由 willis » 2016-07-26, 21:28
I used to own a modified 40D. ISO 800 is usable. With auto guiding, you can have longer exposure in each single frame. Except those bright DSOs, like M42, 3 mins is the starting point for most reasonable ISOs and focal ratios. It is preferable to have longer single exposure and less no. of frames, if time is limited. Use longer exposure time can ensure the signal received is well above the noise ground. That is higher S/N ratio. Higher S/N ratio will make life in post-processing easier.
Tak FS60C, APM-LOMO 80/480, APM-TMB 105/650, SW Black Diamond 120ED, Borg 125SD, SW 12" Dobs , Lunt LS35T, Lunt LS80T
TMB Super Mono 4mm, Pentax XO 2.5mm, Baader Planetarium 8-24mm, Nagler (2-4mm, 3-6mm, 13mm), Ethos (3.7mm, 6mm, 10mm), Explore Scientific 100º (14mm, 20mm)
DBK 21, DMK 21, DMK 41, DMK 51, ASI 178MC
Nikon D810A, Canon 5D II, Fujifilm X-T10