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Tag: equipment

Cooled ASI 224 MC

dew formed

Looking at my camera during these hot days made me think: I was recording planetary images at 27°C ambient temperature, and the camera sensor indicated 35 degrees. A bit too hot for my taste. I put a cooling fan on and a bigger one near the camera, a few degrees went down. So I deployed the cavalry: a TEC1-12706 peltier element and a radiator to cool the camera down a bit. It may or may not have helped the image quality, given that the seeing is a much more impacting factor, and the seeing usually sucks, but the camera sensor went down 25°C. And dew formed (I hate these hot and humid days). The peltier’s nominal voltage is at around 12V, however, I figured that 12V is just too much to handle, so I dialed the voltage down to only 3.5V using an oversized (12A, to err on the safe side) buck converter and a 12V 3A mains power source. The camera’s body is aluminium, its back has four conveniently positioned M4 holes: an old computer’s radiator, some thermal grease, plus pliers and a RPi fan was all needed.



Home Observatory 2019

The balcony, as a temporary(?) home observatory

I am a lazy man, so I automate, leave in place, pre-program — and stuff like that. For Jupiter and Saturn, I made my rather humble balcony into a humble observatory, before the real estate developers (this is a politically correct name for what they really are) fuck up my horizon.

Since accurate polar alignment is not feasible when one can just accidentally kick the mount, just that tiny little bit, and I don’t intend to do deep sky from here, the whole thing is aligned by smell and then guided by the soapbox.



The Whale Galaxy

The Whale Galaxy

On 2019-03-30, from Dângău Mare, I imaged the Whale galaxy, a well known target. I used my N 150/750, Baader MPCC Mark III, Canon 1100D mod, HEQ5 setup, with the IDAS LPS D2 filter in place, and captured 26×4 minutes at ISO 3200. It was surprisingly easy to process the resulting images.

C 32, NGC 4631, Arp 281 [galaxy in CVn] Whale Galaxy, Bálna-galaxis, Herring Galaxy, Herring Nebula 9.1m ø15.5′

The bright companion to the left is

NGC 4656 [galaxy in CVn] Image it together with the Whale galaxy 10.2m ø15.1′ [wiki] [simbad] 750mm

And the Whale’s “breath” is

NGC 4627, Arp 281 [galaxy in CVn] 12m ø2.6′ (tovább…)


A little charging station

I like horizontal extensions :)

I like stuff that’s standard, modular, dumb, fault tolerant and degrades gracefully. The mount, the camera, the heating, the guiding — these all have different priorities, different needs and complexities. This is why I chose to use the 12V 7.2Ah standard UPS batteries, many of them, in separate circuits. This setup, obvious from the way the charging is solved, is for occasional one night sessions, not continuous deployment.


One circuit is for the mount. I put one or more batteries in parallel, or more like max(): the batteries are isolated from each other through diodes.


My Canon 1100D (modified) does work from a USB phone charger, but it has its own 12V battery. It works well, non stop all night, from a single battery, without depleting it. A fellow amateur astronomer has already asked me to make him a similar wonder-box :D See details.

The DSLR was the last item that a voltage other than the one provided by the standard 12V batteries. Its own batteries meant special care, special costs, and thankfully that is over, once and for all. (tovább…)


Bye-bye camera battery

UPS battery powered Canon

I work with a modified Canon 1100D camera, which uses the LP-E10 battery. The battery pack has the tiny nominal capacity of 860 mAh (Canon original), 950 mAh (some copy) or 850 mAh (some other copy), equalling 6-7 Wh. During a long photo session, and depending on the temperature, 2-3 batteries may go out from fully charged to blinking red, interrupting the photo session, and – on the long term – mean further replacement batteries. For comparison, a UPS battery holds at around 80Wh, at least on paper.

While the form factor is proprietary, meaning vendor (or at least product) lock in, the batteries are dumb. Luckily. Luckily the battery pack has no digital identification mechanism, so some crocodile clips are enough to replace them. No need to disassemble one to use the chip or something like that. So I got to work.



M101 Pinwheel Galaxy

M 101 with NGC 5474

The Pinwheel Galaxy (Szélkerék in Hungarian) is one of the last entries in the Messier catalog, discovered by Pierre Méchain in 1781. It has a grand-design pattern, meaning nothing more than that the spiral arms are prominent and well-defined. Also known as NGC 5457, the galaxy lies at 21 Mly. According to this paper,  it has a mass of 9.8×1010 solar masses, way less than the Milky Way’s ~1012  solar masses, see this paper.

As a sidenote, our home is actually one of the most massive galaxies in the wider neighborhood, the exact value depending on the study, placing us somewhere a bit below down to at about half of M31 Andromeda’s mass, which is just heavy compared to the other spirals on the sky. As another sidenote, it is hard to find the masses of galaxies on the internet. As one more sidenote, it is tricky to find out distances of galaxies in scientific catalogs not meant for the general public, thus not containing a trivia section.



Jól kalibrált monitoron mindegyik számnál elkülönülő árnyalat látszik. Ha mégsem látszanak, akkor a megjelenített képek színhiányosan rajzolódnak ki. A monitort valószínűleg kalibrálni kell.

You should see distinct shades for each number. If those shades are not clearly visible, the displayed pictures will lack accuracy. Your display most likely needs to be calibrated (brightness, gamma, contrast etc.).