Tuesday, December 27, 2011

Imaging Near Upham

This Christmas holiday, we visited our parents in Las Cruces as we usually do.  In order to test some of our new equipment, we drove out into the desert near Upham, NM,  north of Las Cruces.   We were headed for the dark sky site that the local club uses but had to stop short due to the road conditions. We did some basic imaging tests ... at least until the equipment frosted over.  We also got a visit from the local US Border Patrol agents wondering what we were doing.

We were able to get this image of the Orion Nebula before shutting down.  This was taken with a QSI-540 CCD through an Orion ED80T-CF 80mm refractor.

We also tested some images using a Canon 450D riding piggy-back on the mount.  Here is one of the belt of Orion

This is the star field around the PacMan nebula

Wednesday, November 30, 2011

Eunomia Traverses California Nebula

While post processing a set of images of the California Nebula (NGC-1499) that I collected on Nov 28, I noticed a moving object in the field of view. This image shows the position at 05h00 UTC and the relative path.

I computed the motion relative to the star-field to be about 40 arcsec/hr. The corresponding absolute motion across the sky was too slow for a low earth orbit satellite and too fast for a geosynchronous satellite. I gathered it was likely a solar system object. On the other hand, comparing the brightness to other stars in the field, I estimated this object to have magnitude between 7 and 8, larger than expected.

I was not sure how to cross check this against know objects but some colleagues from the Austin Astronomical Society helped me out. Harden pointed me to the Central Bureau for Astronomical Telegrams (CBAT) and Mike checked Otwell's Astronomical Calendar and found an entry for the asteroid "15 Eunomia" stating that it would be at opposition on Nov 28 in the California Nebula at magnitude 7.9. Sounded like a match! I later found a published graphic of the path of the asteroid further confirming the match. In wikipedia article I read that 15 Eunomia is the largest stony asteroid and was discovered in 1851 by Annibale de Gasparis ... I little earlier than my observation.

Wednesday, November 23, 2011

Travel Case for LS60T

I replaced the stock case for my Lunt LS60T-HA PT/FT Solar Telescope with one I crafted from a Pelican-1450 case with custom foam inserts.  I used a Poyethylene Foam Sheet from Foam Factory.  It is a 2" thick sheet of 2.2lb polyethylene closed-cell foam. Not only do I have room for the DMK41 Video camera, I am also able to close the case with the Televue Sol Searcher still attached.

Sunday, November 20, 2011

Custom Cases for Losmandy GM-8

In preparation for next year's trip to Haleakala, I created two custom transport cases used for my Losmandy GM-8 Mount.  The tripod and counterweight are placed in a High Performance Resin Case HPRC6300 and GEM head and controllers in a Pelican Storm iM2620.  Total weights are 49lb and 46lb respectively.  Technically, the HPRC-6300 is 62.5" overall size.  I am hoping this is close enough to 62".  Cases are both available from http://www.bhphotovideo.com

The HPRC6300 is a sold as a tripod case and is the only hard-sided model I found that opens like a coffin, rather than like a tube.  This makes it ease to pack and access other items. Under the tripod is a telescope cover, to the right of the tripod is a lithium power supply.  The counterweight and shaft are nestled in between the tripod legs in a "swimming noodle" split down the middle.  Other bags contain cables etc.

Here is everything unbundled from the HPRC6300.  I created some custom foam blocks to support the tripod on either end.  A noodle covers the counterweight shaft and another snaps on the outside of the upper tripod leg holding the tripod firmly in place when the lid is closed.  The bags contain various cables and power adapters.

I built the custom insert for the Pelican iM2620 case by layering stiff foam sheets. I used a Poyethylene Foam Sheet from Foam Factory.  It is a 2" thick sheet of 2.2lb polyethylene closed-cell foam.  A single quarter sheet is just enough to create the needed 4 layers.  All foam cuts were made with an electric kitchen knife.  The bottom layer has slots to accommodate the ADM saddle plate and the base.  

Second layer of foam does most of the work of holding the mount head.  Layers have been glued using Contact Cement from hardware store.  I tried the recommended Super 77 spray glue but that was both harder to control and less effective as an adhesive.

Third layer similar in profile.  Notch in the lower left is to hold some counterweights.  Recessed areas in the center holds the Gemini board and hand controller in place.

Mount sits down in the holes.  I have left extra room for the polar scope which I have yet to receive from Losmandy.

This extra piece of foam provides a platform for extra bits in the next image. Also helps hold the mount in place.

The Gemini module and hand controller fit in the recessed notches.  The ADM dual saddle plate rests on top of the extra foam platform.  Extra counterweights sit in their slot.  Not shown is a final piece of 2" foam wedged into the lid of the case with two holes to accommodate the motor housings. When the lid is closed, everything is pressed firmly and no stress is placed on the motor housings.

Friday, November 11, 2011


Though silly, it was fun to see the date-time turn to all elevens today.   This is an iPhone screen capture from a date-time website.  The site has since changed so you can no longer see a totally numeric date and time.

Saturday, October 1, 2011

Modified Wiring on Aurora Flatfield

I purchased a Gerd Neumann Aurora Flatfield Panel on-line. The quality of the panel itself was very nice as is the resulting illumination but the mechanical aspect of the wires connecting it to the inverter block are very flimsy.   I figured this would last only a little while before I broke the wires so I decided to improve it.

The first change I made was to encase the inverter in a custom plastic box.  I exposed the 12V input to the inverter with an RCA jack, just like those used on my dew heater controller.  I modified a 12V AC adapter with an RCA plug.  For the AC signal to the Aurora panel, I used a panel jack for a 1/4" phono plug.    This removes all of the stress on the thin wires going into the inverter box.

On the panel itself, I carefully drilled a hole through both the front translucent panel and the back opaque panel.  It is really easy to crack these by accident but not a disaster if that does happen.  I mounted another 1/4" phone jack through this hole and wired it to the original wires going to the electroluminescent sheet sandwiched between the two panels.

The panel can then be connected to the inverter with a simple cable with phone jacks on each end.  Only caution is that, when energized, the exposed wires in the previous picture will give an electric burn if touched.

Sunday, September 25, 2011

Losmandy GM-8 Dec Puck

I recently acquired an ADM dual adapter plate for my Losmandy GM-8 mount which allows me to use both V and L style dovetails.  It is also longer than the stock GM-8 plate.   One of the problems that I discovered is that when the RA axis is slewed to the East and the DEC axis points near North, the adapter plate crashes into the RA motor assembly.

In order to remedy this, I created a "hockey puck" of scrap aluminium to sit between the DEC assembly and the adapter plate.   The puck measures 3.5" x 0.75" with two through holes spaced 3" on center.

The puck is the bright silver colored part in the images below.  You can see that with this puck, the adapter plate just clears the motor housing in this position.   In fact, there is now no orientation in which the adapter plate collides with the motor housing.

Near North Horizon - Mount on East Side

Near North Equator - Mount on East Side

Saturday, June 4, 2011

Super Nova in M51

Image of SN 2011DH which I took on June 2, 2011. I discovered this SN in my images prior to reading about it on-line! Unfortunately, my first image was about a day after the initial discovery. It was still pretty cool!

Saturday, May 14, 2011

CGE Gets New Cables

I have been plagued with connection problems in the RA and DEC cables on the CGE since the second day after I received it.  Typically, run-away slews as the controller is unable to receive encoder pulses to detect mount movement.  My first instance of this problem was in the middle of the New Mexico desert on my first field-trip with the new mount over a year ago.   I wasted the entire evening under magnificent skies debugging the mount with a multimeter.  The problem is that the RJ-45 connectors do not make very secure connections, especially since Celestron chose to run a 9th signal wire through the connector shield.  You got to be kidding!

I finally bought one of Gary Bennett's CGE cable kits. This completely replaces the cables and the crappy RJ-45 sockets with beefy screw-on 8-pin connectors.  These are very well designed kits and require no irreversible changes to the mount.

In the image below, note the connector block on the left side of the pier.  This is were the RA and DEC cables plug in.  The connector circuit board under the plate is also replaced.  Shadowed behind the orange knob, you can see where the other end of the RA cable plugs in.  Again, Gary has provided a single-block aluminium piece that, along with another circuit board replaces the original RJ-45 socket.

Full view of the new CGE Cable Kit from Gary Bennett.

Update September 2012 - Cables have been going for a year and a half.  Not motor runaways since I replaced the cables.  Best money I ever spent on this mount.