Salvatore Iovene / Mostly astrophotography and code

Another image, the third one, coming from the three-man team of Samuel Diaz Lopez, Colin McGill, and me.

Unfortunately, this time too I could not contribute any actual raw data. I’m still suffering from some unidentified problem, probably differential flexure, so most of my subs have elongated stars.

This time we aimed our weaponry towards NGC 4725, a nice, one-armed, intermediate barred spiral galaxy about 40 million light-years away in the constellation Coma Berenices.

NGC 4725 is a Seyfert Galaxy, suggesting an active galactic nucleus containing a supermassive black hole. (Source: Wikipedia)

The image was acquired during several nights this May, and consists of:

• L: 27x900” and Ha: 9x1800” with a GSO RC10, Atik 4000, AP900.
• RGB (38+39+48)x300” with an Ian King’s Ikharos 8”, Atik 460ex, Paramount MX.

The processing was done entirely with PixInsight 1.7.

After riding for a few years on a Marin Alp Fairfax, a hybrid bike with road ambitions, I decided it was time to gift me with something better.

With my birthday coming up, and taking advantage of the fact that I was in Italy for some time, in Veneto, a region densely packed with cyclists, I went bike shopping.

This Trek Madone 3.5 was the bike of the year 2012, and is a great compromise of speed and comfort. Great bang for the buck, and 20% off because it’s last year’s model.

It’s got a Shimano Ultegra group and Shimano 105 brakes.

I took it for a ride yesterday and it really felt like night and day compared to my previous bike. This thing accelerates like it has a will of its own. It’s easier to reach faster speeds and maintain them. The group shift with a quiet click and it feels very appeasing.

Now I’m going to have to hope for good day weather and night weather. Is that too much to ask?

Samuel Diaz Lopez, Colin McGill and yours truly have worked on another fascinating galaxy.

This time, however, due to technical problems now solved, I haven’t been able to provide any actual data, but the image shown in this post was processed by me.

It was acquired with:

• Telescopes: Ian King Ikharos RC8, GSO RC10
• CCD cameras: Atik 4000, Atik 460ex
• Mounts: Astro-Physics AP900, Paramount MX

NGC 4631 (also known as the Whale Galaxy or Caldwell 32) is an edge-on spiral galaxy in the constellation Canes Venatici. This galaxy’s slightly distorted wedge shape gives it the appearance of a herring or a whale, hence its nickname. Because this nearby galaxy is seen edge-on from Earth, professional astronomers observe this galaxy to better understand the gas and stars located outside the plane of the galaxy.

NGC 4631 contains a central starburst, which is a region of intense star formation. The strong star formation is evident in the emission from ionized hydrogen[4] and interstellar dust heated by the stars formed in the starburst.[5] The most massive stars that form in star formation regions only burn hydrogen gas through fusion for a short period of time, after which they explode as supernovae. So many supernovae have exploded in the center of NGC 4631 that they are blowing gas out of the plane of the galaxy. Wikipedia

The acquisition consisted of a grand total of 19 hours, divided like follows:

• Luminance: 31x900” (Samuel)
• Hα: 5x1800” (Samuel)
• RGB: 35x300” per channel (Colin)

I’m quite satisfied about the processing, which was made entirely in PixInsight 1.7. For starters, the deconvolution was very successful, and it allowed the revealing of many details in the core. Then, I was able to successfully use the MultiscaleMedianTransform process for noise reduction, and that’s a really powerful tool, if you know how to use it.

I’m also very satisfied with the amount of faint dust all around the galaxy: that’s not something you see in every image of this object.

It was also my first time combining LRGB and Hα data, and that turned out fine.

Now on to the next target!

Astrophotography, an incredibly rewarding and challenging hobby, in which so many things can go wrong, never stops finding ways to stomp you.

Since my friend Samuel installed his GSO RC8 on my mount in Nerpio, I had been tormented by trouble with elongated stars.

You probably won’t believe me now, but I’ve been struggling with conflicting evidence: it was tilt, no it wasn’t; it was flexure of the OAG mirror, no it wasn’t; it was bad tracking, no it wasn’t, wait it was, no really it’s not, hold on a second it is!

Multiple experiments with short and long exposures kept giving me conflicting evidence whether the tracking was indeed poor or not. I’ve had elongated stars with only 10 second subs, or perfect stars with 1800 second subs.

Last night, at last, I found that the clock in my mount had been running 8 minutes late. Thankfully, my mount has a near perfect polar alignment (1’ 10”) and a better orthogonality of the optical train (40”), so after a home reset I was able to perform a new 6-star alignment.

Apparently the wrong time confused the pointing and tracking algorithms, because after fixing it and aligning again, all the tests I’ve performed yielded round stars down to 15%.

In the following image, you can see a stack of nine 1800” subs on the galaxy NGC 4725 in H-Alpha. The stars are nearly perfect, and there’s some hints of matter in the spiral arms. I’ll probably continue and try to reach more depth, and then I’ll take luminance data when the Moon is gone, and merge data with Samuel and Colin to see what we get.

NGC 4725 is an interesting galaxy because of its peculiar one-armed configuration.

I don’t need to mention that now that things appear fixed, the bad weather is returning, do I?

Samuel and I had been set on starting a collaboration already for a while, and we recently invited Colin McGill to join us.

Our equipment consists in the following:

• Telescopes: GSO RC8, Ian King Ikharos RC8, GSO RC10
• CCD cameras: Moravian G2-1600, Atik 4000, Atik 314L+
• Mounts: 10Micron GM2000, Astro-Physics AP900, Paramount MX

We still need some work to perfect all three setups (all suffer from collimation problems, and mine is the worst, with some more serious collimation and/or tilt issues, but it looks we have a great potential working together from the dark skies of Nerpio.

Our first image, which you may consider as a test or an experiment, captures the galaxy names NGC 3628, is an unbarred spiral galaxy about 35 million light-years away in the constellation Leo.

NGC 3628 was discovered by William Herschel in 1784 and is well know for being part of the famous “Leo’s Triplet.”

The image above is the results of 22 hours of luminance and 9 hours of RGB data, acquired over the course of several nights this April. This is my take at processing the joint data, and I’m sure Samuel and Colin will do just as good or better.

I’m really satisfied at the amount of faint signal we got despite the “slow” equipment (both Colin and I are at f/8, while Samuel is at f/6, if I’m not mistaken.)

The image shows a large amount of tiny background galaxies.

Off to the left, unfortunately out of the framing, lies the tidal stream that extends some 300,000 light-years away from the galaxy.

I’m really excited to share some progress on my astrophotography setup. For those of you who don’t remember, over 7 months ago I purchased a used “Costruzioni Ottiche Zen” Simak 240.

Unfortunately the specimen presented an acute pinching somewhere in the optical train, and despite several attempts, following the instructions of the manufacturer, the problem could not be fixed.

I’m not sure whether the seller swindled me or not, I don’t have any reason to doubt him, but hard facts are hard to belie.

After I’ve shipped the telescope back to the manufacturer, we will know if it’s something that might have happened during the original shipping.

For some reason better left untold, it took forever until I was able to make progress and get the Simak 240 off my mount, and replaced.

I now have a GSO RC8 that my good friend Samuel lended me (and I suppose I’ll just buy it from him), which is still not working as I would like.

However, last night I discovered that the tilt and/or decollimation issues are rather paltrier than I thought, and the bulk of the problem lied in a poor configuration of my guiding setup!

After tweaking my mount and MaximDL, I was able to finally get a star shape that is close to decent, albeit not quite there yet. I have a few things left to try, and then hopefully the thing will be collimated properly and I’ll just never touch it again, come what may.

Finally, did I ever forget to mention, there’s some small issue with internal reflections. You can see it in the image, and it belongs to a magnitude 5 star about 1 degree out of view.

It’s a stack of 3x900” + 17x600” on NGC 3628, quickly treated with PixInsight:

• STF applied to HT
• HWT 6x2 + 5x1
• LHE
• Deconvolution
• ACDNR

With luck and determination, I should be able to improve the guiding further, and then I’ll be closer to a good setup.

I had hoped, for a brief moment, that my elongated star were the result of guiding problem. I made a short video of my aligned subs on NGC 3628, and that gave me some prospect that the optical train were not tilted.

Alas, it was short lived. I made a few tests to examine the diffraction spikes, and as you can see in the image above, and also here and here, there is a double-spike mishap.

The waiting game continues, until the next time the problem can be troubleshooted.

Here’s a picture of my current astrophotography rig. Unfortunately, the little adventure I’ve been having with the Simak 240 has unfolded itself to an early grave, and it’s my intention to have it professionally repaired and then get rid of it.

In the picture above you can see my loyal and sturdy 10Micron GM2000, simply an incredible piece of hardware, now sporting a GSO RC8 given to me by Samuel.

The lad has worked like a plough horse to get things running, and now we’re 99% down the road. There’s a minor, but nonetheless noticeable, tilt issue on the optical train, so I hope the good Sam will manage to fix it on his next trip to Nerpio.

It’s been a long 7 months since I purchased a second-hand Simak 240 that turned out to be afflicted by some pinching. Despite the best efforts by my friend Samuel, who doesn’t live too far from my remote observatory, it could not be fixed.

Several trips, several attempts, and it would just not go away. As I have resolved to send the telescope to the original manufacturer for repairing, Samuel gave me his RC8.

It’s an 8 incher instead of the 10 incher I had originally bought, and a little slow at F/8 (compared to the Simak 240 at F/5.6), but it’s well tested and it was already in Nerpio, so it only needed to be transferred to my mount.

After an incredible string of bad weather, in what has turned out to be the rainiest winter in Spain in recorded history, finally Samuel took a chance and travelled to the observatory location to install his telescope (soon to be mine) on my staunch GM2000.

Here’s my first light, which I’m very happy about. The seeing was terrible last night, and I think the collimation could be improved, but I’m glad the nightmare is pretty much over.

Now I’ll have to ship the Simak to Venice, hometown of Costruzioni Ottiche Zen, have them repair it and certify that it works fine now. Then I’ll try to sell it on the Italian territory.

I hope that my being well known in the astronomy community thanks to my work on AstroBin will shadow the fact that I can’t show any good pictures made with the Simak 240.

Here’s the AstroBin link for this M81: M81 on AstroBin