Ad Astra Observatory

Hi,

So with the failure of MaxDSLR to be a one-stop-shop to fix my
astro-software needs, I’m doing a total rewind to figure out what it really

is that I need to do in order to move forward. I apologize that this will
be a rambling treatise of self-indulgence, but you’re both used to it. (:

Here are the use cases that need to be satisfied in order to take an
astrophoto:
– mount must be pointed at target object
– “main” camera must be focused

– “main” camera must have shutter tripped to start and stop exposure (with
lots of images in a single exposure run)
– images must be downloaded from “main” camera
– a guide star must be selected
– “guide” camera must be focused

– “guide” camera must send corrections to mount

If all of these things happen, I end up with lots of images that need
post-processing to become a single astrophoto. Post-processing will not be
covered in this document.

As of 2/15/2008, I use a mixture of software and hardware to satisfy the
use cases:

TARGET ACQUISITION
– mount pointing: (no PC attachments)
– Gemini hand controller can choose among several catalogs of objects, and
slew the mount to point at them
– I think up an object list, write it down, take it out to the mount, and
make target choices from the list.

MAIN CAMERA CONTROL (main camera is a modified Nikon D70 DSLR)

– main camera focusing: (Focuser is ASCOM-compatible and uses 1 serial port)
– I use FocusMax in “Jog” mode, where I can input numbers to say “go to
this position”
– I shoot photos of a bright star, and I open the photos in Photoshop 7,
where I inspect the photos for best focus (usually flipping between 2 or 3

“is A or B better?”)
– To determine precise focus, I use diffraction spikes; the thinner, the
better. For scopes without a spider, I attach wires to the front of the
scope to make spikes.

– main camera shutter control: (no PC attachments)
– I built a standalone “gizmo” that has an LCD and keypad to put in

exposure times and counts.
– The gizmo is not back-lit, so I have to keep a flashlight handy
(possibly ruining an image) to check how many shots are left.
– This has to be done at the mount.

– image download: (1 USB port from D70)
– Keeping Nikon Capture open during an exposure run (even if Nikon Capture
didn’t initiate the exposures) will cause NC to download images

– NC automatically names the images YYYYMMDDD_001, _002, etc.
– I copy these images either by memory stick or over the ‘net to my
“inside” computer for post-processing.

GUIDE CAMERA CONTROL (guide camera is SBIG ST-4)
– guide star selection (no PC attachments)
– there is a 6x magnification finder on the guidescope. I use it to center

a “bright enough” star
– I know that I’ve found a star by reading the numbers on the ST-4 control box

– guide camera focusing (no PC attachments)
– I have a focusing eyepiece; I point the guidescope at a bright star, put
in the eyepiece, and move the (manual) focuser until the eyepiece registers

“in focus”
– replace focusing eyepiece with ST-4 head

– guide camera corrections to mount (no PC attachments)
– guide camera has dedicated connection to the mount. Corrections are sent
directly from ST-4 CPU to mount via “autoguider” port

Any use cases that say “no PC attachments” means that I have to be out in

the shed, with a flashlight, to work on that.
I’d like to move more stuff into software so that I can check on things
from inside the house.

– I bought a DSUSB-IR1, which replaces the gizmo with a USB-controlled device