Jump to content

740427863_Terminatorchallenge.jpg.2f4cb93182b2ce715fac5aa75b0503c8.jpg

username

Members
  • Posts

    284
  • Joined

  • Last visited

Everything posted by username

  1. I'm so sorry to hear you got blagged Mick, I hope you do try and follow it up. We're not all bad astronomers saying we're in Sweden though, some of us really are here! I've personally only ever bought from ABS and got stuff shipped from UK to Sweden. I have gifted paypal before but ONLY if I have dealt with the person before otherwise if they want gift i just cover fees Apart from the advice Mick has given from the ABS fraud section I have a couple more bits of advice; Postal charges to overseas for stuff bigger than a letter are extortionate over here, if a seller quotes cheaper than UK be wary (why i don't sell on UK ABS as it just wouldn't be cost effective). Swedish ideas of data protection compared to UK are non-existent. If you want to know if someone is who they say they are and live where they say they do and lots more go to www.ratsit.se . I was astonished when I was told about that site Even mobile numbers over here are in the directory so get any number off of them. It's bad that malovelent people are out there but I hope people don't get put off doing business with Swedes and us in exile over here
  2. My first thought is that whilst it may be possible I'm not sure if the correction before the eyepiece would be the same as the correction after the eyepiece. Whilst the angle of the astigmatism may be able to be easily corrected for the degree of abberation would be changed by the eyepiece. So +0.5 before eyepiece may come out as +1 at the eye end for examples sake. Plus the ey epiece can introduce distortions themselves. Secondly do you really need correction at that degree of astigmatism? I have some in one of my eyes and I can observe fine with it. I can't remember my perscription off the top of my head but I think it's 0.5 for short sighted astigmatism. Basically only eyepieces which give low enough magnifcation so that the circle of light coming out of the eyepiece (the exit pupil) is large enough that it gets affected by your astigmatism should need correcting. If the exit pupil is small enough so that the surface of the eye its hits is locally just spherically aberatted then you should be fine. Check this chart out at the bottom of the page. It's quite likely you can get away with it http://agenaastro.com/televue-dioptrx-astigmatism-corrector-0-25-drx-0025.html Have you tried observing without your glasses? Plus you can get eyepieces which have enough eye relief for glasses if needed.
  3. I don't observe with fast reflectors but I get a little bit of this in my mak, could the softening be a bit of coma on the edge? At high mags you may not notice it in dim stars but on the moon it could be more noticable. Like I said though I don't observe with fast reflectors so it could be absolute twaddle
  4. i think what everyone has got to remember with their newts is not too freak out if the secondary is a bit too small or bit too big. The synta scopes are mass produced optics and what makes them cheap is the manufacturers being able to standardise and stream line the production lines. That means standard tube sizes and secondaries which is going to limit the scope of compromise between illumination and secondary size. If a 10" scope is really a 9.5" scope it isn't too bad and it's still a lot cheaper than what the equivalent would cost 20 years ago. Plus as has been said before a small secondary might mask edge of mirror defects.
  5. you'll be alright with that on your own, just temporarily peg places if it's windy and there must be a quiet area of a london park somewhere you could try in daylight again. tunnel domes are easier than the 30 year old patrol tents we had in scouts!
  6. I think I edited it back in whilst you were replying as I don't think you had replied by then. I clicked submit and realised that I hadn't done it. I always send emails with 'Please find attached.......' with no attachments too. Always wake up to emails asking for the files The edit feature is new to me anyway, before I had to litter threads with corrections.
  7. hi the app link i edited back in as i forget whatever i'm doing within 10 seconds of starting it the cn link is here, it's about a gary seronik article and he comments on the thread. he knows a lot about newts http://www.cloudynights.com/ubbthreads/showflat.php/Cat/1,2,3,4,5,6,7,8,9,10,11/Number/2822245/page/341/view/collapsed/sb/5/o/all/fpart/1 the secondary is only ellipsoid if you look at it from a normal direction, when it's at 45 degrees is profile is circular so take the minor axis, the short side there's some suggestions in that link about what to do but it may not be much of a problem, you could sort out full illumination and find you got a turned down edge or something bad
  8. Put the dimension of your newt on this web app and it will tell you the percentage illumated field of your newt. If your dimensions don't give any fully illuminated field the the secondary is too small. There was a thread about this on cloudy nights. I'll see if I can find it. Whats the minimum axis of the secondary on the 250px? A 63mm should be about right for them but if it's too close to the primary then it will lose light. http://stellafane.org/tm/newt-web/newt-web.html
  9. Whilst you may gain portability with something smaller you may not be observing faster with a mak. With the winter just gone (that seems to be hanging about) my 4 inch mak could take well over an hour to properly cool. Just something to think about if you go mak/sct route. Have you considered making/buying a dob base for your 8" explorer?
  10. I would have to agree with the scope first crowd. I've made some eyepiece purchases to give some options at high power and I'm luck that I have a slow scope (so everything works ok). However all my astro funds are going towards a bigger better scope now. What you see will ultimately always be limited by your telescope aperture and quality of primary finish/objective finish/telescope design (and the weather ). Not saying that decent eyepieces aren't worth it though.
  11. teleskop service got back to me (very promptly) and its 50mm. @mr q which seems to agree with what your saying. Its 33% like an sct or my mak. well above 30% was what I was worried about. The 150p co is a bit smaller. @ star gazing thanks for help I've negotiated a new scope with the gf with the agreement that its the last toy for some time. I'm visual atm but wanted to get an all rounder with imaging later on and the 150pds keeps appearing on the list.
  12. They say on their site that they don't accept technical queries from joe public. I'll email Teleskop Service as they have had the majority of my astro money so don't feel weird asking them. I suppose it depends if they know off hand/have an open box example to check though. I'll report back in case people are searching for the same thing in future...
  13. It's infuriating that they don't list it. I saw a post from a couple of years back that quoted 29% from another source but that would make it smaller than the 150p which i thought improbable as the primary was closer to the secondary for back focus with cameras.
  14. Does anyone know the size of the central obstruction of the 150pds please? I can't seem to find a value after trawling the net. I'm thinking it should be bigger than the 150p CO due to the moved mirror but none of the suppliers have it listed and I haven't found any thing on the forums. Thanks in advance
  15. no problem. tbh whilst you can never over mount a scope but an az4 is probably a bit overkill for the smaller maks. I got it to get a better scope which is still being decided upon If you were looking at spending that sort of money though maybe look in to a nice geared photo head. I found the balance point on my 102 mak was sometimes at the point of the photo thread mounting depending on what diagonal/eyepiece/dewshield combo I head. On the friction/push tripod I tried (wasn't great quality) it could still be sort of unsteady depedning on what i had on the scope
  16. Az4 head is to large diameter at base for eq2 tripod and eq 2 head catches on the north pin of az4 tripod
  17. Sorry I missed the first bit, at constant wavelength they do have same energy. You expose for longer due to the mount of them per time per area. As a DSO is very far away and radiates for arguments sake isotropically the amount of photons reduces by the inverse of the square of the distance but the flow of photons to your detector may be infrequent but will be regular.
  18. Aren't you just referring to the flux of photons. You expose any image for longer if the amount of photons per unit time at the area of detection is small compared to if it's large. The stream of photons will always be constant if the conditions are the same. Just less of them.
  19. There's a L shaped adaptor for the AZ4 for scopes that have the photo attachment. The skymax 90 and 102 don't have standard dovetails so if you don't get the adaptor you'll need rings and dovetail for the az4. If you go rings and dovetail route it's easy to remove the photoadaptor from the bottom of the mak. I took delivery of the AZ4 for use with my 4" mak a couple of days ago,I just got rings and dovetail for versatility. I haven't checked yet if it will fit my eq2 tripod (no time to play ) but will check tonight if I remember (if I forget PM me and it will show in my email). One thing I have found with a photo tripod and my skymax 102 is that it could still be quite hard to balance as there is no leeway in the mounting point.
  20. The way I understand it is that they are an occurence of an event involving 'actual' particles. Sort of like if two people swimming in a pool both causes waves which join and either cancel eachother out or make a bigger wave. If that wave pushes the ball that's also in the pool then the ball has been pushed by a 'virtual' swimmer. I may be wrong there. If the universe is expanding then the probability of real particle interactions causing virtual particle events both reduces and increases. Things are moving further apart so interact less and with less energy as the energy has more volume to cover. That's the reduction. However matter in the universe can't distribute evenly fast enough to compensate for the expansion so there's local concentrations (stars galaxis etc). Working on the assumption that virtual particles exist due to real particle energy events and the number of real particles in the universe is constant then it's a balance between the rate of expansion and the speed of matter diffusion in the universe. Or something like that?
  21. I've often thought the same; bit of aperture loss due to meniscus front end, lack of snazzy coatings inside (I'm sure we'd be inundated with supplier acronyms if they did) so refraction/reflection loss, secondary diffraction.... I set about trying to find out once but trawling through the sources online you often find yourself in theoretical arguments that take the fun away. Better to go outside and look at something
  22. Good shot! Yep, I regretted leaving for work this morning. Not as bad as yesterday though, the wind took my breath away
  23. I have a Skymax 102 on eq2. I like it because it's small, light and easy on eyepieces. I observe mainly from a balcony and the small form of the scope is really apppreciated.I haven't found cool down to be too long with this size either although I haven't anything to compare it too. I don't like it as the aperture is pretty small although ok for solar system/double stars. In it's defence the seeing round here is normally pretty atrocious especially from the balcony and the built up area so not sure how big in aperture I could actually go. Looking at upgrading but think I will always keep it for solar/grab and go.
  24. Yep, they still do my degree administered by the biosciences which was biological and medicinal chemistry however not straight chemistry. When I signed up my degree was straight chemistry with stuff like molecular and cell biology. Now all the chemistry modules are more biorelated. They even stopped physcial chemistry for a bit hence Professor Shaw teaching us it on the sly It was extra to our degree modules. Unfortunately it costs at least 10 grand a year to teach a Chemistry student. Lady Ga Ga courses are more profitable
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.