A breakthrough

Last night, after much anguish, I finally had a breakthough in fixing my guiding problems. I discovered that corrections with a frequency higher than five seconds led to a situation in which I was basically chasing the seeing.

It didn’t occur to me, because I would expect that if guiding at one or two seconds, not five, especially since I’m guiding with a focal length of 230 mm.

However, guiding integration times of seven to ten seconds yielded pretty perfect stars. Unfortunately I had time for only one 120-second experiment before it clouded up, but the guiding graph was flat, so I’m confident that things should be fine now.

More tests tonight!

A trip to Nerpio

Because of the incessant troubles I’ve been having with my astrophotography setup as of late, I decided to take a trip to visit the Nerpio establishment.

For those of you who don’t know, my equipment is currently hosted by AstroCamp, and situated at an altitude of 1600 meters on a massive in the south of Spain.

AstroCamp is located in a pristine and remote area, without any light pollution to speak of, and excellent weather (except these past winter and spring, which have been disastrous throughout Europe.)

I had never been there before: for the initial setting up, I simply shipped my equipment over and let them install it for me. However, I took the opportunity to go check out the area and have a little vacation. I also met Samuel, who has been helping me so much with my astrophotography problems.

The trip started last Thursday, May 23rd, with me arriving in Madrid late at night, and Samuel hosting me for the night. The next day we left early for the 5-hour drive across the Spanish countryside, finally reaching Nerpio in time for lunch.

In Nerpio, I stayed at El Molino, a nice, little, cozy hotel/restaurant with some excellent food. However, the only sleep I could get was between 7AM and 1PM, during my three days there.

Getting from the small town of Nerpio up to the observatory required a 4x4 jeep vehicle, and some driving skills. The road is a rugged, menacing serpent, sometimes steep, often treacherous.

After we left the paved bit behind us, the scenery quickly became that of a harsh, inhospitable land. Reaching the peak meant being in the most remote place I’ve ever been, and the view that presented itself before my eyes was staggering.

The images cannot give justice to the beauty of the land, and I was thoroughly impressed.

The observatory itself was also a pleasant surprise: the two large sheds host a good number of different astrophotography setups. The Software Bisque mounts, the Paramount ME and its new little brother, the MX, dominated the scene, but there were also a few ASA DDM mounts, some 10Micron GM2000 mounts (one of which mine) and a couple of lesser mounts too.

The weekend started well, with me replacing the OAG with a supposedly better one, connecting the mount via LAN in addition to the old serial connection (this step needed to use the 3rd party ASCOM drivers that would allow me to semi-automatically create a thorough alignment model), and doing some nice cable management, which seems to be my second most preferred hobby.

Despite the horrible weather throughout the whole winter and spring, I was lucky, and all three nights offered cloudless skies. The full moon didn’t bother me because I was there to fix my setup, not gaze at the star.

Something I wanted to test, as soon as possible, was weather the poor performance I was getting from my OAG guiding setup was due to an incorrect mounting of the OAG itself, or something wrong with my SBIG ST-i guider camera. The problem was that finding a guide star was absolutely too difficult, and it just didn’t look normal, to me, that the guider camera would offer so little sensitivity.

So I tried to swap my SBIG with a Starlight Xpress Lodestar, which is renowned for its sensitivity. However, to my complete dismay, I was unable to install the Lodestar’s drivers. This task would take the bigger part of the night and the next afternoon, which is something I find utterly unbelievable.

I spent the night improving my polar alignment (it only took 10 minutes and I got down to only 34”!) and constructing a full alignment model for my mount.

The next day, after I finally managed to get the Lodestar working, it was prime time: the most important thing was to figure out why the my guiding yielded elongated stars. You can read my previous posts on this blog, but it boils down to there being star elongation along the RA axis, and nobody knowing why.

After a quick test, I was deeply saddened to find out that the problem was not gone. On the contrary, it had slighlty worsened! As dawn put an end to the aspirations of my guiding setup, Samuel and I headed down to El Molino to rest for a few hours.

On the next, and final, day, I stiffened my setup using a plastic bar: connected directly to the Losmandy plate, it extends directly below the main imaging camera, and all the cables coming from both cameras are fixed to it. This way, the pull of the cable can’t generate differential flexures of sorts.

To completely rule out the possibility of differential flexures, I also borrowed a small Lunatico EZG 60 guide scope, so that I could test the guiding both from the combination of the Lunatico with the SBIG ST-i, and the OAG with the Lodestar.

With the night closing in, after a very strong, and sometimes scary hailstorm, I was ready for the final tests. There wasn’t much time, though, because the next day we were due to leave very early, so I could catch my flight.

The first thing I learned was that the SBIG ST-i is indeed a great disappointment: the Lodestar could show a lot more stars, when using the OAG on a random patch of sky. I moved the telescope around and saw that with an integration of only 5 seconds, the Lodestar could always find more than one suitable guide star. That was good news.

After performing a perfect balance on both axes, focusing both guider cameras and centering the small Lunatico guider scope, I attempted to guide. Unfortunately, with both options, the result was the same: a good and flat declination graph, but a bad one on the RA axis. The star elongation was not fixed.

I tested guiding both at 0.25x and 0.50x (with 1 being the sidereal speed), with the same poor results.

Exhausted and out of ideas, I had to call it a night and decree the end of the trip.

What’s in the future? I firmly believe that the equipment is now perfectly placed, properly stiff, and requires no actual physical changes. This morning, as Samuel and I were driving back to Madrid, I had an idea that I couldn’t have had on the previous night, for how tired I was. My mount has a parameter to calibrate the response to static friction: that could be why the mount seems to overcorrect during the guiding, which yields to poor results.

I’m going to have to wait the next clear night to check it out, otherwise I’ll ask Ivan Mariotti, of 10Micron, to help me out.

One last paragraph goes to the Simak 240. I could spend many hours, during the day, trying to troubleshoot the optical issues I’d been facing with it. The final verdict is that the most serious problem is with the focuser, a JMI EV2, that has a very poor axis alignment, and that would cause optical tilting and astigmatism.

Moreover, somewhere in the optical train, there is pinching and more tilting. It’s impossible to correctly align the front meniscus, because even slight different in the tightness of the screws would produce visible optical defects.

I don’t think this is a telescope fit for astrophotography, unfortunately. Or it might be, but only if you are ready to do some tuning and troubleshooting as you go. With me being over 2,000 km away from the observatory site, I’d rather have a setup that requires a little maintenance as possible.

The Draco triplet

Thanks to a few clear nights last week, Samuel, Colin and I were able to release a new image. This time we tacked the Draco trio, a group of galaxies some 100 Mly away: NGC5981/82/85.

The collaboration between Samuel, Colin, and me finally sees some data contribution on my part. These are the acquisition details:

  • Samuel: 20x900” L, with GSO RC10, Atik 4000, AP900.
  • Me: 11x900” L, with GSO RC8, Moravian G2-1600, 10Micron GM2000.
  • Colin: 142x300” RGB, with Ian King Ikharos, Atik 460ex, Paramount MX.

NGC 4725

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.

New bike day!

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)
  • : 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

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.

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