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Found 18 results

  1. Hey guys.Its kronos here, and i m here with my Celestron firstscope.As you know ,its quite small with a focal lenght of 300mm.That means i can clean the mirros without unscrewing anything.What can i use to clean them that i can find in my house?Also can i use babywipes to clean them?
  2. I have just got a second hand Astromaster 130EQ. I want to say that i have collimated scopes before without the use of a laser but in this case i have 2 questions as this is so far out i cant see what i am looking at half the time. So hopefully you can help, thank you. Info about the first problem: The secondary mirror fixing screw that hold the mirror and the collimation allen key bolts were so loose the secondary mirror had rolled facing the bottom of the OTE. In every other case the holding screw never needed touching and all i had to do were make small adjustments with an allen key, no screwdriver was needed. So this case is a whole different scale then any other collimation i have ever needed to do. You probably all know that i need to get the center of the eyepiece in line with the center of the mirror before can move on with this step. Question 1 What is the best way to do this, shall i just eye it for now? (i have seen people measuring to the center of the eyepiece and then do the same with mirror but then i still dont know if the mirror is facing me directly.) Info about the second problem Every other time i have collimated a scope the mirror and scope were very low quality and just used for practice basically. The old scopes were used to see if i wanted to go further into this hobby which i definitely do. Any how the old scopes had a flat mirror and i could find the center by placing the mirror on paper and tracing a circle template. The thing is this mirror is concaved so any template iswill have to be pushed into the vurve (i think). Question 2 So how can i center the mirror without placing it face down on a piece of paper which cant be a good thing? Thank you. I hope i have not gone on to much, thank you for your patience in reading a long winded post.
  3. Heyyy its me again! Today me and my friend went out to observe! We spotted the moon and focused on it,took some okay pictures with my phone without an adapter( that means having to hold up my phone over the eyepiece 's tiny hole). Then we tried moving towards mars, relatively close to the moon. It wanst a dot but like a small circle with some colour, afterwards we moved towards stars,but instead of seeing these circles with the secondary s reflection in the middle, we saw small circles (like mars but smaller) they were green blue and red coloured i didn't think much of it but then i checked the mirror. And i saw some dust.... Pics bellow.Is it the mirror or is this normal? Also if its the mirror, how do i clean it without removing it, i have a celestron firstscope btw. Thanks.
  4. I have a pair of 15x70 binoculars but due to neck problems I am struggling to use them even when tripod mounted. I am thinking of making a mirror mount but I don't know if they are any good? Can someone please advise me on which mirror I need, size and thickness, fixing method etc.? Do they suffer from dew problems in the UK and if so is there an effective way around this? If anyone could advise me on this it will be very much appreciated. Thanks
  5. From purely visual & practical angles, are there any disadvantages or advantages between F4 or less, to F6 or more, in a Newtonian? F4 (or less) means shorter focal length so shorter tube but lower magnification. But what other pros & cons are there? Quite a few scopes between F4 & F5, maybe the most F5 up to F6 seems to be 2nd most common. What advice for buyers can be given from experience on best F ratio for 6, 8, 10 & 12 inch apertures in respect of optics features, maintenance & scope dynamics? (My first Newtonian 8 inch was F8 - too long. Second 12 inch was just under F5 - only just portable. Current is 10 inch F5 - lighter but I miss the 12's solidity if not bulk).
  6. Hi everyone. So I'm interested in grinding my first mirror and building my first telescope. I've been reading all that I can about telescopes and watching videos on YouTube. What I want to make is what would probably be best described as a Nasmyth Cassegrain style telescope. My initial idea is to use a 12 inch parabolic primary ground to a focal ratio of 15 and a flat secondary. With a 15 foot focal length the end result will be approximately a 9 foot tube, which is fine, that's actually what I want. I don't care that it won't fit in the trunk of my car, it's not an issue. After reading some articles I've learned that most Cassegrain style telescopes use a convex secondary and a steeper curvature on the primary. Would this be better? Would aberrations be worse with a flat secondary? I want as sharp of an image as I can get without sacrificing either aperture or focal length. It seems intuitive to me that a faster primary would result in a poorer image than using an f15 with a flat secondary...thoughts?
  7. Hello All! Currently, I have a Meade ETX 90 telescope. I really like it and get great views of the moon and planets out of it. However, I am hoping to upgrade to a large reflector. I am looking at various scopes ranging from the Orion SkyQuest XT8 to the forbiddingly pricey Orion SkyQuest XT12i Intelliscope. I know that aperture is one of the most important things to consider in a telescope, but I also realize that people can get "aperture fever" and go for scopes that are unnecessarily large. I am wondering; Is a bigger aperture worth the price jump from 8'' to 10'' or from 10'' to 12''? How much more will I be able to see? I have heard that the best telescope for a person is dependent on the kinds of things they want to observe. I don't really look at deep sky objects (though I am getting increasingly interested in them), and mostly enjoy the moon, planets, and a few double stars. I want a telescope that will accommodate this, but is also able to have a great grasp on deep sky objects. Honestly I think I am on the right track with the scopes I am looking at, but I really want some advice on which size is best for me. What do you think? Thanks for the advice!
  8. Hello, Am very new to this so apologies right from the start. I have recently just bought a skywatcher akyliner dobsonian 200p and i set it up. However the image is very blurry even when i remove all magnification and just look into the primary mirror eveything looks very blurry including the moon or nearby trees etc. I am unsure what the issue could be as i am eager to get started on my stargazing! Could someone please assist me or at the very least point me in the right direction. Kind regards
  9. A very nice condition TAL 1.25" mirror diagonal. Optically and cosmetically in excellent condition, just don't use it any more. £25 plus postage via PayPal fees paid or bank transfer. Stu
  10. Next up on the brown carpet..... ?? A very nice, Baader Maxbright T2 mirror diagonal in excellent condition, just a little dust on the mirror. This has 99% reflectivity, Sitall glass with 1/10th lambda surface accuracy. Male T2 connection one side and Female the other, both with original screw-on caps. Looking for £125 posted or £120 picked up at SGL11. Paypal fees paid or bank transfer please. Cheers, Stu
  11. This is a somewhat custom built, but very nice Denkmeier PowerSwitch. The original William optics diagonal was not in good shape when I received it, so I have replaced it with a nice Baader Maxbright Mirror diagonal, 1/10th wave lambda surface quality, T2 fittings either end. It also has a T2 quick changer fitted to allow correct positioning of the PowerSwitch. Everything is in very good to excellent condition, the diagonal just has some minor dust on it but is otherwise in excellent condition. The PowerSwitch allow you to use straight through, multiplied or reduced views with the slide of a lever, very simple, although clearly you need to refocus each time. Total cost of the components in this is rather high, probably approaching £400 or more! This would be very handy for binoviewers in SCTs or fracs with good back focus. The T2 diagonal has a nice short light path with a clear aperture of 35mm so most 2" eyepieces can be used with no noticeable vignetting. I use a 31mm Nag in these diagonala without problem. It is also handy for solar viewing with a full frontal filter, or potentially a Quark to give variable magnification, back focus allowing of course. Looking for £195 ono plus P&P via PayPal fees paid or bank transfer. I will put this on ABS too in the near future. Cheers, Stu
  12. I've just acquired a rather tired but fundamentally intact Fullerscopes 6" F8 reflector with MK.111 mount. This appears to be an earlier example, supplied with optics by Brunnings of Holborn - the mirror is marked on the reverse, though much of the writing has faded. Although the existing coatings are shot, I shall probably send this away to Galvoptics. but wanted to get see if anyone can shed some more light on the history and probably quality. Not sure if this is plate glass or pyrex, it appears neutrally coloured with no obvious tint - there are a few chips on the back rim at 3 o'clock which might testify to brittleness. The white rectangular sticker appears to be written in ball pen, with something like 'MD / 49' on the top line and perhaps Kirkwood on the bottom line. There are no visible marks on the flat/secondary. I might try a UV lamp to see if I can tease out any more detail from the worn text.
  13. Hi, new here so don't know if this is right place for this question. Can anyone suggest where to obtain a long focus 6" spherical mirror f12 ( minimum f10 ) preferred? Thanks, Robert H
  14. Hi friends, I'd like to make this sunspotter device for my personal use. It seems that I need to buy the following components: - Achromatic lens, 60mm, focal distance 700mm - Mirror 50mm x 50mm - 2 Mirrors 25mm x 25mm But I can't find any website selling any of those . I've seen lots of parabolic mirrors being sold in sizes >= 6'', I've seen tiny achromatic lenses, or lenses costing a fortune. Any advice on where to get lenses and mirrors is appreciated. I haven't looked for the plywood yet, but getting it should be easy
  15. I have had my Tal 2M 6 inch newtonian since 1998 and the mirrors have just about had it. (main has a scratch and foxing) I use my Skywatcher 127 mak/cass at the moment but I would like to get the old Tal back in commission because of the field of view aspect. 6 inch newts have come down in price these years and I was wondering would it be cheaper to buy another 6 newtonian or get the mirrors recoated.
  16. Hey guys A guy in my area is selling a 13.1" Coulter Odyssey, the 2 mirrors. I'd want to get an idea on the optical quality of them. He bought the many many years ago, and they still in the original package, hasn't been used. 1. Would the optics degrade over time if they were wrapped up? 2. What is the general quality of the mirrors. I have heard the optics can vary alot, and they generally not that great for planetary views. 3. He is selling them (and he mentioned the Rocker once) for around $350, is this good for a un-used mirror. I'd like to build a really nice DSO / Planetary Dob, and this gives me hope if the optics are really good. Any advice, tips etc would be greatly appreciated. Tx guys
  17. Howdy folks Whats the best way to clean a mirror, specifically what i think might be tiny metal flecks without causing scratches ? there arent many and it doesnt affect visual use, but i'm tihnking it might affect taking pictures with it and leaving them in place while moving the scope might cause problems too as they will no doubt move from the vibrations of just moving the scope from one place to another is it doable? or best to leave them where they are ?
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