Skywatcher Star Adventurer - Unguided Focal length & Exposure times

[raymo]

Sidereal rate will result in a star that barely moves, because obviously the
mount's trying to keep the star stationary; you need to use the mount's slowest slewing[or guiding] speed,[ if it is motorised] or control manually, so that the star takes at least a minute to cross the screen from right to left, then reverse direction, and another minute back to the starting point.
When doing the first couple of iterations you can reverse direction after about 30 seconds, as the inaccuracy will be obvious. You will need longer runs for the inaccuracy to show up as the alignment gets close to your aim.
This sounds a pain in the a--, but after a few times it becomes easy.
You can change your accuracy requirements according to the focal length
of your imaging optics. If you mark the ground in some way, so that you can plonk your mount down pretty much in the same spot each time you use it
you can considerably reduce the time it takes to do DARV. It will probably
take 45 mins or more the first time, as you get the hang of it, and come to see how much you need to move an axis to correct x amount of inaccuracy, but after a few setups you should get down to 15-20 mins.
cheers raymo

[Jasp05 (Aaron)]

Just as a progress update. I went out to my dark site last night to try and get a more accurate polar alignment by eye. No drift align. Basically set my latitude to the 23.4 degrees and pointed in the direction of SCP. I made 2-3 adjustments to azimuth in the first few subs. Latitude seemed to be fine.

Attached are some of the fruits of a night's work.

Andromeda is a stack of 3-5 images (I can't remember how many) with subs varying between 3 & 5 min. Cropped and tweaked in Lightroom.

Orion is a single 5 min sub at 200mm ISO 3200 - tweaked in lightroom (I have another sub at 50mm on Orion thats picked up Barnard's loop after one sub. Which I never thought I'd get tbh .)

And LMC is single sub @ 5min 50mm F2.8 ISO 1600 - tweaked in lightroom




So much happier with the results and am pretty confident that it's polar alignment that done me in on the first few nights out. But I will practice drift aligning from home in the meantime and work on building up my data for each object. (going to need hours on these things to really bring out the finer detail and reduce noise).

Thanks for the tips along the way guys.

[jenchris (Jennifer)]

Rough alignment by compass on my mobile - 30sec x 6 plus 2 darks at 5000iso 135mm canon 70d