Jump to content

Narrowband

PeterStudz

Members
  • Posts

    983
  • Joined

  • Last visited

  • Days Won

    3

Posts posted by PeterStudz

  1. 1 hour ago, GasGiant said:

    This is a great thread, really useful.

    Maybe I missed it, Can someone explain how you polar align please ?

    Is it simply pointing the pointy end north as accurately as possible ? 

    Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ? 

    “Maybe I missed it, Can someone explain how you polar align please ?

    Is it simply pointing the pointy end north as accurately as possible ?”

    For visual that’s accurate enough and all you need to do. There are ways of getting it more accurately aligned, but unless you are trying to do long-ish exposure astrophotography don’t worry about it now.

    ”Also, im at 51 degrees. Should I use the 50 or 52 degree wedge ?”

    It doesn’t matter… 50 or 52 will be more than good enough. 

  2. It’s all very personal with no right answer. Eg the only filters I’ve found useful are the Astronomik UHC and a variable polarising. IMHO the cheaper UHC filters are a bit pants and the variable polarising I’ve only used on Mars. But for me it’s been very useful on Mars. 

    But for me I found a chair so useful. I don’t need to “stoop”, but in my job I stand/walk all day and the thought of having to stand for another 4 hours at my Dob (which I’ve done) doesn’t make me feel very relaxed! 

    • Like 1
  3. 38 minutes ago, bosun21 said:

    I have owned and sold two of them. I can't get on with my face pressed against the eyepiece. I have to be comfortable when viewing the planets for any amount of time. Give me a large eye lens and 70°+ FOV with at least 18-22mm eye relief anyday. I'm more than happy to be the odd one out in this case. Optically though the SV 3-8mm zoom is great.

    I have the even more “budget” Svbony 7-21mm zoom and I have similar issues with FOV and eye relief. I sometimes observe wearing glasses (my daughter always). In fact she can’t stand the thing and I get comments like “errr… not that thing” if I go anywhere near it. Although there’s obviously better out there It’s put us both off zoom eyepieces. That and the fact BST StarGuiders (which I have) have proved optically better anyway. 

    • Like 1
  4. On 23/01/2024 at 11:20, Kon said:

    I am not sure which scope you have but with my 200P the focuser was the issue. It has a lot of wobble. When I was collimating it, I found that all looked great with the cheshire but a star test was a bit off. Putting the cheshire back in it was off. I found as I was rotating the cheshire along the focuser it was wobbling even if I thought I had tighten it, or the tightening was never even. That of course throws your secondary being off, although it may not be the case. I resolved it by doing the collimation and making sure when I inserted eyepieces to be tighten the same way. The way the focuser is hold in place by the two thumb screws is also goining a lot of play. Not an issue for visual but for planetary imaging I wanted to have it spot on. This way star tests looked perfect.  Life is too sort for this kind of thing so I recently moved to a low profile focuser as it is a lot more steadier and with the use of Baader clicklock I get even tightening. I have eleiminatedthe wobble of the focuser and it has made collimation a walk in the park.

    Interesting. I haven’t found this with the focuser on my 200p. However, I have taken it completely to bits and put it back together. I have also installed a Lacerta fine focuser, so it’s not quite the same as it was. It’s all rock solid. 

    The only play that I noticed was in the stock extension tube for 1.25 eyepieces. I replaced that with something more substantial and of a different length. I did that because I didn’t like the amount of draw-tube that extended into the light path. Probably makes no visual difference but it annoyed me! So much so that I thought of taking a hacksaw to the end of the draw-tube. But a different extension tube sorted that too.

  5. 1 hour ago, Stu1smartcookie said:

    I really dont know why i messed around in the first place !!!! 

    Thanks again 

    Fiddling with collimation when it isn’t necessary and making it worse is something that I’m sure everyone with a Newtonian has done at some point. I certainly have. And it’s often a sign that the weather is cloudy.

    Sometimes you get complete beginners launching into it, getting in a mess, then coming on here when it really wasn’t necessary… first just get your new toy out under the stars. Before trying to fix a problem that might not exist!

    • Like 1
  6. The tube I used was meant for model aircraft - fuel supply to a glow-plug engines - from the days when I made model planes. It’s flexible but quite stiff. If you put the slow-motion cable back on, tighten the thumb screw, and move it back and forth you should see if it works. 

    In fact the idea came via someone else and was used to help prevent fixings vibrating loose from running model engines. 

  7. If you mean the locking screws working loose then it’s a common problem. 

    I solved it by putting a small section of plastic tubing over the tread of the thumb screws. Just long enough so that when you tighten the screw it compresses the tube a little. That extra friction prevents the thumb screw moving and working loose. 
     

    IMG_0624.jpeg.537e06c8bdd7ee9d59bbfe7156167500.jpeg

    • Like 12
  8. Yes, I saw and thought about the acrylic sheet thing. I can see how it would be easier if trying to flock within a narrow tube. But for my 8” Dob it was so easy and straightforward to just stick it down the length of the whole tube I couldn’t see any benefit. I also flocked the inside of the focuser drawtube. Not sure if that was necessary but it was so quick and easy I thought that I might as well try. 

    • Like 2
  9. I flocked my 8” Dob 2 years ago when I was still very much a beginner. For me it was far easier than I thought and after I’d stripped the tube down the actual flocking took under a couple of hours. In fact I had the whole thing back together, collimated and observing the moon as it got dark. 
     

    I did the whole tube in 3 sections following the advice of someone on here. Although I found a head-torch useful when sticking the sections down. 

     

    • Like 1
  10. I also prefer the first softer image. To me, having done mostly visual, it just looks far more natural. I’ve been through the “over sharpening” thing in mobile imaging where I think it’s even easier to get caught-up in and where you are very much on your own. 

    • Like 1
  11. I have a NeXYZ but for me (we are all different) I found it over engineered, heavy and in practice no better than a simple, much lighter £10 adapter. Other than the moon I’ve taken smartphone snaps of…

    The Sun

    The International Space Station passing the sun

    Jupiter

    Saturn

    Mars

    Venus

    Neptune

    Uranus 

    Orion Nebula

    Various Star Clusters

    A Comet

    The Ring Nebula 

    Dumbbell Nebula

    Various Globular Clusters

    Various Galaxies

    Probably forgotten something. Basically everything that you can see at the eyepiece. I find it useful to record my observations and occasionally a bit of fun processing especially on those far too many cloudy nights. 
     

    To get an idea of what people are doing have you had a look at the “Imaging - Smartphone / Tablets” on this site…

    https://stargazerslounge.com/forum/279-imaging-smartphone-tablets/

    • Like 1
  12. Collimation issues can be seen by doing a star test. A beginner can do that too.

    From experience my 8” Dob takes about 50mins to fully cool. I generally allow 1hour but that doesn’t mean I don’t look/observe before hand. For a start it’s useful to be able to learn and recognise tube currents.

    A sky looking clear does NOT mean good seeing. You can have a crystal clear sky and very poor seeing. Sometimes you can judge poor seeing by stars “twinkling”. Sometimes not. Poor seeing is often caused by the jetstream which is 5-7 miles above the earth’s surface. It’s invisible naked eye. 

    You need a night of good seeing to do a star test. Otherwise it’ll appear “fuzzy/wobbly”. If a star that’s high in the sky is heavily twinkling then don’t do a star test. Or maybe give it a go in order to practice, learn & recognise poor seeing. 

    • Like 1
  13. 10 minutes ago, dweller25 said:

    @DAT


    A star test will immediately tell you if your scope is collimated or not.

    But good star test or not if looks like cotton wool and is unstable then your scope is either not cooled down or you have a poor quality sky.

    My scope is perfectly collimated and I know when it’s fully cooled, so if the views are poor - which they frequently are for me as I live just north of Manchester, then I know the sky quality is poor.

    This ⬆️. A star test is essential and something you should learn to do.

    • Thanks 1
  14. 8 minutes ago, DAT said:

    I think it must be more of a collimation issue otherwise I assume the picture would not be ok on the 30mm ep. At some point I will take up someone’s kind offer of help and get to the bottom of it. For the meantime I just have to keep trying and be patient 

    Poor seeing will be more obvious as you push the magnification. Eg for me on Thursday Jupiter looked small but tack sharp at x80 to x100. But at x170 and above it was a fuzzy mess.  

    • Like 1
  15. 1 hour ago, dweller25 said:

    The issue you are having could be poor seeing/jetsream related ?

    I thought it might be. There has been some very poor seeing the last week for me in Southampton. Monday the exception but still it wasn’t great.

    Astronomy requires patience. I can now recognise poor seeing, dew, transparency, collimation issues, stray light, when the OTA hasn’t  cooled enough… Eg for cooling I think it’s useful to look at targets as soon as you get setup and learn to recognise the issue. For me being able to recognise all of the above took about a year, maybe more. 

    • Like 1
  16. If dew is the problem you’ll notice it on your finder(s) first. So much so that I can’t see the finder cross-hairs let along the target. For this reason I have a finder dew shield too.

    If you think that your secondary has dew shining a light at it, down the focuser, will confirm or deny.

    As for collimation… have you done a star test? 

    The rapid change in temperature of bringing the OTA back into the house where it’s warmer will quickly create condensation on your mirrors (primary and secondary) and in situations where you haven’t even got dew. You will then need to wait a considerable time, sometimes a couple of hours, for the condensation to evaporate.

    Also keep in mind that heat from around your eyes/face can cause condensation to form on the glass of your eyepiece too.

    • Like 1
    • Thanks 1
  17. 1 hour ago, bosun21 said:

    I’m out again tonight to capture Jupiter again hopefully with better seeing conditions. After which I will switch to visual on some of my favourite targets. I’ll try and squeeze in a bit of Lunar also if I can bear the cold that long.

     

    BC24E374-AFAB-4F52-93CF-6ADE48C7011B.thumb.jpeg.3c3608ac1ba308fe3498b5f37411eef7.jpeg

    Good luck and Gods Speed! Seeing not the best here in Southampton and I’ve come in for a break. Although I could easily make out the GRS.

    • Like 1
  18. 8 hours ago, GasGiant said:

    Tempting. Expensive, though that version looks well made.

    Apart from being tarted-up the one at FLO looks like that in practice it’ll will work the same as the design on this site. The drive motor is identical, the pillow bearings look practically the same. The only real difference I can see is that the segments are made out of wood faced with metal. Where as the design on here has the segments all aluminium.

    Although personally I wouldn’t have the drive motor hanging off the end (more of a chance of it getting accidentally knocked) and I’m not a fan of the cut-outs. Although they will obviously make the unit lighter it will flex more and possibly introduce unwanted vibrations. 

     

×
×
  • 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.