Some thoughts and questions:
- Do you have a 2 inch Diagonal?
- At F/6, you want some well corrected eyepieces. The Russell eyepieces are not what I think of as "my first special" eyepiece.
- For what you are doing, DSO's, I think you want something of very good quality with at least a ~65 degree AFoV, maybe more.
- I have experience with TeleVue, Explore Scientific and Meade widefield eyepieces. I hear good things about others. Just about any TeleVue wide field would make a "first special eyepiece" but they are expensive and I think the Explore 68, 82 and 100 degree offer better value. Maybe not quite the same perfection as TeleVue to experienced eye but very good and much more affordable.
The Meade Series 5000 SWAs and UWAs are optically very similar to the ES's but I find the Meade bulbous twist up eye cups unusable. On the used market, they seem to be less expensive than the ES's and can be a bargain. I have the 24mm and 16mm Meade Series 5000 SWAs. I had them for a year or two but rarely used them. One day, I decided to remove the blubous eyecups. From that day on, they became regulars...
I hear good things about the APM/Lunts and similar eyepieces but I have no personal experience.
In your situation, with a 102mm F/6, I see some eyepieces I would consider.
- ES or Meade 1.25 inch 24mm 68 degree. In my mind this is the best bang for the buck in terms of a 1.25 inch Widefield. It might not be quite the 24mm Panoptic but it sure does a good imitation. And these eyepieces provide the widest TFoV in a 1.25 inch Widefield. They provide a reasonably wide 2.53 deg field in your scope.
The APM 30mm Flatfield: I have not used this eyepiece. It has a 38mm field stop which would provide a generous 3.56 degree TFoV in your scope at 20x with a 5mm exit pupil. Maybe Don Pensack can comment on the quality of the correction but if it is quite good at F/6, then this could be a life time keeper.
- Used there are a number of eyepieces but I don't know anything about the Australian market. A 34mm ES 68 degree would be a nice fit as a low power wide field.