Ad Astra Observatory

Art Morton wrote:

> The three below are from the new camera, not set up correctly, and
> they are bad. The do show potential.
These are good “proof of concept” shots. Did you shoot these in K3? In
Max? In Max Essentials?

Man, 1280×1024 is a *lot* more screen space than 640×480. Looks like

you’re covering about the same physical area on the screen, though.

The shots looks a little dim, like you weren’t getting enough light. I
usually aim for the “max” value in the histogram to read a little under
128 (the halfway point), because images brighten some when you stack
them. In K3, there’s a nice histogram meter that helps with this.

I think that the graininess in the images is more from the dimness than
from not stacking enough frames. but obviously both could help.

Very nice proofs, though. You got the software working, and now you can
proceed with smacking the camera around until it does the right thing.
> I have no NP-127 and it is raining.
How did you solve the “optics in the focuser” problem with Moonlite?

> I am slapping this on the back of the ATD80 and shot something.
Still plenty of time on Saturn. By the end of next month, Jupiter will
start being doable, too. Can you see Sagittarius from your deck?
> I have a good process to fix any AVI’s that have gone south.
I need to figure this out. I often get the same thing…
> These images are shot at 30 fps, and with this size of scope that is
> not enough exposure time.

Yes, probably not. I start running out of light around 9,000mm to
12,000mm effective focal length with an 8” scope. That’s where I start
needing exposures greater than 5fps (that is, 1/5sec) will allow. Since
that’s the longest exposure my webcam will take, at that point, I’m
limited to shorter focal lengths (8,000mm seems to work OK, although
it’s smaller), or getting more light (which means a larger scope).

I would think that the 80mm would start to peter out around 5,000mm to
7,000mm efl.

Certainly, the first thing that I do with planetary photography is to
take the shutter speed as *slow* as it will go, and then tune the
Barlows to get me as much magnification as I can before I run out of light.

> I will move this down to 7.5 FPS, which is the lowest I can go with
> the 1280×1024 format.

If you can go slower by dropping to 640×480, you should do that. 5fps is
no problem, and honestly, the first webcam that comes out that can do
1sec images will sell like hotcakes.
> What I have found on the Erin is that there is a plenty of
> illumination to see stars. So much so, that I can pick this as the
> guide camera in MAX and guide nicely.
Very cool. I am using 0.6sec exposures with the ST-4. I imagine that a

15-years-newer CMOS could pick up stars with 0.2sec exposures. It might
be worth it for me to see if the NexImage will work as a guider —
keeping the thing in focus would certainly be easier, since the ST-4
takes nearly a second to download its image over serial, where obviously
the NexImage can spit 30fps over USB…

hm.

> The other odd thing about the camera in MAX is that I have not been

> able to bin on or off the camera.
It’s the camera firmware, not Max, that determines what binning modes
are possible. For instance, on DSLRs, you have to bin in both axes the
same amount, so you can do 2×2 or 3×3 but not 3×1. I imagine that the
camera itself doesn’t support binning, so Max can’t really do anything

about it.

Good stuff! I look forward to seeing more out of the camera.

Is your intention to use it as a guider?

J