is this a good deep sky object astrotography equipment

Tony Gondola:
That's a great small rig.

except that he didn't mention about a filter wheel and filters, and the flattener for the scope; he'll need a flattener at the bare minimum

everything else seems fine, OP might possibly need to get dovetail risers so that his filter wheel (or even, camera), doesn't hit a tripod leg when scope is pointing near zenith

if he doesn't want risers, he can get a pier extension, that's another way to do it

Dan Wertz:
Is the weight limit on the AM3 a little low for that setup?  The AM3 lists 17.6 lbs without a counterweight, and the Fluorostar 91 is 12.3.  Then add the camera, filters and guiding stuff.

Personally, I think I would pop for the AM5N.  I use the AM5 and I really like not having to deal with the counterweight.

Big cost difference though...

Oscar:

Tony Gondola:
That's a great small rig.

except that he didn't mention about a filter wheel and filters, and the flattener for the scope; he'll need a flattener at the bare minimum

everything else seems fine, OP might possibly need to get dovetail risers so that his filter wheel (or even, camera), doesn't hit a tripod leg when scope is pointing near zenith

if he doesn't want risers, he can get a pier extension, that's another way to do it

533 is a pretty small sensor so he might be ok with it to start. You're right about the wheel and filters though. That's gonna add a penny...

I have a similar setup, so I’ll provide my opinion:
Go for a bigger mount (AM5, NYX-101, iOptron). This will give you room to grow.

You could stretch your budget by skipping the PowerBox, for now, unless you need dew heaters.  It helps organize everything, but I don’t think it’s essential. Doesn’t the ASIAir have 12V outputs?

If you’re technical, you could use a Raspberry Pi running StellarMate or your own OS. This can save you a little money, and you’re not locked into the ZWO ecosystem. However, it’s not as easy to use, although StellarMate has made some big improvements. They also have their own hardware, which includes power management.

Nikolai Shkurko:
Camrea ZWO ASI533MM Pro Cooled Monochrome Astronomy Camera

EDIT: Ignore my comment, I should read the thread before I post...
For a monochrome camera mabye you want to consider a filter wheel or filter slot and filters. Or do you plan to do only monochrome images?

Oscar:
definitely buy the AM5N instead of an AM3, if you plan on buying the Quattro

Can an AM5N handle a Quattro 300P ... that's a giant telescope!

If you’re thinking of a 250 or 300 Quattro, I’d probably go GEM.    I have a 250 and has an ioptron hae69ec, and while it tracked ok, that was a lot of weight on a big lever arm.   Polar alignment was a pain due to shifting of the mount with the az screws loosened to adjust PA.   

maybe start with a smaller used mount and then sell it when you decide to upgrade to a larger scope.

Nikolai Shkurko:
But they weigh allot don't they or only the 300p

GEM mounts are much heavier, but the counterweights mean that the mount head is balanced on the pier/tripod, which makes Polar alignment less troublesome.     You're not going to have a very light and portable setup with a Quattro 300.    Even the 250 that I have is not very portable.   And since it's so large of a diameter, the weight is well away from the mount head so you have to have a mount with a much larger capacity than the weight suggests, and the wind catches the large newts so the need for a heavy tripod and mount are even greater.    I have my 250 and AP Mach 2 on a Ioptron tri-pier on a JMI wheeley bar and roll it out of my garage and then put it on wood blocks to level and make solid.   I wouldn't consider transporting it around through.