Based on feedback from Stargazers Lounge and last nights ( brief, cloudy) experience, a new world of setting up the GEM is on my horizon:
1. Mount and tripod taken outside a couple of hours/hour before observing.
2. Telescope attached, collimated, balanced ( mirror very slightly heavy).
3. Polar scope used to align telescope to celestial north (aided by app on smart phone, showing where Polaris should be on a reticule; also use the same app to set time/date).
4. Using eyepiece, two star alignment carried out ( using Arcturus and Mizar ).
5. Add two (or three?) calibration stars; Deneb, Altair and Caph; again, it offers a limited list.
(Now use the Polar Align routine in Nexstar+; last night the telescope used Deneb; it was almost dead centre anyway, so maybe Polar Scope is good enough?)
7. I now replace the eyepiece with my Revelation 2" Barlow and Nikon D5300; Bahtinov mask in place and last night I used Deneb to focus the telescope.
8. Skew to a star close to the DSO I am after and use SYNC. Et voila, DSO will then be dead centre on GoTo.
Camera Settings
Going to try:
ISO 1600 - its noisy, but 800 doesn't seem sensitive enough for low surface brightness objects like galaxies.
Long Exposure Noise Reduction ON - and I will not take darks since the camera will do this AFTER EVERY LIGHT SUB automatically then process the raw using the in camera dark.
High ISO NR OFF
Exposures of 60 seconds seem easily attainable, from my experience two nights ago ( but that was also using the Polar Align in Nexstar+, 120 -180 seconds are also worth trying.
Hopefully its clear tonight!!
News!!
The 90 mm telescope rings have arrived, just waiting on the dovetail plate. These are really for the time when I have a Skywatcher 80 ED Apo, with a Skywatcher ST80 piggy backed for guiding., but I am going to try using the Skywatcher ST80 itself for imaging. I think it's a fantastically good telescope for the money and TBH when I have looked at the Moon, Jupiter, Saturn and various stars, the chromatic aberration seems pretty minimal, hence the experiemnt.
1. Mount and tripod taken outside a couple of hours/hour before observing.
2. Telescope attached, collimated, balanced ( mirror very slightly heavy).
3. Polar scope used to align telescope to celestial north (aided by app on smart phone, showing where Polaris should be on a reticule; also use the same app to set time/date).
4. Using eyepiece, two star alignment carried out ( using Arcturus and Mizar ).
5. Add two (or three?) calibration stars; Deneb, Altair and Caph; again, it offers a limited list.
(Now use the Polar Align routine in Nexstar+; last night the telescope used Deneb; it was almost dead centre anyway, so maybe Polar Scope is good enough?)
7. I now replace the eyepiece with my Revelation 2" Barlow and Nikon D5300; Bahtinov mask in place and last night I used Deneb to focus the telescope.
8. Skew to a star close to the DSO I am after and use SYNC. Et voila, DSO will then be dead centre on GoTo.
Camera Settings
Going to try:
ISO 1600 - its noisy, but 800 doesn't seem sensitive enough for low surface brightness objects like galaxies.
Long Exposure Noise Reduction ON - and I will not take darks since the camera will do this AFTER EVERY LIGHT SUB automatically then process the raw using the in camera dark.
High ISO NR OFF
Exposures of 60 seconds seem easily attainable, from my experience two nights ago ( but that was also using the Polar Align in Nexstar+, 120 -180 seconds are also worth trying.
Hopefully its clear tonight!!
News!!
The 90 mm telescope rings have arrived, just waiting on the dovetail plate. These are really for the time when I have a Skywatcher 80 ED Apo, with a Skywatcher ST80 piggy backed for guiding., but I am going to try using the Skywatcher ST80 itself for imaging. I think it's a fantastically good telescope for the money and TBH when I have looked at the Moon, Jupiter, Saturn and various stars, the chromatic aberration seems pretty minimal, hence the experiemnt.
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