Equipment
 
 

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All of the images on this site have been taken with one of five telescopes and one of two cameras.  The telescopes are a homebuilt 10-inch Newtonian, a Celestron CG9 1/4, an Astro-Tech AT66ED, a Meade 2045D. and, finally, an Explore Scientific ED80.  The 10-inch has always been on a homebuilt fork mount, further described below.  Until 2016, the other scopes were all used with a Losmandy G-9 mount.  Just before TSP 2016, I purchased an iOptron 45 Pro mount, and that has replaced the G-9.  It has GOTO which works extremely well.  At my age, it was getting harder and harder to get down on my hands and knees to find targets.

   The primary camera, by far, is an SBIG ST2000XM but a few images may have luminance from a StarlightXpress MX716 with color from the ST2000XM.  The ST2000XM has a CFW-8 with Astrodon LRGB filters.  In April, 2009, I purchased an H-alpha filter and added O-III and S-II filters in December, 2009.  Most of my imaging is done at one of four locations.  The locations are my observatory at West Point, Texas, my backyard in The Woodlands, Texas, Prude Ranch at Fort Davis, Texas (where the Texas Star Party is held), and the Fort McKavett state historical site (where my astronomy club has regular star parties). 

The picture at the left shows my observatory with the telescope stored.   The year after I retired (1999), we purchased 10 acres of land several miles outside of West Point, Texas and started building a log cabin and the observatory.  The observatory consists of an 8 x 12 prefabricated building, a 12 x 20 deck, and a rolling cover to house the telescope.  The poles at the corners hold tarps which serve as windscreens when needed.  The building has almost all the comforts of home, including a double bunk, power, water, telephone, TV, heat, A/C, computer, and portapotty.  The telescope can be operated either from the deck (in good weather) or from the building (when it's too hot or cold).  The picture below on the right shows the setup for nice weather.  I like to stay outside as much as possible to enjoy the sky while the images are collecting.  The black box is a cover for the laptop, which protects it and shields the screen -- essential at star parties and very desirable even if I'm the only one around.  My JMI Accutrac V and Motofocus controls just rest on the deck beside my chair. 

The 10-inch telescope was constructed in the late 70's while I was living in Chicago.  The mirror is a full-thickness Coulter f/5.5 with a excellent figure.  I have replaced the FRP tube shown in this picture with an aluminum one, and that has made a substantial improvement in stiffness.  It contains a Novak mirror cell, spider, and diagonal holder.   Upgrading from a  rack-and-pinion focuser to a JMI NGF with Motofocus several years ago made a great improvement in my productivity and image quality.  I built the fork mount in the local high school shop.  The head is 1/2-inch steel plate, with 2-inch pillow blocks and shaft, and the fork is 2 x 4 x 1/4 steel box with 1-inch self-aligning bearings.  The head is mounted on an 8 inch, 22 1/2 degree pipe elbow which, in turn, is on a 8 foot by 20 inch diameter concrete pier.  The 11 1/2-inch drive gear was purchased from Aeroquest about 2001 and the rotating rings were a second-hand purchase at TSP a year or so later.  A Telrad, Orion 9x50 erect-image finder, and a piggy-backed Meade 2045D complete the setup.  I do have setting circles but rarely use them.  However, I purchased an Argo Navis at the 2007 TSP and am using it occasionally to locate targets.  Even though I've been pretty lax about refining my coefficients, it almost always puts the object of interest somewhere in the field of my SBIG ST2000XM.  But most of the time I still just star hop using the finder, Bright Star Atlas 2000.0, and Uranometria.

This picture is a more detailed view of the equatorial head and drive gear.  The worm and drive motor assembly are pivoted and spring loaded.  The two large bolts at the top of the plate provide the altitude adjustment for polar alignment.  I have a removable push-pull tool for the azimuth adjustment but have only had to make one touch-up of the alignment over the years. The concrete pier is 8 feet deep and 20 inches in diameter. which explains the stability.  I got the electric company to drill the hole when they were installing the power poles for my log cabin on site.

 

 

 

A close-up of the declination drive is shown at the right.  The clutch shown replaced a wooden one, and is modeled after the one on the drive gear. The old wood/aluminum tangent arm has been replaced with steel.  The remainder of the drive is still hardwood and 1/8-inch aluminum plate.  A 1 rpm Edmunds DC motor drives an 8-32 bolt running in Teflon bearings.  The bolt moves a piece of aluminum plate in a track, and a pin perpendicular to the plate rides in an adjustable slot in the tangent arm. 

The other scopes are pretty standard.  The AT66ED was the second most used, after the 10-inch, until I got the ED-80.  I use them for my wide-field images, from my backyard or at star parties.  The Celestron CG9 1/4 is also used from those locations.  I always add a 0.63 focal reducer so the focal length is very close to that of the 10-inch Newtonian.  It has been a workhorse and performed flawlessly for 20 years.  I did finally have to send the G-9 equatorial head back to Losmandy for reconditioning in 2006 when I was no longer able to adjust it to remove the gear slop.  They replaced essentially all the moving parts quickly and at a reasonable cost.  However, I sold it when I acquired the iEQ45.

In late 2007, I purchased the SBIG ST2000XM, used, with a color filter wheel and AO-7.  I've been using it exclusively since early 2008 but only began to make color images in September of 2008.  So far, I have not used the AO-7 and am not sure I ever will.

With very few special exceptions (like M42 or the Pleides), my individual exposures range from 30 seconds to 10 minutes, with 4 or 8 minutes being the most common.  Longer exposures show slightly less electronic noise and, for the same total image time, and take up less hard drive space but both of these factors are becoming insignificant as technology improves.  Shorter exposures are less affected by cosmic ray, meteor, and satellite contamination, guiding error, wind, blooming or bloating (depending on the type of camera), and operator error.  When the wind is so bad that guiding is impossible, I use 30 second unguided exposures and keep the few that escape the gusts. 

Although not really equipment, I should mention my acquisition software, which is Astroart 3.0 -- a delight to use -- and my starhopping package.  When star hopping, I start with with Bright Star Atlas 2000 and the Telrad, then switch to Uranometria and the 9x50 finder, and end with (normally) 1.4 x 1.8 deg. charts printed with Megastar, using 10 second camera images for final positioning.  This process is not needed with the Argo Navis or the iEQ45 GOTO, but I still use the books and charts to plan my field.

Image processing is done with AIP4Win, with some final touch-up in PaintshopPro or Photoshop.  Many of my images use G2V calibration, where the filter coefficients are established using images of solar class stars.  See www.kellysky.net for a complete description by one of the developers of the technique.  Al's site also has excellent instructions for general image processing.  He has been my "guru" throughout my imaging experience.


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