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gilesco

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Posts posted by gilesco

  1. 7 minutes ago, Ouroboros said:

    Yes, that makes sense. As do the last few posts. I had refractors in mind specifically and for which the sensor should be centred.  
    I suppose I’m thinking about a situation in which you forgot or weren’t able to take flats at the time. You might at a pinch get away with ones taken earlier or later. Better than nowt anyway. :) 

    While it doesn't account for dust, some software has methods and algorithms for creating artificial flats, APP has a method for this, it is supposed to help with Vignetting.

    So far, flats have been detrimental to my results, so have been working with just Darks.

    But I agree, flats are a real pain, certainly if you don't have a permanent setup, and especially when you're in the situation we're in right now, where it seems to have been at least a month since we had any imaging time (here in the UK).

    • Like 1
  2. 13 minutes ago, vlaiv said:

    And for that price, I would rather change my ASI1600 for ASI6200 and simply software rotate / crop away instead of mechanical rotating :D.

    Yes, rotators do seem to have a hefty price tag, I appreciate they are often sub micron accurate, but for framing purposes that just isn't a necessary part of the requirements, I'd quite happily have some drift during rotation tasks on an EQ mount if it is just framing use - as long as there is no movement during acquisition and tracking.

    • Like 1
  3. 29 minutes ago, vlaiv said:

    Exactly, it's not overly complicated to turn reference design into PCB layout - there is software to do that easily and board printing companies expect that you send them layout in particular format.

    The picture also shows that there have been multiple revisions since original production (assuming v1.0 was the initial production version). These revisions come about for various reasons:

    • A supplier of a particular component no longer becomes available, or a cheaper but equivalent component becomes available.
    • Minor changes, e.g. They discover that while the reference specification may ask to use resistors with a 5% error tolerance, that they can get away with cheaper resistors with a 10% error tolerance, without any hit on their Q&A (although over time this may affect operational life of the device).
    • More major changes - for example, introducing programmable firmware, where the firmware was not programmable in a prior release.

    I've worked for manufacturers producing PCBs, you would be amazed at the levels of cost cutting and production optimisations that are considered during a single product's life. Some affect the overall life of a product, but that is less of a concern towards the end of a products support cycle.

    In any case, I don't think cameras that use the same sensor are always effectively the same, every manufacturer has to go through a process of optimisation for cost, and there are lots of options from the reference specification to implement differing performing cameras where the only thing they might share is the imaging sensor.

    • Like 1
  4. 5 minutes ago, vlaiv said:

    I highly doubt that astronomy camera manufacturers actually have their own R&D teams that put together all that.

    I believe they just take the reference implementation and pack it into suitable housing. I bet that if one took two different cameras apart, one would find same electronics next to sensor.

    Yes, the sensor will come with a spec sheet that will detail how it needs to be connected, but I'm certain that ZWO assemble the components and solder them onto the PCB, hence the ASI120S Rev1.6 marking on this board, if it wasn't ZWO, they wouldn't call it ASI

    20201111_162044.thumb.jpg.5c79b24641ce5cb49bbdc29930990673.jpg

  5. The imaging sensor is a single component, it needs to be mounted onto a PCB, and attached to whole set of other components, probably including:

    • Some sort of Microcontroller
    • Some sort of Memory and memory buffer
    • Some clock mechansim
    • Cooling Mechanism
    • USB Controllers
    • etc...

    All the above cost additional to the sensor, it is likely that the £500 you are looking to save is being saved in the above components, because everyone is buying the imaging sensor for the same price, and only the bigger customers will be able to get a small edge on the sensor alone.

    I used to work for a manufacturer of IT components, and one of the products was a SoundBlaster 16 compatible sound card. I was providing the UK support for the imported products. Then one day someone phoned up with a strange issue, he had recorded something via his soundcard and sent it to a friend to playback. The friend reported that it sounded like the guy had been breathing Helium. So he played it back on his computer and it sounded normal.

    What had happened? Well I asked him to return the sound card and examined it. It turns out on the new batch of imported cards the PCB assembler had decided to wire an existing 25Mhz clock to the chipset where it actually required a 33Mhz clock (or was it vice versa). Thus not having to put both clocks on the PCB and saving themselves about 25p per card. So when a user recorded a sound at a sampling rate of say 44kHz, they actually recorded at a different kHz value. It would play back fine on a similarly defunct card, but on cards that had the correct clock wiring the sampling would be wrong.

    And, anyway, the Altair might become a game changes, it might cause other manufacturers to lower prices, or it might have stretched the limits of cost savings to affect operability and performance.

    As far as we know, given the lack of response so far to your questions, very few are out there in use, and as you say, not much chance of the clouds breaking either (here in the UK). We're happy that you or someone will take the jump and report back though. :D

     

    • Like 1
  6. 45 minutes ago, andrew s said:

    Unfortunately,  we don't have an astronomy press that quantitatively compares equipment. While with optics this is difficult with CCD or CMOS cameras the basics can be easily  measured. In fact anyone set up to do astro photography can do it.

    It is also a fact of life few if any SGLers will have access to multiple equipment with, in this case, the same camera chips. That's why we have not been able to help.

    I did point out the only comparison I new about which showed camera can differ but it was not the chip you were interested in.

    A good way to ascertain the quality of a particular piece of equipment in a "by and large" and "in general way" it just to peruse the various galleries of images that get posted on various websites (e.g. astrobin).

    These images are generally posted with metadata which informs you all about the equipment and software that was used to obtain and produce them, and often a little about the methodology involved.

    This is what drove me to buy my ZWO cameras, which at the time I thought very competitively priced. I think I would continue to buy ZWO in the future, not exclusively, but no reason not to. The only time I had to contact support online via their forums was with a broken ASIStudio on Linux, they responded pretty quickly. 

    I'm failing to tie up some of the comments in this thread with my own experiences...

    • Like 1
    • Thanks 1
  7. You don't need to get an SSD drive, I use one of these:

    Seagate BarraCuda 8TB 3.5" SATA HDD/Hard Drive

    Sorry- cut and paste looks a bit funny, but it's a spindle 8TB disk, for around £165, it's in my desktop system, mounted as an "archive" drive, I don't need fast access to my old data, but nice to have it, and cheaper than a SSD drive.

    • Like 1
    • Thanks 1
  8. 2 minutes ago, Rusted said:

    Thank you both.  :thumbsup:

    I know what the words mean but not what the components look like.

    Time for an inward gaze through the casing.

    I'll be back. :)

    Yes, it doesn't look like a normal consumer unit, to be honest, so some investigation will be needed. It seems to indicate that you disconnect a second line to the rectifier to handle ~230V. Put in a second line, and it will double up an input of ~120/130V.

  9. 2 minutes ago, Rusted said:

    My shiny new Mean Well RS150-12 PS has arrived. It has no instructions and NO mains voltage markings.
    Not even an external adjustment switch. Yet it warns against using the wrong mains input voltage.

    Would anybody like to guess whether such goods are always 230V in the EU?

    My online dealer, RS Europe, doesn't answer such "technical questions" from private customers.

    I have searched for this information online but came up blank.

    Now I am afraid to connect it to the mains in case I fry it with too high a mains voltage.
    Could the absence of such information indicate 230V 50Hz is standard?

    Yes, I am well aware of the dangers of exposed mains on the screw terminals and shall house it safely.

     

    mw rs 150-12.jpg

    http://www.farnell.com/datasheets/2286959.pdf

    • Like 1
  10. Well it certainly looks a washout for next weekend, and am still waiting on delivery of equipment. So currently considering 20th/21st November as next potential window of opportunity. Failing that, 11th/12th December, or 18th/19th December would be the only two remaining windows of 2020 for me.

  11. 13 hours ago, rodrigol said:

    You would have to cut the foam, I guess. I personally wouldn't do it because the focuser motor sits lower than the focuser knobs and the fit would be very questionable. This would put a lot of pressure on the focusing axle when the case is closed. 

    Well, I'll have to take a look at that when it finally arrives, I don't have a permanent set up, so it's either going back in the case, with or without the Sesto Senso 2 attached pretty often, or the case doesn't get used at all.

  12. Just now, vlaiv said:

    Framing is a bit strange?

    Yes, you might want to rotate the camera about 90-110 degrees, you might get some wider expanse and further detail, but sometimes it's good to see a different frame orientation, so many frame the same way and it just becomes another M31 😀. But as the OP stated, he was just checking the optic issue he saw, so get the impression he wasn't making a serious AP attempt.

  13. 23 minutes ago, FLO said:

    @Matt01 That must be frustrating. At least DHL's tracking info confirms it was collected from our warehouse yesterday. 

    DHL are a good courier, I am confident their tracking will make sense in the morning. If it doesn't please drop us an email, we will then chase them for you when we reopen tomorrow. 

    HTH, 

    Steve 

    DHL are a good courier, not had problems with them.

    Would just like to point out though, that DPD, from a receivers point of view, are an excellent courier.

    If I had the option to choose a courier at checkout, I would choose DPD if it was an option to do so, their tracking is seconds accurate.

    • Like 1
    • Thanks 1
  14. 2 minutes ago, Starwatcher2001 said:

    I can semi-understand a non-technical show setting up a telescope incorrectly... this gem is from an astronomy course: "The Life and Death of Stars" from "The Teaching Company".  (Which is actually a pretty good course, despite the prop failure)

     

    image.png.15a9fb86d759b84f337b584405d9fcd5.png

    I assume they buy the telescope just for the show, just as they put the wood panelling in just for it as well... wonder what Nd where they dispose of them afterwards.

  15. 2 minutes ago, Kryptic said:

    Seeking wisdom as to how to go about focusing one of these please

    https://www.rothervalleyoptics.co.uk/rvo-32mm-f4-mini-guide-scope.html

    With a lot of pain!

    It's a helical focus on a normal 0.75 thread, so:

    1. You rotate (and rotate, and rotate some more) the black bit at the end until you reach focus.
    2. Once you achieve focus you can rotate the red bit to fix focus in place.

    You don't need absolute perfect focus for guiding, so hopefully once you've achieved rough focus, you won't be trying to change it all that much.

    The black bit is on a normal M48 thread by the looks of things, so it can take a lot of rotation to get it in place, I would recommend setting it up during the day and first achieving focus on a landmark that is very far away (1-2km or more). Then point at stars at night and try and find a sweet spot from that point.

     

    • Like 2
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