Buoyed with the success of the NJP with Pumpkin, I decided to start upping the ante. Pumpkin was mounted offset to one side, but I decided that Veronica should be balanced over the Dec axis. I was already a little concerned whether the DA’s would hold Veronica, and I wanted one less thing to worry about regarding balance. So I reworked the DA’s so they’d fit in the center of the mounting plate, and mounted up Veronica.

At the same time, I decided to mount a couple of finder dovetails on the mounting plate, so I would have a place to mount Guido. That was a measured success; it totally worked for guiding (see guide data below), but was not so cool for using Veronica’s finder; something I’ll fix presently.

Here’s the guide data. The mount is so smooth, it’s silly.

I had been having trouble last night with subframe length; skyglow was eating any images longer than 3 minutes. I wanted to test some 10m and 20m subframes, so I decided to add the Ha filter to the mix. This made focusing a challenge, although the 3-day moon did help out some by staying up late enough that I could use it as a focus target.

Getting FocusMax working again was a bit of a pain. It took about 2 hours (or 3?) before I was up and running and ready to start guiding.

The winter nebulae had set by then (it was about 11:30 or so), and the spring ones weren’t due up for hours, so I decided to run the Ha filter on the spring galaxies. M101 was the target of choice; because the polar alignment isn’t exactly perfect, my “bracketing” exposures missed the galaxy (because the GOTO was inaccurate; I need to add “re-synch on nearby star” to my workflow habit). Once I resynched, Temma put M101 on the CCD.

The bracketing exposures showed that 10m exposures were fine, but 20m are a little too long (I’ll work out later whether 15m can be done).

I had earlier figured out that I can go about 2 hours, 10 min. past Meridian before hitting the pier. I set this up in the mount safety limits, but I still need to make sure that’s actually doing something.

Because I was 30 min. before the Meridian, I set it up to run for 2.5 hours (20x10m exposures, allowing for download time), set an alarm clock, and took a nap. At 3:30a (yes, it took awhile to get started), I went out, to find that the telescope had hit the pier. It actually hit the pier during the last exposure before I got up, though, so not too bad.

I crunched the data once I woke up, and here’s what I got. I think that my data processing workflow could use some help; I stacked this using “SD Mask”, for reasons passing understanding, and got some strange diagonal noise added.

But, this is 16x10m images, 2h 40m total, of M101 in Ha through Veronica.

I re-synched the mount on a star rising in the East (Deneb), and slewed to NGC6888 to see how Veronica could do on a “real” Ha object. I set it up to run for 3 hours (18x10m), knowing that I would be up by 6:30a to turn everything off.

I went to bed, had a crazy bad dream about the mount running into the roof and somehow falling into a lake (wow), and woke up to the mount having lost the guide star because of the sunrise. I only lost one image there, too. Not bad again!

I was a little off on the GOTO again; it was 3:30 in the morning, give me a break. I only got 6 useable subframes of NGC6888; I think a cloudbank hit at some point in there.

NGC 6888, The Crescent Nebula in Cygnus, 6x10m, one hour total exposure, Ha

A reminder that the reason these are grayscale is that this is the red channel only, as the Ha filter only lets data into the red channel.

So, my impressions?
First, the NJP is absolutely destroying my circadian rhythm. I am so tired I could sleep standing up right now.

Second, the mount is so stupidly accurate that I don’t know what to do with myself. The first time I tried to cut the guiding data this morning, PemPro reported a PE curve of +/- 0.0. When I look at the raw data, other than the big jumps that happen in Dec whenever the shutter trips, all of the data falls between 0.0 and 0.4 pixels. From the previous night’s data, I had an RMS periodic error of about +0.3/-0.2, or a swing of about 0.5″. Tonight’s data looks similar. That’s a 20x improvement over the best performance I ever achieved with the G-11 (+/- 5″, 10″ peak-to-peak). NJP good? I’m sold.

Third, I think the RCC is a lost cause. It makes my telescope hard to collimate, and it doesn’t seem to do as nice of a job flattening the field as the MPCC does (take a look at the corners of the images). Now that I am using clip-in filters, and have a mount that is really guideable, I think that I’m ready to pull the RCC, get Veronica reset back to normal, and use the MPCC from here on out.

Fourth, I don’t know whether the IDAS LPS and Ha filter are not behaving properly together, or whether my optics need cleaning, or dew prevention, or image processing, or what, but these images seem a lot noisier and generally uglier than the Ha stuff I was doing last spring. I’ll get my Ha mojo back, just something to note.

Finally, I can’t wait to see what the mount can do once I’ve aligned it properly! Unguided? Crazy long focal lengths? Oh, I think we’re going to find out. Stay tuned.

Things have changed a lot since the last time that I ran Focusmax. Among other things, I have built up a whole new astro-PC, and I never really understood FM well enough to just make it work out of the box, so I was essentially starting from scratch last night.

It was a gorgeous evening, dark sky because the moon is 3 days past full, and clear as a bell until midnight. I’ll get to that later.

I had characterized my focuser before sunset, so I knew that Pumpkin was near focus, and that the ends of the focus run were set properly.

As an aside, I also discovered “Configurations” in MaxIM. Very cool. It remembers which cameras, which exposure type, etc. were up so you can swap from “guider only = PEC” to “main cam only = Focusmax” to “main/guider = DSO”… nifty!

So I needed to set several parameters very carefully in Focusmax. I figured out several of them, but it took hours, and a lot of experimentation.

Here is how the night went.

I tried a “first light wizard”, which is supposed to “characterize” the focuser. The problem was, I couldn’t get it to stop scrolling out. It kept defocusing the star more and more until either the star was too big for the subframe, or the star was too dim for FM to detect.

I learned some things.

First, a 100×100 box is more than large enough for FM to work with a fairly out-of-focus star (anything that’s less than 1500 steps out of focus should fit, on Pumpkin). 50×50 is actually a pretty good size; it keeps “double stars” from creeping in, but you have to have the focuser in a pretty thin band of focus (within about +/- 500 steps), or you end up doing a lot of “it’s out of the box, increasing the size” stuff at the ends of the V-curves. Works, just twice or 3x slower.

You want to set a exposure length that is long enough to get a hit even when you’re at max defocus. I started with 3sec, went to 5sec and then 8sec. I think that 4 or 5 is probably the right answer now that I can restrict FM to the area near focus. Maybe lower, but again, you run into “can’t find a star, increasing exposure time” stuff, which just eats time.

I never got a first-light to complete. The “characterization” of the focuser never finished, because FM ran the star until it was bloated beyond belief and kept going until it lost the star. Here’s what I think was happening. According to something I read on the ‘net, there is a “max increment” or something like that, it’s in the focuser driver settings. I always thought this had to do with the “jog” function; ie “don’t jog more than ‘max increment’ in one go”. Something to do with overheating the motor or some such. I am now led to believe that this is “how many steps out of focus will FM go during the first light run”. So I need to change this from 10,000 (current setting; focuser never jogs more than 3500 anyway) down to about 1,500 or so. That might get the first light wizard going.

OK. So. I never got First Light working, so I just decided to force a V-curve. I did the “set the beginning, set the end, set the step size” type first, got a so-so curve, then swapped to the “set the middle, set the half-width, set the # of steps” type and ran off 3 good V-curves. With these 3 curves alone, the differential thingy (PI?) is at 26 (steps?) or so, about 50µm apart. Doing a quick calculation of focus tolerance:

Focus tolerance (depth of field) = 2 * f * d
where f is the f-ratio of the scope and d is the Airy Disk diameter, which is:
d = 2.44 * lambda * f
where 2.44 is a constant (why), lambda is the wavelength of light (bluer light has less tolerance than redder, so Ha at 656nm is easier than “white light”, which peaks near 555nm), and f is again the f-ratio.

Focus tolerance for Pumpkin in “white” (really “green”) light is 63µm. Veronica is about the same, 65µm.

So 26 steps (I already calculated the focuser to be doing ~2µm steps) is enough to hit the focus band, but getting it a little more dialed in would make me feel better. More V-curves next time out.

Now that I kind of understand what I’m doing, I need to start running lots and lots of V-curves. I’ll need curves for every setup; Each combination of scope, camera, and filter needs work. At some point, I will be able to figure out how much offset to use when the Ha filter is in; that will save time. But there is a lot of work ahead on Focusmax.

For Pumpkin, with the IDAS LPS and no Ha filter, I used exposure time of 8s, bounding box of 100, half width of 500, and step size of 25 (for 40 steps on the curves), and had pretty good success.

That’s a good starting point for V-curves for future scopes. I can crank it down to 3-5s exposures once I’m comfortable with the focuser.

I played around with different star fields. The area near M44 (but not the cluster itself; too many stars) is pretty rich with medium-brightness stars that FM seems to like.

I had to shut things down when the scope hit its safety limit and the clouds rolled in, both within a few minutes of each other, near midnight.

Finally! A Virgo galaxy. I’ve had some kind of mental block about shooting in Virgo, so I finally forced myself to shoot down here.
M104 is on the edge of being too small for the FOV, and this isn’t a great shot, but another new galaxy for the webpage and more to come.

Like M42 is a “tester” object for winter, M81 is a tester object for the spring. It’s big and bright and there’s lots of detail to bring up. In addition, if well-framed, M82 is often an added bonus on the outskirts of a large FOV.

Both of these two images are from the same dataset.

This one includes darks, flats, and bias frames (in addition to the lights).

This one is just darks.

I’m still working out the new workflow that involves FITS images and all these extra non-astronomy frames I have to shoot. Also, I find that my processing skills are delightfully random between nights, even on the same data. shrug.

This is a “freebie” version of M82. It was way off in the badly vignetted border of the above M81 images (M81 was centered). But once I applied flat frames to the images, there was enough data in M82 for at least a “tester” image of it. I don’t know what happened to the red. Don’t ask.

This is a tale of two images. These were taken on successive nights.
Same setup, same exposure time, everything.

The first night was unguided.

… and the second night was autoguided with my trusty ST-4.

This was kind of a test of the G-11 Gemini to see how good it could perform without a guider.
The guided image is definitely better. But the unguided one is not too shabby.

After 4 overseas trips in 4 months, I finally had some time to really get some time under the stars and get back to the “spring” galaxies that I’d raced to catch last May. This is an unguided shot, 2 hours. The new Gemini mount really hung in there. Looking forward to seeing this with more focal length, more integration time, and guiding.

One of those objects that just doesn’t get much press.

This is a huge nebula, the size of M42, and well-placed in the sky, between the foot of Gemini and the head of Orion.
But I’d never heard of it until I started searching with my DSO filter software.
This is an object that should get more attention in the Fall when it comes back around, but here’s a quick treatment.

This time I went nuts and punched up 4(!) hours on M63.

That’s by far the most I’ve ever done.

This was unguided, while I was still testing out the new mount. Looks pretty good. Would probably be tighter with guiding. But *look* at all that detail!

I decided to quit messing around with trying to get both galaxies in the field at once,
and just concentrate on getting a good shot of M81.
This is a 3-hour integration, unguided 3-minute subframes.