Author Archives: Geoff Dryland
Neil suggested I should combine my two images of M27.
I didn’t know how to do this because they are of different scale and not aligned, plus, how to integrate only part of one image into another.
Well the first part turned out easier than I thought. I put the two images into MaximDL and selected align. Having chosen the two stars in each image and pressed align, it automatically re-scaled the images to match!!! Job done.
The next bit was the most difficult as it required layers. After searching the internet for a tutorial on layers, it took the best part of 6 hours to A. understand both the tutorial and the American accent and B. to get my Photoshop to work in the same way as the tutorial. Anyway this is the first time I have ever tried this and the result shows it.
I had been waiting to get a night to take new data on this but time was running out , so I re-processed data from November 2019. Since I took this data I’ve found that DSS doesn’t stack it properly so I have re-stacked it manually and tinkered with it in Photoshop to come up with this.
You can see the star that is causing the nebula at dead centre. This was taken using RGB filters only, 1 hour each in 4 minute subs.
Then along came a clear night (finally). So rather than redo the image in RGB, I did it in Ha, O3, S2. Again 1 hour each but in 5 minute subs.
Stacked manually again and really processed hard to bring out the outer ring of blue.
For both images I used the RC 6 inch telescope with the Atik 314L+.
Looked last night for the comet but found that it was sitting right behind my neighbour’s tree. So want to bed at midnight. I thought I’d have one last go from my upstairs bedroom window, and there it was!
This is taken with my Nikon D90 SLR, using the 18-200 lens at 200 (effective size is 27-300), 15 seconds at f5.6 and ISO 640, from the window sill ( very Rogeresque). It’s slightly out of focus but this is the first image I have taken at night with this camera so I’m happy (I’ll try again tonight to improve!). This Comet is very bright and is visible with the naked eye so it’s worth trying to spot it.
Got around to making the closeup of the “Headphone” nebula last night.
After making a great effort to focus, get the PHD to work and eventually finding the planetary, I started imaging at 10.45pm. Above is the first result of 12x 5 minute subs. I tried stacking in DSS but it wouldn’t have it as it said there were too few stars! So I moved to Maxim DL where I auto aligned and stacked. This is the result. Extremely disappointed. As before, I have the star drift problem. In the past I have blamed this on: Poor Polar alignment, Focus, Reflection off the Spider, PHD not being very accurate.
Then I noticed that none of the subs seemed to have any drift. So I went back into Maxim DL and MANUALLY aligned all 12 subs. I then stacked these and the result is:
It would appear that the auto stack in both DSS and Maxim DL has been the problem all along.
I have taken more subs on this so will go back and add them then process using MANUAL align.
Has anyone else seen this really good/funny Youtube video by Biscuit?
Try it and see that expensive kit has some stiff competition from a DIY setup. (Provided you can source the cheap items……………see Lee!!).
Andy made a few comments about this galaxy so this is trying to give a better view of it.
I’ve added some more luminance to give a total of 2 hrs 20 mins to the ngc2903 image. A quick process to try to show the full extent of the galactic arms, especially the one coming round the bottom of the galaxy. This is the full image with no clipping so it is 16.8 x 22.5 arcminutes.
Andy, just realised I gave you the FOV but you wanted image scale. Image scale is 0.97 Arcseconds/pixel
target of 12 mag.
So here it is, ngc2903 in Leo.
Taken with the RC 6″ and Atik314. Luminance only 30 x 4 minutes subs.
I’ve been wondering why the stars appear to have a small amount of drift because the elongation is not in the line of Dec or RA. I’ve come to the conclusion that it is Focus (even though the Bhatinov mask shows its OK). When I magnify up a long way, I can see a slight out of focus in the direction of the oblong stars. Could this be it? Answers please to the God of clear skies asap.
The image explains why. Visually this is what you see. In the centre is a “bright” star with 2 faint galaxies in the 8 o’clock position next to it. These are NGC 2475 and 2474 which where mistakenly thought to be the planetary (even SkyMap Pro has them all in the same place). However, the planetary is some 30′ north of these (right in this image). It wasn’t until the narrow band filters came in that the error was discovered. It is now called “The head phone nebula”
This is a quick 8x 4 minute in each Ha, O and S. To show where everything is, I’ve used the Takahashi and the Atik 4021 to give a wide field of 103′. The planetary is 7′ x 7′ and shows the difference narrowband makes! I will be going back at the next imaging night for more data and with the RC 6 inch and Atik 314 for a close up look with the FOV of 16′ x21′.
Don’t forget to click on the image to get an expanded view.