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Terrierist

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Posts posted by Terrierist

  1. Just under two weeks and I'll be in Fuerteventura for seven nights, I'm really looking forward to taking my camera with me to try and shoot the Milky Way and some widefield scenes whilst there.

    My equipment - Nikon D 7000, Tokina 11-16 AT-X Pro f2.8, stopped back to f3.5 to try and help with coma and a Manfrotto 755XB tripod that would support a small bungalow.

    I'm lucky to know the Island quite well and have some targets in mind already, there is one piece of the jigsaw that doesn't quite fit and I'd really appreciate your help and comments on it.

    My plan is to shoot multiple exposures focused on the sky/stars, stack them and then layer mask with some foreground exposures stacked too.

    I have seen a way to do this in Nebulosity in the video below from Dylan O'Donnell, it looks like you can click on a star in Nebulosity and use that as an anchor point, but it has thrown a couple of questions into my head.

    1) If I shoot four images at 28 seconds each at 11mm (using the 500 rule with crop-sensor adjustment of 1.5 applied 11x1.5 =16.5, 500/16.5= 30.30 rec) to allow some headroom, won't the sky have moved significantly enough to cause the software issues in  stacking the view accurately?

    2) The moon will be waning and go down below the horizon at around 22:49 but will be a 33% waxing crescent, will this affect my chances of shooting the Milky Way?

     

    Thanks in advance for any help.

     

     

  2. Don't do what I did and think that it's a simple upgrade from photography - It's a totally different animal and takes time, patience and some amount of money to get good results. If you are going to buy new, expect to budget (without a camera) at around a £1000/$1200 for a good mount and telescope. STAY AWAY FROM EBAY - until you understand a little.

    A good way into it is to buy a (good) mount and use your DSLR with a long lens on the mount, once you put a telescope on it, things start getting more and more involved. 

    Do NOT  scrimp on the mount, buy once, buy well.

    As others have said, Making Every Photon Count is a great book, familiarise yourself with your local sky by buying a star chart. Either that or obtain one of the excellent free programs such as Stellarium or Cartes du Ciel. I find a star chart easier to use just sitting there and looking at the stars.

    As a newcomer myself, I'd recommend you look at a refractor to start off with, they are easy to use and take very little maintenance - be wary of buying an inexpensive achromat version though, as you will suffer from Chromatic Aberration with a lot of them. The size of the scope and auxiliary equipment you will eventually use all depend on the mount you select. The HEQ5 is (as stated) the advised entry level mount, you can get away with an EQ5, but you can only expect so much as the mount has a lower payload.

    Why do you need a good mount over a telescope to begin with? Depends how well you want to track the object you are imaging in the sky. It is all down to cost and what you want from your images.

    If you want a relatively inexpensive way into the hobby that will get you up and running - and give you OK sort of images, search EAA (Electronically Assisted Astronomy) this is a little bit easier to get to grips with as you can use an Alt-Az mount at first to get you going. The other mounts mentioned are GEM (German Equatorial Mount) and your images will not rotate as much with them.

    Long-winded post, but I really hope it is useful, this forum and the majority of its members are brilliant,  they have helped me immensely and I 'm sure they will help you too.

    • Like 1
  3. 2 hours ago, vlaiv said:

    Not sure if there is simple explanation, but let's try one :D

    Light is wave, electromagnetic wave. It can have different wavelengths, and indeed electromagnetic waves have very large range of wavelengths that define their characteristics (radio, microwaves, infra red, visible, ultra violet, x-rays, gamma rays).

    Visible light has certain range of wavelengths and each wavelength we perceive as color of the rainbow (when you look at rainbow it is light separated into individual wavelengths).

     

    THIS!!!

    Great to read @vlaiv how do you explain to a newcomer about the RF of light and what is captured in camera?

    But for me as a very, very simple beginner, what would be a simple narrowband system?

  4. Really looking forward to going back to Corralejo in January 2019, this time I will be armed with my Nikon D7000, a Tokina 11-16 f2.8 and a 200 mm Tamron.

    Do any SGL members have any experience of the Island and structures to image around, please?

    I know El Cotillo and Toston very well, but I'm looking for more remote sites with abandoned houses/features etc to capture from.

    We'll have a hire car whilst there so I'm hopeful to do at least two nights out of the seven.

     

     

  5. Well, that was another interesting night!

    Was it a success? In some ways, yes it was. I managed to get rid of the little seagulls that I now realise were down to the temporary EQ3-2 Tripod I was using. 

    I'd mounted everything up in daylight and got the new EQDir cable I had purchased fired up, a simple com port change was all it needed and I was direct to mount.

    Polar alignment was a two-stage thing, firstly, ball park with the Polemaster and then onto Sharpcap for a final tweak, the QHY camera DID NOT!!!! Want to play at first and left me scratching my head. I'd put a USB extension cable on to relieve some cable pull and it really wasn't happy. After removing the extension it was all sweetness and light, reported PA error on Sharpcap was 20 seconds, very happy with that as the PA error when I started was 5 minutes 50 seconds with Polemaster.

    Being close to Polaris, I tried to set that as my first sync star in Stellarium, this threw a hissy fit and wouldn't accept the co-ordinates and crashed on sync. I swung over to Capella and lined that up, plate solved for confirmation in APT and tried to sync, again, Stellarium crashed. Tried again and this time it worked, for now. I wanted to to attempt my first EAA in that area and slewed to Pleiades, this synced first time after a very short plate solve and I thought things were looking up. 

    As a confirmation I slewed back to Capella and the result was way off, I had to find the star with my finderscope and then re-sync, it just wouldn't have my CTRL+3 commands, I platesolved in APT and tried to sync in that, it came up as success but something wasn't right as every time I slewed, the system wasn't storing co-ordinates - except for Pleiades.

    I set Sharpcap running and got some data from 6 second exposures that live-stacked in front of me, a sort of result.

    Slewing to the Double Cluster nearby, Stellarium reported it was on target and by this time I was getting cold and grumpy so started a new live stack sequence going. The following images are what appeared, after sending them through astrometry.net it seems I was a way off, but these are a stack of 20 images of 27 seconds exposures which seem to have come out ok, I hadn't properly focused the camera as all the other faffing about had taken my eye away from that. I didn't capture anything whizz-bang super duper, but I have now seen my first 9th and 10th magnitude stars from my red-zone polluted back garden. 

    The wife came out and shook her head in dismay as I huddled over the laptop screen, dew forming and me muttering that I couldn't feel my feet, it was time to call it a night and have a look what my first, fraught EAA session had given me.

    Has it put me off? No. Has it made me want to do more? Yes.

    I'll be really glad when I get the pier sorted, it's being welded together shortly and I will have to lay the concrete slab for it soon. I can't wait to have a permanently mounted system that I can place a scope on and go

     

     

    test1.thumb.jpg.57b5d57ae1f36d87deff2b6a09272b7f.jpg

     

    test2.thumb.jpg.d5eb300b535931271ae25c9baba4f9ba.jpg

    • Like 3
  6. 3 minutes ago, Stub Mandrel said:

     

    (don't be an EAA hair-shirt purist, capture your stacks and use them for a bit of AP as well!)

     

    It's just what I intend to do, Neil! :D

    I'm on the Sharpcap Pro License and will be aligning before I try anything. 

    Short session planned for tonight, will post what did/didn't work out along with the images, hopefully.

    Kev

     

  7. 4 hours ago, Martin Meredith said:

    Hi Kev

    I think the name of the game for EAA is simplicity. You can get perfectly good images for our purposes -- which is mainly observation rather than AP -- without cooling, without guiding, without (much) calibration (some kind of bad pixel removal is useful though), and without post-processing. I do all my EAA-style observing in alt-az under these conditions. So long as you can set up your kit to get reasonable tracking for 15-30 second subs you should be OK (you can produce decent images with even shorter subs too). Speed is important though. I operate at f4, and I'd say most EAA-ers operate at f5 or under. I have one USB cable from camera to laptop and that's it. So my advice would be to try out EAA with a minimal setup based on what you have and see whether it delivers for you.

    Martin

     

    Martin.

    Thanks for the reply and info, tomorrow is being shown as relatively clear up until midnight, fingers crossed. 

     

  8. 5 hours ago, Stub Mandrel said:

    I suggest you share some of your pictures and what you think the issues with them are.

    If you can't get half decent images with your present kit, you might find the investment in a cooled camera or an EQ6 brings expensive frustration rather than improvements.

    My experience is that getting advice and building experience is as effective as spending money!

    I agree with you Neil.

    However, with the very limited time I have at the moment and until I have a permanent mount outside, EAA may well be just what I want to do. 

  9. 3 hours ago, Thalestris24 said:

    Yeah, I was just referring back to the op's struggles to ordinary dso imaging. At the focal length of a 130pds and a 178 -> very small fov. Sure, he can give it a go!

    Louise

    Cheers all..

    The 178 has been my camera on my previous scope, a WO ZenithStar 71. When funds allow then I'll buy a more suitable camera, but for now! I could always put my DSLR on the setup, but then I would be at or around the mount's weight limit.

    Let's see.

     

    PS, I have Steve's two books and re-read them regularly, still loads to learn.

     

    Kev

  10. 8 hours ago, Thalestris24 said:

    Hi Kev

    Yes, you should be able to do EAA (electronically assisted astronomy) with your setup. Do you have a coma corrector or reducer? I've been thinking of getting a 178mc-cool myself :p. Just wondered what difficulties you've been having with dso imaging? Maybe someone here can help/advise :)

    Louise

    Hi, Louise.

    I think I've been struggling with the mass of information this extremely technical hobby requires, to be honest. That and the cloudy nights and set-up / take-down etc etc... I'm not giving up as I am just about to build a pier to allow me to be ready within five minutes or so, that will help I'm sure.

    I don't have a cooled camera as of yet, that is down the list after saving for an EQ6R, one thing this hobby and indeed, this forum, has taught me is that to get good results you need to invest a fairly sizeable chunk of money.

    The coma corrector will have to wait for now as it will divert funds from the EQ6R although I do understand how necessary they are with the 130 PDS.

    My difficulties with DSO are integration time from a Bortle 8 site and actually getting good calibration frames, the flats are especially difficult not having a temperature set point for now.

     

    Kev

  11. 1 minute ago, vlaiv said:

    I would say that you have everything you need to give it a go, really.

    SharpCap can do live stacking, so it's just the matter of trying it out.

    https://www.sharpcap.co.uk/sharpcap/features/live-stacking

    https://docs.sharpcap.co.uk/2.9/13_LiveStacking.htm

     

    Good evening, @vlaiv

    I've just been reading one of your replies to a post in the forum, this looks very interesting indeed.

     

    Kev

  12. Hello.

    I've been trying, rather unsuccessfully, to image various DSO and globulars.

    I came across the Video Astronomy section of SGL by accident and it piqued my interest.

    My set-up is as follows, tuned EQ5, SW 130PDS and ASI 178 MC camera, guided by a SW 50mm Guide Scope and QHY 5 Lii C. I have SharpCap Pro, APT and all the usual suspects for stacking/processing

    Would my setup be suitable for Video Astronomy/EAA (is that a correct term?)? I don't want to capture APOD's but I would like to view (and save the images) for my own use and enjoyment.

    Thanks in advance for any help.

    Kev

  13. 13 minutes ago, ollypenrice said:

     

    Which looks like a 'best fit' with your problem?

    The fact that a scope is new doesn't mean you should expect it to be collimated after delivery. This is unlikely, alas.

    Olly

    Hi, Olly, and thanks for the link.

    I've got seagulls everywhere! I'll have to wait for the collimator to arrive and see what I can find with that, but I do think that the EQ3-2 Tripod the scope and mount were attached to last night certainly added to the issue.

  14. 4 minutes ago, david_taurus83 said:

    Tracking? Guiding? You wouldn't notice any minute movements visually through the eyepiece but a camera will record them.

    After looking at what equipment I was using last night, I *think* that this is the answer.

    I'd taken my steel (round) legged EQ5 tripod apart for the puck at the top. This has gone to my friends to be incorporated in the pier I am building with his help.

    I was using an EQ3-2 tripod (square legged) and noticed it was about as steady as me after six pints.???

    Could I be on the right track?

     

  15. Hi All.

    I Joined the 130PDS club over the weekend after reading the reviews and seeing the shots with the 'scope. 

    I've never seen the Pleiades as beautiful or as sharp and was itching to get a camera on the set up.

    When I did, the stars all appeared like little Seagulls, all the way from the centre out to the edges, is this likely to be a collimation issue (with it being a new scope) or is the mount/tripod moving likely to be more the issue?

    A little confusing to see such bright stars that appeared sharp through the eyepiece and then the sky looking like Blackpool sea front when I switched to the camera.

    I forgot to take an image to display the problem, I apologise.

    Looking forward to getting the Cheshire from @FLO when Royal Mail can be bothered to deliver it...

     

    Kev

  16. Sir, thank you for an amazingly comprehensive reply.

    Could you help me with the following as I do not know how to achieve what you mention - "Just take couple of bias frames and look for smallest pixel values across the image - no pixel should have as low value as 4ADU. Ideally you want your lowest values to be >40-50ADU. If you have some sort of stats tool - just look at min in each bias file, and if each of them has min pixel value larger than said ~50 then your offset is good. If not - look to increase it."

    How do I find smallest pixel values and ADU from the Bias images?

    Thanks in advance.

     

     

    Kev

  17. On 09/11/2018 at 18:46, emyliano2000 said:

    2 nights ago I took advantage of the moonless night and I went for it again. This is the final result. A total of 9 hours worth of exposures.

    LRM_EXPORT_823169948845332_20181109_064025519.thumb.jpeg.8026398ed664b0818ad28dde5b684321.jpeg

    Better?

    Well done, I hope to be able to image this target as well one day, thanks for sharing and giving inspiration

    • Thanks 1
  18. Folks, your advice, please.

    Current set-up - William Optics ZenithStar 71, 9x50 Skywatcher with QHY5ii for guiding EQ5 (tuned) ZWO ASI178MC un-cooled with IDAS LP2 2" inline, EQMod/APT/PHD2.

    I've seen some pretty stunning images produced with an un-cooled camera and wonder what I am doing wrong?

    I'm running the camera at Gain-0 and Offset-25 as I'm applying old ISO logic lower the gain, less noisy the image. Does upping the gain a little have such an adverse effect with a CMOS camera? Being under city skies, what sort of integration time should I be looking at for something like, say, Pleiades or M13?  Would dither help, if so, how the heck do I set it up as for the life of me I can't sort it out! :D

    I'm starting to build a pier and the base for this will be going down in the next couple of weeks, It really looks like astronomy is here to stay with me and especially imaging as I find it such a bloomin' interesting challenge!

    Image attached, this was about 2 hours of lights with flats, bias and darks processed in AstroPixel Processor.1547320780_Andromeda06102018.thumb.jpg.31647e6c0968b00c9de6f9e9a0431b57.jpg

  19. On 10/11/2018 at 06:56, nightfisher said:

    Your mount would handle a few nice scopes like 127 and 150 Maksutov, but you will always have a narrow field of view with these and the 150 mak is a long focal length, another nice scope to consider is the GSO 150 F6 newt OTA, a very good performer on a lot of stuff from Luna to some dso

    Jules, many thanks for the recommendation, will look at this.

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