Can a visual estimate be the only confirmation of speed?

What is the name of your state? Michigan

I had my informal hearing yesterday morning.

My question is, can a visual estimate be the only evidence needed to find you responsible for speeding? I thought that the officer had to verify the visual estimate with the radar.

I started preparing to fight my case from the day the ticket was issued. I have been driving for 10 years and have never been pulled over for speeding. I have zero points on my record. I believe I was going the speed limit and was the wrong car targeted. I was the first car up the hill on the highway and found an officer waiting, speed trapping, hidden from my sight behind the incline of the hill, he quickly threw on his lights, giving me time to stop adjacent to him, on the shoulder.
I prepared a public records request and sent it certified to the police chief. Nearly a month later, the Friday before my hearing, I still had not recieved my requested materials, so I called and made it clear to them that I was coming to pick up the paperwork from their Records Beareau. I did so, and while I was there, I noticed that they could not provide me with a certificate of the speed measuring device used. According to them "a copy did not exist". I spoke to the Sgt. in charge of putting the paperwork together and he said he "didnt know what I was talking about". (Good thing I knew what I was talking about.) The Sgt. also tried to discourage me from fighting the ticket, saying it was generous of the officer to give me a 50 in a 45 when I was actually doing 66. He had a bad attitude, and made me wonder what he was hiding.
My main defence, before this issue arose, was about the apparent limited visibility from the officers point of view (hilly terrain, and interference from other vehicles around me, and on the over passes).
With all of my research, I found that the certification of the speed measuring device is required in Michigan, by the M.S.M.T.F., for any readings from the speed measurement device to be admissible in court. The morning of my hearing I finally got in touch with the State Police Sgt. that handles the M.S.M.T.F., which in turn verified that there was not a certificate.
I noticed that the Judge was quickly finding everyone "responsible" that was called before I was. All of the tickets were from the same officer that pulled me over.
Then it was my turn. I had a file full of eveidence, pictures, documents, ect., and had printed out everything I would say ahead of time. I noticed the judge did not have much interest in any of my evidence. However, I did prove that the radar reading could not be used against me. But it baffled me when the judge quickly found me responsible for 50 in a 45 due to his visual estimate. I thought that the visual estimate had to be verified with the radar gun?? How can someone tell you how fast you are going in their head, and especially tell the difference of 45 m.p.h. and 50 m.p.h.
I am obviously appealing, and thinking of hiring an attorney.
I feel my testimony may have encouraged some harrasment from the police officers at the department. Later that evening, after my hearing, my husband was pulled over in my car. I had already warned him to be careful while driving it, fearing I may have really pissed them off. The officer sped up behind him on a 25 m.p.h. road to pull him over. He called me while he was waiting for the officer to come back to the car, saying that he wasn't told why he was pulled over, and that he knew he wasn't speeding. The officer let him go with a warning for "not yeilding to on coming traffic". He told me he seen the officer, and had plenty of time to pull onto the 25 m.p.h. road.
Thanks for taking the time to read. Any advice about visual estimates would be appreciated.

[JETX]

An officer can issue a citation based on any reason that he might have of the offense. This could be 'clocking', radar, or even a guess.

I have seen cases where an officer only visually estimated a speed and when testifying his 'estimate' was allowed due to the officers experience in the field.

The issue you face is how to show the court that the officer was NOT correct in issuing your ticket.