About 90 Millimeter Observatory

Meade 90mm on Celestron CG-4 mount

Meade 90mm on Celestron CG-4 mount

I have always believed that where you setup your telescope is your observatory. Keeping with that thought, my observatory is in fact, my backyard. I’m sure that with many amateur astronomers, that is true. Although I do travel to dark sky sites, most of the time I setup in my backyard. The name 90 Millimeter Observatory came about because the telescope I use the most is a 90mm (3.5”) refractor. I do employ three additional telescopes here at my observatory simply because I enjoy the variety that each one provides. Four telescopes round out the observatory’s equipment:

  • Meade ETX60 AT 60mm (2.3”) 350mm f/5.8 Refractor.
  • Orion AstroView 90mm (3.5”) 910mm f/10.1 Refractor.
  • William Optics Megrez 90mm (3.5″) APO 621mm f/6.9 Refractor.
  • Orion AstroView 120mm (4.7”) 1000mm f/8.3 Refractor.

Sky Conditions

The sky conditions at the observatory are typically poor due largely to light pollution. While the township does have outdoor lighting ordinances in place, they are not enforced. As a result the observatory is in a Red Zone. The faintest star visible to the naked eye is magnitude 4.5 on the very best of nights.

Current Projects


The ongoing project here at the observatory finds it roots in the Astronomical League’s Urban Observing Club. The Astronomical League’s introduction states, “The purpose of the Urban Club is to bring amateur astronomy back to the cities, back to those areas that are affected by heavy light pollution.” It is with that goal in mind that the 90 Millimeter Observatory continues to observe and report on deep sky objects visible in small telescopes. I hope to encourage both seasoned and beginning amateur astronomers to enjoy the night sky from their backyards and join the fight against misdirected and wasteful lighting.


Photographing deep sky objects presents some interesting challenges to amateur astronomers but astrophotography under light polluted conditions can be frustrating indeed. Having seen results obtained by others, I know that astrophotography under light polluted conditions can be done with relatively good results if the proper steps are taken.

I’ll be using a readily available DSLR for this project. To be more specific, I’ll be using a Pentax *ist DS2 Digital Single Lens Reflex camera in a few different configurations as follows:

  • Piggyback – Mounting the camera and lens on top of a telescope on a mounting. This configuration will be used for long-exposure wide-angle images of the sky.
  • Afocal – Using the camera with its lens attached to capture an image through the telescope’s eyepiece. I’ll try this configuration for Lunar and Planetary imaging.
  • Eyepiece Projection – A method of astrophotography where the image is formed at the focal plane of the camera by the eyepiece in a telescope. No camera lens is attached to the camera, only the telescope’s eyepiece is used.
  • Prime Focus – In this configuration, the camera is attached to the telescope without any eyepieces or camera lenses in the optical path. The telescope then acts as the camera lens.


With this project, the 90 Millimeter Observatory joins up with local astronomy clubs to support their public star parties and community outreach events. We also want to reach out to the area schools and provide them with a “Family Astronomy Night” which would include an indoor presentation followed by observing through telescopes for an hour or two.

Feel free to comment on the observations we make here at the 90 Millimeter Observatory.  We just ask that you keep it clean and simple. No bashing or degrading anyone. It’s for all to enjoy.

About Me

I have been an amateur astronomer since 1970. My first experience was during one evening sitting outside with my older brother, I pointed to what I thought was a thin cloud that seemingly appeared every night. He looked at me and said, “Wait here”. A few minutes later he came out of the house with his bird watching binoculars, handed them to me and said, “Look at that cloud and tell me what you see”. For a few minutes I was speechless. Finally I said, “A lot of stars”. He then explained to me that I was looking at the Milky Way which is what our galaxy is called. I was hooked from that point on and often would take his binoculars out at night to see what else there was to see. Of course he grew tired of sharing his binoculars so, that Christmas he gave me my first telescope, a hand-held 30mm refractor. Maybe that’s not much of a telescope, but I can’t thank him enough for giving me that telescope and introducing me to astronomy. It truly has been a magnificent journey.

What do you think?

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