I failed many attempts to visually, with binoculars, and my telescope to spot Comet 21P/Giacobini-Zinner. Some magazine and web sites reported the comet might reach visual magnitude but I was never able to see it. Finally, on 13 May I decided to test how faint it was. I set up my Canon 50mm EF f/1.4 lens for a wide field shot (see images below) at multiple high ISOs and exposure times. I was able to capture the comet in a 211 sec photo at ISO 1600 pretty much where it was suppose to be but clearly much fainter than I was hoping for.

My next opportunity was taken on September 15th at 3:08 AM. The comet was reported to be traversing M35 on that date so I took a chance, slewed my telescope to M35, and shot in the blind. I never saw the comet visually or through the telescope. This one had been a real challenge to capture.

The particulars of my setup were:
Telescope:   Autoguided Meade 10" f/6.3 LX200/GPS telescope at prime focus with no filters.
Camera:      Hutech modified Canon Rebel T5i
Exposure:   155 seconds at ISO 6400 with the resulting image processed in PhotoShop.

Location of Comet 21P/Gliacobini-Zinner traversing M35  09/15/18 3:08AM

Comet 21P/Gliacobini-Zinner traversing M35  09/15/18 3:08AM