finally everything arrived. My old rig was quite overwhelmed with my
ambitions and had to be replaced. Why so?
First reason was the old mount. The mount is undoubtedly the most
important part of your equipment. No fancy OTA will produce sweet DSO
images without a proper tracking mount. And “proper” means: The
mount must be able to carry the optics with ease.
New aspect: Visualize the impact of seeing while taking images of Venus.
Image acquisition & processing: I took three different images of Venus during the recent few months. All of the images were taken with the exact same hardware and setting – a ASI ZWO120MC-S Color planetary webcam with a 3x Barlow lens on top of my 750mm Newtonian reflector carried by the Skywatcher EQ3 -Pro mount. All images were recorded as .avi files (2min @ 60fps) and stacked (20% best) and sharpened in Autostakkert!3.
& „It’s too much!“ – beginning backlash-errors or the EQ3 -Pro
29.04.2019 – 04.05.2019
New aspects: – first time with an auto-guiding system – Guiding shows first signs of overcapacity – revisited a target for noise reduction – first „proper“ galaxy – longest project so far
Image acquisition: So finally every part of my new guide-scope arrived and I could use phd2 for proper guiding for the first time! Last session I had unsolvable difficulties with the guidecam, the „ToupTek Camera G-1200-KMB Mono Guider“. I stayed in touch with astroshop.de and they finally replaced my guidecam with another model, the ZWO ASI120mm mini-mono. This camera arrived and the current guiding setup now looks like this:
During the last
sessions I slowly build up the dream of autoguiding my images. There
are many advantages of having a guidecam with a guidescope attached
to your main scope.
to use the guidescope for advanced polar alignment in phd2. There
you use the attached scope to trace movements of stars to determine
the polar alignment offset. Phd2 is then able (because it’s
clever) to give informations about with direction you need to nudge
the scope in order to perfect the alignment.
to use the guidescope with its cam to plate solve. Plate solving is
the ability of the PC to count the stars on a given image and
compare it to a given database in order to determine the current
position of that image in the night sky and give a set of
coordinates as an output. Some of you might ask: Why not use the
main camera for that? Well, upon now I used the old Olympus E510.
This camera can not easiely be controlled by a PC. So in order to
use the main imaging cam for plate solving I would have to take a
picture, grab the CF-card, transfer the image to the laptop… Long
story short: once set up, I don’t want to touch the main camera
any more (focus!). Problem is: I need to align the polar scope and
the main imaging scope properly in order to use the plate solving
Last but not
least: The ability to guide with phd2 to
exposure time! I was up to 60 seconds on lucky sessions, others
were more like 50 seconds.
the framing. Without guiding I had the problem that the image would
shift ever so slightly. Even when 60 seconds would give me pin
point stars, a night long session would result in a noticeable
movement of say half a screen! So I needed to go out and slew back
to the original position from time to time. With guiding phd2 would
check that for me.
reliability of the system. Without guiding I used say 1/3 of the
images max! Some sessions were down to one image out of every 5
frames or so. That was due to bad alignment and other imperfections
of my mount. Increasing this quota would give me much more data on
a given target!
This time I wanted to
capture tow cool galaxies in one frame. I searched Stellarium the day
before and found those two beautiful galaxies. They fit into the FOV
of my camera/scope as I use an old Olympus E510 and a Skywatcher
150/750 Newtonian reflector. Challenge was to frame the objects right
into one frame and not accidentally cut one galaxy off. So I chose a
high ISO 1600 (max with my camera) and like 60’ test frames to
locate the galaxies. Due to my little mount with high inert slewing
errors I had a hard job of even finding the two of them. After that I
needed to fit them into one frame. My sister and her fiancé can tell
the story of me trying to move the scope just ever so slightly than
taking a test shot, wait for 60’ then reslew. Than me realising I
slewed in the wrong direction. Me reslewing again. Taking another
test shot. Off again. Where are the galaxies at all? Reslew. Test
shot. Searching….. Uff! It was tough.
This two images of the Orion Nebula
were taken using a smartphone hand-held in front of the 2” lens.
This evening I observed a few DSOs with my Skywatcher 150/750
Newtonian on my little Skywatcher EQ-3 Pro mount. Doing visual
astronomy is normally not really my thing but I wanted to give it a
try. I was surprised, how much of M42 the Orion Nebula was visible
trough my little 6” newtonian scope. But than I couldn’t resist
to hold my LG G6 in front of the lens to shoot some images. I then
tried to get the exposure time of that single frame exactly in such a
way that it would match the experience with the eye. So here they
I took video files of both
planets on the morning of the 23th of January. It was a
Wednesday so I was (again) in a hurry. Setting up the scope was not
that hard but keeping the last trouble with the moving Venus in mind
I took one more look through the polarscope to align a bit more
properly than last time. Then I searched and found Venus. Again the
planet was so incredible bright, that was not able to choose the
right settings for exposure and focus. I tried my best ether way.
Jupiter was a more easy part. I did some over exposes videos to
capture the moons of Jupiter and then fiddled around to find the
sweet spot for exposure, gain and “brightness” (whatever this
item means). I finally managed to grab three files before I had to
end the session. Focus? A nightmare!
This time I had one target and one target only in mind (finally managed to obey my own rule!): M42. The last session gave me 32x1min light frames to work with and hence a lot of noise in the image. After setting up the scope I was about to frame the image. This was my first do-over of an object where I was about to ADD data to my already captured data-pool. I had already framed an object to my wishes as I framed M31 (Andromeda) to snugly fit into my DSLR frame. This time I had to match the previous image framing with enough precision to be able to add the two sessions together. My problem about this was that my mount tended to move even so slightly from frame to frame. So first and last frame and all the counter-re-framing had to fit as well. I did my best and framed M42 after focusing on a nearby star with my bartinov-mask. Then I hit the “run” button.
New aspect: Revisiting a target to improve quality and seeking for the next
Venus: This was a shot in hurry. On morning the 5th of December I set up the scope in a hurry to capture Venus. Polar alignment, balancing: All quick and dirty because of the limited amount of time. The result was a hard job to even find Venus with the scope and the attached webcam. After finding Venus I struggled with the right driver-settings. Venus was so incredible bright that even focussing was a nightmare. The bad polar alignment made I just worse. Venus, taken with a 3x barlow, hurried to leave the FOV whenever I thought that I got the settings right. Then I needed to reslew and start all over again. I managed to capture one video file with a very unstable Venus and an unclear focus.
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