NGC4565 Experiment

[CCD-Freak]

So...I wanted to try something different to get "up close and personal" with galaxies so I tried an experiment imaging NGC4565 by attaching an ASI-482MC non cooled planet camera on my Ultima C8 on my GEM45 mount.  I figured that with enough exposures and dithering I could get a smooth image.  As usual everything was working against me...the seeing was bad, the scope was a bit out of collimation after the 200 mile road trip among other things.  I exposed 100 x 120 seconds captured and processed with Astroart 8.  But even with all the issues I think the experiment was a success.   I am a bit amazed that a non cooled planetary camera could work this well on a DSO.   I will be working with this setup during galaxy season to see if I can get it dialed in and hopefully I can get a night of good seeing to test it's full potential. 

[wimvb]

Very nice result.

My first dso astro camera was an ASI174MM with cooling. Sadly, this model is now discontinued by ZWO, and only the non-cooled and mini versions are still available. These models are marketed as solar camera and guide camera. The ASI174 has, just as the camera you are using, for todays standards a small sensor and large pixels (5.86 um). The large pixels gave the camera a large full well depth, but unfortunately also a high read noise, and it had strong amp glow. Nonetheless, it was in my opinion a great dso camera for galaxies, and very much underrated.

I believe that @tomato uses the ASI178 camera for dso imaging with his Esprit refractor. This is also one of the older generations of ZWO astro cameras. This camera also has a small sensor and very small pixels. It was also offered in cooled and uncooled versions. Just as the ASI174, the cooled version is no longer available, and the uncooled version is marketed as a planetary camera.

Paired with the right optics, these cameras can perform very well as galaxy hunters, providing a suitable crop factor and small files.

Edited April 22, 2023 by wimvb

[tomato]

Great result. As @wimvb has mentioned, I opted for ASI178 cameras to use with my Esprit 150 F7 refractors, albeit retrofitted with Peltier coolers to help stabilise the operating temperature to improve dark calibration in particular, lots of amp glow with this sensor. I also bin 2x2 to image at 0.94 arcsec per pixel which is frankly still too optimistic for my sky conditions.

However, I have been satisfied with the results but ironically I’m about to embark on an experiment to see if a RASA8/IMX571 combination coupled with a radical crop of the image can perform at least as good if not better than my current set up.

That’s AP for you, always something new to try.😊

 

[CCD-Freak]

This is what ZWO says about the ASI482MC and the large 5.8 um pixel size are some of the reasons I decided to try it for galaxies.

SNR1s=0.08lx

Sony is introducing SNR1s [lx] as an index used to quantitatively evaluate picture quality at low illumination. SNR1s [lx] is an acronym consisting of “SNR” (Signal-to-Noise Ratio), “1” (represents that the signal level when noise = 1 is 1), and “s” (for Security). The lower this value is, the greater the image quality will be at low illumination.

The 5.8um large pixel size allows unprecedentedly low SNR1s value of 0.08lx for ASI482MC. While ASI385MC is 0.13lx, you may see it is almost 2 times better, which brings the camera a fantastic nickname – “The King of the Night”.

 

The amp glow is not too bad either.

Edited April 22, 2023 by CCD-Freak

[wimvb]

@CCD-Freak does the sensor have amp glow?

[CCD-Freak]

The ASI482MC does have some amp glow but it calibrates out easily.  It has seems to have much less amp glow than my ASI178MM.   Here is a single 120 second sub.

Edited April 22, 2023 by CCD-Freak