Tag Archives: 14″ Newt

Merope & Tempel’s Nebula (NGC1435)

Image centred at:
RA: 03° 46′ 18″
Dec: +23° 56′ 04″
Field of view: 25.46′ x 18.82′

Merope & NGC1435 (Tempel's Nebula)The Pleiades open cluster in Taurus is one of the brightest and most recognisable objects int he winter sky. As a first LRGB image using the 14″ Newtonian, and to test the setup of the off-axis guider, I imaged the area around Merope (23 Tau). This was also the first use of a Bahtinov mask that I got laser cut by Oxford Hackspace. The focusing mask works excellently – this should be a real plus, especially for any planetary/lunar work.

The particular area of nebulosity imaged here around Merope was discovered by Wilhelm Tempel on October 19th, 1859, and is catalogued as NGC1435. The dust isn’t in fact the nebula from which the cluster formed, rather that the Pleiades happen to be travelling through a particularly dense part of interstellar medium. This dust scatters blue light from the cluster members, resulting in the reflection nebula visible to us.

The image shows strong diffraction spikes from the secondary spider, as would be expected. There’s also further diffraction visible around the brightest stars dark shadowing present at 60 degree angles, which is the result of the mirror retaining “clips” (they are not actually clips – they are part of the cell in the case of the 9 point Orion Optics mirror cell). To remedy this would require a mask to be added over the outer edge of the mirror to cover these over – this is maybe something I’ll think about making in the future to help deal with tricky situations like this! 

The additional dark shadow pointing to the right appears to be the focuser drawtube intruding on the internal light path inside the scope – that’s probably something that can only be cured by either a shorter drawtube, or shortening the truss tubes. Again. Maybe I’ll wait in case I decide to change coma corrector at some point, in which case it’ll probably need a change to the focal plane position anyway.

The image was taken on the evening of the 7th Jan 2018 through the 14″ (350mm) Newtonian, with an ST2000XM and an MPCC v1 coma corrector. Total exposure was “only” 2h 32m (L: 59m (20x1m, 13x3m), RGB: 31m (10x1m, 7x3m) each channel). Processing in Pixinsight and Photoshop CS4.

Nov 2017 Lunar Mosaic

The 4th November 2017 gave me clear skies with a very bright moon in the sky – this gave me  good opportunity to use the rebuilt 14″ Newtonian scope for some imaging work, now that the scope truss tubes have been correctly milled down to the right length. 

Using the ASI120MM camera with a 742nm nr-IR filter, I imaged the moon at its native focal length (1582mm), using Firecapture to grab the video. The data totalled 56GB in all!

The finished mosaic consists of 18 frames: each of these was the result of stacking the best 12%  (quality-wise) of 3000 frames. Each of the frames were 0.18ms each (with gain set to 54), and were captured at around 31 frames per second.  To try to avoid issues with exposure mismatch, all the exposure details were kept identical throughout the 36 minutes  or so it took to complete the whole set of videos across the face of the moon.

99% Moon on 2017-11-04
Mosaic of 99% Moon on 2017-11-04 at 80% resolution (3MB image size)

The videos captured were aligned and stacked using Autostakkert2, and each of the stacked images were processed using identical wavelet settings in Registax6. 

To create the mosaic itself, I took all the images into Microsoft Image Composite Editor (ICE) and let it get on with the process of aligning and stitching the images together. It did a remarkably good job! I had also tried the Photomerge function in CS4, but ICE did a better job here: Photomerge was good but left a couple of slight merging artifacts – misalignments on the limb, mostly. 

Final processing took place in Photoshop (smart sharpening, levels, curves, etc) with the result being a 20Mpixel image weighing in at 7+ MB for a high quality jpg. Here, I’ve reduced the image to 80% of the original resolution to aid web viewing!

Images were taken starting at 2215UT from West Oxfordshire, UK. 

Lunar Imaging Gallery – 16th May 2016

Some further lunar work – as before I worked using the ASI120MM in combination with a 2x Barlow lens and the 742nm near-IR filter through the 350mm Newtonian.

A productive evening, with six images of good quality in what was at times fairly good seeing – I would like to try running at a slightly higher scale (by using a different Barlow). i do have a 4x Imagemate, but I’m not sure the quality or the resultant focal length would work quite as well.

As it turned out, this was an evening where I bagged a few of the double ringed (concentric) craters on the moon, as well as some interesting Rille features and domes.

Images are as follows:

Clavius with Longomontanus, Scheiner and Blancanus – a good amount of detail in this image and I’m especially pleased with the detail within Rutherfurd (on the southern edge of Clavius). Street M is visible with a small concentric craterlet within.

Longomontanus and Clavius, 2016-05-16

Moretus, with some very good detail coming out of the wall and surrounds. The lunar south pole region (with Newton tucked just behind the hills) is to the bottom of the image.

Moretus, 2016-05-16

Copernicus – a classic lunar crater, and one where I’ve got a much better result than I’ve previously acheived. I particularly like the collapsed edge visible to the south – perhaps a little more scale might just let me sharpen up the detail within the crater a little… Also visible are the Hortensius domes (to the left in the image) lying just to the north of the crater of the same name – lunar domes are shield volcanoes which often have a small craterlet at the peak.

Copernicus, 2016-05-16

 

Rimae Hippalus and surrounds. So much going on in this region – bullialdus by itself is a nice looking crater, and nearby the complex rille structures of Rimae Hippalus cut across Hippalus and the surrounding regions, leading up to Agatharchides. The lunar dome Kies Pi is easily visible and concentric crater Marth in Palus Epidemarium is also present in the bottom right of the image.

Rimae Hippalus and Surrounds, 2016-05-17

Another busy nearby field, showing Pitatus, concentric craters Hesiodus A and Marth. Lots of rilles also visible, including Rimae Hippalus, Rimae Ramsden, Rima Hesiodus, rilles in Pitatus, and Rima Campanus cutting between Campanus and Mercator. Kies Pi is again obvious.

Mare Nubium and Palus Epidemiarus, 2016-05-16

A view north of Bullialdus including the interesting “rippled” texture between Darney and Euclides.

Bullialdus and Mare Nubium, 2016-05-16

The last two make a rather nice mosaic, though this was a quick job and I haven’t tried too hard to eliminate the edge of field noise, or the slight mismatch between levels.

Bullialdus Region - Mosaic

Lunar Imaging – 17th Mar 2016

I took the opportunity to do some further imaging of the Moon and Jupiter during a clear evening on the 17th March – as is common, the moon was high, and the transparency wasn’t great for any narrowband work, and as such it gave me an opportunity to work more on some high resolution work.

The seeing wasn’t great, and I took a different approach to imaging this time by using subframes on the ASI 120MM to get a high frame rate and allow large numbers of frames to be captured (thus increasing the chance of capturing good frames).

Images as below are of Clavius, Tycho, Rupes Recta (the Straight Wall) and Rima Birt, and Vallis Alpes (Alpine Valley) with the central rille (just!).

Clavius 2016-03-17, 20:02UT

Tych 2016-03-17, 20:27UT

Rupes Recta and Rima Birt 2016-03-17

Vallis Alpes 2016-03-17, 20:18UT

Jupiter – March 2016

Planetary work is not really my strongest skill in astrophotography, but with Jupiter near it’s highest in this and the past few years, it is well placed for photography from the UK.

Additionally, this is one of the first chances I have had to get images with the large 14″ reflector using my ZWO ASI-120MM. I chose to use the Astronomik 742nm Near-IR filter to try to improve the results: on both occasions it has resulted in much better resolution than with unfiltered white light. In addition I used a Meade Series 4000 2x Barlow lens. With regard to conditions,  I think I’m a little limited by my observing location where I have to observe over the top of our row of houses – the thermal currents (including from boilers, open fires, etc) are likely to do little to help the seeing here..!

First image is from the 17th March during Callisto’s shadow transit (taken at 23:08UT)  – Callisto itself is also visible at about 7 o’clock (and clearly resolved into a disc – at 1.5″ the seeing was clearly not so bad..!).

Jupiter 2016-03-17, 23:08 - with Callisto and Shadow Transit

Second image was taken on 22nd March 2016 – the results weren’t quite as sharp as those from the 17th. Unsure if this is a focus/collimation issue, or if the seeing just wasn’t as good. The processing is a little heavier to try and bring out the cloud contrast where possible too. Collimation of an f4.5 scope is fairly critical, and any slight shift can reduce image quality quickly. Equally, at f9, focusing is tricky with a fairly dim extended object – this is something I need to work on in the future – a Bahtinov mask is on the list of makes for when I have successfully rebuilt this scope.

Jupiter 2016-03-22, 22:43:52

All images were 2 min videos, recorded using FireCapture, processed in AutoStakkert, Registax 6 and Photoshop CS4.