Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
06-29-2018, 08:52 AM   #1
Senior Member




Join Date: Jan 2018
Posts: 129
Pentax Q for astrophotography beginner?

Anyone tried an equatorial mount used with a Pentax QS1 to shoot the Milky Way? Or is it a lost cause with such a small sensor...

Interested to hear from any astrophotographers pushing the limits using the Q 😅

06-29-2018, 12:06 PM - 1 Like   #2
Pentaxian
photoptimist's Avatar

Join Date: Jul 2016
Photos: Albums
Posts: 2,584
An equatorial mount certainly enables both longer shutter speeds and stacking that can overcome the limits of the small sensor.

The biggest challenge is finding a decent wide-angle lens unless you want the bigger challenge of building your Milky Way shot from a bunch of tiles.

Good luck!
06-29-2018, 09:19 PM - 1 Like   #3
Site Supporter
Site Supporter




Join Date: May 2016
Photos: Albums
Posts: 1,223
Hopefully they'll announce a Q-S2 with GPS and an Astrotracer!
06-30-2018, 12:20 AM   #4
Senior Member




Join Date: Jan 2018
Posts: 129
Original Poster
QuoteOriginally posted by leekil Quote
Hopefully they'll announce a Q-S2 with GPS and an Astrotracer!
I just now looked up ASTROTRACER | GPS UNIT O-GPS1 | RICOH IMAGING

And am only now aware of such a use of sensor shift exists. That’s amazing!

07-01-2018, 11:01 AM - 3 Likes   #5
Loyal Site Supporter
Loyal Site Supporter




Join Date: May 2007
Location: Flagstaff, Arizona
Posts: 298
QuoteOriginally posted by 2old4toys Quote
Anyone tried an equatorial mount used with a Pentax QS1 to shoot the Milky Way? Or is it a lost cause with such a small sensor...

Interested to hear from any astrophotographers pushing the limits using the Q 😅
Well in a few words: It ain’t the best!

In a few more words, ....

I went out on the evening of June 29 and took a bunch of Q7 shots of the sky, the last one followed a minute or two later by a couple more with my K-1. Both cameras went for a ride on my polar tracking mount, although that was hardly necessary for the wide field of view and exposure length I used.

The exposures used the same settings for both cameras: Manual, with ISO 400, aperture f 4.0, and exposure time of 30 seconds. White balance was daylight for both cameras, as well.

The Q7 had the 02 wide angle zoom lens on it, set at its widest: 5 mm focal length, equivalent to about 25 mm on full frame. For the K-1, I used my 20-35 mm FA zoom, set at 20 mm. In retrospect, I guess I should have set it at 25 mm, although that would not have made much difference.

The shots shown here were taken at about as late as I could go before local moonrise - around 9:20 PM local (standard time here in Arizona in the summer time). Even so, the K-1 frame is affected by the rising moon.

If all you want are wide field views showing the star clouds of the central Milky Way, the Q7 almost works. See picture 2 for the full field Q7 view (downsized to 1280 pixels across). Compared to the K-1 version (picture 3 below), the star clouds show up comparably. Both frames have been brightened and contrast enhanced in Photoshop Elements. The horizon appears tilted in these images because the cameras are aligned with the celestial coordinate system, courtesy of the polar mount. The celestial equator lies a few degrees below the top of the frames, and runs parallel to the top edges.

When you zoom in, though, the K-1 wins hands down. Pictures 4 (Q7) and 5 (K-1) show a zoomed-in area near Saturn (the brightest object, left of center in each frame). The field of view of each zoom is very similar, but you can see many more, and crisper, stars in the K-1 image. For the Q7, the limiting magnitude is around 6.5, whereas the K-1 goes to about 9th magnitude - a factor of almost 10 fainter. (The magnitude system is the astronomers’ backwards, logarithmic scale for the brightness of celestial objects - bigger numbers are fainter. A step of 1 magnitude corresponds to a factor of about 2.51 in brightness - more precisely, the fifth root of 100 for you mathematicians!) The Q7 limit is probably due to the higher noise in the Q7 images, even at ISO of just 400.

As soon as I set up, I (re)discovered perhaps the most limiting factor in using the Q7 for astro photography: the longest convenient exposure is only 30 seconds. There is a “bulb” exposure setting - BUT YOU CAN NOT PLUG IN A REMOTE CONTROL - there is no socket on the camera. The only way to get an exposure longer than 30 seconds is to hold the shutter button down by hand - not a good idea for long guided exposures!!! - or to use an infrared remote. Of course, you can always stack multiple frames, but that’s a pain!

I also discovered that the FA 20-35 zoom lens has an awful lot of coma flaring away from the center of the image at 20 mm zoom and f 4.0!

The first picture shows the diminutive Q7 perched atop my fairly hefty tracking mount and its home-made mounting bracket.

I was shooting both cameras in RAW+. If anybody wants the original RAW files (they are big!) to try their own PP, let me know.
Attached Images
View Picture EXIF
PENTAX K-1  Photo 
View Picture EXIF
PENTAX Q7  Photo 
View Picture EXIF
PENTAX K-1  Photo 
View Picture EXIF
PENTAX Q7  Photo 
View Picture EXIF
PENTAX K-1  Photo 
07-01-2018, 10:12 PM - 1 Like   #6
Senior Member




Join Date: Jan 2018
Posts: 129
Original Poster
Thanks @AstroDave your rig is impressive and observations very useful to me!
I do have an IR remote at the ready for hands free triggering and bulb mode as an option.
Bought the inexpensive Sightron nano.tracker, supposedly the smallest portable equatorial mount. I really like the idea of being able to pack this with me on holiday trips.

Indeed using a Q-S1 for a successful wide shot of a starry Milky Way night sky with some treeline/ hillside silhouette is my aim.

If stacking helps reduces noise sufficiently, I’m willing to try it. Will download Registax in standby.

I already tried a shot at 300mm with the nano.tracker in lunar mode and sure enough it was tracking an albeit less demanding bright moon, keeping it in frame and let me use the lowest ISO and hence no bad noise.

Waiting eagerly for a nice clear moonless night for some attempts at the sky at night.
07-02-2018, 12:55 AM - 4 Likes   #7
Forum Member




Join Date: May 2011
Location: Marseille Provence
Photos: Albums
Posts: 91
Pentax Q to shoot the Milky Way = Wide Field Astro-Photo ??

QuoteOriginally posted by 2old4toys Quote
- Anyone tried an Equatorial Mount used with a Pentax QS1 to shoot the Milky Way ?
- Or is it a lost cause with such a small sensor...
- Interested to hear from any astrophotographers pushing the limits using the Q
.
The Pentax Q(x) with their tiny sensors are Not at their best for Wide Field Astro-Photography
for Wide Field, you'd better use an APS-C (or a FF) sensor !
+ you'd find more choice in (Ultra-)Wide-Angle lenses for large sensors (Samy)

But the Pentax Q(x) with their tiny sensors are at their Best for Long Reach Astro-Photography
Why ?
Simply because thousands of Deep Sky Small Objects will Never fill an APS-C sensor !
Even mounted on a very affordable SkyWatcher 1000mm Newtonian !
+ these tiny sensors are Very Sensitive ~ DxO ISO 5680 FF-Equivalent for the 1/2.3" in the Pentax Q, Q10 !

a Pentax Q10 w/ the Pentax Adapter on a Skywatcher 200/1000 Newtonian :
= 50 x 30 seconds @ ISO 1600 stacked with DSS 3.2
it's Messier 27 Nebula at 1350 L-Y :



Other (9) Long Reach Astro-Photographies taken with a Pentax Q10 :
The Astro-Q Club! - Page 10 - PentaxForums.com

Good Luck !

Last edited by geo444; 07-03-2018 at 11:00 AM.
07-02-2018, 05:47 AM   #8
Loyal Site Supporter
Loyal Site Supporter




Join Date: May 2007
Location: Flagstaff, Arizona
Posts: 298
QuoteOriginally posted by geo444 Quote
a Pentax Q10 w/ the Pentax Adapter on a Skywatcher 200/1000 Newtonian :
= 50 x 30 seconds @ ISO 1600 stacked w/ DSS 3.2 :
VERY impressive!! How easy is Deep Sky Stacker to use?

I'll have to get out my DA* 300mm and try it on the Q7!

07-02-2018, 07:14 AM - 3 Likes   #9
Forum Member




Join Date: May 2011
Location: Marseille Provence
Photos: Albums
Posts: 91
Pentax Q better for Long Reach Astro-Photography !

QuoteOriginally posted by AstroDave Quote
VERY impressive!! How easy is Deep Sky Stacker to use?

I'll have to get out my DA* 300mm and try it on the Q7!
.
Thanks Dave !

DeepSkyStacker will not be a problem, it will simply do the job as usual :
http://deepskystacker.free.fr/english/userguide.htm
IMO, the simplest Stacking Tool

my BIG problem at Marseille is the Atmosphere's Stability
with your DA* 300mm on a Pentax Q, you'll see the Stars Blinking, Ok !
with a 1000mm you'll see the Stars Dancing...

( 1000mm on a Pentax Q = the same Reach as a Celestron C14 on an APS-C ! )

Many times, I've had to Trash ~ 50% of my 30 sec. subs ~
Here, the Sun Heats the Sea all the day long for more than 300 Days per Year,
at Night, usually the North Wind brings Cold Air over the Warm Sea !

The Precision / Sharpness of your Results depends on your Atmosphere's Stability...
- else it depends on your Determination to Trash every Blurred Sub !

M-106 Galaxy : ~25 Million Light-Years from Q10 - apparent core size 2.5'x 6'
Magnitude minus Air- and Dust- and Light-Pollution worse than 10 ?
M-106 Galaxy : Q10 + SkyGlow Filter + Skywatcher 200/1000 = 88 x 30 seconds @ ISO 1600
Stacking = DeepSkyStacker 3.3



I highlighted 2 Stars close to the Galaxy :
- the Yellow one named USNOA2-1350-08095435 : Magnitude 17.3
- the Blue one named USNOA2-1350-08095450 : Magnitude 17.1
the distance in between is about ~8.5 arc second

Dumbbell gets More Pixels :
Messier 27 as seen from a Canon Eos 20d = 2.4 MPixel / cm˛
-vs- shot by the Pentax Q10 = 44 MPixel / cm˛
Both were shot at ISO 1600 :
https://www.dpreview.com/galleries/7467909648/photos/3037792/dumbbell-gets-more-pixels

Good Luck !

Last edited by geo444; 07-03-2018 at 11:08 AM.
07-02-2018, 09:42 AM   #10
Loyal Site Supporter
Loyal Site Supporter
Mikesul's Avatar

Join Date: Sep 2009
Location: Phoenix, AZ
Posts: 4,851
These astro pictures are just so cool!
07-03-2018, 09:24 AM   #11
Site Supporter
Site Supporter




Join Date: Sep 2006
Location: midwest, United States
Photos: Gallery
Posts: 3,514
Fabulous images geo444. You're pushing the Q to maximum. Well done. Wouldn't the Q also do well with the planets? They rarely fill the frame either. Some people use webcams hooked to a telescope. 100s of frames reduce noise greatly.
Thanks,
barondla
07-03-2018, 10:11 AM   #12
Loyal Site Supporter
Loyal Site Supporter
Mikesul's Avatar

Join Date: Sep 2009
Location: Phoenix, AZ
Posts: 4,851
The wonders of this little camera just never quit! Love these astro shots.
07-03-2018, 11:30 AM - 3 Likes   #13
Forum Member




Join Date: May 2011
Location: Marseille Provence
Photos: Albums
Posts: 91
Pentax Q10 sensor ranking among the Sony Starvis Sensors

QuoteOriginally posted by Mikesul Quote
These astro pictures are just so cool !
QuoteOriginally posted by Mikesul Quote
The wonders of this little camera just never quit ! Love these astro shots.
.
Thank you very much Mikesul !

QuoteOriginally posted by barondla Quote
Fabulous images geo444. You're pushing the Q to maximum. Well done...
.
Thank you very much Barondla !
as I said 2 posts before :
these tiny sensors are Very Sensitive ~ DxO ISO 5680 FF-Equivalent for the 1/2.3" in the Pentax Q, Q10 !
=> see Pentax Q10 sensor ranking among the Sony Starvis Sensors below ->

QuoteOriginally posted by barondla Quote
Wouldn't the Q also do well with the Planets ? They rarely fill the frame either. Some people use webcams hooked to a telescope...
.
No reason the Q won't succeed with Planets : they are Hundreds of times Brighter than Galaxies / Nebulae !
you'll have to use the Q, Q10 in Video-Mode, then Convert the AVI file to PNG pictures
then you'll have to Discard every blurred picture to keep the best
then download RegiStax* or a similar Stacker...
Good Luck Barondla...

DeepSkyStacker align different subs using the Bright Stars Relative Coordinates
RegiStax align the pictures ignoring the dimmer stars
because of Shorter Exposure

QuoteOriginally posted by barondla Quote
... 100s of frames Reduce Noise greatly. Thanks, barondla
Don't worry about Noise, Planets are Bright, you'll have to Reduce Blurring instead !
- the Max Apparent Size of Mars is less than 25 Arc-Second...
watch 8.5 Arc Second on my M-106 :
https://www.pentaxforums.com/forums/136-pentax-q/369368-pentax-q-astrophotog...ml#post4342865

Pentax Q10 sensor ranking among the Sony Starvis Sensors
:



Sony Starvis Criteria : BSI Sensors > 2000 mV / µm˛ @ f/5.6 in 1 sec. exposure :
CMos Sensor Sensitivity Measurement = MilliVolts per SquareMicroMeter = mV / µm˛ @ f/5.6 in 1 second accumulation
Datas from Sony Sensors Specification Sheets

Verified Calculations are here :
Maxi Astro (Ciel Profond) au NX mini...
Maxi Astro (Ciel Profond) au NX mini...



Last edited by geo444; 07-04-2018 at 12:08 AM.
07-03-2018, 04:47 PM   #14
Senior Member




Join Date: Jan 2018
Posts: 129
Original Poster
@geo444 am I looking at this right that the bigger Q7 sensor is actually “less” sensitive than the smaller Q10?

Do we place the QS1 as the same with the Q7 and the Q at the same place as the Q10?
07-03-2018, 07:11 PM   #15
Loyal Site Supporter
Loyal Site Supporter
Mikesul's Avatar

Join Date: Sep 2009
Location: Phoenix, AZ
Posts: 4,851
QuoteOriginally posted by 2old4toys Quote
@geo444 am I looking at this right that the bigger Q7 sensor is actually “less” sensitive than the smaller Q10?

Do we place the QS1 as the same with the Q7 and the Q at the same place as the Q10?
Yes the QS1 should have the same sensor as the Q7 just as the Q10 was the same as the original Q. The Q7 sensor is a bit larger than the Q sensor which for most puposes makes it better but the Q sensor will give a bit more reach. The wide angle 08 will be a bit wider on the larger Q7 sensor. I do not think it has a lot to do with sensitivity but there may be something about the later cameras which does that.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, fire, midnight, mirrorless, pentax, pentax q, pentax q10, pentax q7, q-s1, q10, q7, summer, tablet, time
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Astrophotography + SMC Pentax-FA* 24mm F2 AL [IF] bnhoj Pentax SLR Lens Discussion 13 09-09-2018 01:33 PM
Landscape/Astrophotography lenses for Pentax K-30 tigerz1995 Pentax K-30 & K-50 2 02-18-2018 08:25 AM
Pentax 20mm f2.8A or Lawoa 15mm f4 for Astrophotography? stemked Pentax K-1 3 05-04-2017 07:49 PM
Pentax 300mm lenses for Astrophotography LennyBloke Pentax SLR Lens Discussion 7 09-09-2016 09:23 AM
Beginner photographer, beginner with Pentax W.Scott Welcomes and Introductions 11 05-11-2014 11:44 PM



All times are GMT -7. The time now is 08:55 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