Tips & Links

 

On this page, I am going to put random tips arising from my experience as a Mac-based amateur astronomer. Many of these tips will include links for additional information. Maybe, as the list grows, an ordering scheme will emerge.


Installing an air conditioner to pre-cool my telescope

The latest addition to the Megnaritaville Observatory is a small air conditioner, mounted in the wall and
aimed at the focal plane end of the LX200 PopeScope. The air conditioner is not expected to keep the observatory cool. GIven the thermally transparent construction of the roll-off, an air conditioner like this can only maintain a 10-to-15 degree differential with the outside air temperature. At GMARS, in the summer, that barely means keeping it below 100 degrees. However, what it will do, is cool the back of the scope and allow it to reach equilibrium with ambient air temperature much quicker. The air conditioner was purchased at Lowe's and cost about $110 on sale.


Using AstroPlanner to polar align telescope

One of the nifty features of Paul Rodman's AstroPlanner program is the "assistant"
for doing polar alignment. I am a fan of the "iterative" method, especially with fork-mounted Meades, and AstroPlanner makes the process very convenient, as well as provides valuable feedback on whether the process is getting you closer or not to accurate alignment. I strongly recommend its use with this qualification: The average pointing accuracy of a Meade GOTO scope is about 4-5 arc minutes. You should not expect to "converge" to a pointing solution that has much greater accuracy than that. If you need better, try drift alignment, for which AstroPlanner also provides a helper. For more on AstroPlanner, go here.


Conserving your USB ports

The Core2 Duo Mac Mini that I use for my observatory
has a remarkably generous set of ports for an entry-level system. With four USB ports and a Firewire port,
it has a lot of connectivity. However, when you start needing ports for telescope and camera control, they can start running out fast. So, I put all the slow input stuff on one port. I attached a four-port USB dongle to one port and use it for the keyboard and mouse, along
with a Keyspan USB-to-serial adapter that provides communications to the scope mount. None of these items uses much bandwidth, so just one of the Mini 2.0 ports is more than adequate to service them. That leaves me three USB 2.0 ports - two for handling data to-and-from cameras/guiders and one that has a USB-to-serial converter for DSLR shutter control.
I also have a Firewire cable for webcam control. All these cables, by the way, run in a large conduit under the observatory floor from my desk to the pier. Because of the distance, the USB cables have 2.0 active repeaters.

Added 2008.03.16 - I have discovered an interesting thing about the USB ports on the Mac Mini: They are not all equal. Some applications (Starlink and Nebulosity, so far) cannot recognize cameras attached to certain ports. Obviously, the workaround is easy (move the camera to another port).


Replacing the power supply on my Meade scope and running it on a UPS

One of the things I have learned from Dr. Clay Sherrod - Jedi master of all things Meade - is that the power adapters that Meade sells for its scopes are not regulated and, under load, will starve the telescope electronics. The AutoStar controller can interpret the voltage blip as a command and the scope goes haywire. The solution is simple: Use a regulated power supply. I bought mine from ScopeStuff - see here. I should also mention that the power adapter is plugged into an uninterruptible power supply - a battery back-up with surge protection. The combination really seems to minimize those completely unexplained runaways that Meade AutoStar scopes are prone to do.


Holding down the weight of accessories on my scope

Let's face it, the 14-inch LX200 is way too much scope for the mount (but not

for the reason most people think -- it isn't the forks, which are actually quite strong. It is the spacing, or lack thereof, between the bearings in RA axis). Anyway, it is important not to unnecessarily add weight to the system when mounting piggyback scopes and cameras. I saved at least five pounds by going with ADM Machining's mini-dovetails, top and bottom. Anthony Davoli's accessories are first-class and, for mounting small refractors and 3-D weight systems, every bit the equal of Losmandy. Check out ADM's website here.
 
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