Ad Astra Observatory

Art Morton wrote:
> J,
>
> Can you make a blue channel out of a green and red? That is strange
> to end up without a blue.

I think that it’s because I shot my flat frame incorrectly. With the
stupid images “looking” grayscale in max, but secretly they’re color
(because they’re RAW — I really wish the &%*& thing would let me shoot

JPG), I’m betting that my “flat”, which was shot against twilight sky,
was actually quite blue instead of being white or grey. So when I
applied the flat (flats are applied by division: light/flat), the large
blue values in the flat made teeny tiny fractions of the blue in the
original image. I still don’t really have my flat-shooting thing down.

So I’m going to reprocess without the flat and see if the blue channel

comes back. I haven’t been getting great images out of Kate yet, but
until I get the guiding under control, I’m not ready to blame the telescope.

Between new scope, new mount, new computer, and new workflow, it may be
until the end of the summer before I’m really “cooking” again. So I work
at it.

By the way, The Bundle of Joy is due during the next moon cycle, so I
may not get any photography done in June.
> Drifting away:
>
> What you have said so strange. I have had the G-11 using every amp
> the power supply could muster with the 29 lbs of counter weights and
> the SN-10 and there was not drift. The stepper motors burned out, but

> there was not drift. How high were the correction numbers in Max?
> Look at this:
If I turned the guiding off, the numbers in X would go 0, -0.07, -0.1,
-0.2, -0.4, -0.7, -0.9, -1.3, …, -2.4 a pretty steady increase in -X.
Every once in awhile, I would get -1.1, -1.0, -1.1, where it would come
back a little and then continue the march. I have tried a variety of
aggressiveness settings to try to correct out the drift, and I can get

it to where it kind of does a 0, -0.2, -0.05, 0.1, 0, -0.2, … where I
kind of oscillate with overcorrection and big negative drift and
correction and..

When I turned on the ST-4 in manual mode, I had to tweak the calibration
times up a little — I think that’s because of the 0.3 sidereal guide
speed (this was easier to set on the old G-11, btw). No biggie. But,

just like my old G-11, I would see 0, 0, 0, 0, -5, 0, 0, 0, 0, 0, 5, 0,
0, -5, 0, 0… so a whole bunch of “no discernable drift, followed by a
“holy crap, it moved by a whole pixel!” followed by no drift again.

My plan is to completely rebalance the mount, redo the pointing model,
and re-tail all the wires and make sure nothing is pulling. If that
doesn’t fix it, I will see if it’s a polar alignment problem. I am 99%

sure that the mount is level. This is to say that the bubbles on the
mount claim it’s level, and I have no reason to believe that the bubbles
are out of true (although I also have no reason to believe they are *in*
true, either).

Right now, the camera is oriented such that RA is on the vertical axis
of the camera (I was leaving it in place so that my flats would be
right, but I’m tossing my flats. stupid blue flats.). The FOV is about

20′ in that axis, and the object went from centered to nearly off the
top of the field in 150 minutes. So call it starting at 10′ and ending
at 3′ or so. So 7′ drift over (call it) 140 min = 1′ in 20min = 3” per

min. I don’t know how far off the polar alignment would have to be in
order to produce 3” per minute drift, but that seems pretty extreme. The
camera gets 0.8”/px, so that’s 2.5 pixels per minute of drift, which
feels consistent… 5min images, ~12pixel drift, yep, feels about right.

Anyway, that feels like something that I should be able to see doing a

polar alignment. I’ll tweak the polar alignment when the moon is bright
again.Maybe I’m off a bit. shrug.

> http://www.cyanogen.com/products/maxim_tut.htm
I’ll check this out when I get home tonight. Thanks for passing it along.
> Below is my data from a couple days ago and from 2-11-08 and 4-25-08.
> These are different cuts at LRGB with Erin. Not much color. There is

> a lot of data here and not a lot of color.
I like the edge-on galaxy. I have to say that nebulae in general make me
feel like I’ve accomplished more than galaxies — there’s just a ton
more color and often more detail, too. I’m forever getting blown-out
cores and nonexistent outer arms on my galaxies. Somewhere between sky,
skill, and processing, there’s room for improvement. I would love to see

what I could accomplish from someplace dark. Good data would be a joy.

I’ll send out a reprocess of M64 tonight. I’m going to rebalance before
I boot up, and then I’ll see if I can get anything on M63.

J