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First light with ASI224 and selfmade refractor

CMOS EAA dso equipment refractor
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#1 GazingOli

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Posted 05 August 2020 - 08:13 PM

Hey fellow electronic stargazers,

 

after building my custom triplet APO scope everything went significantly better in EAA for me - it really started working! So I decided to try with color instead of my ASI 120 mono. However people say that b/w cameras are more sensitive than color cameras, so I was cautious not expecting too much. Someone who knows advised me to buy an ASI 224 for my 80/480 APO, telling me that this camera should fit and is extremly sensitive. So I bought a used one for 200 EUR, looked like new though.

 

Would this bring back the trouble I had with my first scope (80/400 Fraunhofer) and the ASI 120?

 

I set up my Equipment - light polluted area with an international airport nearby and an almost full moon rising.

 

First try was M27 - looked ok but not really impressive compared to what I did last week with a borrowed ATIK Infinity. Little bit better though

 

M27.jpg

 

I think I have to improve in getting this one better.

 

Then I rushed to M20 (full moon rising!) - I tried it two weeks ago with the b/w ASI120 and wanted to know whether I could get it better in color.

 

M20.jpg

 

Well - that suits me really fine! Looks very good for me as a newbie to EAA and the very first time using this camera.

 

M17 is in the monthly challenge and I am nearby - so let us give it a try.

 

M17.jpg

 

Well, well - not bad either. And the best thing: camera and teleskope work together perfectly in SharpCap live stacking. Really like it should be - stacking like clockwork. No trouble at all!

 

Next object in the the monthly challenge list ist M102

 

M102.jpg

 

Slowly but surely I get aware that I obviously put together a fitting couple. I had some trouble in getting into EAA. I got the ASi 120 working with the new refractor. However I still had the problem that after a few frames I got rotating stars. So I usually stopped live stacking after 10 frames maximum. And I wondered what people meant when they were talking about images improving by the number of frames stacked. For me the first frame was often the best with the ASI 120 mono. And I did not know what to do about it.

 

When trying M51 last night was the time when I realized that patience with this new combi is key: just wait and see what ist happening. And I really never saw M51 live this way! Visually I do not see anything in my backyard and my EAA trials so far were not very encouraging. But last night it was:


Edited by GazingOli, 06 August 2020 - 05:01 AM.

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#2 GazingOli

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Posted 05 August 2020 - 08:16 PM

M51.jpg

 

after this one I wanted to try M81 - for me just a hazy ball so far. Could I get more with this camera?

 

M81c.jpg

 

Obviously yes - I can. And I am sure I will be able to improve this one too by the time.

 

What a night! I am really happy that I bought the ASI 224 and can truely recommend it for this kind of scopes! The good quality of the triplet APO lens sure helps to improve live stacking capability of SharpCap. I had one trouble when I had to remove the camera for a moment during the session. After that I was out of focus and did not realize it at first. Everything went bad at this point. Almost no live stacking possible anymore. When I got back in focus everything went perfect again. So sharp images are an issue for live stacking and a fraunhofer with f/5 focal ratio might cause some trouble as far as I learnt.

 

Good night - and for me it was really one

 

CS.Oli


Edited by GazingOli, 06 August 2020 - 05:08 AM.

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#3 Alien Observatory

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Posted 05 August 2020 - 08:41 PM

I think you are well along the learning curve for EAA.  These images are very good.  You also discovered that the smaller cams (224 / 290 / 385...) work very well with the smaller telescopes.  waytogo.gif 

 

As far as the ZWO 120, I could not get a decent image with it (I would consider it a guide cam only)..  Pat Utah :)


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#4 GazingOli

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Posted 06 August 2020 - 01:51 AM

The ASI120 for was a way to try low cost EAA. As the pixel size is equal to the 224 and it is b/w I thought it should be all right. But the best I could get out was something like this.

M20_Trifida.jpg

 

And I really do not understand why the rotating stars and why not with the ASI 224 even though there are 5 times more frames in the picture above (post #1, second image). Also the communication between camera and notebook (Core i5) works much better with the ASI 244. I seemed as if the ASI 120 did not want to let go the frames. Especially bothering when you try to focus oder center an object.

 

CS.Oli


Edited by GazingOli, 06 August 2020 - 02:25 AM.

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#5 gwal0

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Posted 06 August 2020 - 05:43 AM

Hi Oli,

as far as I see it, the "rotating stars" are "rotating hot pixels." I saw an image that you took after taking a dark frame, and there the "rotating stars" were gone.

Best regards, Gerd



#6 GazingOli

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Posted 06 August 2020 - 08:40 AM

Thanks Gerd, you are right! I double checked the protocol of the image and there was no darkframe subtracted.

 

Here is a different example without and with darkframe subtraktion using the ASI 120 mono:

 

M27ASI120ohneDark_verkl.jpg

 

M27ASI120mitDark_verkl.jpg

 

Thank you!

 

CS.Oli


Edited by GazingOli, 06 August 2020 - 08:45 AM.

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#7 mclewis1

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Posted 06 August 2020 - 12:20 PM

That last image looks familiar grin.gif

 

I don't want to hijack the thread into a different area (and I love those images from the imx224 based camera) but I thought I'd add some more pics from another ARO130 based camera (like the ASI120 mentioned above) for comparison. You can do some nice EAA work with really inexpensive USB cameras and even ones that use that much maligned ARO130 sensor. These images were taken 5 years ago. 

 

They were taken with a Mallincam AGm camera on a C11 at f3.3 (Meade reducer) on a CGE mount. The gain was at 7.5 (3/4 of the limit). They are single 30 second exposures with no stacking, no filters and no additional processing. The dark field correction was enabled in the MallincamSky software, the histogram was adjusted a little and they were converted to JPEG. The skies were just better than mag 5 and temperatures were in the low teens C (mid 50s F).

 

While most will attribute the images to the big C11 I did also shoot many of the same objects with a C6 on the same night with very very similar results. The real benefit here was from the f3.3 SCT focal reducer and not the extra aperture.

 

M27 - The dumbbell 

post-15367-0-49796800-1439239433_thumb.j

 

M17 - The swan

post-15367-0-46008000-1439239511_thumb.j

 

And my favourite (I love how deep this went) m57 - The Ring

post-15367-0-45153000-1439239388_thumb.j


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#8 GazingOli

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Posted 06 August 2020 - 01:20 PM

Hi Mark,

 

you are right, and I did some of it - see the other thread: https://www.cloudyni...ast/?p=10383160

 

However color is much more impressive for me and most important the ASI224 works much better with my computer (Core i5) which means more fun less frustration during the sessions!

 

CS.Oli


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#9 mclewis1

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Posted 06 August 2020 - 05:46 PM

Oli,

 

I agree there's no question about the benefit of color, particularly with an audience watching the images. But every so often we also seem to forget about how fun and effective a basic B/W camera can be too.

 

It's an interesting comment about the ASI224 camera working better than the ASI120. There have been numerous changes to the USB buffering in later cameras, and I also wonder if the USB chipset used is the same?



#10 alphatripleplus

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Posted 06 August 2020 - 06:08 PM

I have to agree with Mark - colour cameras are definitely favoured for outreach, while B&W can seem very one dimensional.

 

However, if your goal is to see as deep in as little time as possible, the most sensitive monochrome cameras will beat any colour camera. I started with an ASI224MC, but then moved to mono cameras in part because of their greater sensitivity. Both my mono cameras  - old CCD tech LodestarX2M and newer tech ASI290MM mini - blow away the ASI224MC in terms of sensitivity based on my experience with all three cameras.... but the monos are indeed one dimensional.smile.gif



#11 GazingOli

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Posted 07 August 2020 - 12:38 AM

I had a lot of trouble using the ASI 120 mono USB2 with my notebook (Core i5). Data did not seem to flow smoothly. Sometimes I had to wait more than 30 sec until a 6 sec frame was displayed on the screen. Even in daylight with short exposures it did not work smoothly. Very annoying if you try to find an object or get in focus.

 

So far nobody would explain what the problem was... I even changed the cable (same length!) With no effect.

 

The ASI 224 with USB3 works like a video cam by day, submits each frame as it is done. Just perfect.

 

I would of course appreciate having a more sensitive bw cam in addion to the ASI224 but I am insecure which one to try...

 

CS.Oli


Edited by GazingOli, 07 August 2020 - 12:39 AM.


#12 gwal0

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Posted 07 August 2020 - 08:48 AM

It looks as if there is already a recommendation from alphatripleplus, namely the ASI 290 MM mini (2 Mpx). But this is a guiding camera. I would therefore recommend the more expensive ASI 290 MM (same sensor), which has USB3 (it is unclear from the advertising for me, whether the mini version has USB3).

Best regards, Gerd


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#13 GazingOli

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Posted 07 August 2020 - 10:35 AM

Thanks Gerd for the advice! USB 2 might run me into trouble again.

 

According to the AGENA BUYER's GUIDE at 'Table 5: ZWO Astronomy Cameras - Additional Specifications' the ASI 290 Mini Mono is USB 2!

 

https://agenaastro.c...yers-guide.html

 

Anyway: I will enjoy color for a while now before I go for another bw cam smile.gif

 

CS.Oli


Edited by GazingOli, 07 August 2020 - 10:36 AM.

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#14 alphatripleplus

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Posted 07 August 2020 - 11:16 AM

It looks as if there is already a recommendation from alphatripleplus, namely the ASI 290 MM mini (2 Mpx). But this is a guiding camera. I would therefore recommend the more expensive ASI 290 MM (same sensor), which has USB3 (it is unclear from the advertising for me, whether the mini version has USB3).

Best regards, Gerd

For DSOs with the 1/3rd inch 290MM sensor, you don't need USB3 speeds. I can stack 1s or longer subs all night long at USB2 speeds with the 290MM mini with no latency. If on the other hand, you were interested in planetary imaging, where much higher frame speeds are used, USB3 would be the way to go.

 

For many people the bigger issue is that they may want a larger sensor than the 290 or 224, but I am not aware of a much larger sensor mono camera that matches the sensitivity of a 290MM (or my old LodestarX2M).


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#15 gwal0

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Posted 07 August 2020 - 03:03 PM

Thank you Errol for the clarification!

Best regards, Gerd


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#16 mclewis1

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Posted 07 August 2020 - 06:16 PM

For DSOs with the 1/3rd inch 290MM sensor, you don't need USB3 speeds. I can stack 1s or longer subs all night long at USB2 speeds with the 290MM mini with no latency. If on the other hand, you were interested in planetary imaging, where much higher frame speeds are used, USB3 would be the way to go.

 

For many people the bigger issue is that they may want a larger sensor than the 290 or 224, but I am not aware of a much larger sensor mono camera that matches the sensitivity of a 290MM (or my old LodestarX2M).

Yes, but ... lol.gif

 

I assume that the USB3 chipset offers some benefits over the older USB2 one regardless of the sensor used. It's not just about raw or potential line speed, there are quite a few variables (buffer size, processing speed, etc.) that will determine how "smoothly" a camera will operate with any particular host computer.


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#17 GazingOli

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Posted 08 August 2020 - 01:53 AM

It looks as if it is a little bit of a trial and error game...

 

CS.Oli




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