Very Amateur Astronomy

I think I’m running out of objects to image in Cygnus now! This one is the Crescent nebula, a bright emission nebula standing out from a region full of faint nebulosity. It is a target and indeed a region that would benefit from a modified camera, something I really must get done. However I am pleased with the result from what is essentially quite a short total exposure, if I get another night this week I may have to grab another couple of hours to bring out the fainter background structure.

It would be nice to try this area with the 250mm reflector to, higher resolution should bring out the very faint bubble nebula which is also in this field, but invisible at this scale and resolution.

I’m running out of ideas for widefield nebula to image at this time of year, any suggestions gladly welcomed, perhaps a field trip for a go at the Rho Ophiuchus Nebula.

Imaging Equipment

• William Optics ZS66SD
• William Optics MkII 0.8 Field Flattener
• Canon EOS 1000D (unmodified)
• Astronomic CLS CCD Filter

Guiding and Mount

• Vixen A70LF Refractor
• Modified Philips SPC900NC Webcam
• IR/UV Cut Filter
• 0.6x Focal Reducer
• Celestron CGEM Mount

Exposures

• 32 x 5 minutes (160 minutes total)
• 29 x bias
• 29 x dark
• 31 x flat

The images were calibrated and debayered in Iris then aligned, stacked and processed in Pixinsight.

This is part the Cygnus Loop (The Veil Nebula), a vast supernova remnant, taken on the evening of the 16th of June from the roll off roof shed. The loop comprises several well known objects, one of which, the Western Veil (NGC6960) I have previously imaged with the 250mm reflector. Also included in this widefield image are the Eastern Veil (NGC6992) on the left and Pickering’s(Fleming’s) Triangular Wisp (NGC 6979) in the centre right.

This area was another target for my summer widefield nebula mission, and is located not far from my previous target the Eagle nebula. Unfortunately it’s just a bit to big to fit in the area corrected by the William Optics field flattener on the ZS66, I’d like to try the new Skywatcher flattener with it at some point to see if that does a better job.

Imaging Equipment

• William Optics ZS66SD
• William Optics MkII 0.8 Field Flattener
• Canon EOS 1000D (unmodified)
• Astronomic CLS CCD Filter

Guiding and Mount

• Vixen A70LF Refractor
• Modified Philips SPC900NC Webcam
• IR/UV Cut Filter
• 0.6x Focal Reducer
• Celestron CGEM Mount

Exposures

• 40 x 5 minutes (200 minutes total)
• 31 x bias
• 31 x dark
• 31 x flat

The images were calibrated and debayered in Iris then aligned, stacked and processed in Pixinsight.

Taken on the evenings of the 21st and 22nd of May this is the north american nebula, a large emission nebula in the constellation of Cygnus.

Imaging Equipment

• William Optics ZS66SD
• William Optics MkII 0.8 Field Flattener
• Canon EOS 1000D (unmodified)
• Astronomic CLS CCD Filter

Guiding and Mount

• Vixen A70LF Refractor
• Modified Philips SPC900NC Webcam
• IR/UV Cut Filter
• 0.6x Focal Reducer
• Celestron CGEM Mount

Exposures

• 57 x 5 minutes (285 minutes total)
• 21 x bias per night
• 15 x dark per night
• 21 x flat per night

The images were calibrated and debayered in Iris then aligned, stacked and processed in Pixinsight.

We have had the joy of a few nights of clear skies over the last week, and I took the opputunity to get in some imaging. I wanted to try my hand at a nebula, but finding something of both reasonable size to make use of my field of view (42.3 x 63.4 arcmin) is proving a little difficult.

After a bit of hunting around I saw that the Veil would be coming up over the house from about 1am onwards which would give a decent 3 hour window for imaging before the skies brightened up to much and below is the result

In the end of course I actually ended up getting about an hour and a half of data, of which about an hour was really good, the lesson being to stop mucking about with software and just stick to what works. However, this is a good start and something to be moving on with, the image itself shows some issues with colour correction, the reds are to brown for instance. However I was happy with the result on this nebula from an unmodified DSLR.

This weekend we have four nights of clear skies forecast which I am hoping to make use of, and this time going back to my trusty William Optics ZS66SD to take a proper wide field image of this area.

It’s been a while, and I apologise for not posting sooner as I’ve not been entirely inactive, just rather unproductive with processing. Most clear nights have been spent tuning and learning about the CGEM, and most spare days spend on modifying the scope. The result of this is that I now have reliable clean guiding, the main fix to achieve this was to put in locking bolts for the primary mirror.

Most photography time has been spend on a wide view of M106 and NGC4217, with several other galaxies also visible. I’ve had significant problems during image processing with noise, which I guess is a result of my new ability to expose for much longer periods, I need to investigate a suitable maximum exposure time for my light polluted skies, ten minutes may be to much.

I had 33 good ten minute exposures but the fainter areas of M106 were getting lost in the large amounts of noise, mostly red grain. In the end I decided to make use of all of my test images which included a stack of 5 minute exposures and some which were not flat fielded in order to improve the signal to noise ratio, so the total number of exposures used was 83, which works out at about 11 hours and 40 minutes of data. Some experimentation with my new found ability to guide will be needed to make the most out of exposures at this sort of length.

Here it is anyway,  not the best image but proof at least for me that more exposures equals good SNR.

I’ve spent some time over the last few evenings working on getting better colour correction and I’m happy to have made reasonable progress to the point where I have re-processed my last two galaxy images, have a look and see what you think .

Both galaxies show much more natural colour than before, and allow for a greater stretch and a much easier to manage background colour.

The same with the Leo triplet, m66 especially is showing more detail in the structure.

I’m very happy with the progress on these two images, thanks to a great deal of assistance from John Murphy in the use of Iris and some very useful directions for taking better flat frames. The next step is to image a g2v type star during imaging session to work as a correct reference for my colour correction.

A bit of a work in progress this as I don’t have enough light frames as yet, but here is the first image from the new mount :

The Leo tripet is a small cluster of galaxies sitting next to each each in the constellation Leo, they are M66 (top left), M67 (bottom left) and NGC3628 (right).

This is the first image using the new CGEM mount and the second image using the CLS CCD filter and it shows a few problems. Visually the first problem that I see is the colour balance, this is a direct effect of using the new filter which has shifted the colours way over into the blue and I’m having trouble working out a good method to correct it.

The second problem is the slight stretching of the stars along the RA axis, this is primarily a result of periodic error which I need to work on. I’ve gone back to using guidedog for guiding on this image as guidemaster was giving me a lot of issues, it still needs a bit of fine tuning. I also want to test out the guiding facilities in EQ Align to see how that deals with the mount.

Also as a direct result on the horrible street light over the garden the images all had an awful amount of gradient in across them, happily however Pixinsight was able to deal with that problem. I’ll have to remember to stick my big cardboard box over the light next time.

It always fun to get something unexpected when out imaging, something unexpected in the image that is rather than unexpected things not working. Before I have had planes across the Moon, red and green trails across an image from an airplanes wing lights, the very random trail of an out of focus bug or something zipping around high above.

Tonight though I got this whilst imaging the Leo triplet :

It looks like a satellite flare but from which of the many hundreds of objects in orbit I couldn’t say.

We had an entire weekend of clear skies! Unfortunately that means we also had a full moon as apparently the two things are connected these days, or at least that’s what it feels like. Lacking the ability to take photos of anything else (I need a 4 x Barlow for Mars) I spent a lot of time testing guiding with the sphinx.

On the first night I used the excellent EQAlign to get my polar alignment as close as possible. The guiding after this was massively improved in declination with very few corrections required, probably the best dec guiding I’ve seen from the sphinx. The RA however was all over the place with very rapid oscillations that the guiding had problems with.

Second night, I spent a lot of time getting the balance of the mount as accurate as possible, had another go with EQAlign to tweak that side then tried again. The result? Excellent RA guiding, but now the declination is a mess showing a slow oscillation as it seems to drift first one way then the other. The horrible declination backlash of the sphinx made this very difficult to manage and adjusting the movement speed or aggression settings only sped up or reduced the oscillation period.

I really like the sphinx, I’ve had a great time with it and learnt a lot, but I think the time is coming for it to be replaced. It is overloaded these days, and the performance of the mount suffers because of this.

Anyway, before heading to bed on Saturday night I took a stack of 100 images of the full moon through the 250mm reflector.