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Chefgage

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Posts posted by Chefgage

  1. On 28/02/2023 at 20:45, ollypenrice said:

    All sorts of dangers threaten our security. Telescope thieves in the middle of wheat fields rank, in my view, somewhere beneath velociraptors accidentally revived from the fossil state by a bolt of lightning. Fear of the dark is essentially irrational, though not entirely. Our eyes are our primary source of information and we are genetically programmed to be nervous when they don't work - such as in the dark. We don't have to let ourselves be dominated by this programming because we are rational beings. As such, we can reflect on such dangers as...

    - road traffic accidents

    - accidents in the home (very common. Bathrooms are particularly dangerous and don't mention staircases or roofs.)

    - muggings. (For some reason, muggers prefer city streets to isolated wheat fields.)

    - falls.

    - DIY. (Chopsaws, angle grinders and chainsaws are a particularly good bet, but don't underestimate nail guns, drills, hammers, screwdrivers...)

    - walking while carrying glass.

    Moving a few thousand bullet points down this list, you are in your field. You see someone coming towards you. You take out your mobile phone (though a half-chewed bacon sandwich would do in the dark) and, in the unlikely event of it not being an irate farmer, you say, 'Your photo is already on the cloud.'

    Think it through. Your wheat field may be the least dangerous place you ever visit.

    Olly

     

    I really like the idea of threatening someone with a half chewed bacon sandwich :)

    • Haha 1
  2.  I can't overstate how disappointing the view was. 

    That sentence there what you wrote is the main reason I switched from visual astronomy to astrophotography. I was using a skywatcher scope at the time 8" apparture, 1200mm focal length. Even with this scope, nebula, galaxies etc are nothing more that fuzzy blobs. Unfortunately that is really all you will see with a naked eye. Although sky quality, less light pollution, better optics, larger apparture etc. all will help to tease out some detail but nothing like what your photos show. That's just how our eyes work I'm afraid.

    What I started to understand is that although the view might not be that impressive, spare a thought to how long those photons have been traveling before they get to your eye piece. Try using a manual scope to try and find as many galaxies, faint fuzzies etc, by using star charts and star hopping. That way it's more of a challenge. Or just give up on visual astronomy and stick to astrophotography. That's what I did and find it alot more enjoyable now.

    • Like 1
  3. On 12/06/2023 at 15:19, Louis D said:

    Yes, but not the same local time.  That was my point about being a slave to UTC when comparing the local views at the same time.  Taken to the extreme, you might be asking why is it so bright out when it's UTC 00:00 (midnight Greenwich) in New Zealand.  It's the same time, so the sky should be the same, right?

    Thanks. Having re-read what I posted I was indeed confused (I am going with the amount of vodka drank:) )

    UTC time has its place but not with what I was asking. Thank you for making understand.

    • Like 1
  4. On 18/12/2022 at 20:33, Elp said:

    A flat exposure less than a second is unusually quick from what I've read and tried with various cameras, more so when using an lenhance. What do your overstretched stacks look like?

    I will post up an overstretched stack later. Also you mention it appears greatly after an DBE in pixinsight. That is one of the first parts of my processing. I will post that up too. It's got me thinking now. I might just be assuming that my flats are ok and after DBE that is what it's supposed to look like. As I posted above I might take two sets of flats next time and do a side by side comparison. Only issue I have doing this is finding a way of doing a longer exposure flat as my light source is set on the lowest value to get me my usual 400ms flat.

  5. On 21/12/2022 at 22:46, Stuf1978 said:

    The 294MC Pro gets a lot of bashing for this and it's mostly unjustified. Mine has calibrated perfectly evertime, you just need to ensure your individual flats are over a few seconds long and jobs a good'un 😃

    I might have to take a couple of sets of flats next time. I aim for an adu of about 30000. With my led light panel and l-enhance filter this gives me an exposure time of 400ms. My lights seem to calibrate fine at this exposure time (this is using the 294mc-pro).

    Mentioned above at this low exposure time I might be limiting the amount I can stretch the image but my images seem to process ok (from my point if view). I might try taking two sets of flats and doing a side by side comparison using pixinsight (which is what I use for processing).

    The issue I see though is exposing for a couple of seconds is going to give me a very hight adu value though isn't it??

    • Like 1
  6. On 18/12/2022 at 22:51, Budgie1 said:

    The ASI294MC Pro (cooled version) is a nice camera with a sensitive sensor. It has a reputation for having an issue with the calibration frames, as has already been posted, which means you may be able to pick up a second hand camera for a lot less than you may think. ;)

    Regarding the "issue", I did have some problems to start off with but only when using the L-eXtreme filter. For broadband imaging I use just a UV/IR cut filter with a gain of 120 and offset 30. With the L-eXterme filter I use a gain 200 and offset 30.

    In both cases the camera is set to run at -10°C and when taking the flats I aim for 26,000 ADU and exposure of 2-4 seconds. I also use flat-darks, to calibrate the flats, and don't use Bias frames, just darks.

    Interesting your ADU value. I read somewhere to aim for half way to the 65000 value so 32500 ish. That seems to give me good results. To get this value with an l-enhance filter my exposure time is 400ms.

    As others have said a longer exposure time is needed but I don't seem to need this?

    Unless I do have problems but I am fixing them when processing?  Either way I will stick with what I do 🙂

  7. 1 minute ago, Elp said:

    I have the uncooled but it demonstrates the same issue. When taking flats and applying them you get a strange random green red uneven pattern across the frame, it's even worse when using an lextreme filter. Reading up on it I've found utilising a gain setting near the switch of low to high gain can make it worse so then I've tried a gain of 250 (over 200) which improves it a little. Also dimming your flat field so you can take long seconds long flats also reduces it, but the issue is still present. My last flats were 5 seconds long with minimal histogram peak.

    I see. I must have got one of the good sensors then as I don't get any of them problems. I use a gain of 120 and using a flat led panel to take my flats. I use the lowest brightness settings in the panel and when using the l-enhance filter I use an exposure time of 400ms for my flats (the asiair gives me a time of 500ms for an auto exposure flat) but I find that a tad too long based if the graph.

    I guess I can count myself lucky then.

  8. 5 hours ago, Elp said:

    The 294 colour is the one that has the issue (not sure about the mono), I'm still working on a solution but slowly improving. The 183 does have amp glow but dark frames calibrate it out. If you are looking to utilise other manufacturers I would also look into those options too.

    Importing, VAT is added at cart on AE, duties will apply on the value of the item and shipping when it enters the country, for cameras I find there's little difference to justify importing them but that probably only applies to the more popular brands. You can sometimes save a lot via importing.

    Sorry to jump on this thread but what issue are you having with the 294mc pro?  I was not aware there was an issue with it. Mine calibrates fine. Just wondering if an issue may present itself at some point.

  9. 18 hours ago, iantaylor2uk said:

    I know some people say flat frames should be a few seconds exposure but I have found with my ZWO 071 camera they are usually only around 50 milliseconds or so with a UV/IR filter, and around 300 milliseconds with an L-Enhance filter. This is with a flat light pad over the top of the telescope. I tend to use bias frames rather than flat darks, and these are usually taken at the shortest exposure your camera has, with a cover over the telescope. You can re- use the bias frames from one session to another.

    I use a zwo asi294mc pro camera and agree with what you say. I know some people say aim for 3 seconds for the flat darks as that will give you the correct flat dark. But I always use 0.4 seconds with the flat led panel on a low setting.

  10. Captured this over two nights back in the summer.  Processed the first night and posted it on here.  Only just got round to processing both nights together.

    Capture information
    HEQ5 Pro mount
    Skywatcher 72ED Refractor
    ASIAIR pro
    ASI294mc-pro colour camera
    Optolong L-Enhance filter
    ZWO ASI120mm mini guide scope

    Gain 120
    EXP 240s
    Lights 83
    Darks 58
    Flats 58
    Flat Darks 58

    Total exposure time 5 hours 32 minutes

    Captured over two nights.  
    05-08-2022 Moon below horizon
    19-08-2022 Moon 86° 17' 45.7" from Target 51.9% Illuminated

    Stacked in DSS and processed in pixinsight

    NGC 6992 Uncropped

    NGC_6992.thumb.png.9aae753cfcf6386830635fba55368d3d.png

     

     

    NGC 6992 Cropped

     

    NGC_6992_cropped.thumb.png.eb7dc8b8d2076b7e764f7fcd50f6fa20.png

    • Like 12
  11. On 24/11/2022 at 09:37, LaurenceT said:

    I'm new to imaging, only really started this year. I am using an Asiair and have SkySafari and Stellarium installed on my laptop for reference purposes.

    What I'm really after is a way to see all the available targets of a particular type in my area for that night on a single screen while indoors planning my session.

    I am obviously able to use SkySafari for instance to select a target from a list and see its position and movement but that's only giving me one target at a time. 

    Perhaps I'm asking for the impossible but I'd appreciate some comments.

    If I understand you correctly, in sky safari click on search then tonight's best. That gives you a long list of targets and based on your location you can sort by rise time etc..

    • Thanks 1
  12. On 18/10/2022 at 20:35, F15Rules said:

    On the contrary, I start to worry when my app shows clear skies in the evening!🥴😂.

    Joking apart, I have found the Met Office weather app to be the most reliable..many of the online "weather apps" are junk, and completely unreliable..especially when they claim to be able to give you an accurate forecast for 14 days ahead!

    My son in law works for the Met Office, so I know how seriously they take their forecasting..at a local level, despite all the technology of today, it's still remarkably difficult to forecast accurately local conditions for more than a day or two ahead.

    If you don't already use an app, try it it, it's free and easy to use..

    https://www.google.com/url?sa=t&source=web&rct=j&url=https://play.google.com/store/apps/details%3Fid%3Duk.gov.metoffice.weather.android%26hl%3Den_US%26gl%3DUS%26referrer%3Dutm_source%3Dgoogle%26utm_medium%3Dorganic%26utm_term%3Dmet%2Boffice%2Buk%2Bweather%2Bapp%26pcampaignid%3DAPPU_1_-P5OY5b9Gd__7_UPi_mLkA4&ved=2ahUKEwiW2aiQwur6AhXf_7sIHYv8AuIQ5YQBegQIBhAC&usg=AOvVaw098HrUZQWqSYedj6QdnkUj

    Dave

    Looks good apart from percentage cloud cover is not shown. I like to see this on a weather app. It's why I use XC weather as it shows an hourly percentage cloud cover.

  13. 15 hours ago, bosun21 said:

    I know that quite a few members use these as a power source for their equipment. What I would like to know, is are they any good? and can anyone recommend one that they have found decent. 
    PS:-  what type of connection do they use? Many thanks  

        Ian 

    I use this one

    https://www.halfords.com/motoring/tools/garage-equipment/battery-chargers/halfords-6-in-1-jump-starter-power-pack-654898.html?istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istFeedId=367c5610-f937-4c81-8609-f84582324cd6&istItemId=wrirtqtpq&istBid=t&_$ja=tsid:|cid:17363835999|agid:|tid:|crid:|nw:x|rnd:2651873092412831121|dvc:m|adp:|mt:|loc:1007055&gclid=CjwKCAjw7eSZBhB8EiwA60kCWyY___s1_FKFGmZOjWRK23_2jTrPx_Dep4JZXs_E7hNNr9WACDtmaxoCfOsQAvD_BwE

    I power my heq5 pro mount, asiair pro, 2 dew bands, astro camera, guide camera, pegusus power supply all off this and it lasts a good few hours.

    • Like 1
  14. 12 hours ago, AstroNebulee said:

    Hi

    A couple of questions on my focuser lock screw for my scope. 

    1. How tight do you have to have the screw tightened up normally to lock it and would it cause the focus tube to to move out of collimation atall. 

    2. Does anyone know what size they are as I'd like to get a replacement one as mine doesn't seem to grip the focus tube well and can still move focuser when engaged. On closer inspection it looks as though there's a bit of damaged threads. I've got a feeling it's an M6 30mm one, though not seem to be having much joy on a search. 

    Lee 

    IMG_20220901_193509.jpg

    IMG_20220901_193643.jpg

    I have the same scope. I try to use the focus lock but in my experience it does affect the focus when you tighten it up. I use a bahtinov mask and an asiair to focus. As you tighten up the focus lock you can see the focus slightly adjust.

    • Thanks 1
  15. Capture information
    HEQ5 Pro mount
    Skywatcher 72ED Refractor
    ASIAIR pro
    ASI294mc-pro colour camera
    Optolong L-Enhance filter
    ZWO ASI120mm mini guide scope

    Gain 120
    EXP 180s
    Lights 76 (over two nights 60 and 16)
    Darks 20
    Flats 20
    Flat Darks 20

    Total exposure time 3 hours 48 minutes minutes 
    Moon below horizon

    Decided to re-process this one in a sort of hubble palette colour scheme.

    1598876282_TheRosetteNebulaHubblepalette.thumb.png.573ba6d8491aecc526f42829107ca838.png

    • Like 7
  16. Capture information
    HEQ5 Pro mount
    Skywatcher 72ED Refractor
    ASIAIR pro
    ASI294mc-pro colour camera
    Optolong L-Enhance filter
    ZWO ASI120mm mini guide scope

    Gain 120
    EXP 240s
    Lights 36
    Darks 29
    Flats 29
    Flat Darks 29

    Total exposure time 2 hours 24 minutes
    Moon below horizon

    Stacked in DSS and Processed in Pixinsight

    Hopefully going to add more data to this when we get longer astro darkness.

    NGC6992.thumb.png.23208421bebfb5d32757af80ab1d6911.png

    • Like 4
  17. On 07/06/2022 at 15:11, Rodd said:

    I don't know--I just realized that Starnet (as apposed to starnet2 or starxterminator) does not include all stars it removed on the starsonly image.  Tiny ones are missing (or are very dim).  So what it turns out to be is a form of star control.  When you add back the stars using the formula I provided and compare it to the original image--the stars will be fewer, fainter, and smaller, which can be good things, no doubt.  But sometimes its too much star control, and some stars that one would like to be present are not.  At least your formula prevents this--you get a 1:1 exchange.    Maybe combining the formula in a way that allows one to weight one side or the other depending on the image.  But that is beyond me...

    "Damn it Jim, I'm a doctor, not an engineer!"  Star Trek OS

    On my next image processing I am going to try your formula definitely.  I am keen to see the difference.

    • Like 1
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