Don't forget final results are worse than theory, Canon Banding is Not Measured :
https://en.astronomike.net/deep-sky/nebulae/162986.html
The Eos 1D Mk 4 is slightly more Sensitive than the Pentax K-5 at ISO 1600
ISO 1600 difference could be worse if shooting with Newer Canon cams
3 Re-Scaled DxOmark Full-SNR Charts Comparison posted in 2011 :
Pentax K5 vs Canon 7D : comparaisons et raisons
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Re-Scaled DxOmark Full-SNR Charts with base ISO & ISO 1600 Detection Thresholds :
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Forum: Pentax K-5 & K-5 II
10-30-2016, 04:36 AM
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At the moment I like the K5 more than the K3 II because of the ISO 80 setting. I have the feeling that brighter objects (Galaxies, Star Clusters) are better for the K3 II with higher ISO (800) and shorter exposure stacks and dim ones better for the K5 with lowest ISO (80) and longer exposure.
NGC6888 by pete_xl, auf Flickr
This is the Cescent Nebula NGC6888 and its neighbourhood from last night shot 30 x 300s with the K5 at ISO 80 from the balcony with bad seeing and hazy skies.
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Forum: Pentax K-5 & K-5 II
10-08-2016, 01:46 AM
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...but depending on the lens or telescope used and the target one may give it a try.....
 Mond am 19.Feb. 2016 by pete_xl, auf Flickr
This for example is a panorama of six ímages stacks from 1-minute-film-seqences taken with an Olympus OM-D E M5, a Pentax-A 5.6/400 , the pentax 1.4x and 2x TCs with the camera in HD digizoom mode. The final Image is 4549 x 2508 size. It was an easy job and at least a lot of fun :)
6 Clips from tripod -> Import to Magix VideoDeluxe -> export as JPGs -> drag each sequence into Autostackert (free) -> combined to panorama with Microsoft ICE (free) -> PP with Lightroom CC
If Pentax (like other Brands) would deliver a "lossless HD-crop" for the movie mode that would serve as a lossless digizoom that would be great (also for other video applications).
---------- Post added 10-08-16 at 10:58 ----------
I started a new approach on the "Heart nebula with K-5" because I disliked the scruffy stars in the first one. I used a star mask and frequency separation to process stars and background separately.
IC 1805, IC 1795 und NGC 896 - überarbeitet by pete_xl, auf Flickr
Data: 45x180s, ISO 800, 80/480 mm, Pentax K-5
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Forum: Pentax K-5 & K-5 II
09-24-2016, 10:14 AM
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I did my astrothings with my new K3 II in the passed year. Yesterday I put on the good old K5 once more to go for a dim nebula from my suburban light polluted balkony.
I did not do any comparison between K3 II and K5 until now but anyway the K5 is a great tool for faint DSOs I think.
This is the Heart Nebula (IC 1805) with its companions IC 1795 and NGC 896. 45 shots of 3 minutes exposure at ISO 800, F6.0 with a TS 480 mm telescope. Hope you like it....
 IC 1805, IC 1795 und NGC 896 by pete_xl, auf Flickr
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Forum: Pentax K-5 & K-5 II
09-30-2016, 03:31 AM
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Very nice! Super clear and sharp!
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Forum: Pentax K-5 & K-5 II
11-01-2015, 01:19 AM
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I just received a copy of Sky & Telescope's "Skywatch 2016" magazine where my Bird Rock photo appears full page on the inside back cover. Watch for it at your newsstand.
full pic and story on flickr: https://flic.kr/p/sfVsPE |
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Forum: Pentax K-5 & K-5 II
10-13-2015, 01:53 PM
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PENTAX K-5 II s • 80 ISO • Sigma 150-500mm f:5-6.3 APO DG HSM • Pentax O-GPS1 GPS Unit
15" exposure at 04:26:35 GMT+2
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Forum: Pentax K-5 & K-5 II
10-12-2015, 04:54 AM
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Forum: Pentax K-5 & K-5 II
10-05-2015, 11:14 AM
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Forum: Pentax K-5 & K-5 II
10-01-2015, 04:37 PM
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 My composite of the eclipse. Unfortunately clouds came in when we hit totality. k5 + sigma 170-500mm at around 450mm
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Forum: Pentax K-5 & K-5 II
10-01-2015, 01:25 PM
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You find some in the Astrophotograph Group :)
in the discussion "Totality!".
this is mine............ |
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Forum: Pentax K-5 & K-5 II
03-16-2015, 08:42 PM
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Orion Nebula, Pentax K-5, ISO 3200, 30 sec, DA 55-300mm at 300mm/
f 5.8 with Pentax O-GPS1 Astrotracer. You can see a bit of trailing, I got an even better calibration later on in the night, but then the clouds rolled in.
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Forum: Pentax K-5 & K-5 II
01-21-2015, 09:18 AM
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Completed my horsehead in HaRGB. 11x1200" in h-alpha and 13x120" in RGB
HaRGB
Just Ha
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