M31 – IMT3b Observatory

Imaging Report 15th-16th December 2022

As it was a work night and Dave was working I was imaging from the back garden and not the dark site. I started late in the evening and had issues sorting out the autofocus in NINA which meant I was even later than I had planned.

Using the OptoLong L-Pro filter and the native camera driver (not ASCOM) :

The target was decided by Dave as M31 (Andromeda Galaxy), I decided on 120 second exposures at -15℃, gain 0 and offset 30 (Photographic Mode). I finally started to capture data at 19:55 when M31 had already transited 45 minutes earlier.

M31 single sub (stretched) via NINA Imaging Session

I believe the dark shadow to the left is the QHY OAG prism, I may have to reduce it’s depth in the light path or rotate it 45 degrees so it sits on the long horizontal axis.

Once M31 had reached approximately 50 degrees altitude and was starting to set in the West my guiding started going awry especially in RA. I put this done to either balance issues or cable snagging so that’s something I need to look at in the future.

After shutting down earlier than I thought due to the guiding issue and the pending rising Moon I decided to do my darks, flats and dark flats. However my Pegasus Flatmaster refused to connect to NINA so I decided to fix and complete this task on a different day.

I only managed to capture 62 subs which totals just over 2 hours. I was hoping to get at least 6 hrs for a single session and something approaching > 12 hours which means I will need several more nights to capture my required amount of data for M31.

Not a great first outing but given I hadn’t imaged in ages this was expected. I can honestly say that although a OSC coupled with the new harmonic mounts such as the ZWO AM5/Pegasus Nyx are very convenient as part of a lightweight holiday travel setup. OSC also is easier processing but still I can say I’m not a total fan due to the loss of high frequency data, high HFR focus issues and in the case of the QHY268C the noise banding issue which although appears to be removed by darks etc still is unnerving.

Update (17/12/2022)

Have resolved my Flatmaster 120 panel issues but I feel I’m better off with a fully controllable fixed panel instead of a manual panel so I will look into that.

My Darks, Flats and Dark Flats are now done (25 of each) all performed at -15℃ to match this session temperatures but there is still not enough actual data to start processing.

Equipment Check-up

So after ages I’m planning to perform some imaging after being challenged by Dave to produce a OSC image of M31 with the QHY268C that can be of print quality.

The first step was upgrading all the necessary software to make sure both the NUC and laptop would not be interrupted during my planned imaging session.

Windows10 latest Updates (Dec2022)
SGPro (4.2.0936)
NINA (2.1 HF1 Beta002)
ASTAP (2022.12.09)
ASCOM (6.6SP1)
Pegasus Ultimate PowerBox (1.6.1230.46)
iOptron commander (5.9.0.2)

The iOptron CEM60 mount hadn’t been updated in ages and it showed :

HandControllerV2 : 210106
MainBoard : 190716
RA board : 201005
DEC board : 190716

After performing the firmware update procedure, the mount was now showing the following levels :

HandControllerV2 : 220119
MainBoard : 211018
RA board : 211018
DEC board : 211018
Catalog : 150429

Of course I will need to perform a new zero mount position following the upgrade. Tonight I will also be changing the OpenPHD algorithm to PredictivePEC as described by Cuiv the LazyGeek :

https://www.youtube.com/watch?v=BfvmlR3It1o

Viewing Report 4th January 2022

17:53 – 02:34

Clear night! So I’m going to setup and let the dome run all night if it stays clear which is the forecast as I have work tomorrow.

I have run the guiding assistant on PHD2 so that I can hopefully better track objects. The drift in frames from the last time out whilst using the ST80 as a guide scope was less than ideal. I have now put al the new settings suggested into the PHD setup and have swung round to do a focus run on a star near to M32.

After successfully running autofocus in SGP at 23,560 on Luminance I have now slewed to M32 to gather more data that is desperately needed to resolve the outer spiral arms of the companion giant galaxy M31.

So it is now just gone 9pm and whilst the guiding is managing to stop trailing of stars, the image is moving between frames, enough to loose the object over the course of 4-8 hours. This is clearly not good enough and it does look like the focal length of the ST80 is simply not long enough.

To get around the problem this evening I have turned guiding off, as the exposures are short (3 minutes) the trailing of stars is not an issue. At midnight I took flats for M32. I then centred on M78 for the rest of the night. Before starting I performed another focus run as the focus point had changed over the night with the temperature drop.

I choose the same exposure settings and Gain 139 and Offset 21 settings as for M32. -25C was the temperature but this time I rotated the camera by 90 degrees to also fit in NGC 27309.

So I left the scope running and it completed at around 2:30am with 40 frames taken across 4 filters giving me 30 minutes per channel. This will be enough to get started and if clear tonight I will setup for another run at M78 and hopefully improve the guiding.

Update. On reviewing the files this morning it looks like I forgot to select the filter in SGPro which means all my M32 and M78 images from this evening are in fact luminance only! Which is ok for M32 but for M78 I need some colour. Below is the weather data for last night.

Viewing Report 2nd January 2022

19:26 – 01:30

I started with M76 Ha as I need some frame for this object. I already have many hours in OIII. However after starting to image I realised the guiding, which is currently being tested through Dave Boddington’s ST80 was not pointing through the slit correctly as M76 was near the zenith. This means I have suffered from trailing as the guider was trying to guide on long stars due to diffraction.

I swapped to a different object, this time M32 as I have not imaged this directly before, just as a happenstance of imaging M31. I have chosen 180s exposures using Gain 139 Offset 21 to keep the saturation of the core down. At 300s the core was blown out.

M31 can be seen to the left and lower left of the small galaxy. M31 covers a large part of this image! So how well was my guiding doing?

The guiding looked fine. 0.52 arcsecs total error which I am happy with. I stayed up until just before midnight and then left the observatory running. In the morning I noticed the dome shut around 1:30pm due to the images after that looking like flats.

I also noticed this morning that the images were drifting so the guiding is not quite right as the image drifts. I will next time out run the guiding assistant and see if that helps.

Update the image scrubbed up fairly well but I lost a lot of frames to drift and trailed stars and then the dome closing. Resulting image around 3 hours 12 minutes exposure of which 48 mins was Luminance but there was cloud affecting many frames.

Below is a copy of the nights weather data.