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New Camera – EAA with ZWO ASI224 with NexStar 8SE

EAA dso equipment ccd observing
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#1 Astrojedi

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Posted 11 August 2015 - 02:26 PM

Wanted to share my experience of using ZWO’s ASI224 camera for EAA.

 

ASI224 is an interesting camera from an EAA perspective. Specs include: OSC, 1/3” CMOS uncooled sensor, 1-2e read noise, 75%-80% peak QE, high & uniform RGB IR WL response and 9k well depth.

 

 

Note the discussion here is a continuation of this thread (http://www.cloudynig...o-alt-az-mount/) in the CCD & Imaging forum. As I am now leaning more towards EAA with this camera I decided to share my live viewing experiences in the EAA forum. I will still continue posting any results/experience with imaging using a post processing workflow in the CCD forum.

 

Below are some results from last night and details on settings and how the camera performed.

 

My setup for the night included: NexStar 8SE (on an Alt Az mount) @ ~f/3.7, ASI224, FireCap for image capture (FITs), AstroToaster for live stacking and a heavily light polluted backyard.

 

I typically take 4 sec subs and find that usually 25-50 subs are sufficient to bring out detail in brighter DSOs (i.e. total integration time of ~2 minutes or less) but I let it run to 200 subs in the background as I am viewing the object and playing round with the settings.


Edited by Astrojedi, 11 August 2015 - 03:03 PM.


#2 Astrojedi

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Posted 11 August 2015 - 02:38 PM

Used 13x4s dark frames for calibration of all images.

 

M8: 50x4s (200 sec total integration time) Gain 300

M8 50x4s G300

 

M16: 50x4s (200 sec total integration time) Gain 300

M16 Eagle 50x4s G300

 

M17: 50x4s (200 sec total integration time) Gain 300

M17 50x4s G300

 

 

M20: 50x4s (200 sec total integration time) Gain 300

M20 50x4s G300

Edited by Astrojedi, 11 August 2015 - 05:45 PM.

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#3 RandyC

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Posted 11 August 2015 - 07:51 PM

Hi, i think those are excellent. I would love to try those short exposures on a big dob someday. I never stack in EAA but if it made a difference in getting people off ladders, i would. What software are you using? If the total exposure time is 200sec, how long are you actually taking images and stacking before ur done? It would be great to show someone at Stellafane or another star party that their giant F5 dob is capable of ladderless EAA.


Edited by RandyC, 11 August 2015 - 10:56 PM.


#4 Astrojedi

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Posted 12 August 2015 - 10:23 AM

RandyC, I think this will work well on a Dob. The one challenge I faced when taking exposures <1 sec with my 8 inch SCT at f/5 was that stacking was a challenge for certain fainter DSOs due to lack of sufficient alignment stars. With a larger Dob you may not face that problem.

 

Also given the size of the sensor there may be FOV considerations. Not sure if you are able to use a FR.

 

Have you seen this thread: http://www.cloudynig...24#entry6660100

 

There seems to be sufficient SNR to stack. You could try Astrotoaster or DSS Live.

 

For the images above I have taken 4 second exposures using FireCap in FIT format and live stacked using Astrotoaster 

 

 


Edited by Astrojedi, 12 August 2015 - 11:12 AM.


#5 Chevelle72

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Posted 12 August 2015 - 12:11 PM

Wow, those are terrific images! Correct me if I'm wrong but is this the camera that sells for around 350 to 400 dollars? 



#6 Astrojedi

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Posted 12 August 2015 - 12:48 PM

Yes, it is around $350! Very versatile camera IMO. I use it for guiding, viewfinding and EAA.


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#7 Astrojedi

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Posted 12 August 2015 - 12:53 PM

More images from last night. Inspired by Don from Hawaii I deployed my Orion 50mm f/3.2 guide scope for some "wider" field images with the ASI224.

 

The fast focal ratio combined with the high sensitivity camera is a very satisfying combo.

 

M8 Lagoon 30x7sec

M8 Lagoon 30x7s 50mm

 

M17 Swan 30x7s

M17 Swan 30x7s 50mm

 

C14 Double Cluster 5x5s

C14 Double Cluster 5x5s 50mm
 
M31 Andromeda 50x7s
M31 50x7s 50mm
 
M31 is a hard subject for EAA as the dust lanes require long exposures and stretching completely blows out the core. In about 3 minutes worth of exposures I started to see some detail. The attached image is a ~350 sec integration. Not bad for a 50mm scope!

 


Edited by Astrojedi, 12 August 2015 - 01:24 PM.

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#8 A. Viegas

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Posted 12 August 2015 - 01:28 PM

Impressive shots.  EAA has come a long way and there are so many new camera options popping up now, its really great.  Thanks for the ZWO224 pictures.   What is the longest integration you can do with the 224? 

Al



#9 Astrojedi

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Posted 12 August 2015 - 03:00 PM

In theory no limit on total integration time but would need to stack a lot of subs (I would not do very long single exposures with this camera).

 

Given that for EAA I mostly use an Alt Az mount usually after 10-20 minutes field rotation starts to impact image quality (depending on where you are pointing). With a properly polar aligned EQ mount that restriction is removed (but personally if I spend more than 10-15 minutes integrating I feel I lose the 'live' aspect of observing).


Edited by Astrojedi, 12 August 2015 - 03:01 PM.


#10 Stew57

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Posted 13 August 2015 - 12:10 PM

I am more of the minute or maybe two is starting to get too long for live view crowd myself. Your images are great however. What is the longest single exposure that you can do with this camera?



#11 Astrojedi

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Posted 13 August 2015 - 01:06 PM

Mark, I am on the same page. I typically don't do integrations longer than 1-2 minutes for live viewing. Usually within a minute I start to see quite a bit of detail. 2-3 minutes makes it look nicer. But if desired one can push the total exposure time to 10-15 mins for faint DSOs if not viewing in a crowd.

 

As this is not a video camera the longest single exposure you can do is quite a bit longer  (1000s) but without cooling it would not yield good results.


Edited by Astrojedi, 14 August 2015 - 09:51 PM.


#12 Alex Parker

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Posted 14 August 2015 - 09:30 AM

Hi,

 

Nice results - really illustrates well the utility of stacking very short exposures.  The amount of detail and brightness you got with the 50mm is impressive.



#13 RafaelP

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Posted 14 August 2015 - 01:13 PM

Based on your thread I purchased the same camera!  I will be using it with a Celestron C5 and an iOptron SmartEq Pro.  Look forward to seeing more images and any tips you may have.

 

I live in heavily light polluted Manhattan, so I may only be using it for the planets while in the city.

 

~Rafael



#14 Astrojedi

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Posted 14 August 2015 - 09:49 PM

Thanks Alex

Rafael, congrats on the purchase. The camera is straight forward to use but let me know if you have any questions.

#15 DonBoy

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Posted 15 August 2015 - 03:09 PM

 

My setup for the night included: NexStar 8SE (on an Alt Az mount) @ ~f/3.7, ASI224, FireCap for image capture (FITs), AstroToaster for live stacking and a heavily light polluted backyard.

 

I have a similar setup as yours.  I tried to use FITs and the final stacked image was b&w, no color.  Inorder to get color I had to use the Debayer option and work in BMP which is 8bits.  

 

So my question is were you able to get color using FITs extension in your stacks and how or did you resort to colorizing your images?

 

 



#16 Astrojedi

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Posted 15 August 2015 - 04:12 PM

 

 

My setup for the night included: NexStar 8SE (on an Alt Az mount) @ ~f/3.7, ASI224, FireCap for image capture (FITs), AstroToaster for live stacking and a heavily light polluted backyard.

 

I have a similar setup as yours.  I tried to use FITs and the final stacked image was b&w, no color.  Inorder to get color I had to use the Debayer option and work in BMP which is 8bits.  

 

So my question is were you able to get color using FITs extension in your stacks and how or did you resort to colorizing your images?

 

 

Don, before I start AstroToaster I open DSS and set the debayer option there for the FITs files. Then as per my understanding when AstroToaster runs it uses these settings from DSS.


Edited by Astrojedi, 15 August 2015 - 04:12 PM.


#17 DonBoy

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Posted 15 August 2015 - 05:02 PM

Well I've done that also and it didn't exactly work.  But I just figured it out.   The issue wasn't AstroToaster/DSS, the issue is in FC.  There is no FITs setting if Debayer is checked.   I had to set FC up for FITs in 16bit mode and then I was able to get color information in the FITs lights, but I lost color on the FC preview screen.  So if I wanted to see color on the preview I had to check off Debayer but then I wouldn't get color FITs captures.  It would be nice if one could preview in color and capture in color FITs.

 

Link to some 8bit images from last night.

 

http://www.cloudynig...22#entry6733147


Edited by DonBoy, 15 August 2015 - 05:05 PM.


#18 Astrojedi

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Posted 15 August 2015 - 05:35 PM

Ok. I never check the debayer option in FireCap. Never worked for me. The image becomes a sea of R G B pixels.

 

If you want to preview and image in color using FITs, Sharpcap 2.6 will do it. But really would love to have a LL equivalent for this camera.

 

Really good results. Surprised at the color you got in just 10x10 stacks.



#19 DonBoy

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Posted 15 August 2015 - 06:30 PM

Astrojedi,

 

The camera is very sensitive and low noise, the only weak point I see is it's FW (fill well) it easily saturates.  This became evident when I tried to image M92 and the cental core of stars caused excessive blooming and color distortion. 

 

I'll try and get on NSN tonight with the ASI224 and give it ago with 16bit FITs.


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#20 wenjha

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Posted 16 August 2015 - 02:55 AM

Astrojedi,

 

The camera is very sensitive and low noise, the only weak point I see is it's FW (fill well) it easily saturates.  This became evident when I tried to image M92 and the cental core of stars caused excessive blooming and color distortion. 

 

I'll try and get on NSN tonight with the ASI224 and give it ago with 16bit FITs.

the FW is small but dynamic range is very high of this sensor

dynamic range = FW/RN(read noise)



#21 Astrojedi

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Posted 16 August 2015 - 10:52 AM

Don,

Yes, I was discussing this exact topic in the CCD thread. The well depth is only 9k and given the high sensitivity of the camera it saturates very quickly.

 

But the key attribute of this camera, which is why I bought it is the low read noise (1-2e) which means I don't need long exposures to overcome the read noise. In fact a 5s exposure is equivalent to potentially a 15-20s exposure on the Lodestar and still achieves very good dynamic range (via additional subs).

 

For DSOs with very bright regions I don't use longer than 5s exposures (you really don't need longer - in fact I find I start to lose information). You can also reduce the gain to 250 which helps a lot (also with amp glow).

 

Here is an example of M13 using 5s subs (EDIT: Also attached a single sub for comparison - compressed JPG). Although I got a very good single 5s exposure I let it run to 50 subs which allowed me to use minimal stretch and not blow out the core. Using 10s exposures I could not avoid a blow out.

 

M13 50x5s G300

 

Hope this helps. I will try to join the NSN broadcast.

Attached Thumbnails

  • M13 1x5s G300.jpg

Edited by Astrojedi, 16 August 2015 - 11:07 AM.

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#22 Astrojedi

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Posted 16 August 2015 - 11:40 AM

Galaxy hunting through a light layer of clouds. The objects were ~20 deg above the horizon when viewed. Used AstroToaster.

 

Tried 2x2 binning on the M33 which helped with sensitivity but the clouds and light pollution both impacted contrast quite a bit...

 

Will try some post processing on the M33 as there is quite a bit of data in the stacked image but AstroToaster is limited in its processing capabilities.

 

Same setup as described in the first post. Exposure times:

 

M33 150x5s

M102 40x5s

Attached Thumbnails

  • M33 Trianglum 150x5s 2xbin 2.jpg
  • M102 40x5s G300.png

Edited by Astrojedi, 16 August 2015 - 11:41 AM.

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#23 DonBoy

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Posted 16 August 2015 - 02:11 PM

 

Here is an example of M13 using 5s subs (EDIT: Also attached a single sub for comparison - compressed JPG). Although I got a very good single 5s exposure I let it run to 50 subs which allowed me to use minimal stretch and not blow out the core. Using 10s exposures I could not avoid a blow out.

 

Astrojedi,

 

Using this camera is certainly a new adventure and a departure from using my MallinCam X2.  It takes a lot more software and more effort to get decent results.  We all have our own techniques and mine needs a lot of work.  I'm not convinced that 5sec or 10sec is the ideal exposure setting.   Infact, I don't know what is or what are the best settings, that will all depend on conditions and trial and error.    My results using 10sec exposures and a gain of 300 worked well for me for a first go, but maybe I could lower the gain and run more exposure or more stacks, I'm not experienced enough to know.  But assuming good conditions it still is something that only experimentation and time will tell.



#24 Astrojedi

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Posted 16 August 2015 - 06:43 PM

 

 

Here is an example of M13 using 5s subs (EDIT: Also attached a single sub for comparison - compressed JPG). Although I got a very good single 5s exposure I let it run to 50 subs which allowed me to use minimal stretch and not blow out the core. Using 10s exposures I could not avoid a blow out.

 

Astrojedi,

 

Using this camera is certainly a new adventure and a departure from using my MallinCam X2.  It takes a lot more software and more effort to get decent results.  We all have our own techniques and mine needs a lot of work.  I'm not convinced that 5sec or 10sec is the ideal exposure setting.   Infact, I don't know what is or what are the best settings, that will all depend on conditions and trial and error.    My results using 10sec exposures and a gain of 300 worked well for me for a first go, but maybe I could lower the gain and run more exposure or more stacks, I'm not experienced enough to know.  But assuming good conditions it still is something that only experimentation and time will tell.

 

 

Yes, definitely a different animal. It requires a different approach as compared to both traditional imaging and video cameras. Unfortunately we don't have a LL like SW experience yet for this camera which would definitely help.

 

With regards to settings, the additional control over camera settings is both a blessing and a curse. Allows for better output if you are willing to invest the time but makes for a steeper learning curve.

 

I am hoping that through my experimentation I can find a more repeatable process for successful viewing as using shorter exposures definitely carries a significant benefit in terms of EAA for anyone with a typical Alt Az goto mount.

 

Also looking forward to Atik's solution as they were producing some decent results using 4-5s exposures in that video. But that is likely to be 3x the cost of this camera.



#25 Astrojedi

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Posted 18 August 2015 - 03:03 PM

A couple of Globs using ASI224, FireCap and AstroToaster. Tried a lower gain setting (250) to see if there is any impact on dynamic range or color. I think there was some improvement but had to take 5-10 more subs to compensate.

 

Saw a lot of detail in ~10 subs for both and the noise was also pretty well controlled. The additional time really helped with dynamic range and also SNR which allows for a less aggressive stretch

 

M28 22x3s

M28 22x3s Gain250
 
M22 40x5s
M22 40x5s Gain250

 

This weekend I will dust off my Lodestar X2C and LL and try to compare results. I think ASI224's sensitivity is comparable (potentially better in IR) but hard to beat the superior user experience of the LL software (no need to juggle 2 apps).


Edited by Astrojedi, 18 August 2015 - 03:11 PM.

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