Quote:
Originally Posted by Slawomir
It's me again... 
From what I have seen in terms of quality of images (and also financially), it might not be really worth it to swap KAF-8300 for a 50% smaller ICX-814. For narrowband imaging, I would not stick ICX-814 on any scope above 600mm FL, with 400-500mm FL being ideal for this sensor in terms of FOV and image scale (arcseconds per pixel). Maybe it would pay off to wait a bit and see how CMOS sensors evolve over the next year or two  I feel that Sony will eventually come up with some very nice CMOS sensors suited for astrophotography, with very low read noise, good QE and a decent size chip. |
You do make a good point however I guess the biggest issue I will likely end up having when Sony bring out their larger sensors is whether I can afford one! They may be very nice but they'll likely have a large price tag to go with them too
Quote:
Originally Posted by gregbradley
I think the QSI would also be a great choice but with the Aussie dollar being weak it becomes expensive. Although not too much considering the cost of a filter wheel, an OAG and all the adapters to attach them all. And then the possibiiity of tilt and flex.
But if you already have the filter wheel that is a saving.
QSI and FLI are 2 of the best out there. Starlight Express are also very good. I like the all in one design that really started with the SBIG STL series.
Several are now doing it and anyone with experience will know the advantages of a system that gets rid of potential flexure and misalignments. They really cost you sharpness in your images, probably more so than poor seeing.
As far as new Sony sensors I think the low noise Sony Exmor R CMOS sensors are already arriving. I notice there is a planetary cam with something like 1 electron read noise.
CMOS no doubt will be the longer term future but not for a while yet. My Sony A7rii sensor has less than 1 electron read noise at some ISOs. Too bad about the chromatic noise from long exposures!
QHY has a few Sony Exmor CMOS cameras listed on their site. No doubt some future release. Also what appears to be a high end Chinese back illuminated CCD that potentially could be interesting (it would have to prove itself).
As far as scaling pixel size to work out comparable read noise - where did that datum come from?
Sony ICX sensors are way cleaner and more sensitive than the Kodak KAF 8300. Look at the many KAF8300 images around. They are very good but tend to take lots of extra exposure time to arrive at a deeply saturated and clean image. The Sony would take considerable time off needed to achieve that result.
I think your ICX814 would be hard to beat unless you wanted to use it at long focal length but even there you could bin 2x2 and really slam it home.
Small pixels would still have plenty of resolving power at 2x2 with such low read noise.
Greg.
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Neither QSI nor FLI have filter wheels that accept 36mm unmounted filters sadly, although the FLI can be mounted onto a SX wheel such as you have done... Somehow.
Some of those cooled CMOS planetary cameras have mindblowingly low read noise. The QHY42 (still in production) is going to have 1.7e- in a 4mp cameras, 11um pixels though which is far too big for my current system.
The scaling of read noise to pixel noise was purely a calculation comparison of flux vs read noise to calculating the exposure time to become read noise limited within a calibrated image.
(3.69^2/5.4^2)*(8.5^2/4^2)*(0.65/0.48)= 2.72
So this is pixel surface area * read noise * QE in Ha which gives the total exposure time difference between two cameras on the same telescope. It doesn't take into consideration the cleanness of the sensor though, the lower dark current, purely read noise limited imaging.
I am going to be imaging at 650mm so with the 3.69um pixels thats working with 1.17"/pixel. It is 1.44"/pixel with the ICX694. This is without using a focal reducer though (still considering it).
Ultimately, money wise, getting the QHY22/23 is the cheapest option for me as I already have a good QHY filter wheel. The only hardware issue I have with QHY is their power cable being big, fat and heavy. Is that a reason to change cameras?
In saying that, from the two QHY cameras I have owned (QHY5LII and QHY9), I have never been overly happy with the ASCOM drivers that they have provided and this to me is a big reason for me considering spending that bit more and changing. I'll need to do some research onto how they perform, if they're anything like the two I've already dealt with I'll definitely be swapping companies. Everything works perfectly with their in house software EZCap, this however doesn't allow any form of automation to my understanding though.
I'd love a FLI, I bank account says no
QSI would be nice but it does involve a decent investment loss in changing down from a full Astrodon 36mm set to a 1.25" set. The Atik cameras a good and reliable, rarely hear anything bad at all about them in fact. The SX Trius range has been around for a while, more expensive but are they better than the Atik or QHY (software aside) for the price?