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mbalkham

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Posts posted by mbalkham


  1. I think you might be right. I remeasured the spacing and it looks like my 4 holes are not equally spaced around the circumference (not by much). I was not far off centre but obviously not close enough and that was pulling vanes offline a little. 

    I've filled the holes and will redrill tomorrow above the last lot. Will triple check all the measurements and accuracy of the pilot holes before redrilling.

    I think I'm parallel to the primary. I'll check again. Will also check the focuser alignment again. 


  2. 12 hours ago, Starflyer said:

    Can I ask why you moved the spider to a 90° orientation from 45°?  It's probably a personal preference thing, but I much prefer X shaped diffraction spikes to horizontal / vertical spikes.

    I have another post on this specific question (Spider upgrade - orientation of vanes - Discussions - Scopes / Whole setups - Stargazers Lounge).  I didn't get a definitive answer on that thread nor from the manufacturer of the new spider. General wisdom was that it wouldn't make a difference optically, but my thinking was about ease of collimation. I wanted adjustment towards/away from the focuser with one screw and then left to right with the other two. I think this means easier adjustment as you don't adjust in more than one plane when you make an adjustment. I also think it will help support the focuser and weight of the camera/reduce any flex at that point of the tube.


  3. Hi all, 

    Anyone tried to fill holes in a carbon fibre tube? More cosmetic than structural (see pic). Also want to stop light for darks. Currently using black pvc tape! Looking for tips/ tricks. 

    Current thinking is thickened epoxy with black pigment (or perhaps graphite?). Something like this https://www.epoxyworks.com/index.php/adding-pigments-to-west-system-epoxy/

    Prob also paint over inside with black acrylic paint. 

    Thanks in advance

    Matt

    20201208_173140.jpg


  4. Hi all,

    I'm upgrading my spider vanes to the TS Optics double carbon spider (Teleskop-Express: TS-Optics Carbon Double-Spider for 295-310 mm inside tube diameter (teleskop-express.de)). The aim here is to be a bit stiffer and hopefully hold collimation better plus to tighten my diffraction spikes. I will also us copper foil on the vanes for the secondary heater rather than wires.

    I've been trying to find advice on the orientation of the vanes relative to the focuser. Everything I see online points to one of the vanes being inline with the centerre of the focuser. However on my OOUK CT10 the stock spider is offset at 45 degrees to this. That makes collimation more tricky as the adjustments tilt/twist the secondary not relative to the optical axis (the two left thumbscrews are not parallel to the optical axis).

    Question am I overthinking this just install in the existing holes or should I redrill the fixings in a more usual pattern relative to the focuser?

    Thanks in advance

    Matt   

    20201125_095333.jpg

    spider.JPG


  5. Anyone know if the polemaster will work in this location? It did on the top of the losmandy plate (maybe 100mm further from axis) but I wonder if my tube will obscure the view?

    I read a field of view of 11x8 degrees. My polemaster is 450mm from the end of the tube and 50mm above the tube. If my math is right then a 4° angle at 450mm is 31mm so the polemaster shouldn't be obstructed?

    Proof will be in the test next clear night but interested to hear what people think. 

    20201020_132545.jpg


  6. Anyone got there hands on these filters? Can you recommend which of the NB filters suit which application? Thinking I want NB1, NB2 or NB3 for emission nebula from bortle 5 backyard. This is going in my secondary imaging setup piggybacked on my newt which currently comprises EOS R with various lenses. Ideally looking for something similar to duoband I use on the primary rig with ASI071. 

    https://www.teleskop-express.de/shop/product_info.php/language/en/info/p11557_IDAS-NB2-Dual-Band-Nebula-Filter-with-Drop-In-Filter-Insert-for-Canon-EOS-R-Mount-Adapter.html

     

    20201016_210934.jpg


  7. 32 minutes ago, rnobleeddy said:

    Can anyone with a beltmod on an HEQ5/EQ6 let me know if it improved dither times?

    I've gone for RA + DEC dithering. This seems to work well in that the mount is stable, however, dithering takes about 50s to complete. This isn't the end of the world if I'm exposing for 300s as it's a lot faster than darks, but it'd clearly be better not to lose so much time. 

    My guess is that the backlash in the DEC axis means it takes a long time to move and settle down, but the only other experience I have was an EQ5 where I set it to dither in RA only.

    My belt modded NEQ6 dithers quickly (I haven't measured but I'd guess maybe less than 10 seconds). I'm not sure it's down to the belt though. Sounds like some other setting/issue? I have settle of 1s set after the dither. In the attached image I have taken 6 120s images and 6 dithers in about 12.5 mins so def less than your 50s dithers maybe 5-10s per dither.

    Have you changed the amount of dither from the defaults? Mine are just default values (I forget what they are and aren't in front of that computer at the moment). I guess backlash could mean it takes longer to move the required amount of dither but it's moving a number of (or fraction of) a pixel so not like a lot of movement needs to occur. 

    Are you running the guiding and dithering over a wifi connection or locally? If it's waiting to confirm receive info to confirm the dither movement it might take a little longer? 

    20200930_213151.jpg


  8. Just now, astrosathya said:

    the parameters seem to be almost the same. the guiding exposure was 3s to beat the seeing which is usually 1.5".  I am myself finding it hard to digest. :)

    Suggest you look at pixel resolution. Maybe the guidescope focal length is incorrect in one set of guiding. Iwould think this amount of change is unlikely to be down to the belt mod.


  9. 12 minutes ago, astrosathya said:

    Recently I had belt modded my HEQ5-PRO and last night i gave it a full run and i was absolutely stunned to say the least about the guiding results I achieved. I was left wondering if its even too good to be true! 
    Below are Before and After images of guiding.

    guiding on 30042020-2.JPG

    afterbeltmod4.jpg

    Something funny going on with these results. Error in pixels about the same top and bottom (0.27-0.24). Looks like something else has changed?

    • Like 1

  10. I've belt modded my NEQ6 and seen a slight improvement but I doubt you'll see much if you are already at 0.8"RMS. Maybe 0.1" if you're lucky but seeing, balance, PA etc. will affect things more than that. Belt mod def helps with backlash and runs a bit quieter.

    I've also added zero backlash mod also from Rowan but yet to get the best from that (still needs tinkering). And I have replaced bearings, hypertuned, and upgraded other components.

    Worth saying I am really pushing the weight on my mount (over 20kg of imaging and 20kg of counterweight) and am seeing typically tracking between 0.6" and 1" RMS.


  11. On 22/08/2020 at 06:22, michael8554 said:

    Roughly speaking there are three shapes of stars due to guiding:

    Small round stars, fat round stars, and elongated stars.

    So if you want small round stars you'll have to work on your guiding.

    RA RMS is 50% to 70% higher than Dec, which means elongated stars.

    I was in the elongated stars situation.

    Best RA I could consistently get with OAG was below 1arcsec at 1280mm focal length, , but Dec was even lower, so I set a small drift in PA and set Dec Min Mo to up the Dec RMS to match RA.

    Michael

    There's a sneaky trick. Very clever, I might play with this at some point if I can't get RA and Dec closer to one another my some mechanical means.

    Just got my OAG and redistributed some weight onboard for better balance either side of the flip. Moved the computer/power etc. on top rather than on the side so much closer to 50/50 weight distribution now.

    2C0A2257.jpg

    2C0A2464.jpg


  12. Thanks all for the tips. Next clear night I'll give a few a go. 

    Looking at OAG which could help me plus save some weight. Failing that might look at new guidescope rings. Prob move the onboard rpi and dew heater for better balance. Going to fiddle with ra meshing again. Try shorter guide lengths. Sort a couple of cables. Check balance with ammeter. Plus a couple of other things!

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