iTelescope.Net Supported Exposure times are 60, 120, 180, and 300 seconds on our internally or externally guided systems - some wide field and short focal length telescopes will guide up to 1800s (supported calibration files also include 600s, 1200s and 1800s) see the specific telescope page for details and example below:
*Supported means we will have the proper calibration files for the listed exposure times as well as the times that the system is physically capable of maintaining proper guiding at. Any unsupported times will have a much higher chance of poor guiding and poor quality images.
Optimal Exposures depend on your target, filters and telescope you are using. For luminance filters we suggest from 120 to 300 seconds per sub exposure at bin 1x1.
When using higher exposures (300s+) and Luminance filters, be sure to check our Telescope Information Page for the system you are using to see if it has a Non Anti Blooming Gate (NABG) or an Anti Blooming Gate (AGB). Systems with Anti Blooming Gates will be capable of longer exposure times on bright objects (like large stars) before excessive blooming during exposures. NABG systems will have blooming problems much faster then AGB systems, so be sure to use lower exposure times on NABG systems. For more information on Blooming, see our Blooming FAQ.
For Red, Green and Blue filters we suggest binning 2x2 and using exposure times of 120 seconds to 300 seconds per sub exposure.
For Narrowband filters Ha, SII and OIII you can start with sub exposure times of 300 seconds, however for best results we recommend exposure times around 600 to 1800 seconds (if supported) when using one of our internally guided systems.