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

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.