Choosing a sensor/camera EAA/EEVA (IMX385/IMX482/IMX485)

[JediScp]

Hello,

I've wrongly opened a topic on "Getting started with imaging" where I as was asking for a suggestion on choosing a planetary camera for EAA/EEVA. I decided to open a new topic here despite being a matter frequently discussed because I'm still struggling to make a decision about choosing  and buying a dedicated camera.  I've been gathering elements about 4 color cameras which I consider viable for my low budget. I'm not considering mono cameras unless the outcome is really outstanding compared to color. Also I'm avoiding cameras as ASI294MC/ASI294MC PRO/ASI533MC PRO/ASI183MC PRO or others because they largely exceed my budget.

Can anyone help me taking a decision? I will use in a Orion Optics VX6 Advanced in a HEQ5 GoTo mount. I hope this topic helps other people with the same doubts.

The ZWO ASI482C in my setup although it may seems to have good features for EAA/EEVA it should require a barlow (astronomy.tools / CCD suitability)  when the seeing is Good or Exceptional. Does it matter very much in DSO under such conditions? My main observation preferences are globular clusters, medium sized galaxies/nebulae. Planetary AP (already happy using a DSLR in a manual GSO 254/1250 dob) and autoguiding come as add values, so I'm not really focusing on these.

Thank you so much in advance,

Clear skies

In 150/750 Reflector	ZWO ASI385C	ZWO ASI482C	ZWO ASI485C	QHY 5III 485C
Color/Mono	Color	Color	Color	Color
Cooled	No	No	No	No
Sensor	IMX385	IMX482	IMX485	IMX485
Pixel Size (microns)	3,75	5,8	2,9	2,9
Resolution (not so relevant)	1936 x 1096	1920 x 1080	3840 x 2160	3864 x 2180
Resolution per pixel (ideal between 1 and 2)	1,03	1,6	0,8	0,8
Megapixels	2.12	2.07	8.29	8.4
TFOV (in my telescope)	0.55° x 0.31°	0.85° x 0.48°	0.85° x 0.48°	0.85° x 0.48°
QE (higher = better)	80%	85%@530nm	85%@530nm	High (?)
Read Noise (lower = better)	0,7e-2,7e	1,5e-12,9e	0.7e-6,4e	1.0e- to 2.4e- Standard Mode, 0.6e- to 1.09e- sHGC Mode
SNR1 (lower = better)	0,13lx	0,07lx	0,18lx	0,18lx
FPS (in full resolution) | not so relevant for EAA	67 (12 bit)	57,50 (12 bit)	27,5 (12 bit)	18,5 (16 bit)
Internal Memory	none ?	none ?	none ?	128DDR
Exposure Range	32 μs ~ 2000s	32 μs ~ 2000s	32μs~2000s	10μ-300s
Full Well Depth (higher = better)	18700e	51000e	13000e	12236e
Bit Depth (higher = better)	12bit	12bit	12bit	12bit
Optical Window	AR	AR	AR	UV/IR cut and AR coated
Back-focus (mm)	12,5	17,5	17,5	11
Extra Info	Full compatibility with  ZWO software + All Sky Lens	Full compatibility with ZWO software	Full compatibility with ZWO software	2.5mm All Sky Lens

[M40]

Hello JediScp, I took a similar path to you in making a speadsheet of one form or other listing the data of each camera. Great move because you can spot things like pixel size etc but that is not the only part of the jigsaw. The first time I tried eeva I learnt what under sampled was. The pixel size of the camera I used at the time did not suit the telescope at all and the image became very blocky. By sticking in the camera and telescope in the FLO CCD suitability calculator it instantly went to the significantly under-sampling side of things.

From this, I input my wishlist cameras into the calculator with the telescope and then was able to select a suitable camera/CCD that worked well with the telescope. Moving then to the FOV calculator, I then reduced the choice even further by making sure the camera could provide the right sort of image from the objects I want to view. Out of interest I finished with the ASI385C.

So the answer to your question is to use the FLO online calculators to ensure the camera will work with you telescope then make sure it works with the FOV that you want to image. I am definitely not the one to confirm this, but as to colour v mono, I believe that you get three times the number of pixels using a mono than the colour so possibly better definition when using mono. I will let others confirm that one

All the best and hope it helps.

[vlaiv]

Especially with regards to "under sampling and blocky stars" and how good results are from current version of astronomy tools

[JediScp]

Wow. Thank you very much M40 and vlaiv. I'm now outside observing and once I return I am going to read this valuable information about under sampling vs over sampling and how to avoid it and when can be considered. In fact my spreadsheet had a couple more lines concerning all the possible ways to achieve the green color (whether through binning or the use of a Barlow which I want to avoid) in CCD suitability calculator. Thank you and I'm also leaning towards ASI385 as it seems to match better to this reflector, but still have to be sure. Once I'm done with reading I will get back here. 

 

Thank you FLO for the calculators.

 

Regards

 

David

 

 

[M40]

14 hours ago, vlaiv said:

Especially with regards to "under sampling and blocky stars" and how good results are from current version of astronomy tools

Thanks for the link vlaiv, far too heavyweight for me, so @JediScp use the calculators as an online guide only. Enjoy