What can a single 10min sub on a RASA 8 give you ?

[Catanonia]

I have often wondered if the RASA 8 @F2 and ZWO 2600MC Pro combo could produce a good image with a single sub. After all the Hubble deep image was a single sub and why can't I try it

And what would it be like in good seeing (2.1) in Bortle 6 skies, would it flood the pixels

For for giggles, last night I pointed the RASA at the Horsehead Nebula and Flame and took a single 10 minute guided sub to see what would happen.

I was lucky that no Satellites / Starlinks came through the image, but was very impressed.

Below is the final processed image from a single 10min sub  (flat, dark, DBE, and other quick processing) compared to raw (jpg) sub that the ASI Air Pro presented after the 10 mins

 

Image

• Single 10min sub at 2xbin with RASA 8, ZWO 2600MC Pro and EQ8-R
• Optilong lEnhance filter
• Processed in PixInsight (Flat, Dark, Bias, DBE, Colour and stretches)

 

So is this practical.

Well 10 mins guiding at 400mm is not an issue on the EQ8-R, but the chances of satellites is high. Perhaps 3 or 4 10min subs would work (to remove any satellites)

But overall, extremely impressed with the result for a single sub.

 

 

Edited March 7, 2022 by Catanonia

[alan potts]

I was told it was not possible to bin OSC cameras, I have the 071 and thought to do the same thing, but after being told never did. Very good capture for only 10 minutes though.

Alan.

[Catanonia]

19 minutes ago, alan potts said:

I was told it was not possible to bin OSC cameras, I have the 071 and thought to do the same thing, but after being told never did. Very good capture for only 10 minutes though.

Alan.

Yes possible and follows same processes as you would with normal images.

[Catanonia]

Updated the thread with more details and a quick process of the single sub

 

[Elp]

That's nuts, I'd be happy with that and you don't even have to stack and can do more targets in a night.

[Catanonia]

26 minutes ago, Elp said:

That's nuts, I'd be happy with that and you don't even have to stack and can do more targets in a night.

I am going to continue the experiment tonight and add another 3 or 4 10min subs and see what I get.

I can already tell (and expected) that the single 10m sub gave more detail than my combined 1min stacks (x10).

[Elp]

Though not as the same level of speed I too am in the process of experimenting on the same target, native focal length Vs a 0.65x reducer with my Z61. Haven't had much opportunity at the moment to try it in depth. It will be interesting to see your outcome.

[clarkpm4242]

Nice.

@Catanonia what method/kit do you use to generate flat frames on your RASA?

Many thanks

Paul

[Catanonia]

7 minutes ago, clarkpm4242 said:

Nice.

@Catanonia what method/kit do you use to generate flat frames on your RASA?

Many thanks

Paul

White teeshirt drapped over the dew shield scope end and pointed to sky next morning under the same camera cooling conditions.

ASI Air Pro auto calculates the exposure needed for flats based on the settings in place.

[Catanonia]

Got another 8 x 10min subs to add to this tomorrow

[The Lazy Astronomer]

10 hours ago, Catanonia said:

I can already tell (and expected) that the single 10m sub gave more detail than my combined 1min stacks (x10).

I'd be interested to see a side by side comparison, with identical processing, if you have the time. The 10x1min stack would have had more doses of read noise, but I wouldn't have expected a noticeable difference just viewing the images, so this is most intriguing. 

[Adam J]

On 07/03/2022 at 08:40, alan potts said:

I was told it was not possible to bin OSC cameras, I have the 071 and thought to do the same thing, but after being told never did. Very good capture for only 10 minutes though.

Alan.

you can bin in software after debayering. 

Adam

[Catanonia]

@The Lazy Astronomer Here are the results.

• 1st image is 2 hours in 1min subs 2xbin
• 2nd image is 1 hour in 10min subs 2xbin

Processing is pretty much the same in both images.

What you can see in the 10min sub version is a ring flare from one of the bright stars (The star in the top right of the 1st image) that the 10min sub picked up and becomes more visible with stacking.

I had to bin 2x 10min subs due to excessive satellites and plane trails, something that 10min subs will greatly increase.

Interesting experiment from a Bortle 6 sky, certainly got more detail, but combined with more hassle in each sub.

 

Edited March 8, 2022 by Catanonia

[alan potts]

3 hours ago, Adam J said:

you can bin in software after debayering. 

Adam

I must give it a try, Astro Photography Tool does have setting at x2 x3 and x4 which does appear to change the view and sensitivity of the camera when doing 1 second captures for focus and framing but I have never tried to use it for an exposure longer than 1 second.

Alan

[Adam J]

8 minutes ago, alan potts said:

I must give it a try, Astro Photography Tool does have setting at x2 x3 and x4 which does appear to change the view and sensitivity of the camera when doing 1 second captures for focus and framing but I have never tried to use it for an exposure longer than 1 second.

Alan

I would do that with care, often (with exceptions) binning a CMOS at readout lowers the bit depth and actually does not have any advantage over software binning. You effectively place it in a video readout mode. 

Adam

Edited March 8, 2022 by Adam J