Jeff's Blog

I’ve been asked a couple times what I do for power in the field. Here it is.

• 2 x Everstart 24DC-6 flooded lead-acid hybrid deep cycle/marine batteries wired in parallel. 75AH each, 150AH in total
• 0 gauge cable with nice ring connectors throughout, including between batteries (ignore the pics, I had 4-gauge on between the batteries then with 0 gauge to the inverter)
• 80A ANL inline fuse on the positive side
• Xantrex ProwattSW 600 pure sine wave inverter (For the mount exclusively)
• DuraCell Digital inverter 400 (for two laptops and everything else, modified sine wave)
• Enercell 3-outlet DC cigarette adapter for the Parsec 8300M
• Battery Tender Plus 12V 1.25A charger

This system powers everything in the field, mount, two laptops, focuser, powered USB hubs, and camera. And anything else I want to throw at it. I keep it in the car when it’s cold out, and run extension cords to the gear. After two nights in a row of heavy use without a charge the voltage will still be 12.3V.

The only maintenance needing to be done is the occaisional top-off of the batteries with distilled water. I’ve only needed to do that once, and it was very little.

After two nights of heavy use in a row it’ll take about 3 days to fully recharge using the 4-stage Battery Tender unit. That is a fantastic charger by the way.

Needless to say, no power worries in the field. 🙂

I still have two Duracell Powerpack 600’s. I’ll take one with me, for dew heater use and/or DC powered hairdryer use. But these don’t see much use any more.

Pictures:

I compiled the code found at http://www.astrometry.net/use.html on my Fedora 11 box (a VM really, hosted by VPSLink) in Boston. A couple edits to a couple makefiles, a bunch of yum installs for devel RPMs and I was off.

I fed it a test that it came with, and voila:

[root@galaxy demo]# /usr/local/astrometry/bin/solve-field  --overwrite apod4.jpg
Reading input file 1 of 1: "apod4.jpg"...
jpegtopnm: WRITING PPM FILE
Read file stdin: 719 x 507 pixels x 1 color(s); maxval 255
Using 8-bit output
Extracting sources...
simplexy: found 1467 sources.
Solving...
Reading file "./apod4.axy"...
Field 1 did not solve (index index-219.fits, field objects 1-10).
Field 1 did not solve (index index-218.fits, field objects 1-10).
Field 1 did not solve (index index-217.fits, field objects 1-10).
Field 1 did not solve (index index-216.fits, field objects 1-10).
Field 1 did not solve (index index-215.fits, field objects 1-10).
Field 1 did not solve (index index-214.fits, field objects 1-10).
Field 1 did not solve (index index-213.fits, field objects 1-10).
Field 1 did not solve (index index-212.fits, field objects 1-10).
Field 1 did not solve (index index-211.fits, field objects 1-10).
Field 1 did not solve (index index-210.fits, field objects 1-10).
Field 1 did not solve (index index-209.fits, field objects 1-10).
Field 1 did not solve (index index-208.fits, field objects 1-10).
Field 1 did not solve (index index-207.fits, field objects 1-10).
Field 1 did not solve (index index-206.fits, field objects 1-10).
Field 1 did not solve (index index-205.fits, field objects 1-10).
Field 1 did not solve (index index-219.fits, field objects 11-20).
 log-odds ratio 102.203 (2.43256e+44), 24 match, 1 conflict, 104 distractors, 33 index.
 RA,Dec = (187.099,56.6898), pixel scale 170.367 arcsec/pix.
 Hit/miss: ++-++-+-+-+++---+-++++-+-----------++-------+--+----------+-----------------+------c
----------+-
Field 1: solved with index index-218.fits.
Field 1 solved: writing to file ./apod4.solved to indicate this.
Field: apod4.jpg
Field center: (RA,Dec) = (187.2, 56.72) deg.
Field center: (RA H:M:S, Dec D:M:S) = (12:28:44.881, +56:42:55.986).
Field size: 33.1393 x 23.7307 degrees
Creating new FITS file "./apod4.new"...
Creating index object overlay plot...
Creating annotation plot...
Your field contains:
 Part of the constellation Draco (Dra)
 Part of the constellation Ursa Major (UMa)

How cool is that? It also writes out a FITS file, and some PNGs which show the constellations in there, or any other object.

On 11/22/2010 I ordered one of these bad boys:

http://www.wickedlasers.com/lasers/E2_Series-104-63.html

It *just* arrived. Better late than never I guess. But this thing is powerful, whoa.

Here’s a pic of it:

I was mostly heading out, not expecting it to be as clear as it ended up being, to do some fine collimation work and focus scripting in Maxim. However, it just was so clear that I figured I’d do a couple hours of imaging instead, even though the seeing, as has been continually the case recently, wasn’t good. I had to leave early however, as I had a busy Sunday ahead. So, here’s the AT8RC mounted on the CGE-Pro, Parsec 8300M, motorized filter wheel, ATFF field flattener, and motorized MoonLite CS, setup, pre-wiring:

Here’s my FocusMax focus run from 9PM.

21:00:47  
21:00:47   System: MySystem
21:00:47   ** Beginning Focus run **
21:00:47   LS: -0.072583 RS: 0.072609 PID: 9.76 NFHFD: 10
21:00:48   Move direction: Out
21:00:48   Temperature = 16.0
21:00:48   Filter number = 0
21:00:48   Current position = 6419
21:00:48   Focus Start: 6453
21:01:07   Target star found at  X = 1719, Y = 1304
21:01:07   Focus exposures will be 0.11 sec
21:01:11   Position , HFD , Mean Best Focus , X , Y , Flux
21:01:11   6453  ,   7.47  ,  0  ,  1712  ,  1317  ,  1106068
21:01:11   HFD < NearFocus HFD
21:01:15   6409  ,   6.31  ,  0  ,  1709  ,  1319  ,  1109319
21:01:15   On the wrong side of focus
21:01:22   6047  ,  25.41  ,  0  ,  1710  ,  1320  ,  1023097
21:01:27   6153  ,  18.33  ,  0  ,  1712  ,  1321  ,  1281629
21:01:27   On correct side of focus
21:01:27   Move to Near Focus HFD
21:01:31   6268  ,  11.19  ,  0  ,  1708  ,  1319  ,  1088295
21:01:31   ** Starting Near Focus **
21:01:31   Position , HFD , Mean Best Focus , X , Y , Flux
21:01:31   6268  ,  11.19  ,  6417  ,  1708  ,  1319  ,  1088295
21:01:35   6268  ,   9.74  ,  6407  ,  1708  ,  1320  ,  1047245
21:01:38   6268  ,  10.85  ,  6409  ,  1708  ,  1321  ,  1052828
21:01:41   6268  ,  10.99  ,  6410  ,  1708  ,  1319  ,  1158818
21:01:44   6268  ,  11.17  ,  6412  ,  1707  ,  1321  ,  1035770
21:01:48   6268  ,  11.98  ,  6414  ,  1706  ,  1319  ,  1170274
21:01:48   Best Focus is: 6414
21:01:53   6414  ,   6.62  ,  6414  ,  1708  ,  1319  ,  1247415
21:01:53   Position = 6414  Avg HFD =  6.62
21:01:54   Focusing Completed
21:01:54   Focus time = 67 sec

I took a 15 second exposure in Auriga, at 9:56PM (the bright star in the center left is Phi Aurigae), which was fairly straight up and dense:

I ran this through CCDInspector, which gave me:

Good enough. I decided to skip fine collimation and just see what M106 would look like at 480s with 5 subs LRGB each. I wasn’t expecting much at all, especially as I started imaging it fairly low in the sky, while the 1st quarter Moon was still up. M106 would hit 88 degrees at 1:08 AM, and the Moon would be just setting then, but I had to pack up before that.

So here’s M106 (and NGC4248).

Specs:

• 480s x 5 LRGB each, for 160mins total, L binned 1×1, RGB binned 2×2
• 10 darks 1×1, 10 darks 2×2
• AT8RC (1625mm focal length, f8)
• CGE-Pro
• Orion shorttube 80 and SSAG guider with Maxim guiding via ST-4 to the mount
• quick and dirty processing in Maxim and PS CS4, levels and curves, HLVG, Carboni’s Tools, unsharp mask

I really really really like the MoonLite’s, so I thought I’d put up a blog entry on using the CS Model with my AT8RC scope. First, I zero’d my drawtube. I have the 1.5″ one, which at 6135 steps/inch comes to 9202 steps, minus 500 for safety, gets me 8702 total steps of travel. I set the driver to max increment 3000, min step 0 and max step 8702, leaving the steps/second at 125 in Full mode. I jogged the drawtube out manually to 27mm (which is where I measured it by hand with a ruler last time) which ended up being 6443 steps out. My scope comes with two 25mm and one 50mm spacers, and I’m using the 50mm already. If I stick a 25mm in, I’d only have 2mm left of drawtube play, not enough. But I do have a 1″ brass compression extension that I might use and that would use up ~6135 steps of travel, leaving me with ~300. I might or might not use that. So far I haven’t seen a need.

After manually jogging out 27mm/6443 steps out, here’s my initial focus run on SAO 25502, which is Mag 3.7 (4 is recommended, 3.7 is close enough). Puts me at 6423 steps out. Amazingly close to where I manually jogged out.

Since the night was a waste anyways, but I couldn’t do a multi-star collimation with CCDInspector, I just figured I’d take a quick look at rough collimation with the single-star de-focus method CCDInspector also provides. I forgot which star I slewed to, but it was something fairly straight up and fairly bright, but it wasn’t Sirius if I recall. Pushed the drawtube out to 8131 and took an image. Not bad, fairly close.

Pushed the drawtube out to 8331 to de-focus a bit more, and it shows rough collimation to be pretty close. Close enough for imaging work for sure.

Now back to focusing. I wanted to see if my filters were parfocal. Slewed back to SAO25502…

…and did a couple focus runs per filter. Here’s a screenshot of my last luminance focus run.

• 20:48:   6423 steps out – Luminance
• 20:52:   6433 steps out – Blue
• 20:53:   6433 steps out – Red
• 20:55:   6433 steps out – Green
• 20:56:   6431 steps out – Luminance
• 21:24:   6411 steps out – Luminance

That’s pretty close to being parfocal if you asked me…

Here I am in the middle of a field in Middleburg, VA. Super pretty area. Quiet, peaceful, no one bugs me, and I even get pretty decent 3G reception so I can stay on the ‘net via 3G card in the laptop. Bonus!

You can see Mr. Boosky marking his territory here…

Gradually setting up…

Using all ADM plates and rings. Losmandy side-by-side setup with two dual saddles…

This clearly shows the counterweight on the front of the triplet. Helps balance it…

Lapdome junior. Keeps the netbook safe, dry, frost free, dew free, and shields the light from it.

This Stanley Fat-Max rocks.

I run off AC. I have two 75AH deep cycle batteries in the car attached to a Xantrex pure sine-wave inverter.

CCDInspector screenshot of the field of the Orion triplet tonight with the Astro-Tech FF. Again, not perfect, but not way off either, so I didn’t mess with it.

Here’s a screenshot of Maxim and guiding. Gusts to 30MPH, this was pretty much what I got all night unfortunately. I’ve really not had good guiding in a long time.

Here’s the AT8RC field of view with CCDInspector tonight. Not bad, I didn’t feel like messing with the position of the camera/FF in the focuser drawtube so I left it alone.

Here’s a screenshot of FocusMax, Maxim doing the guiding with the SSAG. For the moment I’ve using ST-4 direct to the mount guiding.

Another, guiding got a little better here.

Here’s the new Orion ED80T CF triplet refractor with the dew-shield fully extended, and the MoonLite CF focuser attached. The stock focuser on this scope is quite good, and sturdy, but I’ve become a fan of MoonLite’s stuff, so I sent the scope to Ron@MoonLite, he patterned and machined a custom flange for it and sent everything back. The focuser is rock solid and dead center (see the CCD Inspector 3D jpegs below). It comes with an interesting feature – a shaft lock, which is a small thumbscrew on the left side, which clamps down on the crayford shaft. Works amazing. I had gotten focus to where I wanted it in Maxim DL, and then tightened the screw, and voila, no shift, or change of focus. The tube is carbon fiber, the lens cover is metal and screw-on, which is a real nice addition. The dew-shield locks in place with a thumbscrew/compression ring, another nice feature.

Here’s a bit of a close-up of the MoonLite CF.

And with the 4.5″ drawtube extended almost all the way.

And with the dew-shield fully retracted.

It comes with a pretty nice 2″ diagonal. I’m not using this, as this is an imaging-only scope.

Here’s the scope with my imaging equipment inserted. 2″ Astro-Tech ATFF field flattener, Orion Nautilus motorized filtered wheel (and 2″ LRGB filter set), and the Parsec 8300M CCD camera.

Another shot. This where I guessed focus might be and I was very close. About 1.5″ of travel outwards and I had focus.

So, onto performance. I mounted the scope on the right side of an ADM side-by-side setup. Both the saddles in this SBS setup and dual Losmandy and Vixen so I can use any scope, on either side. The main plate is a thick Losmandy. I counterweighted the front of the scope with an additional ADM Vixen rail up front with a couple Vixen saddles tightened to it as the scope is very camera heavy as is and I needed more weight on the front of the scope/bar. With my Orion ShortTube 80 and Star Shoot Auto Guider on the left side of the SBS plate, I mounted it onto the CGE-Pro, and was off to image. (I had already gotten rough focus just holding the scope in my hand with the camera shooting 1s exposures).

I didn’t realize it, but I didn’t have the camera/field flattener fully square/orthogonal to the scope initially, and you can tell by this CCD Inspector shot.

*After* I shot my test image I thought I’d play with the flattener/camera fitting in the focuser drawtube, and saw it was slightly askew. After a quick adjustment while aimed into a starry section of sky I shot another 120s test and got this:

It doesn’t get much better than that. So, next time I’ll check the camera being square *before* I shoot like I usually do.

Here’s a test image of NGC2264. Nothing special here at all. 3×8 mins LRGB each, plus darks. -20C on the Parsec 8300M, guiding was average to below average. Focus is a little soft, as I spent all of 2 minutes getting focus, and I didn’t refocus between filters. Also, the camera was *not* square/orthogonal to the scope as previously mentioned, which I didn’t notice until after the imaging run.