SVBONY SV405CC Teardown

[Flo94218]

Hello everyone! 

 

I've just received my new and first ever dedicated astrocamera from SVBONY: The SV405CC. This has a Sony IMX294 Micro four thirds sensor and is fairly similar to any other 294 colour cameras from ZWO, QHY, etc. 

There are some downsides, like no USB hub on the back and the fan is attached to the back plate with no vibration isolation in mind (4 chunky screws with 4 locknuts mounted on a metal frame which, in turn, attaches to the back pate with 4 M3 screws). I plan on changing the 4 screws for some silicone studs from Noctua or some other brand.

That's not a huge downside for me, since I'm shooting through a 450mm setup, so vibrations will be, most likely, sub-pixel, though I am planning to upgrade to an RC in the future. I'll deal with that when I get that. 

The other thing that's been bugging me has to do with moisture control. 

First, there's no heating element on the front glass. I believe that's true for ZWO, as well. They claim that the front AR window will be kept above ambient by the heatsink heating up the whole body of the camera. I am not sure how big of an impact this has, since I didn't get the chance to test it out in the field. Probably I'm worrying about nothing.

The second problem is that there are no dessicant tablets permanently mounted in the sensor chamber! See... I thought, since there's no info online, that the AR glass is the same size as a 1.25" filter. I wanted to permanently install a IR/UV cut filter in place of the AR glass, so I went ahead and removed the 4 screws holding the AR glass frame and realized that the glass is actually 31mm. So.. I put it back together, warmed up 4 dessicant pellets in the microwave, put them in the screw-in tube and left the tube in for 24 hours.

Today, I tested it out with NINA, set the cooling to -5C over 10 minutes. Once the sensor reached 0 degrees, fog started forming on the sensor right away. It went away once I heated the camera (over 10 minutes, as well). 

Knowing that ZWO has dessicant tablets inside the sensor chamber, I thought it would be a good idea to open up the chamber and refresh those tablets. 

I've indexed the position of the lid with some masking tape, then unscrewed the 6 2mm hex screws holding down the front plate. Once opened, I realized that there are no dessicant tablets visible anywhere..

I made sure to blow out all the dust with a rocket blower, blew hot, dry air with a hair dryer as I put back the front casing on and, once again, warmed up the 4 dessicant pellets for 5 minutes in the microwave then put them in the tube.

I just did that, so I'll be waiting 24 hours and, tomorrow, will refresh them once again and give it another 24 hours. 

 

 

To anyone that has this camera: do you know if there are dessicant tablets below the board, or is the moisture controlled only by the pellets in the tube? 

Also, to anyone who is looking for a partial teardown of this camera, you're welcome

 

 

I did get the chance to test it out for 15 minutes before the clouds rolled in (of course). That's 15 minutes, 180s x 5 , 125 gain, 30 offset, -5C, l-eNhance + 8 matching darks. 

Shot from just outside Bucharest (B8 or 9, I believe), from my balcony, with poor to awful transparency.

The bayer matrix for this camera is screwed up.. IMX294 has a RGGB matrix, but the FITS are written as top-down (?), so the matrix ends up as GRBG. Problem is, no Auto debayering works in any software (NINA preview is screwed up, PI can't find the bayer matrix info, SiriL doesn't seem to know how to set the colours even after telling the software that bayer matrix to use. The colours after stacking ended up being yellow. I've attached the starless image that I got out from SiriL. I am not sure if this is because of the filter, or something else. Any idea or advice? 

I hope I can get some clear skies next weekend, so I can properly test this camera from a B5 zone. 

[Backyardscope]

I have the same camera, the dessicant chamber is one side of the camera.

I have imaged a few more images, but not had time to process them. The most recent of them here:

I am surprised you did not start this thread on cloudy nights. As it seems your doing a bashing thread.

Surprised at your username flo???? @FLO

Edited December 8, 2023 by Backyardscope

[Kyuss]

Maybe responding a bit to late but....

 

Owning the same camera, i had a similar problem with fog but followed the instructions below:

https://www.svbony.com/blog/drying-tube-for-camera-svbony/