Forgot Password
Pentax Camera Forums Home
 

Showing results 1 to 25 of 30 Search: Liked Posts
Forum: Pentax K-5 11-12-2019, 12:13 PM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By Paul the Sunman
Replies: 11
Views: 570
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.
Forum: Pentax K-5 11-12-2019, 10:29 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By AstroDave
Replies: 11
Views: 570
For a good look at the sun, go to SDO/HMI Continuum Image (click to enlarge image)

For alternate wavelengths, look here: The very latest SOHO images

For more, try BBSO - Latest Images



DeadJohn's "spot" (I'd call it a disturbance at the moment) is right at the edge at about the 8 o'clock position in the NASA SDO/HMI Continuum Image. It's somewhat more prominent in the EIT 304, 195, and 171 images in the second NASA URL above.

And, yes, the sun spot activity has been very low for quite a while.

But, you can see other stuff in front of the sun! https://www.facebook.com/pg/APOD.Sky/photos/?tab=album&album_id=2217550268349180
Forum: Pentax K-5 11-12-2019, 10:14 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By DeadJohn
Replies: 11
Views: 570
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.
Forum: Pentax K-5 11-12-2019, 10:09 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By Apet-Sure
Replies: 11
Views: 570
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.
Forum: Pentax K-5 11-12-2019, 09:13 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By photoptimist
Replies: 11
Views: 570
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.
Forum: Pentax K-5 11-12-2019, 08:57 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By c.a.m
Replies: 11
Views: 570
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
Forum: Pentax K-5 11-12-2019, 07:11 PM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By jmacias
Replies: 11
Views: 570
You've done a great job here. Thanks for sharing.
Forum: Pentax K-5 11-12-2019, 03:34 PM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By StiffLegged
Replies: 11
Views: 570
Well done! :cool:
Forum: Pentax K-5 11-12-2019, 01:19 PM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By tvdtvdtvd
Replies: 11
Views: 570
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!
Forum: Pentax K-5 11-12-2019, 12:50 PM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By kiwi_jono
Replies: 11
Views: 570
Wow - great capture!
Forum: Pentax K-5 11-12-2019, 10:49 AM  
November 11, 2019 Mercury Transit - Orange County, California
Posted By ephophex
Replies: 11
Views: 570
Oh, that's a stunner!


Nice work.
Forum: Pentax K-5 04-18-2018, 05:07 AM  
K-5 For Astrophotography
Posted By geo444
Replies: 1,095
Views: 282,871
.
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 !
Forum: Pentax K-5 04-13-2018, 11:44 AM  
K-5 For Astrophotography
Posted By geo444
Replies: 1,095
Views: 282,871
.
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
.
Re-Scaled DxOmark Full-SNR Charts with base ISO & ISO 1600 Detection Thresholds :
.
Forum: Pentax K-5 10-30-2016, 04:36 AM  
K-5 For Astrophotography
Posted By Pete_XL
Replies: 1,095
Views: 282,871
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.
Forum: Pentax K-5 10-08-2016, 01:46 AM  
K-5 For Astrophotography
Posted By Pete_XL
Replies: 1,095
Views: 282,871
...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
Forum: Pentax K-5 09-24-2016, 10:14 AM  
K-5 For Astrophotography
Posted By Pete_XL
Replies: 1,095
Views: 282,871
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
Forum: Pentax K-5 09-30-2016, 03:31 AM  
K-5 For Astrophotography
Posted By k5astro
Replies: 1,095
Views: 282,871
Very nice! Super clear and sharp!
Forum: Pentax K-5 11-01-2015, 01:19 AM  
K-5 For Astrophotography
Posted By mikeSF
Replies: 1,095
Views: 282,871
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
Forum: Pentax K-5 10-13-2015, 01:53 PM  
K-5 For Astrophotography
Posted By fs999
Replies: 1,095
Views: 282,871
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

Forum: Pentax K-5 10-12-2015, 04:54 AM  
K-5 For Astrophotography
Posted By gazonk
Replies: 1,095
Views: 282,871
I was on holiday and didn't bring a tripod, so I only had the 55-300 and a window as support:


Blood Moon by Espen Vestre, on Flickr

I'm actually happier with the shot I took with my DA35 Ltd macro:


Blood Moon Over Speyer by Espen Vestre, on Flickr
Forum: Pentax K-5 10-05-2015, 11:14 AM  
K-5 For Astrophotography
Posted By XLXW
Replies: 1,095
Views: 282,871
Nice captures.
Forum: Pentax K-5 10-01-2015, 04:37 PM  
K-5 For Astrophotography
Posted By y0chang
Replies: 1,095
Views: 282,871
My composite of the eclipse. Unfortunately clouds came in when we hit totality. k5 + sigma 170-500mm at around 450mm
Forum: Pentax K-5 10-01-2015, 01:25 PM  
K-5 For Astrophotography
Posted By Pete_XL
Replies: 1,095
Views: 282,871
You find some in the Astrophotograph Group :)
in the discussion "Totality!".
this is mine............
Forum: Pentax K-5 03-16-2015, 08:42 PM  
K-5 For Astrophotography
Posted By y0chang
Replies: 1,095
Views: 282,871
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.
Forum: Pentax K-5 01-21-2015, 09:18 AM  
K-5 For Astrophotography
Posted By seti_v2
Replies: 1,095
Views: 282,871
Completed my horsehead in HaRGB. 11x1200" in h-alpha and 13x120" in RGB

HaRGB


Just Ha
Search took 0.00 seconds | Showing results 1 to 25 of 30

 
Forum Jump


All times are GMT -7. The time now is 11:15 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top