Photos of the Observatory

Observatory Looking East
Observatory with                 shutter open
Note I modified the lower shutter to only partially open.  Given my high horizons this does not obscure the sky while offering me some relief from local light sources.

Base Detail

2014                 Optics
click picture for full size image
Note: older AP 900 mount is shown
Almaden Observatory Equipment 2017 05 24

Equipment on Bench
Guide and sky cameras

Detail of Sky (left) and Guide Cameras

The Sky Camera gives me a wide angle view of the sky.  That way I can see if the scope is pointing at clouds.
Rear Bracket detail

Rear Bracket using ADM Ring
shown with older filter wheel

Tour of Interior

Movies of Observatory Operating



FSQ-106EDX III Astrograph Telescope

FLI Proline 16803

FLI Centerline Filter Wheel

FLI Atlas Focuser

Baader Varo Finder
Note this link is to OPT, but I purchased the Finder and Finder Bracket through Astro-Physics
SBig Sti
The default AP bracket uses a press fit for the guide scope.  My local rules require everything screws together.  I replaced some of the Baader components with a custom adapter from PreciseParts.


Narrowband for stars  Stromgren sB and sYel, 20 nm Ha
3 nm OIII
3 nm Ha
3 nm Nitrogen II
3 nm Sulfur

Sky Camera
Orion StarShoot Autoguider
Tamron 1/2" 4-12mm F 1.4 C mount Lens
C to T adapter


AstroPhysics AP 1100AE


THUM Temperature Sensor (used by APCC Pointing Model)

Exploradome I

Observatory Control Software

ACP by DC3 Dreams

ACP Scheduler by DC3 Dreams (now ACP Expert)

Astro Physics Command Center

Sky Camera

My Clarity weather sensor is good at detecting weather that is potentially dangerous to the observatory.  It is not as good for sensing high clouds.  I considered several solutions, but settled on using a surplus Orion StarShoot Autoguider with a Tamron lens (originally intended for security cameras.  I attached this to the bracket at the top of the telescope. I can now monitor the sky and confirm there are really stars up there.

Sky camera showing clear sky

Good Sky
Sky Camera showing clouds
Clouds are gathering

I knew clouds were a possibility when I opened, but this confirmed it.  At this point the Clarity was still saying the sky was clear.  Shortly after this picture was taken the clouds were thick enough that it triggered a weather alert.


Not Ideal.  3 streetlights are visible plus the neighbor to my north has backyard lights.


Quality of the Site

San Jose

Not an ideal location for an observatory.  I am at least in the pink area.  This is why I am going to focus primarily on Narrowband.

Upgrade Saga

April 2017 - May 2017

During NEAF I decided to get the CenterLine that I originally tried to order in 2013.  This will allow an L filter for faster focusing and pointing.

I also switched my sV filter for an sB.

December 2015 - March 2016

Tube sag due to the heavy instrument package has been a concern since day 1.  In early December I tried to reinforce the focuser extension tube using a Parallax ring.  Unfortunately when I measured the results I had made the system significantly worse!! After some advice from the AP maillist I narrowed the cause back to the Parallax rings I installed more than 4 years ago. They never fit properly and thus the scope was never square to the declination axis.  (or so the current theory goes). 

I have now replaced front Parallax rings with Takahashi rings.  These exactly fit my AP mounting plate unlike the parallax rings which required me to oval the holes. I am still planning to support the focuser extension, but this time with ADM rings.  These allow me more ability to adjust once the scope is in place.

Due to El NiƱo the scope has been in the house since December.  I was not able to resume full operation until April.  The good news is that the scope is now tracking perfectly.  For most of the time since April I have not used active guiding.  As of June I turned it back on, but only on a "Best Effort" basis.  If it has problems I revert to self guiding.

October 2015

After talking with the AP folks at AIC I bought an AP sourced Baader Varo Finder kit and put my SBig STi back to work.  Initial tests are mixed.  I got excellent results near the equator, but poor results for M 81. 

Summer 2015

After much deliberation I decided to go ahead and purchase the 1100AE.  The absolute encoders have dramatically improved my tracking performance.  Also the 1100AE is better suited for remote operation since the 1100 eliminates cable tugs. The encoders permit setting a hard limit and provide a means to recover from a "lost scope" condition.

February 2013 - April 2014 Upgrade

It seems like I am doing something each February.  In 2013 I planned to replace the first generation SBig 8300 with a camera that had a better cooler.  Little did I know that this cycle would take 14 months.

I settled on a FLI Proline 16803.  The primary goal was to improve the cooling, but the 16803 will also give me a greater FOV at the cost of less resolution.  As a part of this I also had to replace the filter wheel and chose to get a more robust focuser.  Due to weight concerns I initially bought a CFW-4-5. With this filter wheel I could only configure my system for either Narrowband or Nb4Stars + Hydrogen, but not both.  The order took FOREVER and once it arrived I had to redo the optical path because the camera/filter wheel.focuser was too heavy for the CAA. 

The Orion ST-80 even with the new focuser had enough wiggle to wreck my tracking.  Thus I replaced the guide scope with a simpler and lighter Hutech that screws together.  After experimenting with several guide cameras I ended up with an Orion SSAG.  The images are noisy, but the camera is very sensitive and has very small pixels. Thus it is perfect match to the Hutech (Orion sells a similar scope, but with a "design to cost" mount).

The limitations of the CFW-4-5 proved too much for me.  Thus I ordered a CFW-5-7.  This allows all my of Narrowband and NB4Stars filters to be used at the same time.

I also took the time to redo the lower shutter system.  Now it works reliably.

During the summer of 2013 I analyzed some of the initial photos in this new configuration.  Sadly it looked like a mishap I had with the scope 2 years before had damaged its optics.  So the scope took a journey back to Japan.  It returned in April 2014.  Once everything was together and running the system now works perfectly.  I have perfect guiding, wide field in focus across the entire frame, and all of my filters. 

March 2012 Retrofit

I replaced the wheels the dome rides on with rollerblade wheels.  This allows the dome to turn silently; however, it turns so easily now that it bounces when it stops.

Replaced G-11 with AP 900

Replaced Pier Tech with ATS Pier

February 2011 Dome Channel Retrofit/ Dome Rotation

NOTE:  These instructions are for an older version of the retrofit.  Some of the techniques might apply, but check the Exploradome mail list for up to date info.

This page describes retrofitting the dome with the new wheel channels.

Feb - November 2010 Construction

This web album shows the observatory under construction

Copyrights for Photos

Creative Commons License
(c)2010-2017 Robert J Hawley Some Rights Reserved.
Except as noted, all work on this site
by Robert J. Hawley is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. This permits the non commercial use of the material on this site, either in whole or in part, in other works provided that I am credited for the work.


rjh 5/26/17