compatibility with asi2400mc ?

[bluesilver]

Hi, I am having a bit of trouble trying to find out if this camera ( asi2400mc ) is compatible with my current scope ( Skywatcher Esprit 150 )

The specs on the Esprit 150 tell me the image circle is 40mm
If i use the .77 reducer, it tells me the image circle is 36mm

I am trying to find out if this full frame camera will be a good fit and compatible with the scope and mainly the image circles i mentioned.

I currently have the asi2600mc which is a good camera,
Looking at the site astronomy.tools, it is telling me my arc seconds per pixel
for the asi2600mc and this scope is 0.74 " / pixel which is on the border of oversampling.

With the asi2400mc, the result comes back as 1.17 " / pixel
It looks like a good match in theory, but just not real sure how to work out the image circle compatibility to be sure.

Any advice would be appreciated.

[Stefan Buda]

Peter, are you sure about the 40mm image circle? I doubt anyone would make a decent refractor with an image circle smaller than 43mm, as that is the minimum for covering a full frame sensor.

[bluesilver]

I believe i am correct, but then again, i could be reading things incorrectly.
https://skywatcheraustralia.com.au/product/150-1050-ed-triplet-apo-esprit-refractor/
The specs says:
Diameter of the corrected field 40mm

And the description tells me:
A 2-element field flattener is included to iron out the natural off-axis astigmatism and field curvature of the objective lens, leaving a fully corrected 42mm field of view

Unless i am reading something incorrect here?

[Stefan Buda]

No idea what they mean by that corrected field of 40mm, but you should just ignore it.
You want to use the scope as an astrograph and for that you need the field flattener which gives you a 42mm diameter fully corrected field - adequate for a full-size sensor.

[Camelopardalis]

Peter, my Esprit 100 has the corrected circle listed as 40mm, but I’ve used it numerous times with my Canon 6D and not noticed any issues in the corners.

The 2400MC has similarly large pixels, so I doubt you’ll notice it. I believe the Esprit 120 and 150 have a larger corrected circle.

[Startrek]

Peter,
It’s best to be oversampled than undersampled in Astrophotography
Oversampling gives you the flexibility of using many post processing tools like Binning, Deconvolution and Star reduction etc…

Using my 2600MC with my quiver of Newts provides an image scale of between 0.86 arc sec per pixel and 0.62 arc sec per pixel (oversampled)

My oversampled data provides so much flexibility in my post processing software, Startools

You really want to try and avoid undersampling with your set ups, unless your imaging with short focal lengths.

Cheers
Martin

[bluesilver]

Thanks for all the advice, it is appreciated.
Just a question sort of related to all this, Binning
If i want to bin2 say in Star Tools, am i correct in saying that if i select 50% in the bin option, this is bin2, or should i be looking the other way and try to go 200%
Same thing for bin3 or bin 4
is it 33% and 25% or 300% and 400%

Sorry for the simple question, the other option was to select bin2 when i am imaging using Astro Photography Tool.
But i am think with this option, i would also need to select bin2 for all the flats, darks e.t.c ?

[Startrek]

I prefer to capture in APT with camera bin 1x1
In Startools, the way I check resolution and sampling with the Bin module is select Bin , let it use default 50% then zoom in to 150% to 300% and see if my stars are “blocky” or still round. If “blocky” I use the slider at the bottom and increase to say 65% . Zoom in again to 150% to 300% and check stars again , if still a bit “blocky” , slide across to say 70% or until stars are remain round

Most of the time I usually Bin between 50% to 70% but it changes with each session and with each different rig.

Sometimes ( rare ) when conditions are really good I don’t Bin at all

In other words it’s not a standard procedure

If your not oversampled you can’t take advantage of software Binning

Startools uses a scalable binning algorithm, works beautifully

https://www.startools.org/modules/bin

Cheers
Martin

[bluesilver]

Appreciated,
I never though of zooming in to check out the binning.
Sounds very obvious now, I will check that out next time i use it, appreciated.
Sorry for yet another question and getting off topic a little, but can i ask since you are using the asi2600mc, when you first open an image to process, do you use:
Linear
Linear, from OSC/DSLR with Bayer matrix and not white balanced
Non-Linear sRGB source

I can never really work out which one i am suppose to use with the asi2600mc

[Startrek]

Peter,
Firstly the “most important part of using Startools is that your stacked data set must purely Linear (ie straight out the stacker without any channel adjustments, colour balancing, background calibration etc… )

See attached DSS procedures for Startools

If your DSS linear stacked data set is OSC Broadband LRGB no filters ( eg 2600MC with no additional filters ) then you would load your data set using Linear, OSC/DSLR with Bayer Matrix and not white balanced.

If your DSS linear stacked data set is OSC Narrowband ( eg 2600MC with an L Extreme or Antlia Narrowband filter etc.. ) then you can still use Linear, OSC /DSLR with Bayer Matrix and not white balanced but ……. this won’t allow you to take advantage of the Narrowband presets in the Colour module.

To take advantage of OSC narrowband processing, you must use “Compose” on the top task bar to load your data set , this will process as usual in synthetic Luminance or Mono and when you hit the Colour module you have endless Narrowband presets to choose from to create OSC narrowband images both Bi colour and tri colour ( HOO or SHO etc… )

Attached are some examples

Hope the above and attached is helpful

Cheers
Martin

[bluesilver]

Thanks for reply, explanations and the detailed attachments.
I can see I messed a few of those up, so this is good, something to work on next time.
It is very much appreciated,
Cheers.