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Everything posted by jonstarrysky

  1. Welcome Jonny. I'm glad youre having fun with your new hobby. I am a die hard dobsonian user (6", 10" and 18") and have plenty of collimation kit: the Howie Glatter 2" laser collimator, barlowed laser target screens (TuBlug and Blug) and various sight tubes and other devices: catseye autocollimator, cheshires etc. If you need a hand or advice I'm glad to help. Funnily enough I was interested in exploring your neck of the woods for places to observe, as it is close to Bishops Stortford where I live, and seems to have some darkish skies on UK light pollution maps, eg Lindsell, around Haverill. If you know of any suitable dark sites up that way (eg you mentioned a runway) I'd be keen to check it out if you want to meet up and dodge the clouds.... Collimation isnt that bad once you get the hang of it and have good kit, but I appreciate your initial dread !
  2. I have the unihedron sky quality meter. I will bring this along to any group meetings. Satellite data indicates a doughnut shaped band of dark sky around haverill, this is probably the darkest available in the region
  3. Anyone know observing places buntingford way ? that would be a bit closer for me coming from the east, wrest park may be OK, just over 1hr off
  4. this is my frequent finding, dark sky locations but nowhere obvious to set up, in the highly populated SE this is a problem I'd be up for observing meets at half decent sites not too far from east herts, I guess hearts beds and bucks is a huge area, but perhaps some of us are close by so can agree mutual locations
  5. The town where I just moved to, 1 mile west of Essex, street lights turn off at 12.15am. Will be interesting what effect this has (further than scaring the cXXp out of me when walking the dog late at night). I guess it will help a little, but the orange glow from greater London to the South is the main issue for me, not the local light pollution.....I also observed up Clavering/ Berden way, a rural area in the North part of Essex. This whole area has no street lights, period. Again the Southern horizon is lousy, from greater London far far off......
  6. Thanks for the responses guys, sounds good re ugely green, wld be keen to try that out Simms. Guess its similar (maybe better) to Hatfield forest carpark, which shld be reasonably dark locally but is close to stansted so there'll be glow from that. The darker area south of Haverill will be worth exploring in the future if we can find suitable ground
  7. Envious of tonight's trip out guys Recently having moved to bishops stortford, would be good to meet up with folk based towards the NW side of essex, if there's anyone up that way seeking darkskies. Looking at light pollution maps, there is a horseshoe band of darker skies to the south of haverill I'd be keen to explore Clear skies! Jon
  8. Call Callum, I agree with what u say, stortford area ain't so hot for stargazing. Comparing various UK maps of light pollution there is agreement re a horseshoe shaped band of land around haverill that will give darker skies. The challenge wld be finding a suitable observing area here and the drive. If anyone is keen to explore or meetup, pls pm me. Clavering area will be reasonable, a bit more polluted
  9. Hi all, I'm a new member of the group from Bishop's Stortford. Technically I am an outsider being in Herts, but in fact am only a mile or so from Essex. I would be interested if the day chosen turns out to be promising for clear skies and my lady boss lets me go. The proposed site, which by the way looks interesting, is 90 min drive for me.
  10. Wow I'm really digging these pimped tool boxes, good work, kudos due. As an interim solution how about just plonking a battery inside a small holdall with a bit of padding ?
  11. Correct. First, hats off sunshine for implementing this mod, binoviewing is cool, wide field is cool, so this combines both. It is likely some of the light cone is clipped leading to very small loss of light gathering power, there is a formula relating "intercept distance" (=centre of spider to focal plane) to secondary mirror minor axis and f/ ratio. Likelihood the scope is now breaking the rule slightly buy the proof of the pudding is at the eyepiece :-)
  12. Hi Matt and Callum, err biondi & moogoomonkey. Welcome to the seemingly growing number of B/S atronomers. So far I've just been preparing to observe at home. I'm new to the area and also keen to explore to the N and NE of Stortford where there is a zone of darker skies. This interactive map is useful if you have time to zoom in and explore dark zones. http://www.avex-asso.org/dossiers/wordpress/?page_id=127 I am familiar with Albury for daytime walks eg around the Hall. I think *local* light pollution will be favourable i.e. non-existent, but the location is somewhat close to the greater London skyglow for decent southern skies. I have observed from Berden and that is the situation there. The skyglow from greater London is quite apparent :>-( OK for brighter Messiers etc though.
  13. hey thanks for the replies folks and correcting me about NEAS. I plan to join that group. pm sent to Sam about possible future Stortford area meet up. clear skies !
  14. Hello, all just (re)introducing myself as a star gazer in Bishop's Stortford. I'm keen to find dark(er) sky sites within 1hr drive for observing, and perhaps finding like-minded astronomers who might be interested in meeting (safety in numbers !) to observe. Nearest club is based in Braintree, so not that convenient.
  15. Just to chime in with the crowd about the virtues of binoviewing. I have two pairs and swear by it. You can stay at the eyepiece for longer, being comfortable and immersed in the view. By being able to concenrate better with 2 eyes means the loss in brightness by the beam being split is not really noticable, at least to me on most objects. I've seen plenty of feint DSOs in my binos. I actually have 2 pairs including the quite expensive Denk II supersystem (top end kit handmade in USA) which I might sell if anyones keen on that. Yep, wing eyeguards rock too with binos as mentioned above. Cant remember where I got mine. Baader planetarium perhaps.
  16. Hi Liam, welcome to SGL. I sent you a PM re. possible local sites. I am soon moving to Bishops Stortford, and I will be exploring the area for sites that are passable for observing, please get in touch anyone else interested. clear skies ! Jon
  17. Is this event suitable for small kids to watch ? i.e. stuff to keep interest levels up between the launches, or maybe its just lots of whoosh and bangs all the time....
  18. This is indeed possible. Another funky trick, put a sheet of tracing paper over the open focuser, and point at the moon. When it comes to focus you have accurately identified the position of the focal place of your telescope ! Stargazers Lounge - jonstarrysky's Album: XT10i intercept distance - Picture I guess what you were doing visually is projecting the focal plane directly on your retina. Alternatively you can project it onto a CCD chip. Hey - maybe I can patent this idea and call it astro-photography.
  19. lol, he (C.L.) pulled out of a talk at my astro club, at literally the last minute. Please !!! There is a trend occuring here...... Have a nice meeting guys. Do you do observing meetings too ? I am in Oxfordshire.
  20. Nichol Optical is the other UK optician who does mirrors. Oldham has a good reputation. That is what David Lukehurst uses in his scopes. He is helpful and polite to work with. If you want a premium mirror, there are other options, notably US-based opticians. This is the route I currently take. Otherwise, I'd go with Oldham
  21. I agree TeaDwarf (btw I am in oxon too). This is why PLOP predicts a 40% radius support for a 3 point primary mirror cell, despite the fact that 70.7% radius gives the best overall distribution of mass. Howver the 40% radius support gives a type of deformation which can largely be compensated at the focusser. This is not the case for 70.7%. The silicone ring idea for secondary mounting may be similar conceptually - the deformation is compensated at the focusser. So what is the optimal radius for this ring ????? There is a question for the modellers. It will need to take thickness into consideration....
  22. Olly, this is very interesting. If you have more details and time, can you add this or pm me. My plans considered the expansion issue, so this is very interesting. I was theorising - you are using actual observations. It is really an issue then. The post will be aluminium - at least 2x the thermal expansion coefficient of plate glass and about 4x that of pyrex. I was planning on customising the post with a lower titanium section, which is closely matched to glass re. expansion coefficient. Or Kovax - an alloy that essentially has no thermal expansion. I am suprised at what you say as the silicone when set should have enough flexibility to accommodate the expansion issue.... I had never heard of the ring of silicone idea. Only 3 points, usually nearer the edge than the centre, to best distrubute the mass across the mirror between each support point. And 3 points will always lie in a plane. A circle - in theory if a section of this contracts differently to the resr this will impart a stress on the mirror. 3 points is always a plane. I can however see some of the logic of a small ring. The expansion differential will be smaller and wont concentrate the stress at defined foci....
  23. good point Russ, looks like youre meeting on the edge of the new forest, too far for me :-(
  24. Hi, just a heads up on a thread I've put in the DIY forum, ta Jon
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