ASI183 or???

[LewisM]

Doing the maths for my 450mm focal length setup and typically good seeing, it would seem between 2 and 3 uM pixel size would be ideal. This somewhat limits choices, yet the ASI183 at 2.4uM comes to mind.

I currently use an 8300 chip camera with 5.45uM pixels and not been unhappy but will a 2.4uM sensory deliver sharper results? (FSQ85 - 450mm - f/5.3. Seeing here is typically 2 FWHM or less)

EDIT: just to re-iterate, I have ZERO issues with guiding, the mount or the scope. ZERO. Perhaps my focusing could be better (hand focused with a Bahtinov) but this is not what I am asking about.

[gregbradley]

The ASI533 might be the better choice but its only in one shot colour. The ASI1600 is the most popular CMOS camera. Not expensive (well compared to SBIG and FLI) micro 4/3rds sensor size, slightly lower QE at 60% but a reasonable pixel size that suits a lot of scopes.

I am using the 183mm. You can always bin 2x2 if the seeing is not as good. It doesn't seem to affect the resolution much.

The 183 has amp glow so you need to settle on settings and keep it simple otherwise callibration becomes complicated.

Also put the settings you used in the file names of the images you capture so you know which darks to use.

The amp glow does callibrate out very well so long as the darks are exactly matched.

There is a mono 2600 equivalent i QHY coming out in October. That has 3.76 micron pixels, no amp glow, 16bit and 84% QE in an APSc sized sensor. It will be very popular and will sell out for a while. Its basically a scaled down version of the ASI6200. I am tossing up whether to get that or the 6200 mono. 122mb files though don't excite me with the ASI6200 but maybe the extra field of view is worth it.

Greg.

[LewisM]

I thought about the 533 but it’s not a lot different to the 8300 I suspect. Some but worth it?

I only use OSC so I am ok with that

[Atmos (Colin)]

It'll definitely give sharper results but I'm wondering if the 2.4 micron pixels might be a little small due to diffraction setting in. Not that it really matters as much if you're only wanting to go down the OSC path as that will fatten the stars a bit anyway.

[multiweb (Marc)]

Originally Posted by LewisM

Doing the maths for my 450mm focal length setup and typically good seeing, it would seem between 2 and 3 uM pixel size would be ideal. This somewhat limits choices, yet the ASI183 at 2.4uM comes to mind.

I currently use an 8300 chip camera with 5.45uM pixels and not been unhappy but will a 2.4uM sensory deliver sharper results? (FSQ85 - 450mm - f/5.3. Seeing here is typically 2 FHWM or less)

What don't you dither and use drizzle in PI?

[LewisM]

Oui oui Marc, mais...

[multiweb (Marc)]

Originally Posted by LewisM

Oui oui Marc, mais...

Mais quoi? C'est ce que je fais et ca marche. Economise ton argent pour le vin au lieu d'acheter une autre camera qui ne sera pas d'aussi bonne qualite que ton 8300.

[gregbradley]

Originally Posted by LewisM

I thought about the 533 but it’s not a lot different to the 8300 I suspect. Some but worth it?

I only use OSC so I am ok with that

I'd say its a lot different. Its BSI (backside illuminated) sensor. So it has large wells for its size and 84% QE which is higher than any regular CCD. The KAF8300 QE is around 59%. No amp glow which is one of the more annoying aspects of some CMOS sensors. 3.76 microns is a good size for shorter focal lengths.

As to diffraction I thought that was a lens quality when you stop down too much. Perhaps it happens with small pixels. the 2.4 micron pixels on the 183 are fine with my RHA at 1159mm focal length. I find its quite sharp. I also find it tends to give rounder stars because each star has more pixels showing it.
It does however make it harder to focus. It takes me longer to focus with it.

3.76 microns is probably a better fit pixel size for that scope. The 183 would suit a widefield refractor better but I would want a large sensor for my refractor because I got it for wide images.

Also these CMOS sensors are usually more sensitive in narrowband than regular CCDs.

The ASI2600mc seems to be the one shot colour a lot want. APSc sized, same 3.76 micron BSI sensor, same 80+% QE, very low dark current and read noise. I've seen some excellent images from them.

Greg.

[LewisM]

Originally Posted by multiweb

Mais quoi? C'est ce que je fais et ca marche. Economise ton argent pour le vin au lieu d'acheter une autre camera qui ne sera pas d'aussi bonne qualite que ton 8300.

L'argent n'est qu'un ennui

[gregbradley]

Originally Posted by multiweb

Mais quoi? C'est ce que je fais et ca marche. Economise ton argent pour le vin au lieu d'acheter une autre camera qui ne sera pas d'aussi bonne qualite que ton 8300.

I had fun translating that Marc. My wife and I are trying to learn French.

Greg.

[multiweb (Marc)]

Originally Posted by gregbradley

I had fun translating that Marc. My wife and I are trying to learn French.

Greg.

Bonne chance.

[LewisM]

I learned French for 6 years. Fat lot of good it did for me. I can’t even insult Marc properly

[Atmos (Colin)]

Originally Posted by LewisM

I learned French for 6 years. Fat lot of good it did for me. I can’t even insult Marc properly

Votre mère était un hamster et votre père sentait le sureau.

[gregbradley]

Hahah LOL

[JA]

Originally Posted by LewisM

Doing the maths for my 450mm focal length setup and typically good seeing, it would seem between 2 and 3 uM pixel size would be ideal. This somewhat limits choices, yet the ASI183 at 2.4uM comes to mind.

I currently use an 8300 chip camera with 5.45uM pixels and not been unhappy but will a 2.4uM sensory deliver sharper results? (FSQ85 - 450mm - f/5.3. Seeing here is typically 2 FHWM or less)

Out of curiosity you could try a Nikon1 J5 mirrorless camera (now discontinued) it has a 1"-type 20.8MP BSI CMOS sensor (5568 x 3712 pixels) with 2.4 µm pixels : and if purchased used, would be possiblty be 1/5th of the price (if lucky) somewhere from $250-500, depending on extras. (They were ~$1500 originally with the top spec. lens kit). It has an unusually clean image for a sensor of that size (same size as ASI183 : 13.2 x 8.8mm)although not as good as it Nikon Fullframe brothers but certainly better than some older fullframe and APSc cameras. It has a fold out screen so you could go possibly go totally portable (sans computer) in the field.

I'm interested in a project with 3 or 4 ASI183 cameras or similar on 400mmm to 600mm focal lengths (similar focal lengths to your area of interest) so that's why I'll be trying the Nikon 1 J5 just to see possibilities before possibly shelling out for 4 astrocams.

Best
JA

[multiweb (Marc)]

Originally Posted by LewisM

I learned French for 6 years. Fat lot of good it did for me. I can’t even insult Marc properly

You're getting better.

Originally Posted by Atmos

Votre mère était un hamster et votre père sentait le sureau.

Took me a little while to click.

[LewisM]

Originally Posted by Atmos

Votre mère était un hamster et votre père sentait le sureau.

Meh... ma mère a enlevé les noix de mon père

[Slawomir (Suavi)]

One thing to keep in mind is decreased sensitivity for a sensor with smaller pixels. KAF-8300, in spite of having lower QE, will be accumulating photons at about 3 times faster rate than 183 when used with the same telescope. I'm not sure (I simply do not know) if the RN difference would level things out though.

[LewisM]

I have an SX SXVR-H9C I can compare with (even larger pixels than the 8300)

[gregbradley]

Originally Posted by Slawomir

One thing to keep in mind is decreased sensitivity for a sensor with smaller pixels. KAF-8300, in spite of having lower QE, will be accumulating photons at about 3 times faster rate than 183 when used with the same telescope. I'm not sure (I simply do not know) if the RN difference would level things out though.

No I don't think so. My experience so far with a 183mm compared to both a KAF16200 6 micron and 16803 9 micron (I did have a KAF8300 a few times as well) is that its more sensitive especially in Ha and O111 and S11.

The KAF sensors are probably somewhere like 40% QE or less for Ha whereas the 183 is up around 70%.

Its definitely faster than the CCDs despite smaller pixels.

Greg.