Cheshire Eyepiece

The Cheshire eyepiece is the simplest telescope collimation device. There are plenty of makeshift solutions, like the film canister with the hole in the cap, but the best guide for making a decent one along with all the underlying theory can be found here. One day I've decided to shim my Astroscan front glass to improve the collimation and 3D printed my own Cheshire.

The construction looks very simple, but there are several important features making the collimation and the printing easier.

Astroscan focuser mod

After seeing the eyepieces for the Astroscan discussion on the CN forum I decided to showcase my simplistic focuser modification, which I use to convert my Astroscan into a powerful 101 deg AFOV monocular which I'm often enjoying between 12" dob sessions.

It's basically an adaptor between Astroscan focuser's drawtube opening and the WO UWA 9mm eyepiece with 101 deg AFOV.

DIY 2x54 ultra wide field monocular

One lucky day I have stumbled upon the idea of using the $30 Nikon TC-E2 2x zoom camera adaptor for the truly ultra-wide field observing of the starry sky!

With the help of the 3D printer, I've managed to turn it into a really convenient to use monocular.

Laser collimator external power mod

My red laser dob collimator batteries died on me in the fields, along with their spares. So, I've rigged this convenient harness in 5 minutes in red light.

The image is selfexplanatory, but see details under the cut.

ETX-125 As an Astro Photography Clock Drive

My ETX-125 is mostly accumulating dust for the past several years (you can clearly see that from the images below), as my DSO observing passion is asking for the 12" aperture every time I'm going out to the rural darkness. But I'm always taking the DSLR camera with me to image the spectacular wilderness I'm passing through for hours on the way in and out of my dark sites. Occasionally I'm taking long exposure sky images as well on the tripod... But wait a minute, my ETX-125 has a decent clock drive! In just one evening I've made a proof of concept wide FOV AP rig based on it with very minimal alterations of the Meade fork mount.

The results have frankly exceeded my expectations! It's rock-solid, very easy to make at home and setup in the field, and allows quite a long exposures with an ordinary 50mm DSLR lens (I'm using Nikon Nikkor 50mm 1:1.2). The above image is made with the help of the UHC 2" filter just laying over the UV filter on the lens (it's needed for better optical surfaces alignment, as I couldn't just screw it in, but it is slightly larger than 2"). More images are under the cut, just click "more" below.

DIY Astroscan Telescope Chair Mount

The Astroscan ball scope is my choice of high power binoculars replacement for relaxed observations of wide field objects. To boost the comfort even more, I've made a very simple but extremely efficient and very compact camping chair mount for its base. 

A small pouch and a single pole pictured above are all I need to pack. Both are riding right in the chair's sack.

Meade ETX-125 Electric wiring mod

My modifications of the Meade ETX-125 factory wiring for easier scope control and Bluetooth link to smartphone/PDA integration.

See full details on the Instructables.

Meade ETX-125 Focuser mod.

My oldest telescope Meade ETX-125 focuser modification project (published a decade ago on Instructables):

In addition to improving the smoothness of the focuser motion, this mod allows setting the scope into a perfect focus by dialing a value from the list of settings for each of my eyepieces and camera backs. That's also helpful for arranging exposures with the rear mounted camera while tuning the perfect focal position from test shots' analysis.  See it in full details on the Instructables website.

Edmund Scientifics AstroScan

The AstroScan has a really impressive engineering design. See the good in-depth review here. This is how I'm rigging mine to the task.

Stock eyepieces are really good and also parfocal (28mm and 15mm). Their barrel size is interesting. It is a bit larger than a regular EP of 1"1/4. I suspect it is metric because my Russian eyepieces from TAL reflector fit the AstroScan focuser almost perfectly (this way I can use the 3x TAL Barlow lens with the AstroScan).

DIY Barlowed collimator

I've got a stock laser collimator with my Dob. Its construction is based on some primitive China made keychain laser pointer enclosed in the aluminum tube with a side window. It's really frustrating to work with, so I've been looking for alternatives for a while.

After searching online I've realized that this construction is quite common in cheap accessories from many vendors, the Orion for example.

Car roof carrier - transformer (Continued)

Just added two wheels. Found a pair in my scrap bin (scavenged from an old collapsible shopping cart, I believe). Two small aluminum L-shapes were drilled to accept 2 bolts (one for the wheel, and one for the board mounting) and for 2 screws (to fix the wheel alignment) - each.

In order to keep the car roof carrier function I had to move the footrest / leg / roof rail stop - a bit higher. The new, not oiled yet, insert is visible directly under the footrest piece. The gap between the wheel and the shelf must be wide enough to accept the car roof rail when covered with 2 layers of the tarp. In addition, the higher location of the foot rest makes climbing into the chair easier when it's set high.

Car roof carrier - transformer (Part II, The Chair)

Finally, the test drive of the chair is completed with a great success in the stern conditions of Mojave desert (California). See the photo set of the construction details explained below.

The transformation time I'm getting is less than 20 minutes from opening the trunk door to getting in the chair. However, I have in mind several easy enhancements for particular elements used in the construction, which might halve that time easily, while also removing one of the hand tools out of two required for transformation completely.

The assembled weight of the chair is equal to the assembled weight of the cradle, minus 3 styrofoam inserts and equals to 17 pounds (~8 kg). There are some possibilities for improvement there too, but I felt comfortable enough with that weight while actively observing various objects for 6 hours straight, moving the chair around and adjusting its height often.

What's left to do is to apply some protective finish (more on that later) to all of the surfaces, to add a permanent soft sitting pad, and perhaps a soft backing. So far a folded several times yoga (gym) mat worked just fine for me.

Primary's alignment mod

Finally installed the famous Bob's Knobs mod. Specifically crafted for the Zhumell 12" model, these screws are almost perfect solution for a tool less collimation of the primary telescope mirror in the field. The transaction with these guys went smoothly. The delivery time was surprisingly quick.

Installation was done in place without the mirror cell removal necessary, one knob at a time. Just hold the springs in place.

Car roof carrier - transformer (Part I, The Cradle)

We have a relatively small car (Subaru Forester). Even though the OTA and the mount fit OK inside, when one of the rear seats is folded, there is a very little space for the family and camping inventory left. The 4-night GSSP star party was coming soon. So, it's all started from the building of a dirty car roof rack carrier for my Dob OTA using some 3/4 inch plywood leftovers I had at hands. I called it the Dob Cradle.