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zakky2k

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Posts posted by zakky2k


  1. As an addendum to my last post, the fused quartz window should be a lot stronger than the standard window. Also fused quartz if properly heat treated, i.e. cooled down slowly to stress relieve internally, will transmit ultraviolet light probably below 200nm without affecting polarisation of the light.

    Derek

    Good to know! I've been considering some UV work for planetary imaging. It seems Venus starts showing some decent details at these wavelengths, but I'd really need to move up to bigger diameters/longer focal lengths to get the resolution.

    This comes back to your previous point about sensor size, there is always some compromise to be made! However I'm still satisfied with my choice and the camera performs great, I just wish there was a few more clear nights! 


  2. Hmm, did you try contacting the manufacturer with the sample flats to get their opinion, just in case it is a defect in the filters?

    I would still try capturing the flats with a natural source to ensure the filters aren't interfering with the specific light emitted from your panel.

    There is some similarity between the LRGB illumination/unevenness (i.e. top left corner). Did you try rotating your light box and observing the resulting flats? If any unevenness also rotates then there's an issue with the panel.

    Again, taking some flats outside using the clear blue sky (with simple cloth filter if too bright)  would eliminate a lot of variables...


  3. Your Ha and OIII would benefit from flats to even out the dust motes and any other irregularities, but as others have said if they're all clean then using one flat for all filters can be considered, but I am curious why the artefact occurs with only those two filters?

    Does the Ha have a narrower bandwidth than the others or have some different physical properties to the others (thickness, mounted vs unmounted etc...) which could cause different reflections ?

    Were the exposures significantly longer or did you have to screen stretch more? Either could be highlighting the same properties that actually exist in all other flats just not immediatly apparent. A quick check would be to compare the ADU values for the HA edge within a similar range to the central areas?


  4. Are your filters parfocal? If the SII and OIII are thicker could that contribute to the vignetting?

    It also looked like they were significantly dimmer, which lead me to wondering what light source you're using when taking the flats, and how do you ensure even illumination?

    Just thinking if the "problem" filters might be blocking that frequency causing the uneven illumination. If it's an artificial source try outside at dusk/dawn and vice versa... 7nm doesn't let much light through but clear sky would be enough while Its still bright enough or with longer exposure?

    Word has it Santa's delivering my first OIII and SII filters at Christmas, so I'm keen to figure out hurdles like this!


  5. Zak, I have the QSI 683wsg and am equally impressed. I've had it down to -25 when the ambient has been up around 15 degrees so the cooling is certainly very effective. :)

    Hi Sam,

    I was impressed by how fast the temperature stabilized! It's my first time using a cooled CCD and ambient was low anyway so that might be expected, but nice none the less. After initializing the camera the coolers had stabilized by the time the telescope had slewed to my target!

    Obviously I could have pushed the cooling further but when I read about the diminishing rate of returns cooling has on noise, -25C seemed like a reasonable number. My plan is to maintain the same cooling throughout the year (simplifying calibration and processing).

    So I'm hoping -25C will also be reachable during the hotter months (15-20C at night). It's going to be tight, especially if we have another heat wave in August, but for the rest of the year it will be easily achievable.

    Then there's always the option to maintain two sets of calibration files, (i.e. cold + hot) or alternatively the water-cooling add-on.

    The advantage of W/C would be to sustain a lower temperature throughout the year (i.e -35C), but given the low noise currently present I'd need to spend more time researching if this would be wise choice.

    Zak


  6. Hi Paul,

        I have to admit that the additional features of the RS series probably will not be immediately useful to me, however after years of reading reviews and opinions of the available CCD products, I had already made my choice for the QSI 683 series (built-in OAG, 8pos filter wheel and largest chip with 1.25" or 31mm filters were the key factors for me, combined with seemingly constant praise for the camera's build and image quality).

    It was only when I got to the point of ordering the camera I noticed the RS range, and after comparing the features and discussing with the sales staff it seemed to me like a more future-proof investment, as it would still perform all the functions I needed, offer the potential and flexibility for other applications and *could* be easier to re-sell if I ever wanted to due to a wider range of potential buyers.

    By the way, I've just noticed that QSI now offer a 9mp version with the latest Sony CCD. 70% peak sensitivity, so much for my future proof theory!

    Ah, such is life in this hobby of ours...

    Zak


  7. Hi All,

        I recently purchased this camera based primarily on the company's solid reputation in this and other forums, however I had noticed that the new RS line was available with some additional features that I admit probably won’t be immediately useful (at least for amateur astronomers). 

    After including in my order the optional 8 position CFW with IGP port (QSI's Integrated Guider Port, a built-in OAG), it effectively becomes a 683-wsg8 with the only exception as far as I know that the camera comes with a fused-quartz window protecting the CCD. 

    Additionally I took the wider nose-piece and the Canon lens adapter. Unfortunately due my limited time I was not able to try out the lens adapter. It does require the face-plate to be exchanged with the standard, non-IGP face-plate in order to reach focus, only a 5 minute job in itself but something on my to-do list next time.

    The reputation for QSI's quality is well deserved in my opinion; everything arriving securely packed in its own, high-quality pelican case. 

    Within minutes I had the drivers installed and was able to control the camera and filter wheel through Maxim.

    I decided to leave the standard 2" nose piece on the spare face-plate (the standard, non-IGP version) and attached the slightly larger nose piece to the IGP face-plate.

    This is my first time using a dedicated CCD, so full-frame, low noise, high sensitivity over a wide spectrum and being able to set the temperature were all big firsts for me. I settled with -25C as the ambient was hovering around 0C, and only required approximately 35% cooler power to maintain. Being able to take re-usable darks at a specific temperature at any time proved to be a big time-saver.

    It was also my first time auto-guiding, and following the simple focusing procedures provided by QSI I was up and running capturing data within an hour. 

    The weather was naturally atrocious for the following week, but managed to get around 5 clear nights throughout December.

    For anyone interested, my favorite images are in the album below:

    http://stargazerslounge.com/gallery/album/2912-december-2013/

    Comments, questions and even mild criticism welcome ;-)

    Clear skies,

    Zak


  8. Hi All, I've had an excellent week during the beginning of September for imaging, but now it seems like the weather wont be recovering anytime soon, so thought I'd share my progress.

    I'm still using the SX Superstar as my main imaging camera until I can afford a larger, cooled CCD, so I tried some mosaics to increase the apparent field of view. 

    Two main surprises for me were the Eagle nebula still being visible (albeit close to the horizon) now that I've trimmed a few southern trees  in the garden, and Orion's M42 being respectably high enough for pre-dawn imaging.

    http://stargazerslounge.com/gallery/album/2732-september-2013/

    Thanks for looking!

    Zak

    • Like 1

  9. Looks like you captured some great data, but maybe ease off on the processing aggressiveness?

    The halos around the stars look like they're caused by over manipulating the histogram 'curves', maybe try a more linear approach?

    Noise reduction seems quite high too, introducing artifacts and maybe affecting the details when it comes to sharpening.

    I'd love to see the results after simple stack/calibrate and very 'light' processing (less is more, sometimes!)


  10. Hi All,

    After years of dreaming about a pro-level GEM, of research, reading reviews and any other pieces of information I could lay my hands on I decided in Jan 2012 to go for the old AP 1200GTO, finally being lured away by the 'simpler' mechanics and overall set-up than was offered by ASA's DDM85.

    Then of course it was replaced with the 1600GTO, and although it has been a major update, I agree it still does not offer the same level of tech out of the box as the ASA's or 10 microns, but provision for encoders is there (a bit on the pricey side), new software suite in the form of APCC is due any day and a great new polar alignment scope (RAPAS).

    Mainly I love the fact that I can use it with just the hand controller and 12v battery, perfect for me as it wont be living in an observatory for a least the next year, maybe two.

    It also works great when 'locally' remotely controlled via LAN to USB extender, and was 'portable' enough to lug in and out the few times the clouds cleared, breaking in to 2 manageable pieces.

    As the uncooperative weather has only allowed two brief ventures outside, I'll not comment on its performance, which I am sure is as good as advertised (besides I don't yet even have a large enough scope to adequately test it). But in terms of usability, and the 'just works' effect, I was blown away. (That's saying nothing of the build quality and sheer gorgeousness of it, which is a subjective quality some could argue is shared by all the top-end mounts)

    Shipping to Czech direct from AP was under $1000 (including mount, weights, pier and other accessories), but import duty of 20% was the killer to an otherwise competitive pricing I thought when compared to ASA, although still a couple of grand over the originally stated budget...

    Just my tuppence worth...

    Zak


  11. Hi All,

    Sorry if this is not the correct thread for this topic, wasn’t sure where post.

    Just went out to check the weather for tonight and saw a very bright, deep red object.

    Instinctively I thought it was satellite, and maybe the thin cloud cover in that part of the sky was making it appear red.

    However its magnitude increased until it was by far the brightest object in the sky (the full moon veiled still in clouds further to the south-east).

    I observed for a full minute at least and its magnitude appeared constant, and the object was stationary (Geo-stationary satellite?).

    I called my wife to have a look but by the time she came out about a minute later it had started to dim rapidly and by the time her eyes had adjusted it had all but disappeared.

    This was observed from 49deg North latitude around 20:30 - 20:33 UTC (22:30-22:33 CET).

    I've checked on TheSkyX but couldn’t see any satellites around that time, and the fact it was stationary and appeared such a deep red made me wonder if anyone else had seen it and would be able to identify it?

    All the best,

    Zak

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