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almcl

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Posts posted by almcl


  1. I fitted a pair to my EQ5 for visual tracking, and then ventured into astrophotography. 

    At this point I discovered Tom Carpenter's AstroEQ.  This cost about the same amount, all told, but gave fast slewing, goto and much more accurate tracking and guiding.  If you are into a bit of fabrication of brackets and some soldering, the AstroEQ can probably be done cheaper than the Skywatcher motor upgrade.  

    • Thanks 1

  2. If you can't eliminate flexure any other way, then an OAG will certainly help.  I moved from an adapted 50 mm finder scope to an ST80 (ghastly thing, as others have observed, the appalling focuser flops about all over the place) and then to a camera specific OAG and the improvement in round stars was instant and dramatic.  

    Not sure what camera you are imaging with, but my Canon OAG keeps the prism well clear of the light path:

    0247.jpg.ca9e386ba4e5f0ba98d946c183d6eb96.jpg


  3. 12 hours ago, Atreta said:

    I'd have a second thought about the 200p for astrophotography. If i remember it i correctly it will also not focus properly with a dslr.

    That's not quite the case.  I have been using my Canon 700d with a Skywatcher 200P for five years now and it focusses just fine, with or without coma corrector and with or without a barlow.

    I agree that the PDS is probably a better choice for a dedicated AP scope, but the 200P also works well.

    • Like 1

  4. 1 hour ago, Tom g said:

     I’ve picked Betelgeuse and it was in the West and the mount slewed and stopped in the south

     

    Are you quite sure of your alignment stars?

    For your location in northern France, Betelgeuse doesn't get into the west until around  06.30 GMT.  It doesn't pass the meridian (due south) until 02.30.  


  5. You have quite an amount of periodic error (which PHD2 is mostly guiding out):

    Untitled-6.jpg.5b40620b334442b0936d297328c2ae57.jpg

    This might be associated with the worm period of the mount and might benefit from a bit of 'tuning'.

    But another problem might be the 3 second guiding exposures.  Here's one example of an almost 5 arc sec error which develops between exposures:

    Untitled-5.jpg.767736ec632e862f5e512411cc34a78d.jpg

    That's an extreme example, but there are plenty of other, slightly smaller, ones.  Balancing 'east heavy' and dropping exposure to 1.5 secs (or such lesser amount that the guiding assistant suggests) might help.  

    Your PA error at 7' isn't brilliant but probably isn't affecting this particular issue.

    • Like 1

  6. I switched to an ASI 120 mini mono when the USB port on my QHY 5Lii became intermittent and finally failed altogether.  The ASI works fine, just as sensitive as the QHY and, touch wood, the connector although smaller seems a lot more robust.  I am using it with an OAG and it never fails to find a selection of stars to guide with.  `

    • Like 1

  7. 9 hours ago, kirkster501 said:

    is there such a thing as a 3D printing service at all? 

    I've used a couple of the on-line services.  I think the last one was 3D hubs (possibly here) and the turn round time was about a day, which was quite impressive. 

    They accepted my Sketchup generated STL file (bit of a learning curve there, I found, but all the software was free), quoted a price instantly and let me choose what material to use. 

    It was only a small holder for a guide camera, so didn't cost much.


  8. Almost five years ago I purchased one of Juan Fierros' astro modified Canon cameras.  It has been an excellent performer both as an Astro and daytime camera.

    Recently I had a bit of an issue with a patch of dust or some other contamination on the Canon 700d's sensor.

    Neither Gamma Optical Fluid nor Baader Wonder Fluid applied with swabs were able to shift it.  It didn't calibrate out particularly well, either and was quite close to centre of the frame.  Worse, it started showing up on my daytime photos ( astromodded but  it is still quite usable for daytime photos). I was convinced that I had scratched or chipped the outer filter.

    Fearing the worst, I contacted Juan at Cheapastrophotgraphy and asked if he would quote for replacing the outer filter.  He agreed to have a look and asked me to send the camera to him, even though it has a shutter count of more than 36,000 since I bought the camera from him.  After examination Juan didn't think getting rid of the dust/chip would be a problem, which was encouraging.

    Somewhat to my surprise the camera arrived back this morning and the sensor is now as clean as a whistle!

    But the bigger surprise came when I contacted Juan to ask how much I owed him, he refused payment!  

    What a guy!  What service!

    Here's to next 36,000 exposures!

     

    Here's the dust I couldn't shift: 
    1663571289_Dustbefore.thumb.jpg.2ee307f6a0cfed31e0373e4738066fac.jpg

     

    Here's how it came back:

    After.thumb.jpg.06eefd70604e2d97c8501dc217dd3366.jpg

    • Like 5

  9. There's some great suggestions already, but here are a couple more.

    Startools has been mentioned, get the latest beta (it's stable and free to try) and the latest DSS beta (the one that allows 'no white balance'). Reprocess your data with these and you should see a difference in colour and detail. 

    Consider getting the dedicated TS Canon OAG. I found this made quite a difference to the roundness of stars and allowed me to ditch the guidescope with some weight saving as well. 

    • Like 1

  10. Not an HEQ5, but I did do my EQ5. Still use it.  If you can obtain/make the brackets, acquire the belts and pulleys and appropriate stepper motors, it's all pretty straight forward. 

    I had some trouble with the  RJ11 cables and their sockets, so eventually hard wired the motor cables to the pcb, but that may well have been down to the quality of the cables.

    Tom's support was excellent.


  11. Just now, Adreneline said:

    AP's just one darn challenge after another!

    Ain't that the truth?

    And yet I still find myself looking at some beautiful but impossible target (often posted by a fellow SGLer whose kit when new would cost 10 or 20 times what mine did) and wondering 'could I manage to get something like that?'  

    We love a challenge, don't we?

    • Like 1

  12. Well done!

    It's not an easy target, especially when you can't even see it on individual subs, is it?

    I spent a couple of seasons on it with my Canon, Ha filter and 200 mm lens (and put the results in my 'best of 2018' submission).

    It was a target where I found longer exposures helped (got to 12 minute subs in one batch), and your processing comment inspires me to go back and try using Starnet on it to remove the stars...

    • Like 1

  13. The moon is quite a good target to focus on (when it's available).  If you get the limb looking sharp, you should be able to see the brighter stars, when you move to a non-moon area.

    Another issue, which doesn't affect your present challenge, is the focal length of your guide scope, as shown in the third image above.  Are you sure it's 50 mm?  That sounds more like the objective diameter, focal length is likely 180 mm or so.  This won't affect acquiring stars but will affect guiding. 


  14. 22 minutes ago, symmetal said:

    I'll do a test with a Pingi bag in the microwave as Julian suggests then seal it with a hygrometer and see what the RH is compared to my airing cupboard heater method. :smile:

    I have quite good results with desiccant spark plugs (rather different application, I know) in the microwave: 2 minutes on full power turned the content from pretty pink to deep blue...


  15. 7 hours ago, symmetal said:

    after 4 days in airing cupboard in sealed container with loads of desiccant. 

    How did you condition the desiccant before putting it in the sealed container?

    I ask because with enough desiccant that has already absorbed moisture, in a sealed container it will maintain the %RH at which it is conditioned rather than drying the air.  

    In the museum I worked in we would sprinkle water on the desiccant packs in sealed textile display cases to maintain 60% RH.  This may be what yours is doing if it  hasn't been conditioned recently.  It may be worth drying it out a bit? 


  16. 7 hours ago, JamesF said:

    Doesn't the "mini" model have a USB-C connector

    The mini does indeed have a USB C connector.  So far this has proved much more durable than the full sized one that was on my QHY 5L and which failed dismally after less than 2 years, but that may have been partly down to the much heavier, inflexible cable that QHY supply?

    Whatever suits one's individual circumstances, I guess?


  17. Here are some of the solutions I've tried with my Canon 700d (which perhaps doesn't use quite the same dummy battery):

    238.jpg.87f31bccc3fbb4b751757c194a737323.jpg

    The  accumulator is intended to charge USB devices and coupled with the cable which bumps the voltage up to camera required levels. Cable ref is:

    CA-PS700 USB Power Cable DC Coupler Adapter for Canon LP-E8 LP-E10 LP-E12

    Or a simple linear regulator:

    239.jpg.92d8447da543ca95f6dc42b64cba00ec.jpg

    Thread about this here: 

    It is wasteful on power and needs a heat sink but is very cheap to make and if run off a 12 volt mains transformer works OK

    There's the buck converter like the one Stash_old shows above which I think I got from Amazon:

    240.jpg.a5691424ae97d80b24ea9e9873d4a161.jpg

     

    I did also use a mains adapter but got fed up with having to repair to dodgy connections inside the case and the prickle of low intensity electric shock it produced. Seriously wouldn't recommend this:

    0241.jpg.db3e4910f8cdbf68be393e20a980da6e.jpg

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