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Posts posted by Greathouse202

  1. I've recently been thinking about getting into astrophotography, however as a student the cost of equipment has sort of put me off on the whole thing. However just finished soldiering the once defunct motor in my scope back to life, and wanted to see if it was working, so I rigged up a holder for my phone and pointed it at the brightest object I could find, the moon!

    Here is the result of about 5 minutes worth of work:


    There is a lot wrong with this image, but for an afocal image taken with an iPhone and without the benefit of stacking, it came out all right, and more importantly on the basis of this experiment I think it's worth putting a little bit more effort into, and maybe with an app for longer exposures and stacking it could result in a few decent images.

    Has anyone else tried this? It seems like it might be a good way to indulge my interest in astrophotography until I can invest in proper equipment.

  2. I did a quick and crude measurement of the sagitta with some feeler gauges I use for valve adjustments, and it seems that the .044" measurement is accurate. Which leads me to believe that both of you are correct in thinking the figure labelled RoC is actually the focal length, which as stated would mean this is an f/11 mirror. I guess that answers one question for me, now I just need to figure out what to do with the thing, a 89.5" focal length would make for a simply huge telescope.

    Is there an advantage to an f/11 8" mirror, it just seems like the resulting scope would be ungainly?

  3. I just got a mirror along with a few other telescope bits from a local guy that was cleaning out his attic. The mirror is 200mm in diameter, and has the figures R of C = 85.9" and S = .044 written on the back of it, and I'm wondering what those numbers mean, I was thinking that if it is a spherical mirror R of C could mean radius of circle, but I'm nearly certain I'm wrong.

    If any one could give me some more info that would be great, if the mirror's any good it could be a fun project to build a scope around it. Thanks

  4. If you get time, have a look through the guide to used SCT's by Rod Mollise (click the cat to download it !):


    This covers older models by the main manufacturers and can give some pointers to look for. With Meade I believe it's the mounts that can have issues so be sure to ask lots of questions regarding the mount functionality.

    Thanks for the link, this came in really handy, the scope in question turned out to be a Meade 2080 B 8" SCT (the one with "muli-coatings" and and a 50mm finder), the guy selling wasn't super clear about things, I think he just didn't know much about it, and the scope was not collimated properly, though it was good enough to tell the optics were fine. In the end I was able to get it for a steal due to his lack of clarity etc, which is good since I'm a university student with a tight budget. I did a bit of observing through the scope last night, and collimated it as well as I could given my current lack of eyepieces (only came with a 26mm), the sights even with imperfect collimation were extraordinary and way better than my previous 60mm refractor. Additionally the mount and old school quartz control box work well and should be sufficient for beginning astrophotography some day.

    All told this may be a bit more scope than I need given the fact that I have only been observing for a few weeks, but considering it cost less than an expensive date I think it will do for now. Once again thanks for all the advice it came in really handy when making the deal and understanding the scope.

    • Like 2
  5. Another recommendation for Steve's book, a good general introduction to AP. I'm sticking with a DSLR for now rather than CCD or webcam, and for that I would also recommend Michael Covington's Digital SLR Astrophotography.


    Perhaps this isn't the right thread to ask this question, but is there a reason to go dslr rather than ccd or webcam? I was thinking of maybe going the dslr direction if only because I could use it as an every day camera when not attached to my scope...

  6. I'm picking up an 8" Meade SCT tomorrow (hopefully), and my ambition is to eventually get into dong some astrophotography, however before I dive in I'd like to do a bit more reading on the subject, and I was wondering if anyone could suggest a few good books on the subject? I've been reading loads online but a good reference style book, or even better a beginners book would be nice. Thanks.

  7. Thanks for all the advice, I have been doing a bit of research as suggested and I think that I'm pretty well prepared to give it a look over and determine if there is anything wrong, also I spoke to the owner and asked him to ensure that the scope would be collimated and cooled by the time I get there so I should be able to use the star test (assuming clear skies tomorrow). Thanks again.

    • Like 1
  8. I've acquired both of the books that have been mentioned, and been contacting tons of schools, and the news seems to be in my favor. I seem to be relatively up to speed on my math (at least for a beginner and according to the calc needed by the two books in question), and the representatives from the schools I've contacted have been informative and encouraging , so hopefully it will all sort itself out nicely in the end. Thanks again for all the good advice and for pointing me in the right direction.

  9. It seems there are a few questions about collimation, but unfortunately none answer my question, so here is yet another.

    I'm going to be looking an 8" Meade SCT from the mid 1990's later this week, it's an appropriate price considering it comes with a fair few accessories, and the seller seems pretty trust worthy. However the concern I have is if the scope isn't perfectly uncollimated when I try it out, will I be able to tell that it is poorly collimated, or will it appear as bad optics, and is there a way to tell?

    Thanks in advance for any advice, I don't want to too buy a scope with bad optics, or let a good scope go because it just isn't collimated properly.

    • Like 1
  10. I just purchased a Unitron/Polarex 114 w/ an equitoral mount and tripod, thinking it would be a nice cheap scope to work with until I could afford something a bit larger. The guy I bought it from said he thought it was from the 1960's, which if that's the case it's in pretty good shape, probably thanks to the wood cases it came in. It also came with a sun screen and rod, though the mount portion of that assembly seems to have gone missing over the years, but it seems to have all the rest of it's original equipment, even including the lens cap (which has a bunch of tape residue on it).

    Once I got it home, and after some of time spent observing Jupiter with it, I did a bit of searching and it seems these old scopes have a bit of a following behind them, and can actually be worth a bit of money to the right person, or at least more than the $75.00 I paid for it. So the question now is what should I do with it, if they are a collectors item should I sell it, and if so are what are they worth? post-29630-0-38341300-1363324424_thumb.jpost-29630-0-59002800-1363324433_thumb.jpost-29630-0-89698200-1363324328_thumb.jpost-29630-0-37993800-1363324330_thumb.jpost-29630-0-07907600-1363324407_thumb.j

  11. A warm welcome to the SGL a B.S.in psychology and neuroscience congratulation

    Hope you put it to good use I'm sure you will

    when you decide to get a scope please ask as there are so many pit fulls

    clear skies

    I actually picked up an old 60mm Japanese made Polarex refractor the other day for practically nothing, it's a pretty solid scope with a very stable equitoral mount, similar to the one below.


    However when I go to get a bigger and more expensive scope I'll be sure to ask tons of questions first!

  12. Welcome to the SGL my commonwealth compatriot. How's the light pollution around yours?

    The light pollution is pretty bad in some areas, but we are getting an official star park soon so we will have an area where the city shuts all of the street light off and assures darkness!

  13. Thanks George, I'm actually American (just living in BC right now) so I'll probably be looking at school back in the US, but I'm sure the standard texts etc. are much the same. I'm planning to contact a few universities over the next week or so and see what sort of work I would need to do in order to upgrade for a masters program. Most of the schools I've looked at say on their admissions pages that they will take students from a variety of undergraduate disciplines, though I suspect that I will need to take at least an additional year of courses before I'm ready.

    Thanks again for the advice and insight, I think with the right program and a bunch of prerequisite work I can make this work, just wish I had given this course of study a bit more thought earlier on.

  14. Well, I took AP physics and AP caluclus in highschool, however more recently I have taken two research and statistics classes for pscyholgy, which focus on t-tests, analysis of convariance, linear regressions, chi-squares etc. I've also taken college algrebra (this was required and easier than AP calculus), and a course called "methods of calculus" which covered applied differentiation and intergration. As far as physics, I've taken Physics I, which at my university went beyond what I covered in my AP Physics course in highschool, but not by a whole lot.

    I had planned to take more but needed needed to focus more heavily on biology etc. for my degree. I'm now thinking regardless of whether or not I apply to an astronomy program I will take at least one physics course this summer just for the sake of it.

  15. Id disagree, it would depend on your latitude. At the equator the circumference of the earth is indeed about 25000miles as has been said, but the further north you go the smaller the rotational circumference so by the time you reach the pole you only need to turn on the spot once every 24 hours.


    If you want to find out the exact speed at your latitude in Blackpool which has a lattitude of 53.8° N you would have to use the formula C=2 pi r cos(x), where x=latitude to find the circumfrence of the earth at you latitude and then calculate for the speed you would need to travel. Of course the forula above assumes the earth is a perfect sphere (which it isn`t) and therefore the answer will still be an approxiamtion, but it will be relatively accurate.

    Using 6378km as the radius of the earth and plugging in for 53.8° N I got a circumfrence of 23668km at Blackpool, from there it`s pretty easy to calculate the speed of 986km/h or 612 mph.

    More in the way of over complicating things but sort of fun none the less.

  16. I'm not sure if this particular part of the forum is the best spot to ask this question, but seeing as it is a question about studying the science of astronomy it seemed somewhat appropriate. At any rate on to the question:

    I'm a few weeks away from finishing my B.S. in psychology with a concentration in nueroscience, and I have been applying to tons of neuroscience grad programs over the past several months. However I'm also very interested in astronomy and have been considering applying to a few astronomy/astrophysics programs as well, I am especially drawn to astronomy because I believe that there is not enough interest in the field and I would like to do my part to advance the research.

    My only concern is whether or not I will be able to transition into an astronomy masters program given my current academic credentials; having a science degree I figure I'll be pretty confortable with the work load, writing style and the format of classes, however I'm a bit concerned about falling behind in math. I have taken several statistics classes in the last few years, but it has been around three years since my last calculus class, and while I am compotent mathmatically (80th percentile on the GRE's) I'm certainly not gifted.

    All of that being said my question is what sort of mathmatical ability is needed to do well? And if I were to apply to a program what sort of work could I do in the mean time to prepare myself for the challenge, for example would taking a summer course in calculus be advisable?

    Any input from those of you in the know would be appreciated, and sorry for being a little bit long winded.

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