Full Frame Mono Cooled Camera - Pros and Cons

[Midnight_lightning]

Having upgraded my telescope to a longer refractor (135mm FL 686/915mm) I am looking to now upgrade my cooled camera to larger sensor.  I would like to go full frame but may wait until October  to see how much the new APC-S cameras are. 

In terms of full frame (circa 60mp) I have tried to put together some pros and cons and would be grateful for your thoughts on these and also any experience you have using cameras like the ASI6200MM and QHY600. 

Pro's

1. Large FOV, less need for Mosaic's so faster imaging
2. Produce widefield images with option to crop - flexible framing for small and large targets
3. Wider field will make it easier to remove LP gradients where the frame would have been full of nebulosity with a smaller sensor.
4. Large targets like Andromeda wouldn't fit on a smaller sensor.
5. New cameras are 16 bit.
6. Gain (not sure about this, afaik my SX814 has fixed gain - could increasing the gain on a CMOS reduce exposure time?)

Con's

1. Expensive
2. Requires a good Corrector/Reducer.
3. Adjustment for tilt more demanding.
4. Large amount of data to store and process (how big an issue is processing?). Five times the data I currently hold - will need new HDD's for storage and multiple backups.
5. Potentially greater LP gradients that will be more difficult to remove than with a smaller sensor
6. Testing my scope with a full frame D750 shows some Vignetting.
7. Is CMOS as good as CCD for image quality - my SX814 is extremely good in my view? 
8. My Astro imaging laptop is very low spec (i3) - not sure it will cope with downloading 60mb files{?}.
9. Large EFW - extra weight could add to tilt.
10. Large EFW - size could mean it hits tripod legs (But QHY cameras have camera rotator so may not be an issue - the Rotator is reason enough by itself for me to to buy a new camera!!!)

An APC-S camera would be half the price as I could use my existing EFW with 36mm filters - also cheaper than 2". But I think I would be kicking myself when I couldnt frame some of the larger targets.

I haven't started to look at technical stuff (well depth, QE, Noise etc) yet - its a whole new learning curve for me.

Any thoughts/guidance welcome.

 

 

Edited August 26, 2020 by Midnight_lightning

[nfotis]

For really wide field astrophotography, why not use a short refractor? Or a camera lens like the Samsung 135mm? I have seen amazing stuff done with the latter.

Its cost would be much less than the difference of cost for a full frame sensor and the costly filters, etc.

 

N.F.

[DaveS]

For 135 format you will need 50mm unmounted filters as 2" ones could well vignette badly.

You will definitely need a more powerful computer to handle those files in any sensible time, I would be spec'ing a tower with a Ryzen 12 core and at least 32 gig ram, plus a few TB of SSD or better M2 storage.

[Midnight_lightning]

59 minutes ago, DaveS said:

For 135 format you will need 50mm unmounted filters as 2" ones could well vignette badly.

You will definitely need a more powerful computer to handle those files in any sensible time, I would be spec'ing a tower with a Ryzen 12 core and at least 32 gig ram, plus a few TB of SSD or better M2 storage.

The i3 laptop is just running the imaging, I have a fairly good spec desktop rebuilt a few months ago - Ryzen 3700X, 32GB 3600mhz Ram, 500GB M2 with dedicated lane. I think 8 core rather than 12. Also has a good GPU so hoping APP and PI will make use of this before too long.  Actually I would like to push this PC a bit, I haven't seen it using more than 11GB Ram to date and its rare to see CPU max out.

Edited August 26, 2020 by Midnight_lightning

[DaveS]

OK, then that should be fine, though I hope it has USB3 to handle those huge files. The 6200 cameras bin after download in software, as I think the on-chip firmware is the same as the colour one which bins every other pixel.

[Ken82]

A couple of things I’ve noticed with the 6200m-

you may need to look at 50mm unmounted filters depending on the light cone/f ratio of your scope. At f5 I got star reflections at the edge on every image I took befire changing to 50mm. Remember the internal diameter of 2” filters is only 43mm for Idas and 45.4mm for baader. Of course if your scope is slower than f5 this may not matter. 
 

Any modern multi core cpu should be fine, more the merrier. Look out for m2 ssd drives as these are much much faster than standard ssd. The most ram I’ve ever seen mine use was 25gb so 32+ is fine. 
I know pixinsight developers have been looking into using the gpu but this is not a priority for them so you could be looking at years still for this. 
 

Tilt could be a problem as I’ve just found out. I’ve heard some bad reports about the new zwo tilt adapter so I’d be tempted with the gert Neumann m68. 
 

Optically you’re going to need something exceptional as I’ve also found out. 

Really great camera though and very versatile 😀I expect I’ll probably get another for a dual setup at some point. 

 

[BlueStinger]

M.2 is just a physical form factor so make sure the drive you are looking at uses the NVMe interface otherwise it's just SATA will be no faster than a standard SSD. Easy way to tell is to look at the connector. M.2 NVMe drives have one notch and M.2 SATA drives have two.

[Adam J]

On 26/08/2020 at 17:13, DaveS said:

For 135 format you will need 50mm unmounted filters as 2" ones could well vignette badly.

You will definitely need a more powerful computer to handle those files in any sensible time, I would be spec'ing a tower with a Ryzen 12 core and at least 32 gig ram, plus a few TB of SSD or better M2 storage.

I would say there is no way that a Samyang 135 would give good corners on a 6200 sensor the pixels are just too small and unforgiving. But I am not sure why we are talking about a lens in a thread about a large refractor anyway.

There is a very new ASI2400mc pro coming out not to be confused with the smaller ASI2600mc Pro, at that focal length I would go with the 2400 as its even more sensitive.

*****************Forget all that just seen this is about the mono version, my mistake.

Adam

Edited August 31, 2020 by Adam J

[fireballxl5]

8 hours ago, Adam J said:

I would say there is no way that a Samyang 135 would give good corners on a 6200 sensor

I think that the OP is referring to the CFF 135 refractor...http://www.cfftelescopes.eu/product/refractor-135-mm-f6

 

PS, I'm considering purchase of a Samyang 135mm f2 lens to use with my Canon 6D Mk1. Is this lens good for a full-frame DSLR?

CS, Andy

Edited September 1, 2020 by fireballxl5
added PS

[DaveS]

9 hours ago, Adam J said:

I would say there is no way that a Samyang 135 would give good corners on a 6200 sensor the pixels are just too small and unforgiving. But I am not sure why we are talking about a lens in a thread about a large refractor anyway.

There is a very new ASI2400mc pro coming out not to be confused with the smaller ASI2600mc Pro, at that focal length I would go with the 2400 as its even more sensitive.

*****************Forget all that just seen this is about the mono version, my mistake.

Adam

 

34 minutes ago, fireballxl5 said:

I think that the OP is referring to the CFF 135 refractor...http://www.cfftelescopes.eu/product/refractor-135-mm-f6

 

PS, I'm considering purchase of a Samyang 135mm f2 lens to use with my Canon 6D Mk1. Is this lens good for a full-frame DSLR?

CS, Andy

Read my post. I said 135 *format*, refering to the 24x36mm frame size. To me "full frame" can be confusing, as it refers to an architecture of CCD sensors.l, besides which, who is to say which format is "full".

 

Mods, can you kill the post above, got in a tangle trying to bold on my phone.

[Midnight_lightning]

10 hours ago, Adam J said:

There is a very new ASI2400mc pro coming out not to be confused with the smaller ASI2600mc Pro, at that focal length I would go with the 2400 as its even more sensitive.

*****************Forget all that just seen this is about the mono version, my mistake.

I've read somewhere tat there is a mono version of the ASI2400MC due out later this year - maybe October but who knows with Covid. I have it on my list of options.

[fireballxl5]

59 minutes ago, DaveS said:

Read my post.

Sorry, but I wasn't referring to your post Dave.  I understood your use of the term "135 format" thanks.

BTW, I think that it's fair to use the common term "full-frame" in an astro imaging forum, with a reasonable expectation that it will be interpreted as intended. 

https://en.m.wikipedia.org/wiki/135_film

[DaveS]

OK, sorry. the perils of trying to post from my 'phone. Make the text readable, and half the post vanishes off the edge of the screen.