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coatesg last won the day on May 11

coatesg had the most liked content!

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About coatesg

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    West Oxfordshire
  1. The camera is 77mm diameter - I want to attach it firmly to a dovetail (using a single bolt through the central "slot" on the dovetail). Currently using a three point finder scope ring, but it's just not quite as rigid as it could be...
  2. coatesg

    In the field fixes

    I took an eq mount and my little Tak to Turkey for the eclipse. The scope rings got broken in transit. Solution: parcel tape the scope to the dovetail
  3. coatesg

    Upgrading HD Desktop System with SSD Drive!

    For those saying that platter drives give some warning before failure - maybe sometimes, but *ANY* drive can fail without warning, SSD or platter: always backup your data! I had one out of a pair of RAID 1 drives go completely AWOL in a NAS not so long ago and this without any SMART warnings - the disc's onboard electronics died and were reporting 0GB as the size when I plugged it into a desktop... Equally, it's not unheard of for RAID controllers to fail and silently cause corruption across drives.
  4. As title really - I'm interested in getting some made at work. Just wondered if anyone had already done the same? (and wouldn't mind sharing the plans?!) Want a circular clamp or two to go round the body of the camera (QHY163M) to hold it firm onto a dovetail - can't find any designs online, and not very experienced in designing for 3D! Cheers
  5. Title says it all. Froze my extremities off observing a few objects through my scope (struggling with moon and haze). Setup widefield kit (163M+200mm 2.8L) in readiness for the moon to set. Polar aligned, setup guider, focused. Managed **1 single** 60s LUM frame before the clouds came rolling in again. Kinda getting a little fed up of it now - just can't seem to get any usable clear, dark nights. Is this part of the world that bad for clear skies? I'm sure I remember some in the past... how much for remote hosting and any takers for shared kit...?
  6. Super stuff! the videos are gonna be hard to put on the mugs though
  7. coatesg

    Bought the wrong item?

    It's more a safety point that you don't want it being in standing water or getting rained on, or equally in a sealed compartment with no possibility of airflow. I have similar 4A and 7A 13.8V supplies that I run my kit from - both have large heatsinks at rear to dissipate heat and produce more than enough heat to not have issues with dew and the like when used outside.
  8. Theory says: the noise in the combinned background signal (eg due to moonlight/light pollution) and dark signal should swamp read noise. At that point, there's little difference between taking longer subs, or taking more subs - it's total exposure that matters. You also don't want to be clipping at the top end (but sometime unavoidable - in this case combiining data with shorter exposures in an HDR process is a way to go). The latter has advantages in terms of tracking performance and loss of subs to planes, clouds, etc. but it's not unheard of for the optimal sub length to be so long such as to be impractical! A simple calculator can be found here https://starizona.com/tutorial/ideal-exposure-calculator/ - something a bit more in depth: http://www.ccdware.com/resources/subexposure.cfm For modern CMOS cameras, the read noise is dependent on the gain, so you need to work that out first. In all cases, the optimal exposure is dependant on your local conditions, phase of moon and optical/camera configuration. Of course, you can choose a compromise so you don't have to keep taking dark frames of different lengths!
  9. coatesg

    Stability of PA alignment

    Yes - I'm not saying it does - just that precession of the pole/nutation doesn't require realignment of a polar aligned scope. The scope's polar axis will still be aligned with the axis of the earth's rotation - it's just that the NCP isn't in the same place with respect to background stars.
  10. coatesg

    Stability of PA alignment

    Come error doesn't affect drift alignment. The scope will still follow circles of RA/Dec (but it will affect pointing models on goto mounts)
  11. coatesg

    Stability of PA alignment

    Yes - but Polaris shifting in the polar scope isn't the same as polar alignment shifting - precession affects where the pole points, not where the axis of rotation is. But then, for accurate polar alignment I wouldn't use the polar scope - esp in a permanent setup.
  12. coatesg

    Stability of PA alignment

    (Should add as well, even the pros see this type of thing - have a feeling that Pinpoint was used on the AAT and showed a slow drift in PA due to (possibly) the concrete curing in the observatory foundations)
  13. coatesg

    Stability of PA alignment

    Almost certainly due to the local movement of soil - this will depend on moisture content if you are on clay. Polar motion (https://en.m.wikipedia.org/wiki/Polar_motion) is a real thing, however, but not sure you'd be able to detect this at all (needs a long baseline interferometer to do so).
  14. Depends a little bit on how good your guiding is I think - do you have any details on the ability of the HEQ5 to guide successfully? I say this, as it gets increasingly hard to guide at longer focal length, though a catadioptric is probably easier than a longer tube scope like a newt (less moment of inertia). If the mount is up to it, then a Newtonian would be possibly the cheapest way forward I think in terms of price vs aperture - you will need to learn to collimate though (it's not too hard once you've done it a few times - it takes me longer to take out the camera, and reconnect it afterwards than the actual collimation these days). Having a perm setup also helps enormously.
  15. Hello SGLers, I'm having a bit of a rethink about swapping/repurposing some of my equipment in the future. One option I have is to possibly change mount for my large newtonian so it frees up my Titan for use elsewhere (To be determined). Are there any Beacon Hill MkII mount users on the forum (and possibly users of the mount with a fork configuration)? Wondered if they had any feedback on the mount itself at all? I've seen some poor reviews of the worm/wheel sets around, but that could potentially be worked around by using an alternative source for the worm/wheel set. (Are they even in production still?!) Any feedback info gratefully received!

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