Zeroing In

Last night was a nice transparent night, the moon about a day from full.  Jupiter hovered an inch from the Moon’s head.  A good night for fooling with the system.

My polar alignment should be pretty good, but the scope still doesn’t know where it’s pointing.  My Meade finder scope often has a mind of its own and can be off enough that the target is not even close to being on the camera’s chip.  The coverage of the chip is only 17 x 11.5 arc minutes so it can be painful to locate an object with the camera. Once you find it, and sync the mount, you’re good until you crash into the counterweights with your head and knock everything out of alignment, or make changes to polar alignment, or rebalance equipment, etc. Usually I take off the camera, put in an eyepiece, find the thing I’m looking for, put the camera back on, center the image, and re-sync.  PEMPro has a “Find Star” feature that takes images in a spiral around the current position, and when it hits the target, you can right-click the frame and it will center it so you can sync properly.  I’d thought I’d give that a try.  I will say that it worked like a charm, except I was so far from the target that I grew weary of waiting.  Also, as PEMPro accumulated images — its default limit is 100 — my fairly ancient PC began to act like it was choking with low memory.  I also had trouble connecting remotely, and eventually had to kill PEMPro with the task manager.  So I disconnected the camera, installed an eyepiece, centered Vega, reconnected and centered Vega on the chip, re-synced the mount, recentered the finder, and was back to normal.

I used the TheSky to go to the double-double, centered on one of the pair on the chip, then a look at M57, which centered up perfectly.  Probably won’t stay perfect since the 12″ mirror has a bit of play that will show up as we slew around the sky.  I made a 300 second uncalibrated luminance image just to get an idea where we stand.

M57

M57, uncalibrated, unguided, Meade 12″ at f/10, 300 seconds luminance; ST-10.  Fair transparency, bright moon light.

The oval stars  show there’s a bit of tracking error in RA, which could be periodic error, and I’ll get into PEMPro to see if I can improve that, next full moon.  I would like to, and believe I can, do 5 minutes unguided.  But anyway, that error will certainly guide out. Getting the guiding cleaned up is next, along with auto-focus.  I have been using the guide chip on the ST10, but want to set up the new Orion SSAG autoguider, which I think will work better for narrow band imaging.  The focus is also off, and I will get the auto-focus routine down.  I get fairly good focus manually using a mask, but auto-focus will probably do better than I can, and for remoting, auto-focus absolutely has to work.  Also, there’s vignetting and dust donuts which will disappear with a flat field.  I need a good, repeatable flat-fielding method.  I have a white target set up in the hut I have used successfully and wonder if it would work if placed in the Park 1 target zone.

Figuring out the AP-1200

I installed a Astrophysics AP1200 mount in my roll-off roof hut, now actually more than a year ago. It’s intended for remote imaging from the comfort of my living room, and if I can get it to work from my living room to the Hut, it “should” work from living room to New Mexico. I think I’ve been afraid to really get the system figured out because honestly it can perform far beyond my current level. I have an otherwise cobbled together set up that has worked fairly well, but now I’ve had to put together the pieces and parts to really make it work. So there’s a lot of learning that has to happen. I finally acquired Maxim DL in May, and I believe that TheSky 6, Maxim DL, my SBIG ST-10 and the AP-1200 will all play together nicely in the hut and via remote.

We’re in the back half of November, and it should be getting cold, but we’ve had unusually warm weather, and the new moon will be growing over the coming nights. This is a great time to try to iron out the inevitable weirdnesses of the new system. I’d really like to be remoting to the system from the living room this winter!

Should be simple if it’s broken into simple pieces. Software (TheSky, Maxim, PEMPro) needs to communicate happily with hardware (AP1200, ST10 and CFW8, Optec focuser, Orion SSAG).  I’m gonna make this thing happen!

Suddenly nothing is working right! I slew the scope and the PC reboots itself! This turns out to be a loose serial port connector on the focuser. I connect theSky to the scope, but Maxim is unable to connect. So I downloaded and installed the latest ASCOM TeleApi plugin (from http://www.ascom-standards.org/Downloads/Plugins.htm) and the latest AstroPhysics V2 ASCOM drivers (from http://www.gralak.com/apdriver/). Now I can connect theSky, Maxim, PEMPro to the AP1200. I’ve been setting the Autostart feature of the AP1200 to “No” and using the keypad for initialization. When I park (“Park 1”) the mount is on the wrong (East) side! Jeesh! Now what? There are a variety of weird behaviors I’m getting starting up with the keypad, connecting to the PC, and parking with the keypad.

I poked around in the AP-GTO user group on Yahoo, and of course I’m not the first to  have these issues. First I discovered that I hadn’t adjusted the keypad yet for the end of Daylight Savings Time. That’s what causes the east-side-park thing. I have a permanent setup and am using a PC, so I should be setting Autostart= EXT and initialize via the theSky. I’m only creating another opportunity for confusion with Autostart=NO; it only makes sense for portable setups. So I set the keypad to EXT and restart the mount. Resuming from Park in theSky, the map shows the scope in the park position, but when I try a go-to, it takes off in a totally inappropriate direction. The mount has no idea where it’s pointed. Ok, I have set my location to an East longitude when it should be West! That should make a difference! I sync to Vega, and slew to Epsilon, but it still is wildly lost. Oh, in the AP V2 ASCOM control panel, is a “convert Sync to RCAL” check box which is checked by default. So I wasn’t really syncing to Vega at all! So I uncheck that, agree with the dire warning alerts that pop up, and really sync. And, after a park-disconnect-reconnect cycle or two, we seem to be in the ballpark. In the process, I see that the AP V2 control panel, which is entirely new to me, is really excellent. It’s very comparable to the keypad but with easier layout of controls, so why haven’t I been using it all along…. Also the help materials with it are really good.

My polar alignment was decent, having spent an evening doing drift alignment when I first set up the mount. In the interim, the Great Johnsville Sewer Project caused a surprisingly large 20 foot deep trench to be dug about fifteen feet from the Hut. As a result my pier, which is not as massive as it should be, began to lean like the tower in Pisa. Now that the trench has stabilized, I think/hope the pier will stay put, but I did have to level up the adapter plate for the mount. So I was looking forward to using PEMPro’s Polar Alignment Wizard to repair and verify the alignment.

Sunday night was clear with that milky sky that comes from ice in the air, and an 8 day moon. I fired up the scope and camera, Opened PEMPro and Maxim, and connected the scope and camera. PEMPro is great for this combination of hardware and software. I went thru the handy checklist, collected site info from the mount with the click of a button, and following the wizard, it measured my image scale, about .46 arc seconds/pixel, and established the cardinal directions for the chip. The software prompts you to slew to the South for azimuth measurements, just click “slew” and it goes to a good place. Actually, when I began the azimuth measurement routine, PEMPro had trouble finding a star; when I looked at Maxim, I could see that it was trying to lock on to a hot pixel. So back in PEMPro, there are handy jog controls to move the scope a bit to find a fresh field. After that it quickly found and analyzed a star. In retrospect, I should have used a dark subtraction, that would have prevented the problem.  I was able to get the azimuth to + or – .1 arc minutes in about 15 minutes of tweaking. The next screen I found confusing; you take a reference image and choose a star. PEMPro displays an arrow over the star and you are supposed to tweak the mount to move the star to the point of the arrow. My first set of tweaks was close enough that the star was at the tip of the arrow, and I didn’t understand what I was supposed to do. Apparently nothing! The altitude alignment went as smoothly, although I was getting cold and anxious to finish. I spent maybe an hour and a half on the alignment, and am well within an arc-minute of the pole. I’ll try it again to verify on another moon light night; I think it will go faster with practice. The AP mount has incredibly smooth adjustments for polar alignment. After many years of fooling with a Meade Super-wedge, I really appreciate the precision of the AP.