Equipment

Originally, all of the images on this site were taken with one of three telescopes and one (or two) of three cameras.  By coincidence, they were also taken at one of three locations.  The telescopes were a homebuilt 10-inch Newtonian on a fork mount, a Celestron CG9 1/4 on a G-9 German equatorial mount, and a Meade 2045D which is piggybacked on the 10-inch.  The cameras were a Cookbook 245 which I constructed in 1995, a StarlightXpress MX716 purchased in 2003, and a StarlightXpress MX916 borrowed from my friend Dennis Webb for a couple of months while my MX716 was in for repair.  The locations were my observatory at West Point, Texas, Prude Ranch at Fort Davis, Texas (where the Texas Star Party is held), and the Fort McKavett, TX, state historical site (where my astronomy club has regular star parties).  Beginning is 2008, essentially all of the replacement images are being taken with an SBIG ST2000XM camera and I also started using an Astro-Tech AT66ED for very wide field images (like Arp 317).

The picture at the left shows the observatory with the telescope stored.  A very large majority (305) of the original images were taken here, and most of those with the 10-inch.  All of the TSP and Fort McKavett images were taken with the CG9 1/4.  The year after I retired (1999), we purchased 10 acres of land several miles outside of West Point 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 to 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 control 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.  It was in a 12 1/2-inch FRP tube with a Novak mirror cell, spider, and diagonal holder.  The FRP tube was replaced with an aluminum tube in June, 2008 to correct flex problems with the heavier camera, and it has done that.  About half the images were taken while I was using a 2-inch Meade rack-and-pinion focuser but then I upgraded to a JMI NGF with Motofocus.  That one change 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 a 8 inch, 22 1/2 degree pipe elbow which, in turn, is on a 7 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 regularly now to locate targets.  Even though I've been pretty lax about refining my coefficients, it always puts the object of interest somewhere in the field of my SBIG ST2000XM.

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 in six years.

 

 

 

A close-up of the declination drive is shown at the right.  The wooden clutch shown has now been replaced with a real clutch modeled after the one on the drive gear, and the tangent arm is now 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.  Everything except the clutch was done with hand tools before I got a lathe and milling machine.

 

 

I call this device my Flipper.  It allows me to flip the Cookbook or SX MX716 cameras into position for taking images, or flip to the eyepiece position for centering the target and or taking darks.  There is a spring-loaded eccentric on the back side of the center axle which lets it move very easily but keeps it firmly held in either position.  The eyepiece holder has lateral adjustments for precise alignment with the camera, and the little brass buttons at the bottom are adjustable stops.  There is a 2-inch brass tube on the back side which fits the JMI focuser.  It can be removed and replaced with a SC visual back when I'm using it with either of my SC's.  With my ST2000XM, the Flipper is no longer being used.  The camera is mounted directly into the focuser and I find objects either with the finder scope or, more often, my Argo Navis.

 

 

Here is the Meade 2045D on its piggyback mount.  I mounted one of the fork arms (the one with declination adjustment) on a spring-loaded tilt plate.  That provides smooth and convenient X-Y centering.  It's shown the way it's used for ST-4 guiding.  When used as my short focal length imaging system, the diagonal and parfocal adapter are removed and replaced with a focal reducer and the camera.  Since I got the Star2000 system for my MX716, I've seldom used the ST-4.  It worked well and I acquired many good images that way, but S2000 guiding was so easy, quick, and precise that I always used it, even at the cost of doubling my imaging time.  Now I use the ST2000XM and its separate guide chip.  The 2045D is no longer needed as a guidescope and I have just started using it as an imaging scope with the new camera.  I also have an Astro-Tech AT66ED (essentially a 400mm f/6 telephoto lens).  I do use both of these scopes on the Celestron (Losmandy) G-9 mount at star parties but only a few times on Arp objects. 

 

 

There is not a whole lot to say about my star party telescope, the Celestron CG9 1/4.  I always use it with 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 10 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.  It doesn't have either the tracking accuracy or the optical quality of my Newtonian, but the differences are small. The biggest differences in the image quality are that I almost never get the polar alignment precision in the field that I have achieved with the permanent pier, and it doesn't have Motofocus.

I built my Cookbook 245 in 1995 and added the Low Dark Current upgrade in 1997.  The camera had very few problems but the power supply did require regular repair.  However, I don't think I lost more than a night or two of imaging over the eight years it was in use.  Most problems could be fixed fairly quickly.  I can still remember the thrill of seeing the first images pop up on my monitor.  My first target was the Double Cluster.  I was imaging through a 60mm finder and was limited to 8 sec. exposures by my tracking -- the finder was on my 10-inch Dob which was on a homebuilt tracking platform.  But there were still a lot more stars than I could see through the eyepiece.

I purchased a StarlightXpress MX716 camera late in 2003, several months after I started this project, and most of the images were acquired with it.  The one time it failed, I borrowed Dennis Webb's MX916 while it was being repaired.  I've been very happy with it.  While it is certainly not a top-of-the-line camera, it has a great balance of price and performance.  The very small pixels allowed me to achieve good resolution with a modest focal length scope.

In late 2007, I purchased a used SBIG ST2000XM, 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.  The first color Arps were added to this site in November 2008.  So far, I have not used the AO-7 and am not sure I ever will.

With very few special exceptions (like Arp 152, the Jet in M87), all of my individual exposures ranged from 30 seconds to 4 minutes.  Longer exposures show slightly less electronic noise and, for the same total image time, 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.  I gradually moved from 4 minutes to 1 minute, as a standard.  I occasionally went back to 2 minutes for very faint objects just so I could see the quality of the individual exposures better on the screen.  And when the wind was so bad that guiding is impossible, I used 30 second unguided exposures and kept those few that escaped the gusts.  As I've started taking color images, my exposure times have increased back to the 4 minutes that I had used several years ago, and when conditions are really good, 8 minutes.

Although not really equipment, I should mention my acquisition software, which is Astroart 3.0 -- a delight to use -- and my starhopping package.  I start with Bright Star Atlas 2000 and the Telrad, then switch to Uranometria and the 9x50 finder and/or the flipper eyepiece, and end with (normally) 32.5' x 45' charts printed with Megastar, first using the eyepiece and then 10 second camera images for final positioning.  This process has now been largely eliminated with the use of my Argo Navis and the ST2000XM, but I still use the Megastar charts to plan my field.