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Fraunhoffer

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About Fraunhoffer

  • Rank
    Star Forming

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  • Location
    near London
  1. I started to get a bit stressy with my EQ mount altitude adjustment bolts when doing my polar alignment in the gloom. The long bolt would frequently seize up and the pressure have to released before continuing. I have a Bresser EXOS-2 mount and it looks very similar to the Vixen GP mount / LXD75, EQ5 pro and others of this style. The altitude is adjusted by 2 long bolts that push against a spur on the mount head altitude axis. The spur is at an angle depending on the latitude setting and this angled surface twists the end of the bolt down when pressure is applied. The bolt then jams in the screw threads making adjustment difficult. Ive added a sketch. My solution was to make a shaped block of a hard waxy plastic that would support the end of the bolt to prevent it twisting, and would also slide within the channel where the spur is located. I had hoped to use some PTFE but used a small block of HDPE plastic instead. This is a hard waxy and durable plastic that is actually used for plastic milk cartons. A hard waxy wood might also be used. I cut a card template for the shape of the channel and then transferred this to the plastic and cut and filed by hand, removing a little at a time until it fitted nicely in the channel. I checked the height in relation to the altitude bolts so that the top was the same height as the centre of the bolt (bolt removed for this). Be careful not to jam the block in the channel (if this happens a small hand drill or an awl might help dig it out). The final task was to use a round file and remove material to make a groove in the top at the same height and depth as the adjustment bolt to support the end; removing a little at a time and checking frequently. The result? A buttery smooth altitude adjustment bolt. I can finely adjust my polar alignment altitude without any bolt sticking or jerking or getting too stiff to turn easily. The first time I tried it I effortlessly managed to achieve 1’30” polar alignment error. My mount might not be the exactly the same as yours but I hope this may be useful to some. The usual waivers – you modify your own mount at your own risk. In retrospect this was such a simple fix to an irritation in an otherwise lovely mount. (PS. I have also made a thin large circular washer from a cut up HDPE milk carton that goes between the tripod and mount head - buttery azimuth bolts too). Happy Adjustment Bolts everyone (PPS. I didn't use a metal block since I thought it would wear the threads at the end of the bolt, whereas a firm plastic would not damage the threads. I expected the bolt to bite into the plastic, but using a hard waxy substance would enable it to slide a sthe bolt was adjusted. It doesn't usually have to move very much anyway)
  2. Must look now. Might see how much we could sell ours for.
  3. I'm hoping to get a last look at comet Panstarrs as it's close to Phecda and M109 before it speeds off to the distance.
  4. Weather forecast says it's cloudy, but I'm looking out the window at a clear blue sky.
  5. The wire to the motor would be better facing down as well. The number of times I've nearly snagged the loop on a door handle as I carry the base out. It's now firmly strapped in place with some glued on cable ties.
  6. I was out last night till around 1. Great views of the moon to start with. So clear, found the Areadeus Rille near the interesting rocky formations near crater Julia's Caesar. Then lots of clusters in Ophiuchus sweeping over to M13 and M57 ring nebula which is quite bright if small. Finally comet Panstarrs (again). Its been such a reliable comet. Unlike a couple of others I could mention. Might spend some time with double stars another evening. So many, for some reason.
  7. Thanks for all the suggestions. Ive got 4 on my shortlist so far. 3 with fluid 2 way heads and one with az gears. decisions decisions.... Orion Tritech II weight 2.3 Kg load 6 kg length packed 69 cm length extended 153 cm + safety latch on shoe to prevent things falling out slotted shoe for sdjusting carry bag - might be a bit short when extended Celestron Trailseeker weight 1.81 Kg load 4 Kg length packed 48 cm length extended 178 cm + good for tall people legs can have different angles padded legs for shoulder carry compact when folded up - Horizon 8115 weight 3.58 Kg load unknown (binos upto 100mm dia) length packed 78cm length extended 180 cm + good for tall people - bit long when packed heavy ? Skywatcher AZ Pronto weight 3.8 Kg load 3 Kg length packed 78.5 cm length extended 150 cm + nice geared controls and locking t bars - £ need to add dovetail for camera and scope more expensive heavy ?
  8. Nice sketch. One of my favourites.
  9. Looking very clear at the mo. Might try for a last attempt at Leo Triplet if it's dark enough. What's everyone else observing or imaging?
  10. Pm sent re camping mains hookup reel.
  11. pm sent re Neody' Moon & Sky glow
  12. I want to make up a nice hand portable rig using an ST80. (I have the OTA, nice diagonal and spare eps). So looking for a nice not expensive but steady tripod that could fit in a large backpack. I might add a tracker later in phase 2. Any recommendations for a tripod? I do some other photography so a photo tripod would be ok. The St80 rings I have include screw fitting anyway. Thanks
  13. Doing some test runs today.
  14. Tinkering with a few things this eve. I've been working on my polar alignment and cone error and want to check if I can now get 2 minute subs unguided @ 400mm. Or,how long before star trails.
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