Updated 14:35 UT (Jun 23) to reflect that I found a third UNID on my imagery after writing the original post
Saturday/Sunday night 21/22 June was very clear. As I had some trouble getting to sleep, I decided to make use of it to do a survey of the GEO belt, from my secondary site Cospar 4355 which is in the polder just outside of town, some 10-15 minutes by bicycle. The sky is a bit darker there and I have a better view to low elevations. Using the 1.4/85mm Samyang lens, I can expose twice as long as I can from my regular town center site 4353. The downside: so many objects on the images to identify and measure....
This observing site, in a polder park with meadows and polder ditches, is very tranquile. A choir of frogs was chanting during my observations, and meadow birds were adding their voice too. As I was observing, a low blanket of ground fog started to form, with my camera on tripod popping up just above it.
At the moment I am still slowly working myself through the 54 images taken, identifying objects, but I can already report that I captured
UNID 1 was observed as a small trail on several images taken between 23:05:32 and 23:23:32 UT (June 21). The 15 second image above shows it near the SIGINT satellite Mentor 4 (2009-001A) and is the first image that captured it. It looks like something in GTO and a very cautious orbit fit to this short 18 minute observation arc indeed suggests a GTO-like, roughly 13160 x 36945 km, 12.8 degree inclined orbit with a period of ~1.6 revolutions per day:
UNID 1 13160 x 36945 km
1 00000U 00000X 14172.96808160 0.00000000 00000-0 00000+0 0 05
2 00000 12.7577 311.8608 3783132 187.8049 143.4679 1.55784798 00
UNID 2 was detected on only two 20 second images taken half a minute apart. It is less trail like (see image above), but slowly moving south when the measurements on the two images are combined. It is either in a somewhat inclined GEO orbit or a GTO object near apogee.
The image above also shows SBIRS GEO 2 (2013-011A), a classified geostationary SBIRS satellite (an Early Warning satellite looking for missile launches in Infra-Red). In addition, an old Russian r/b and a Russian military GLONASS (the Russian equivalent of GPS) satellite are visible. Star trails are slightly blurry because the FOV represents a detail near the edge of the image.
UNID 3 was detected close to alpha Serpens in only two 20 second images taken 1 minute apart. It is clearly trailing. The positions fit either a circular MEO orbit, or a HEO orbit (the observation arc is too short to discriminate). Above, the two images that captured it are shown.
Lacrosse 5 appears to have manoeuvered
The same image that captured UNID 1 also captured the military Radar satellite Lacrosse 5 (2005-016A, see image in top of this post), just as it was emerging from Earth shadow. It was about 54 seconds late relative to 8-day-old elements. That is a lot for only 8 day old elements. Hence it appears to have manoeuvered somewhere in the past few days.