bought an AtikBase running the Stellarmate software at the beginning of the year. Lots of issues in basic functionality talking to the iPad app, WiFi working, software updates required. Software update bricking the WiFi entirely, software not connecting to the iPad app, software that would connect to the iPad app not able to interface with the cameras, software that would interface with the cameras would not interface with the iPad app. Diving into Ubuntu-mate Linux/Unix, relearning terminal command lines. Getting a command line that updates all the software to a usable state (Thanks Atik Support!), interfacing with a VNC or through Windows based Kstars/Ekos planetarium/control software instead of the iPad app, getting plate solving data figured out and loaded onto the Windows PC. It was finally in an out-of-the-box new device condition the first week of April! 3 months of work. Saturday night it was time to see if it could be used.
Updated news from last night’s experiences with the AtikBase and its Stellarmate software.
1). I connected my CGE Mount (original CGE, not a CGEM or CGX), Pegasus FocusCube, QHY5III178M on a guide scope and an Atik Horizon I cooled monochrome imager. The Atik Horizon is on a Hyperstar 14 making a 710mm focal length f/2 imaging system. There is no CGE Mount choice. Once can choose a Nexstar, CGEM, or CGX. Rightly or wrongly, I chose the first one. (I have since learned I should choose the CGEM)
2). All of them talked to the AtikBase / Stellarmate. All were powered from the AtikBase.
3). I connected to it using KStars/Ekos on a Windows PC. I did not try the Stellarmate app on iOS.
4). I was able to image with either the guider or the main imager which were co-aligned.
5). Plate solving worked with either camera. There was no connectivity to the internet, so the plate solving was local on the PC after the image was downloaded. This only worked because I spent hours this past week learning what needed to be downloaded and figuring out how to download it to the PC when equipment isn’t connected. (Plate solving also works directly on the Atikbase)
6). The polar alignment assistant kind of worked. I moved the altitude and azimuth manually Tom get the star to the end of the the two arrows n the display. However neither of the two arrows in the display were aligned with the motion from either the altitude or azimuth. The motion between the three images was double the specified number of degrees. The default of 30 degrees ran the right ascension into the stops. I set it for 15 degrees at 7x speed and the mount slowly moved 30 degrees per step. I ended up with a <4 arc minute polar alignment error. Since this was the first time I did this with Ekos and dealt with running into the stops and not following the arrows on the display, this took an hour or a little more. (Update, I next chose CGEM for the mount and it worked fine as expected)
7). GoTos were accurate and then fine-tuned by the plate solving. This was seemless, using either camera.
. Autofocus. It worked, and seemed to be OK. There was a fair amount of fussing on the parameters. The default parameters certainly did not allow autofocus to operate. The initial step size was too large. Once I changed it to 50 “ticks” or “steps” and started by manually getting very close to the correct focus, checked Auto choose star, and checked subframe, it seemed to be OK. Seemed to be is the key. I checked focus manually with a Bahtinov mask. The autofocus was consistently 225 focus ticks or steps outside focus. This could be either due to an issue with the HFR computation or a collimating issue which makes the out of focus compute better than the obviously sharper star image of a proper focus point. All this took an hour or two to work out. I will need to do a detailed hyperstar collimation experiment to resolve this. A future night of warmer weather. (I fine-collimated the Hyperstar and autofocus worked much better).
9). Imaging. I used Kstars to select objects to GoTo. Once there I did a plate solve to fine-tune. Once there I did sample images and examined the histogram. I do not understand the histograms of Ekos. The scale is wrong and it seemingly does not show either a native pixel value nor a padded value. The Horizon has a 12-bit A/D and I would expect 0-4095. Padded I would expect 0-65535. What I got was a histogram of 0-250 (maybe 255??) with discrete bins with space in between. Even when I know the f/2 system should be saturated I did not see the histogram show saturated pixels. Very unusual and will require study and likely support questions. I would expect either the native (0-4095) or padded out to 16 bits at 0-65535. This is not yet resolved. I was able to schedule N images of a specified duration and have Ekos execute them and store them.
10). Guiding worked. The guiding behaved OK although there is a lag due to sending the image over the WiFi to the PC. There is a 21 step limit in the calibration of the guiding which was sometimes violated. I did not find where to change this, nor did I tune any of the default guiding parameters. It worked, but perhaps not as reliably as PHD2 on this 16 year old Mount. (the guiding worked well direct from the Atikbase a subsequent night)
11). Meridian flip. The automated meridian flip worked. It plate solved and got back to the same spot. The 21 step guiding issue kicked in at that point, so there was a manual intervention.
Overall it was a very informative night spent learning about the AtikBase / Stellarmate. 3 months of work, and hours of prep time got it to what I would consider a successful first night of learning with it. It was good that the plan for the whole night was to learn about Ekos and not to get any useful imagery. If my plan would have been to get useful imagery for a project, I would have been frustrated. Since the plan was to play with and learn Ekos, it was productive. Many questions remain.
A few of the remaining questions: if I were to use a VNC and not Kstars/Ekos on a PC, how does one get the images off of the AtikBase/Stellarmate? At most I can put about 800 subframes in the remaining storage on the AtikBase. With an f/2 system and avoiding saturated pixels that maybe not a very long period. I may have to remove images from onboard storage several times per night - depending upon the target dynamic range. Can one define a park position relative to the Mount instead of relative to the sky? Given the manual nature of the operation with a monochrome camera and a hyperstar (no filter wheel allowed), can the iOS Stellarmate app ever be useful?
Update: Choose CGEM for an old CGE mount. Make sure your optic train is well collimated for autofocus to work. Use a VNC to talk to the Atikbase. The iOS app for an iPad is so far not useful. The histogram is the major bugaboo for me at the moment. It is essentially worthless for how I want to use it. I like the histogram in Dusk. I can see it change when I triple the exposure length. Not so with the histogram from Stellarmate.
I'm looking forward to the next night I can get out when the clouds cooperate.
-Alan.
Recent Posts