Astronomy Report – 2021-10-06 – Guiding and My First Imaging Session

[chris_g]

It’s going to be another night like last night, weather wise that is. Let’s hope I don’t have a repeat with guiding. Sunset is at 18:46 and moonset is at 19:15, astronomical twilight ends at 20:06. Moon illumination is 2.9%, not that it matters. Setup started at 17:00, the western leg had sunk a little and needed another shim. I got the roof pitch to .05” per foot and pitch and roll to 0 in the compass, tripod spots are marked for it’s final position, should be really close to True North. That took about 20 minutes. Scope and equipment will go really quick now.

I accomplished my first imaging session tonight. I took 30 90 second subs of Andromeda Nebula, with 10 dark, 10 flat, 10 dark flat and 10 bias. My focus was tight and guiding was spot on. I spent the better portion of the evening working on getting guiding to work properly. I focused on Jupiter with the Bahtinov mask then I Polar aligned using N.I.N.A.’s TPPA, starting at Jupiter in the south south east sky. I got it to less than an arc minute total error. I slewed to Andromeda, turned on guiding and snapped a single 90 second sub. My stars looked like little bars, just as if my polar alignment was off. I reran TPPA and it was reported being off by almost 7 arc minutes in RA and 9 arc minutes in Dec. I noticed this previously my last couple of sessions but wasn't sure if was something I was doing or not. I reran the entire process in the general vicinity of Andromeda until I was about 45 seconds total error then redid star alignment and snapped another 90 second sub of Andromeda, everything looked good. It seems TPPA works best when starting in the north eastern sky as that is where Andromeda likes to hang out. Someone on the forum had also indicated that some people had reported it worked better if it started close the NCP.

I finally hit the zenith of my learning curve tonight, I had some extremely frustrating nights but it’s been worth it. I ordered the Messier Astrophotography Reference book by Allen Hall, the same author that I started me on this journey back in January, Getting Started: Long Exposure Astrophotography. It should be here some time next week. I also ordered a manual rotator for the scope so I can frame my targets, it also should be here sometime next week.

You can check out the image here. viewtopic.php?f=66&t=21047

Clear Skies!

[bobharmony]

Congrats on your first imaging session, the result is a great start. It sounds like you have your ducks in a row for the setup process and are taking the time to get it right. That will definitely hep with future sessions!

How did focusing on Jupiter work for you? I have never tried using the baht mask with anything but a star, and am curious about how effective it is with an extended object like a planet. When possible I like to use a bright star near my target for the night to focus on. By platesolving the star and syncing the scope in APT, it can make the slew to the target closer than a more distant object would. For M31, I often use Caph in Cassiopeia for focusing with the mask.

Bob

[chris_g]

Congrats on your first imaging session, the result is a great start. It sounds like you have your ducks in a row for the setup process and are taking the time to get it right. That will definitely hep with future sessions!

How did focusing on Jupiter work for you? I have never tried using the baht mask with anything but a star, and am curious about how effective it is with an extended object like a planet. When possible I like to use a bright star near my target for the night to focus on. By platesolving the star and syncing the scope in APT, it can make the slew to the target closer than a more distant object would. For M31, I often use Caph in Cassiopeia for focusing with the mask.

Bob

Quite well actually, the refraction spikes totally stand out on Jupiter and then I used the moons to fine tune the focus to get them as tight as I could, worked quite well for my first run. Thanks for the advise on focusing, knowing how others do things is always is a good thing!

[turboscrew]

Congrats on the victory against the guiding hardships!
Nice picture too,