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jambouk

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Everything posted by jambouk

  1. jambouk
    Good. I just remember I'd drawn something on an older thread to help someone else in a similar sitruation, my drawing is somewhere here: James
  2. jambouk
    Over thinking it is good, it means you want to understand it, rather than accept the view of others. I’ll try and think how to explain it better. Give me 30 mins. James
  3. jambouk
    Common question and it should be clear in the manual about it. The orientation of the reticle is unimportant. Just rotate the RA axis until 0 is at the top, then polar align. Once you’ve polar aligned you can put the RA back to the home position and your polar alignment will be preserved, as once you are polar aligned, moving either the RA or the Dec is fine as it doesn’t alter the polar alignment. Some people remove and rotate the reticle so 0 Is at the top when the mount is in the home position, but that is just personal choice (and a bit of hassle) and does not mean they get a better polar alignment than everyone else with a wonky reticle.
  4. jambouk
    I have no experience of that device, sorry. You first need to work out how much power you will need per observing session, probably in watts, for all your kit. The 7-20 amp hour things are fine if you use it to just power a basic mount for an hour or so, and then recharge immediately after. If you are using dew bands, laptops, peltier coolers, then you need significantly more capacity. This device is 370 watt hours, which at 13v is only 28 amp hours, so £8.57 per amp hour. A 75 amp hour deep cycle lead acid battery is 86p per amp hour... the latter could be charge dup with a small solar panel. Do work out your power needs, then look at what size battery you need, I think this will help. James
  5. jambouk
    Thanks. Are you referring to the Permenant Period Error Correction (PPEC)? If so, I can't see how that differs from the standard EQ8 or even from my AZEQ6. I can't really see much difference from the EQ8, apart from these things: Cable management system for reduced tangling. Improved Connectivity. Improved installation position of motors for improved balance. Improved clutch mechanism provides more holding strength. Improved dovetail groove knob for added comfort and increased locking power. Belt drive on the RA and DEC axes for quiet slewing (previously only the RA axes was belt driven). It doesn't even have freedom find which the EQ8 does. I was under the impression there was something much more fancy with the encoders in the EQ8-Rh, but I am failing to see that. Thanks James
  6. jambouk
    Has anyone used one of these yet? I'd be interested to hear what scopes have been used on it for unguided imaging and what duration subs have been reliably achieved. If there are only encoders on the RA, how does it ensure there is no drift in declination? James
  7. jambouk
    Impressive aberration; I can see why you want to get a corrector. Maybe put a wanted advert on astrobuysellUK and see if you can get one for £80.
  8. jambouk
    I’m not sure what you’ve read about cutting things... I would have thought you stuff the corrector in and it either helps reduce coma or it doesn’t. Show us one of your images with coma.
  9. jambouk
    I find refractors easier to work with personally, than reflectors, so if someone was starting afresh I’d say go for a refractor. But I suspect there is little difference. A short tube refractor will probably have a shorter focal length and wider field of view, which if adding in a reduced/flattener on top will give an even wider FoV - if this is important. Horses for courses.
  10. jambouk
    For most short tube refractors you’d need a field flattener which probably costs as much as a coma corrector... James
  11. jambouk
    You’ve already got the DSLR; the sensor is likely much bigger than your overall £1000 budget could afford if you were to buy a dedicated Astro can; no need for additional wires and power and laptop at the side of the scope; less things to learn. If astrophotography is your thing a DSLR is an excellent starting point, possibly the best starting point, but then you need to invest heavily in the mount and just get an 80mm apo and forget visual observation for the time being. There is no one set up which ticks all the boxes you want it to tick.
  12. jambouk
    What are you trying to achieve and what do you already have; posting a picture of what you want to attach to what may help.
  13. jambouk
    DSLR defo to start with
  14. jambouk
    When did this term become commonly used amongst astronomers?
  15. jambouk
    The 200 reflector is a bit big for the HEQ5; if that is the mount, defo go for a small semi-app refractor.
  16. jambouk
    There is no one scope which does all of this well, and as said above, if imaging is key then the mount is just as if not more important. Buy second hand. Get something like an NEQ6 or AZEQ6 mount, and then get an 80mm [semi-]apo refractor for imaging deep sky objects and either a 200mm reflector or the largest aperture SCT or Mak as you can afford for observing and imaging the planets and the Moon; you’ll need to check the issues with achieving focus with a DSLR before buying the reflector, and likely need a quality Barlow or PowerMate if using that to image the planets. If visual stuff of the deep sky is your thing, go for the reflector. You need more than one telescope to do this all. But whatever you get, you will likely be thinking about the next telescope within weeks. It is a hobby where people’s appetite change and the only real way to know what works for you is to try something; most things second hand hold a reasonable price so very little lost if you buy something say for £400 and sell it a few months later For £400 as it isn’t what you want.
  17. jambouk
    Polar align at night, and mark the position of the feet of the tripod, then don’t adjust the alt or az settings and just plonk it in the same spot during the day light and your polar alignment will be roughly ok. Else leave it out at night if it won't get stolen.
  18. jambouk
    Thanks again; I’d read that link earlier today. The aim is to not spend any money. The existing batteries are there and are in a reasonable shape so seems a waste to get rid of them and then spend money on new ones. I appreciate these will tire and die over time, and then they can be replaced with bigger newer ones, but as long as it’s largely safe, I’ll stick with this for now and fuse it all. Appreciate the help. James
  19. jambouk
    Thanks both. I need to get a bit more 10AWG wire then. For the batteries in parallel, how quickly would you notice a problem with one battery bleeding the other (time frame or charge cycles), and if say both batteries originally had 80 amp hour capacity, but now through aging one effectively had 70 amp hour capacity and one 65 amp hour capacity though both have a resting voltage of 12.95V, is this considered to be a big difference, or would a big difference need to be in the order of 25%? Regards James
  20. jambouk
    1. If the wire to a pair of 12v DC batteries in series is 10AWG (5.3mm2) and is say 2m in length, what gauge and length wire should join the two batteries, or as long as it is at least 10AWG and less than 2m it is unimportant? Are there issues with using thicker wire to join the two batteries together. 2. And if these two batteries were in parallel, what are the requirements of the wire joining these two batteries together? Again, is using thicker wire than the live and positive to the battery pair problematic? 3. And if you can tolerate answering another question, where would you fuse these two set ups? Thanks, James
  21. jambouk
    What filters do you already have?
  22. jambouk
    Left side / right side is unlikely to be the issue. Maybe worth checking this next time you set up to see if it is. Make sure you fully turn off between setups to clear the memory. Glad it is sorted. James
  23. jambouk
    Field of view is determined by focal LENGTH not focal RATIO. For visual, get the largest aperture you can afford (certain potential exceptions for solar, lunar, and probably other targets and observation methods). James
  24. jambouk
    You could put three of these under the grass level on a grassy area, and then just mow over the top of them, and leave them in place all the time, either held in position with a bit of concrete or two tent pegs for each.
  25. jambouk
    As with everything in life, the answer isn’t binary. After sunset, concrete emits the heat it has acquired during the daytime, much more than grass, so there will be heat currents drifting upwards and reducing the quality of the seeing around your telescope. So if you don’t care about the seeing setting up on concrete is fine. If you want the best possible seeing, don’t set up on concrete. If you want perfect polar alignment then unless you have a permanent setup you’ll need to polar align each time you set up; so you’ll need to polar align if you set up on concrete or grass. If you want to reduce vibrations transmitted from you walking around through the tripod and to the telescope, then I suspect grass would be better than slabs. If you want the most stable surface to set up on I suspect slabs would be better than grass, but if you push the tripod legs into the grass firmly at the start, or use something to dissipate the load like anti vibration cups or caravan feet, then I doubt there would be any measurable differences. James
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