10 replies to this topic

[Ittaku]

Mono version of the popular 678MC.

 

https://www.zwoastro...t/zwo-asi678mc/

 

Only a relative efficiency graph is the new information available but this looks like another great NIR imager. It's still quite efficient at the bottom of the blue so likely has good UV performance too.

[John Boudreau]

That mono sensor first appeared in the QHY5III678M planetary camera last year. I tried out a friend's, and it's 1 micron sensitivity was disappointing vs. my ASI462MM. Didn't get a chance to try it out on the 889nm CH4 band though, but It did OK in with Venus UV. Anthony Wesley and Phil Miles also tested one out on Venus 1 micron nightside imaging where it was well behind a Player One Uranus-C. A nice sensor overall, but at least at the longer wavelength end of it's QE curve it didn't perform as well as other Sony sensors.

 

Hopefully the ZWO version will perform better. 

[Ittaku]

That mono sensor first appeared in the QHY5III678M planetary camera last year. I tried out a friend's, and it's 1 micron sensitivity was disappointing vs. my ASI462MM. Didn't get a chance to try it out on the 889nm CH4 band though, but It did OK in with Venus UV. Anthony Wesley and Phil Miles also tested one out on Venus 1 micron nightside imaging where it was well behind a Player One Uranus-C. A nice sensor overall, but at least at the longer wavelength end of it's QE curve it didn't perform as well as other Sony sensors.

 

Hopefully the ZWO version will perform better. 

I'm very happy with my Uranus-C/462MM combo, but for those who've become accustomed to no barlow and want a one to one swap to a mono camera it might make sense. I can't see how the ZWO version would perform better than the QHY one.

[Mitchell Duke]

Am I missing something here? The 462mm and the 678mm seem to be very close. However the 678mm barely edges the 462mm in the 400nm. Chris Go said it was slightly better than the Qhy200mm.

Attached Thumbnails

• 
• 

[Ittaku]

Am I missing something here? The 462mm and the 678mm seem to be very close. However the 678mm barely edges the 462mm in the 400nm. Chris Go said it was slightly better than the Qhy200mm.

What you're missing is they're similar for relative response but the QE of the 462 and 585 sensors is higher.

[Mitchell Duke]

Anyone have the absolute QE graph of the 678mono for comparison?

[Ittaku]

Anyone have the absolute QE graph of the 678mono for comparison?

That would be nice wouldn't it, but it's sorely lacking from anywhere I can find. Just the vague "QE of 83%" from ZWO, which really isn't that much less than the 462 sensor's claimed 89%. The 585 pipping them both at 91%.

Edited by Ittaku, 16 April 2024 - 06:41 PM.

[John Boudreau]

I'm very happy with my Uranus-C/462MM combo, but for those who've become accustomed to no barlow and want a one to one swap to a mono camera it might make sense. I can't see how the ZWO version would perform better than the QHY one.

I would also think that the QHY would perform similarly to the ZWO. There initially was a driver issue that effected bit depth with the QHY and they issued an update, but Wesley had also tested the camera after that update with much the same results. Not saying the camera was a poor one, it's just the larger pixel Sony sensors did noticeably better when tested toward the longer wavelength end of their QE curve. 

 

In the last half of 2023 Sony also released mono versions of the 585 and 662 sensors. Hopefully we'll see astro camera versions using these sensors introduced sometime this year.

[Tapio]

I've read that the 678 can have same grid problem as 178. So not the best for Sun imaging.

Otherwise I would be more interested.

[Ittaku]

In the last half of 2023 Sony also released mono versions of the 585 and 662 sensors. Hopefully we'll see astro camera versions using these sensors introduced sometime this year.

I've been drooling over the prospect of a mono 585 camera for a while since they announced the sensor. The 462 will still beat it for noise but that's likely irrelevant except perhaps for CH4 imaging.

[Borodog]

I've read that the 678 can have same grid problem as 178. So not the best for Sun imaging.
Otherwise I would be more interested.

Flats should fix this.