Posts Made By: tom germany

I am new to these forums and need a little assistance. I am entertaining building a truss dob, but i am struggling deciding what size. I am interested primarily in deep sky objects and as such, have been leaning for 15 to 20 inch primary mirror size. I will probably buy a polished parabolic primary mirror from a quality vendor and build the rest. Now the key question. What can I expect from a 15 compared to 20 in primary mirror. I have an 8" dob that has relatively poor optics and deep sky objects are fuzzy at best. Any opinions or thoughts. thanks in advance for the ideas

I am in the process of designing a truss style dob. I plan on purchasing a polished mirror for my first project. I am looking at a mirror that is from obsidian optics. It is a 14" paraboloid mirror. It's thickness seems to be thinner that a lot of others I have looked at. I am interested in opinions concerning obsidian optics (good or bad) and the pro's and cons of a 1.1 to 1.5" thickness for a 14 inch mirror. I have a choice of Plate glass or pyrex. Thanks for the help

I am looking to purchase a finished mirror for a truss dob I am designing. The mirror is a 14" plate glass and has a thickness of 1.1". This thickness seems to be a lot thinner than most vendors I have seen advertising a 14" mirror. The cost of the mirror seems to be very good (recognize you don't get anything for free!). I am concerned however since the usual thickness for a 14" mirror is closer to 2 or 2.5" What problems will I face by purchasing a mirror that is 14" but only 1.1" thick. The mirror will be a paraboloid design.

For a 14 inch mirror, what are the advantages/disadvantages for a focal length 4.5 vs 5.O. I know the scope length will get longer with the higher focal length. I have heard some mention the impact of astigmatism with the shorter focal length. Is there an optimum?

This issue has been discussed before but interested in differences if any between Nova, Swayze, Pegasus. I am close to making a final decision. Any opinions. They all appear to be quality oriented. Other items that may separate them. thanks for your help

I am considering a mirror that was made by Tom Waineo. The mirror is 16", f5, and 3" thickness. I am awaiting the data sheet on the mirror. I understand the mirror was never mounted. I know the mirror will take longer to reach ambient temps. the use of a cooling fan will help this issue. Are there other issues that I need to be aware of concerning a 3" mirror. I also recognize the mirror will weigh more than a typical 2". Thanks as always for the groups thoughts and opinions.

I have finally completed the initial construction of my 16" truss dob. I say initial because I still need to install a finder scope and tweak some of the parts of the scope like the counterweight system or azimuth/altitude bearings. I also am trying to learn about locater systems or goto systems that can be applied to this scope.
The scope took about a year to build from initial ideas gathered from this forum and other internet ATM sites. I guess its similar to the obsession line in construction. I made the mirror box out of basswood due to weight. The mirror cell, bearings, secondary,holder,spider and focuser were purchased from astrosystems. I decided to go with a ball connector system for the truss tubes since I could not build an effective clamp system. I am pretty clumsy with wood. The mirror is one of the last made by Tom Waineo. It is a 3 in monster thus setting up the need for the wheelbarrow design.
I did get a chance to look into the sky earlier this week and wow! I understand why some say apeture is king! The view was awesome. Still need to work on collimation techiques, but I am going to enjoy this scope.
Thanks for the help and advice during the early days. Lots of good people willing to share their ideas to help me design and build the scope. Thanks

I have recently completed my 16in dob project and looking for advice on what lense collection should i consider for my scope. The focal length is approx f6. I prefer to focus on dso. I can handle 2 in eyepiece but currently have a couple of orion 1.25 eyepieces (17 and 25mm). Any help would be appreciated

I just finished this scope. Its a 16" dob with a 3" mirror. That is why i needed the wheel and handles to make easy transport. I will keep the mirror in the mirror box. I have a ramp for my truck so loading/unloading is pretty easy. Not the prettiest but the images are very good