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Everything posted by Trull

  1. Depending on the season, AAS sticks to the big showstoppers: Moon M42 M45 Planets Albeiro M32 Leo Triplet We have a big solar section - so get Ha, baader herschel wedge, solar film views in early evening sessions as well. Good effort on the outreach - its always rewarding to reap the "wow" moments.
  2. I like a session of about 3-4 hours, but I'm lucky in that I have quite a long attention span and always wear appropriate clothing. The surest way to cut a session down is to be uncomfortable, so having drinks/snacks/comfy seat/mats to kneel on etc is what makes all the difference. Also having likeminded astro-buddies will keep you going.
  3. I did much the same - and then upgraded with a length of fibre networking cable so that I got a far narrower beam. If you ask your local IT bod they will probably have a short length spare... or even buying is about a fiver.
  4. Cracking shots! Really nice faculae on the white light.
  5. I'm travelling down from Aberdeen for a week, staying in one of the cabins (tiddler in tow...and wife only does Glamping...) so will be begging for somewhere to setup the GP-DX and ED103... anyone got a little space?
  6. Part of the problem is sheer size - I was imaging the sun and took 300 subs on my 20D, so as each frame is 15Mb...how can I shift that to you?
  7. This Cloud has definitely had a silver lining!
  8. Looks plenty, I have a DFK21 which will be getting the same treatment as your DMK41 shortly. I tried unscrewing everything - and its just as you described and all as per the manual. Have you tried a Calcium K line filter?
  9. Just gotten my new toy - the "P" version, fitted it to my ED103 and checked it visually with Ethos13mm. Sun looks lovely. Then I fitted my Canon 20D with MaxDSLR 2"nosepiece and I can't achieve focus, it wants to be closer than I can push the focusser! Has anyone else had this problem? I'm aware that some Takahashi refractors have this issue - but I wasn't aware that the Vixen would too. Any suggestions?
  10. I use a script in Spectrum Lab to count the pings and create a text file that Colorgram can understand. Check out rmob.org if you havnt already.
  11. Nice composition - although both of the images are spoilt by your dust bunnies. Have you had a look at your sensor? I'd get a blower and clean it (best plan is to hold it upside down, select sensor clean and then carefully use a hand blower to take those rocks out....plenty of tutorials on web to show you how). Good luck!
  12. I think some others are far bulkier than they need be... incidentally in TorcDobIV I added a second truss arm for stability to take some of the spring out of the cantilever. You have to consider what you are pushing against, I use a virtual counterweight to keep the bottom trunnion as low as possible - which has increased the force needed which in turn means the cantilever needs to be stiffer. The next version builds on this to work with no secondary mirror and convert it to a Chiefspiegler (lenses bought, optical flat bought...just need a full night's sleep and I'll get it sorted).
  13. I run my imaging rig on a very ageing Apple PowerBook G4 at 1.7GHz with 2Gb RAM... never skips a beat. Don't use AV as there are no viruses on Mac anyway. This includes Nebulosity/PHD on firewire cam/Shoestring long exp trigger/Shoestring autoguider adaptor/Canon 350D/ SS2K.
  14. Tut Tut Ian - get thee a copy of Nebulosity, shoot tethered and you'll love working the bias/dark/flats in RAW so much more
  15. Can I also add that although my biggest wow moment was viewing Saturn through my homemade scope, I got a huge rush from showing 350+ other people Jupiter and other wonders at our recent Stargazing Live event at RSPB Loch of Strathbeg in January. Sometimes its just as amazing to share the experience as to do it yourself - so if you can, invite your neighbour to see and you might convert someone for life (or at least possibly gain another dark skies sympathiser)
  16. Sounds fascinating, I'm sure a good number would be interested in this, particularly in the ATM community. Why not stick it in your blog? (so it doesn't get lost)
  17. I've dug out an old photo of TorcDobIII so you can see the simplicity of my telescope. Its more wind resistant and packs down smaller than a solid tube design. Whatever design you go for - it will give you kudos over any other shop-bought scope, have fun and relish it!
  18. Trull


    This is my ATM light machine, sporting a 222mm f/7.3 mirror from Norman at Oldham Optical and a spring counterbalance system it gives me great pleasure to look at the sky. There's no wind area so its pretty stable in use, and the truss arm (now arms) is kept in place with a quick release mechanism for easy transport in the car. For the bearings they are etched PTFE onto aluminium or PTFE gliders onto smoothed wood.
  19. If the scope is not collimated within the acceptable limits then stars will have increasing coma, astigmatism, detail and contrast will be washed out and dim... its not a good place! There's a bunch of interesting simulations showing the different effects on Astro Baby's collimation page. You may find this page interesting too: "Surprisingly, the size of the "sweet spot" depends only on the main mirror's focal ratio (the mirror's focal length divided by its diameter) and not its size. For instance, even a perfect f/4.5 mirror, small or large, can provide "diffraction limited" performance only within a 2-millimeter (0.08-inch) circle at the focal plane. An f/10 paraboloid's sweet spot, by contrast, spans 22 mm (0.87 inch). (For the mathematically inclinded, the sweet spot's diameter is proportional to the cube of the f/ratio.)"
  20. Personally... I'd build a frame using four lengths of aluminium This helps with weight, wind performance and you can pack it really small. My 222mm 1625mm fl dob uses just two truss arms onto the mirror box, secured using bicycle quick release clamps. Works a treat! Just a thought!
  21. Good luck on the project! I've just bought a dial test indicator to make my foucault tester around, and hope to start my own 6" project soon. Ill be using a metal drum 2/3rds filled with water, pierced top to drain grits through (and it keeps the mud off your clothes, which might be something to consider with your plastic design - you could route a drainage channel in...) Plastic drums are very floppy - which would annoy me. Anyway - good luck - and please keep us posted with progress.
  22. Please save up a teensy bit more for the laser - I (and another 4 people from Aberdeen Astro Soc) found the Cheshire to be impossible to use compared with a laser collimation tool. It all depends on your eyesight, I found squinting through a pin hole around a cross of metal onto the primary mirror and examining the results between adjusting the mirror too much of a struggle. YMMV! Compared with just watching the red dot move as you turn the screws its harder. Proof of the pudding is that I collimate every single time, which is always a good thing (particularly if you move the scope by car...). Incidentally, don't fret about the laser's alignment, I occasionally check it by rolling it along a flat bit of steel and watching the laser beam stays flat as it rotates. Never needed a tweak yet (I have the meade collimator). If anyone wants a Cheshire - mine's going for 20quid! PM me.
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