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Catanonia

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Posts posted by Catanonia


  1. On 18/03/2016 at 01:45, MarkCasazza said:

    How it that QHY9 treating you? I read your review from years back and I seem to be in the same place going from a DSLR to Mono CCD.

     

    It is not a well known or accepted CCD and does have it's peculiarities at time. I like the cooling, it set it to -20 and it has no issues getting there. The large sensor format based on the Kodak 8300 chip is nice.

    But there are issues with condensation causing chip issues where the liquid vapour would short out the CCD pins. This has been resolved in newer QHY9 CCD's, but I have had to return mine once due to this and it goes all the way back to Asia for this.

    The filter wheel can be a pain with its design and getting on other parts into the optical train, so hunting for correct adapters can be fun.

    Image quality is very good, low noise, but mine has started to develop quite a few hot pixels after 3+ years.

    The support on the website / forum is good and very helpful.

    Overall, yes I am pleased with it and worth the money (cheaper than other types) at the time. Especially if you get the mono + FW + 2 inch filter combination deal.

     


  2. Really close to the moon last night and was having all sorts of flat / dark calibration issues along with fogging of my CCD.

    I managed to stack together 13 x 10minutes 7nm HA with my 8inch Newtonian running at F2.8  (ASA corrector) and the QHY9 Mono.

    Learnt a lot about the peculiarities of Pedestal values, noise in darks etc etc, but I managed to pull a semi decent image together.

    It also looks like I have a bent spider vein looking at the spikes on the bright star.

    Still also getting comet tails on stars on the top left quadrant (bottom left before rotation) and it is really really bugging me. Must be tilt on that part of the CCD that really shows @F2.8 

    Any way, hope you like a quick Jellyfish.

     

    JellyFish Nebula in Ha 2016.jpg

    • Like 4

  3. Grrr, 

    Learnt why my flats sometimes didn't work properly when being subtracted in calibration.

    Basically "sometimes"  50% ish of the time, my flat files have a Pedestal FITS header of 0 in them and my images don't have anything and when this happens the calibration fails.

    I do the following all of the time using lights only (option in Maxim when imaging)

    1. Image at 60 - 600 seconds lights
    2. Take flats of 1 - 2 seconds to get 1/3 well fill and I take them as lights
    3. Calibrate

    Now step 2 in MaximDL sometimes adds the pedestal of 0 into the FITS files for the light flats and sometimes does not. None of my light images ever have this Pedestal and hence the problem.

    I have a work around of using MaximDL to remove Pedestal and re-save the image, but I would really like to know why MaximDL is adding this pedestal to the light flats sometime and sometimes not. I don't get it.

    NOTE : I don't use any calibrations in Maxim, I only use it to take images and save them. It is a standard install of Maxim with nothing changed in the options. All calibrations etc is done in PixInsight.

     

    Thanks for anyone that can explain what is going on here

     

     


  4. Some confusion with my post. I was referring to cooled CCD's and hence a library of darks at a set temperature. Apologies for any confusion and of course they do reduce thermal variations in CCD readout. I thought somehow you meant thermal currents in the tube. :)

    Also when I take my darks library,  I take the CCD camera off the scope and put a proper lens cap on it to ensure no stray light as Olly says will always get into a newt.

    Darks, flats, bias = massive debate with everyone doing their own thing :)

    • Like 1

  5. 11 minutes ago, The Admiral said:

    Forgive my ignorance on this, but as a beginner to astrophotography I thought that the darks were meant to correct for thermal effects. As such, I thought they'd be dependent on environmental temperature at which you did your imaging, and therefore needed doing each time. Unless you've a cooled chip of course.

    Ian

    Not heard that before. Darks are taken to remove the noise the chip makes due to electronics.  Having a cooled CCD reduces the noise, but darks are best used to remove the random noise effect.

     


  6. 1 hour ago, joecoyle said:

    Yeah that was my thought as well - currently I'm trying to grab all 4 filters in one fell swoop. Leaving about 20 minutes for each colour. I may just have to resign myself to 2 filters per night to acquire a lot more data anyway. Only ever manage an hour of luminance for example. 

    I'm just too impatient and want to get processing my images as soon as  

    I just figured the bahtinov mask would have to go on the actual scope. Not really sure why or if it would make a difference. I can only test and find out. 

    Joe

    I think you may be right. Your set up  as far as focusing is concerned, is not the same for each filter. You have 2 options

    1. Manually change the focus per filter shot or concentrate on one filter run at a time

    2. Buy a computer controlled focuser, set and calibrate it to do the manual shifts when the filter changes.

    This will not stop temperature differences, unless the software you use in option 2 has a measuring method to automatically pick the correct focus. But that said, I have never run into temperature issues even at F2.8 once everything is cooled down.

    The BMask will work for the current filter in place which in your set up is not the same for all filters hence the issue. When I bought my QHY 2inch filters, I made sure that they were par focal (same focus point) to make sure this didn't happen to me. But I have the same issue with my Ha filter which is not par focal to my LRGB ones and hence I concentrate on either Ha or LRGB for a session or re-focus when I switch 1/2 way through the night. At F6 your are on the edge where small amounts are noticeable in images.

     

    Also, you may not have focuser flex, but your CCD may not be totally square with the imaging plane = tilt and hence the star shapes differ in the image. Focusing will "hide" this some what, but I would check your CCD is square. I use digital callipers to check and adjust the camera housing screws to try and dial it out.

     


  7. What scope / focuser / camera are you using ?

    If your stars are behaving badly in the same quadrant it could be down to the dreaded camera tilt, depending on the F ratio you are running at.

    I had massive issues on my set up with a fast F2.8 Newtonian and heavy camera set-up. It was causing the focuser to bend and tilt the image giving massive issues. The faster your scope in F stop, the worse it gets.

    Bad collimation will also make it more evident.

     


  8. Sweet, it is amazing how much of the faint outer regions Ha brings. The danger is to make it look too much like an oil painting with over enthusiastic processing, something I am very guilty of myself. But I think you are very close here, good job.

    How did you merge the Ha element into the image ?


  9. The bottom one is out of focus. Always best to buy par focal filters of the same brand that meet focus at the same point. Otherwise you will need to manually change focus during each filter change that can be a pain.

    Less defined will not give out of focus stars, look at the 2nd image bottom left quadrant and you can see the out of focus stars. Not by much but enough to see it.

    Your guiding or collimation is slightly off too by the looks of it.

    Not much experience of motorised filters, but with the right software, you can change the focus per filter, but again it can be a pain. Best to have par focal filters.


  10. Congrats, I remember the 1st time I captured a galaxy, I had to let everyone know and I was bouncing around the garden like a lunatic :)

    Now the slippery slope of wallet emptying begins, hope your are prepared :hello2:

    • Like 2

  11. 1 hour ago, kirkster501 said:

    No I haven't but they look nice for AP.  Make sure you invest in a Takahashi collimating scope as well if go for it and you do not feel confident in colliamating the two adjustable surfaces of the RC scope design.  They can be a pig to collimate until you get comfortable (still tricky even when you do!).  I suggest keeping away from the RC design unless you like to tinker with things.

    RC design has a large central obstruction so I think the claims in that ad about it being a great visual scope are a tad over-excited.  "Adequate" is a more realistic term for their visual observing characteristics.

    Just my two penneth.  I am sure others will comment too...

    Thanks.

     

    I have Cats Eye and it can't be worse than trying to collimate an F2.8 Newtonian.

    Love to tinker and only for imaging and no observational work.

    So tempted.

     


  12. Guys, 

    Opinions please.

    My images before have been what I would call, over processed. I have tried not to give this a paint effect and concentrated on the stars. 

    I am not sure.  Pointers please good or bad ignoring the star shapes that I sill have problems with.

    Thanks


  13. Can't help with eyepieces and not a visual guy. But for imaging, I would suggest start cheap 1st to see if it is for you. Trust me that it can get very expensive and dipping your toe in the so called water is a wise choice at this stage.

    The scope you have will allow you to image the moon, some planets and some other deep sky objects, but the quality will not be as great as some of the images you see on here. If you get the bug, then is the time to start thinking about scopes, cameras etc.

    For the moon and planets, video is what you are after so you can process the frames and work out the best ones to comprise together.

    A simple web cam will do to start with, you will learn a lot and then you can start to spend the money if you want to go further is my advice.

     

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