Hi all,
BrianW's thread about early observational astronomy pointed out the use of reticles set in a grid pattern to assist with the correct placement and scale of stars during the sketching process.
This got me to thinking about making my own 'grid reticle', not just a simple cross-hair arrangement.
I had a cheapie GSO 2" 32mm reverse Kellner eyepiece that might be a suitable candidate for transmormation. Using the optical fibre that Phil sent me (thanks so much again, Phil!), I arranged the grid pattern onto the field stop (which is where the EPs focus occurs, and gave me a good platform to work on), and fixed them with Epoxy glue.
I tested it out a couple of weeks ago with a sketch of NGC 253 using my 17.5" f/4.5 scope from home. The grid is so easy to make out. Only thing is, as my dob is only push-pull, it can be a pain to re-centre the reference stars back into position. My idea now with a push-pull scope is to use this grid reticle EP to locate and note the reference stars I'll be using to prepare a sketch, replace this EP with my preferred observing EP, and just reinsert the reticle EP to gauge scale as the sketch progresses. As this reticle EP is only of modest quality, this is probably the best way to go about things.
Now, if you've got your scope eq. mounted, the above issue of re-centering isn't a problem,
!
I might add a second lot of fibres to this reticle set to produce a smaller set of squares. This will assit with then exchanging this EP for a higher power one.
I might also look into making a grid reticle in a 1.25" EP for scopes that only use these EPs.
The pictures below show the fibres attached to the field stop, a view through the EP, and the sketch I made of 253 from home under very ordinary conditions.
