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JamesC

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Everything posted by JamesC

  1. Don't overtighten your boots. It cuts the circulation. Same if you really pack them with thick socks - it can be counterproductive.
  2. I'm not sure it is necessary to get anything. With a solid tube you shouldn't be getting dew on the primary while you are outside observing. Once you bring the scope back inside the mirror will be cold and you may well get moisture condensing on the mirror then. Once the mirror has warmed up a bit the water will evaporate. The primary mirror is the part of your scope with the highest thermal mass so it is last to cool down when you take it outside and also last to warm up when you bring it back in. Can you not just leave the scope tilted over so there is no dust settling on the mirror? Alternatively you could just open the small hole on the lid and leave the focusser open too. That is probably enough.
  3. My experience with a 114mm starblast was that a dewshield was not necessary. It will probably help improve contrast by keeping stray light out the tube though. By contrast, I found a dew shield was necessary with a 12" dob. I think the difference is that the secondary on the starblast was largely covered by the bit that holds the mirror so it never presented much area to the night sky. On the 12" the secondary was large, presented a large area to the night sky and cooled quickly. Without a dew shield the mirror would mist up after a couple of hours. I have often wondered if gluing a think layer of cork on the back of the secondary of the 12" would have stopped it cooling so fast and so prevented dewing. On the other hand, would it have kept it too hot and caused tube currents? Also what would you do if you ever wanted to recoat the mirror? I was never brave enough to try.
  4. I love the simple elegance of the Newtonian design, but I have to concede that refractors have their appeal. Aside from the issues normally covered, I think it is the low maintenance and durability of refractors that makes them so desirable. With Newtonians: - The mirrors will eventually need re-coating. - You may want to clean the mirrors every few years (contentious). - You have to collimate regularly (not a big issue with practise). - There is always the risk of disaster, i.e. dropping something down the tube. I think these factors prevent Newtonians becoming objects of desire, instead they are supremely practical work horses. I don't have a lot of experience with refractors, but things I don't like about them (apart from the cost per unit aperture) are: - They are surprisingly heavy which limits their portability and also requires a serious mount. - The eyepiece location is inconvenient. - I don't like left/right inversion (I prefer fully inverted). To me the best refractors are binoculars - the main problem with those being hand shake!
  5. Interesting. My 300p flextube had a similar thing. I've now sold it on and I guess I did knock off a bit when deciding the price because of the flaw. The scratch/flaw/crack/whatever-it-was never got any worse despite plenty use over 3 years in varying conditions. When I removed the mirror to clean it, I felt a lot better because it's such a big hunk of glass the scratch/cut looked minor. I checked the figure of the mirror with a Ronchi eyepiece and it seemed very good to me. When I got the scope, I wondered about making a fuss and sending it back, but decided I couldn't be fagged! I find it really interesting that mine wasn't the only example. I have no idea how these features come about.
  6. Just tested with the binoculars on tripod with objective poking through cardboard and a bit of white paper behind. Surprisingly effective and vastly better than the glasses. I could see the little grouping of 3 spots near 1486 and the 1490 and 1492 groupings (Sunspots). I'm going to have to go eclipse chasing now, so my investment in glasses isn't wasted
  7. Wow! That was cool. Just cut a hole in some cardboard, stuck one of the binocular objectives through and was projecting on a piece of paper. Reckon I could see sunspot 1486. While I was watching a jet plane went across the solar disk leaving a contrail behind!! Only problem with the set up is I can't hold the binoculars steady. Thinking about taking a tripod now.
  8. Thank you. Glad to see you moderators are on the ball. The glasses have that warning on them, but it doesn't hurt to repeat that kind of thing. Perhaps projection is the way ahead. I think I might do that David.
  9. I just got some eclipse shades. I'm going to be away from home for the Venus transit and fancied something I might see a small black dot with in the unlikely event of it being clear. I thought about binoculars and solar film, but decided against it. Just wondering - can you see anything else with these things? Just been looking at the Sun and it looks like a featureless orange disk no spots or anything as far as I can see.
  10. I'm not even an imager, but I've seen on other threads that you can have a scope too well balanced. Apparently you are best to have it slightly biased one way or the other so the drive is always working in the same direction. If the motor flips from pushing on the gears to slowly giving ground to gravity you can get a bit of wobble. Alternatively sell the EQ6 and get a Dob!
  11. Sounds like you are along the right lines. There are plenty of miradores where you can park up and take a view. I liked one near the cable car station. It is an amazing location to do astronomy from because it feels like you are in a crater on an alien planet or something. Thinking back on it I don't know why I didn't try the parking for the cable car station, perhaps there was a reason or perhaps I was just shy. Anyhow if you've got a car you're sorted. Annoyingly there is a bit of noticeable light pollution, but it's still an excellent location. I hope you are taking some binoculars or something with you. I did see binoculars on sale there but they were all the ruby red 'night vision' coating type - i.e. rubbish. You would be better buying something you would like for the long term and taking it hand luggage. I crazily took my Starblast on an EQ1 mount!! I still can't quite believe I did that. These days I would probably take something like a Sumerian Optics scope or a small APO on a camera mount. Mind you the Starblast is darn good value for money. Tenerife is really beautiful - I'm sure you'll love it. Hope you get a spot of walking in. Actually just driving around is amazing. I remember watching sunrise from a viewpoint on the TF-24 after a night's observing. The road along the ridge on the eastern part of the island is some piece of engineering. This is a link to a thread I wrote 3 years ago! http://stargazerslounge.com/observing-reports/83179-my-visit-tenerife.html
  12. While I'm thinking about it, you might start to be disturbed by coma in 2" eyepieces. Add a coma corrector and a 2" OIII filter to the wish list!
  13. Generally agree with the above. You need at least 3 eyepieces: one wide angle - maybe around 6mm exit pupil or whatever you think you can realistically handle; one for DSOs - I think the calls for 13mm are about right; and one for planetary - personally I would go for about 300x (which many people think is too much). For the wide angle, I would consider the Meade 5000 28mm SWA which is still a reasonable price here. Actually I might even be tempted by the 34mm, even although the exit pupil would be too large - just to get the additional field of view (the 31mm T5 would solve that problem, but it's a jumbo eyepiece). For the DSOs I'd either go for Meade 5000 14mm UWA, which I know is pretty good, or else take a punt on the Explore Scientific 14mm 82 degree eyepiece, which I've never seen. There is a school of thought that you may as well go straight for the expensive eyepieces and then you don't need to think about upgrading, but personally I think I would be happy with the above. If that was still too pricey, at f4.8, I think I'd go for generic 52 degree plossls. Planetary is tricky. I might go for a 5mm Nagler, even although the eye relief is tight (the 6mm Delos is probably a much more comfortable eyepiece). There is no budgeting on wide angle planetary eyepieces. Of course you could build an equatorial platform and then use an orthoscopic!
  14. Don't recommend trying to correct the scope. You soon get used to navigating with the inverted view. I thoroughly recommend the right-angle erect image finderscopes. Much more comfortable on the neck than those straight through ones and easier to orientate yourself. Makes it easier to translate from binoculars to finder scope too. Actually I often found it easier to see things in the finderscope than the binoculars because it doesn't suffer from hand-shake. Red dot finders are also useful but if you're just getting one I'd go for the finderscope. You will need to make a dew shield. I also kept the eyepiece cap on when I wasn't using it to stop the finderscope eyepiece from dewing up.
  15. Yeah, until the bin man comes around and decides to do you a favour...
  16. Couple more links to bookmark: 7Timer meteoblue Looks like Saturday will be transparent but with poor seeing. Not that I think you will be going this far, but I have been out on Okehampton Range - dark but oh so exposed... plus I fancy it is a bit of a cloud magnet when the wind is from the N or W. Firing Notice
  17. P.S. Forecast is looking interesting for Saturday night at the moment, but it could easily change. I'd guess the precip during the day will fall as rain. Hopefully the cloud will clear south in time for nightfall. Could be ice/frost later, especially after the rain. P.P.S. I really don't know what I'm talking about so check elsewhere. My favourite links are: BBC weather Daytime Dartmoor webcam Haytor observations Amateur weekly forecast - check the date! Met Office South West/Dartmoor forecast Visible satellite imagery Rainfall Radar Flakey IR animation IR but with hour long gaps
  18. If you set up near the road, you still get a decent view to the NE/NW. How low do you want to look in that direction anyway? You can always wait for the sky to turn and for stuff to come around. The view to the South is slightly blocked by Hound Tor, but how low do you want to look? If you are really scraping the horizon you might be better at a south coast site. The shelter provided by the trees is really important. Stops your scope wobbling, stops your charts flapping, stops your freezing, plus I find a wind scary because I can't hear the bogey man creeping up on me! These photos are from Hound Tor looking NW and S. About the Peak Hill car park there is a lot of light pollution to the SSW (and west), but it is dark towards the SSE. NLO is better positioned a little further E along the coast, but I don't know about the tree situation there.
  19. Yep. I used to have a 12 inch Dob, so walking more than a few metres wasn't really an option, but perhaps with an 8 inch you could go a bit further. If I'm honest I used to shun the NLO and observe from the Peak Hill car park on the other side of Sidmouth from the NLO. You can see quite low from the West part of the car park. Perhaps I should have shown up at the NLO. I guess I wasn't sure if you were allowed to just show up! Weak excuse I know. Actually the Peak Hill car park was popular with meteor watchers.
  20. Pleased to see someone prepared to make a journey out to Dartmoor for observing. It's something I've did quite regularly when I still had my Dob. I'm not convinced about your carpark idea, although it's remarkably difficult to find a good carpark. Ideally you want to be a bit off the road and screened from the lights of passing cars. You want a bit of shelter from the wind, but still with a good view of the sky. There just aren't many car parks like that. The road to Widecombe in the Moor is actually a remarkably busy road so I don't think you will like it there. I reckon you need a range of car parks to choose from. You want some nearby sites that are not too much hassle to get to for those nights that you can't be bothered going any further. You want some Dartmoor sites for observing those really faint objects. You probably also need an alternative low level dark site that won't be as affected by snow / ice / frost as Dartmoor. I nearly got stuck on Dartmoor once when there was thick frost and a dusting of snow on the ground (my car is rubbish in slippy conditions). I now carry snow socks in my boot! You probably also want a good south coast site because there are a lot of interesting objects that are only ever low down in the south from our latitudes - this is a bit tricky for you. Actually the NLO is well sited for looking south, but that is quite a journey for you. Keep in mind that you don't want to be bang up next to the sea because quite a lot of salt (not to mention sand) can be blown in with an onshore wind. Here are some car park suggestions.
  21. A planetarium is a tall order, but clearly this thing doesn't even try. It's difficult with any representation of the night sky, be it chart, globe, software, or planetarium, to get the relative brightnesses looking right, probably because the dynamic range is so large. The different sized blobs you get on charts usually work out OK, but not in all cases.
  22. Edit, edit, edit. I've done lots of editing on the above post! Sorry. P.S. I confess it did used to say "wrong way round" - I've changed it to backwards.
  23. Yep. A lot of astronomical globes are backwards as if the earth was in the centre, where you obviously can't get your head. I think traditionally you see the backs of the figures when it's this arrangement and the fronts of them when it's the more familiar way around. I'm sure others will be able to give you more background. I got the 16 inch inflatable globe which I'm pretty happy with. It looks a lot better than you might imagine for a beach ball, the constellations are the familiar way around, and you can fold it away. My one has a gap where Hydra should be and I think a couple of the constellations were mis-labelled. Overall it's pretty good though. They've resisted the temptation to muck around with the traditional depictions with a few exceptions (Cetus as a whale for example) - and they only have the modern constellations on there and not weird ones like Antinous or Taurus Poniatovii. They score some points with me by having Hercules grasping I think an apple branch with cerberus as a snake. I think I'm right in saying they have Virgo with wings, a palm front and ear of wheat. I read through a copy of Ian Ridpath's Star Tales (online here) with the globe at my side - very enjoyable. To confirm my saddo geek status I also read through A Dictionary of Modern Star Names. Not saying I remember it all by any stretch!
  24. Sorry to dig this up again, but I've just been looking at my planisphere. The ecliptic only makes a good angle with the horizon for spring evenings and autumn mornings, so I'm now thinking the best time for eastern elongation is just February, and just October for western elongation... Anyhow, it remains the case that this spring evenings should be good this year and autumn mornings in 2015.
  25. Oh yeah - I should add I've had my best planetary views in the morning, I think because the atmosphere has had time to settle down. I think there is a lot of turbulence just after sunset, although it depends on the conditions I suppose. I'm not really a morning person. If my musing are correct then September mornings in 2015 should be ideal.
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