One of our customers who wanted to use this telescope for imaging as well as a visual grab-and-go scope had some issues with using it with his 2" eyepieces with a 2" diagonal, so we did some research and it seems we've found a solution for him. Please bear in mind that this is a mainly imaging instrument, so some limitations can be expected when using it visually. The limitations are not quality related. These are just related to the already longer than usual back focus still not being enough for the combination of some large 2" diagonals and 2" eyepieces.
Although we did not test it with 1.25" eyepieces, we believe that there will be no problems with a combination of 1.25" mirror diagonals and 1.25" eyepieces.
(just don't forget that we are not discussing here prisms as those always have much longer optical path than mirror diagonals).
So, I've tested the Sharpstar 100Q Mark II with a
2456103 Baader BBHS Mirror Diagonal as we had no stock of the 2456100, but I believe the size is the same, just the optical quality and coating are even better...
Note that the above Baader diagonal is not a full sized 2" diagonal (then we would not reach focus), so it provides a slightly smaller field stop, but still about 30% larger than a 1.25" diagonal would.
On the eyepiece side I had a
TST2-2 2" eyepiece holder barrel and on the telescope side I had a
A508T2 (same as TSFA2) 2" nosepiece for the first three eyepieces and the
Baader 2408150 for the Televue, simply because I noticed that the A508T2 was touching the side of the TST2-2 adapter and wanted to check if this will help. I found that there isn't much difference as the TST2-2 will leave a 1mm gap anyway, so the size of the A508T2 was not the reason to stop it, or maybe only by a fraction of a mm.
So I think either the A508T2 or 2408150 would be equally good.
Telescope was pointed at Venus.
Here is a list of eyepieces I tested:
1. Vixen NLVW 30mm 65 degrees
Did not come to focus, then removed the barrel/nosepiece from the eyepiece and the eyepiece holder from the diagonal and held it closer to achieve focus. I approximate that it needed about 10-15mm inward movement to achieve focus. This eyepiece could be used only with some modification and the eyepiece holder barrel should be shorter as well in such a case.
2. Celestron Axiom LX 23mm 82 degrees
Came to focus with the drawtube about 5mm out.
Very nice view of Venus.
3.a Hyperion 17mm 68 degrees
I know it's a 2"/1.25" combined eyepiece, but I used it in the 2" barrel and the 1.25" nosepiece that contains the optics of a Barlow was far enough from the mirror surface. It came to focus with the drawtube about 21mm out.
3.b Hyperion 17mm 68 degrees without Barlow part
This way it became a proper 2" eyepiece, although the focal length is now different, 21.8mm
Came to focus with the drawtube about 15mm out.
4. Televue 8mm Ethos (unfortunately could not test it with a 5mm Ethos that our customer had as we had none in stock...)
Came to focus nicely with the drawtube out about 10mm, so I guess a 5mm Ethos would focus as well...
By this time Venus was down, so I pointed it at Vega and then I also tested it on M81/M82. With the Axiom 23mm both appeared in the middle of the field, but had to separately observe them with the Televue 8mm Ethos, which provided a nice view. Cannot say magnificent view as seeing was not the best... too much moisture in the air...