Tŷ Du Observatory

Everyone seems to be taking shots at Lulin at the moment but I haven’t had a clear night for weeks.  Sunday was my first opportunity to take a look at the green comet and  even though Starry Night showed it as being behind my house until after 11pm, it actually appeared in the gap between my house and the neighbours so I was able to image a little earlier than expected.

As the comet is moving quickly against the background I kept exposures to 20 seconds, which in hindsight was not long enough. I’ve spent hours trying to extract as much detail as I can from the 49 frames I took, but my best image is a stack of only 24.

Taken with the usual setup, 1200mm fl 254mm newtonian scope on EQ6 mount. Starry Night, EQMOD, Canon 300D (unmodded). Guided with 70mm cheapo scope using QHY5 guide camera.

As a footnote, I must try and get the Atik 16ic configured as my guider.  The QHY5 is so unreliable, both Guidemaster and PHD crash when using it. I have found that if I leave PHD with the error message on the screen it continues to guide regardless

In the same session I also managed to get a few 3 minute guided frames of M51.  I’ve not been able to get more than 1 minute subs previously, but the guider worked for most of the session, so I’ve been able to stack 20 frames to make this image:

It’s nice to have a colour camera to get these galaxy shots but I think I need to go longer than 3 minutes! Coma is very obvious even in this heavily cropped image – I think I may need to invest in a coma corrector next.

Happy New Year

A new year and a new start for me. I’ve bought a QHY-5 guide camera and some scope rings to have a go at autoguiding. I had several viewing sessions towards the end of last year, but haven’t updated the site as most of the images are duplicates of those I’ve taken before. Now that I can improve my images I will consider rebuilding this site to make it easier for me to update.

I’m looking forward to being able to start imaging fainter objects and also to tease more detail out of those I have imaged in the past now that I can do longer exposures.

Initial tests look promising but I’ve had to overcome a number of issues, such as the guide software crashing every 5 minutes and the weather not cooperating! Last night was my first chance to get everything working but it didn’t clear until after 10pm so I didn’t get to bed until after 3am but I did leave the scope tracking so as not to miss this rare opportunity to image with a clear sky.

Here are a couple of images from last night:

The Horsehead Nebula in Orion	M1 – The Crab Nebula	NGC457 – The Owl Cluster
NGC891 – Edge on Galaxy	NGC2403 2×5 minutes	NGC2403 6×1 minute
NGC2841 – 100×2 minutes

Guided using Guidemaster 2 (beta) 70mm refracter and QHY-5 guide camera. Guide signals from camera to mount, not ASCOM.

Images with 254mm Skywatcher relector on EQ6 Pro Mount with Atik 16ic mono camera.

NGC457 the Owl Cluster was one of the first objects I imaged, so I thought it fitting that I was able to include this amongst my first autoguided images.

Sunday was clear but I knew I’d be up at 6:30am for work so thought it best not to image into the early hours. Instead I completed converting my PC to Linux and set about looking for image processing tools. Hmmm, I’ve been spoiled with the options available to me under Windows and now I’m struggling to find anything that will stack multiple FITS. I can do post processing using the GIMP but without a stacking option (and histogram stretch options) I found I had to revert back to K3CCDTools under Windows. I ran Windows in a VMWare session though

Monday was clear but by the time I get home from Karate it’s too late to set up and I don’t have the energy anyway

So here we are on Tuesday, a clear sky, the nights drawing in and I have everything set up by 7:30pm. I decided to pick out some old friends towards the North, which turned out to give me an insight into the issues I have with mount movement. Focusing my attention on object close to the meridian I was able to increase exposures to 60 seconds in some cases. I had to discard a large number of frames, but those that were usable had much better dynamic range than the 10, 20 and 30 second shots I’d been taking recently.

NGC4605 – Galaxy	M27 – The Dumbbell Nebula	NGC6503 – Galaxy
NGC6946 – Galaxy	NGC5907 – The Splinter Galaxy

I returned to NGC6946 to see if there was any trace of SuperNova SN2008S. I had taken images in January and February around the time this SuperNova was discovered and wanted to see if anything remains. I’ll have to create one of those blink images to show where it is, not tonight though.

Another clear night, even though I can barely keep my eyes open I know these opportunities don’t come around too often so I’d be a fool not to get the scope out again.

I’m still disappointed with the results, the short frame times result in images that lack any depth and need to be stretched to the point that they become black and white
as opposed to shades of grey. But I know this is going to take some time to master so I can be critical as it pushes me to do better next time.

M2 – Globular Cluster	M27 – The Dumbbell Nebula	M81 – Bode’s Galaxy
M92 – Globular Cluster	M102 – Galaxy	M109 – Galaxy

Another clear night, and it looks like there’ll be a few more over the weekend.

I spent some time playing with PemPro and PERecorder to see if I could make a PEC curve for the mount. It looks like each worm cycle has a different profile so I’m not sure how much help it would be. After spending several hours using the webcam to record PE I decided enough was enough and moved on to imaging with the Atik 16ic.

I didn’t get much, it was already late so really it was just a test of the PEC experiment.

M15 – Globular Cluster

M27 – The Dumbbell Nebula

M57 – The Ring Nebula

Even after applying PEC I was still unable to manage more than about 30 seconds per frame.