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nephilim

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Posts posted by nephilim

    Canon lens question

    in Getting Started With Imaging

    Posted

    7 hours ago, nephilim said:

    I think it does as manual focusing wide open at 2.0 is pretty tricky although I'll more than likely be stopping down to 2.8. I will be emailing the other company (last link I posted) to ask if they do a focus ring 

    As a side note Ande I will be buying the Bahtinov Mask from the first link as they do one specifically for the Samyang.

    Deep sky stacker - Calibration

    in Getting Started With Imaging

    Posted

    On 17/12/2020 at 07:03, woodblock said:

    I use deep sky stacker for calibration and registration of images but I wanted to clarify one aspect.

    I start with cr2 files directly from my canon camera. DSS builds the master darks, flats, bias and so on and then calibrates the lights. I get DSS to save the intermediate files as FITS files which at that stage have three colour layers - RGB. So my question is - does DSS treat all these three colour slices as separate images all the way through the process?. So when it builds the master dark for example it combines all the red slices, then all the green slices and then all the blue slices. And does it do that all the way through? So when it combines the master dark with the lights it does each colour slice separately resulting in a file which still has three separate colour layers? I know that the intermediate FITS files do have three separate colour layers.

     

    This has me curious now. I'd have thought that it wouldn't though as when imaging RGB with a mono camera I'm sure you have to also take seprate  calibration frames in each colour channel.

    Canon lens question

    in Getting Started With Imaging

    Posted · Edited by nephilim

    9 minutes ago, Ande said:

    On the original link you posted, does the focus ring  make focussing more precise? It looks like it should as it effectively increases the diameter. 

    I think it does as manual focusing wide open at 2.0 is pretty tricky although I'll more than likely be stopping down to 2.8. I will be emailing the other company (last link I posted) to ask if they do a focus ring 

    • Like 1

    Canon lens question

    in Getting Started With Imaging

    Posted

    33 minutes ago, Ande said:

    After much deliberation I have put an order in for the Samyang lens. All being well, it should be in my eager mitts by tomorrow. Just hoping that I get one that can achieve infinity focus, as a few seem to have received ones that fall just short. Not sure how many of these people have had a filter removed from their camera though.
     

    I watched a few YouTube videos last night, and the Samyang seems incredibly well lauded even by regular, terrestrial photographers. So I should be able to get much more use out of it hopefully. If it performs as well as I hope, then I might even shelve the telescope for imaging notion altogether. The Samyang would certainly be a lot simpler, and more portable. Just need to find the best way of attaching a guide scope, but that’s a way off at the moment. 

     

    Huge thanks to everyone who chipped in. It really is much appreciated.

    A guide scope can be attached using the mount I posted earlier, I'll be using my Skywatcher Evoguide ED50 & ZWO ASI 120MM-S as my guide setup.

    • Like 1

    Canon lens question

    in Getting Started With Imaging

    Posted

    7 minutes ago, Ande said:

    Is the mounting system a must-have? I can see the obvious benefits, and would happily purchased one.  However, the fact that it is overseas, coupled with a pandemic and Xmas makes the pessimist come out in me. I’m keen to get going this side of Xmas, weather permitting.

    You can always try it without but imo you need the sturdiest setup you can get to reduce flexure & tilt. No harm in trying it without first though.

    • Like 1

    Canon lens question

    in Getting Started With Imaging

    Posted · Edited by nephilim

    1 hour ago, Ande said:

    Hi all

    I’m about to take the plunge and buy a Canon DSLR.  I have decided, after much deliberation, to settle on the Canon 80D. I am hoping to get into astrophotography with it. I have just purchased a very sturdy tripod, and ball head. And I also have an Ioptron Skyguider Pro winging it’s way towards me.  What I don’t have is a telescope at the moment. I have my eyes on the WO Redcat, but the pandemic has put this in hold for a bit. Which leads me to my question........

    I can either purchase the Canon with an 18-55mm IS STM lens, or with an 18-135mm IS USM lens. From what I can gather, neither are particularly well regarded. I’ve read reports of focusing problems being an issue around the infinity mark, and also of the image quality being quite poor. But, which of the two will be the most useful to me while I play the waiting game for a telescope?
     

    I realise that the results will probably be disastrous when I factor my own ineptitude into the equation as well, lol. I had considered buying a prime lens of a fairly long focal length for some deep sky stuff, but the good lenses are the price of a decent telescope anyhow. 

    Possibly not the way your wanting to go but I've just purchased the Samyang 135mm 2.0 ED UMC which is a well regarded lens for AP, so much so that there's a whole thread dedicated to it on here. I decided on this lens over a scope after reading this thread. I recommend reading this before you decide.

     

    • Like 1

    Street Lighting Petition

    in The Astro Lounge

    Posted

    I'm lucky enough to live in the North Pennines AONB & our village has just one street light at the very end of the village, we all have to use headtorches to get around at night.

    Crime isn't an issue here at all but that's possibly because the village is in the middle of nowhere.

    • Like 2

    Imaging with the Samyang 135mm f2

    in Getting Started With Imaging

    Posted · Edited by nephilim

    6 minutes ago, nicoscy said:

    I only do EAA, but considering a full moon and only 7 x 10 second frames stacked via ASIAir Pro and no calibration frames, the camera delivers. I used the ASKAR FMA180mm lens at f4.5 with the ZWO Duoband filter.

    No post-processing, this is straight out of a screenshot at the 70 sec mark of a live stack view.

    IMG_0231.JPG

    That's pretty impressive for such a short exposure time. The lack of amp glow & only having to take flats with this camera also appeals to me.

    1 hour on NGC7000

    in Imaging - Deep Sky

    Posted

    On 15/11/2020 at 20:36, Phillyo said:

    I let the dogs out earlier this evening and noticed that it was actually clear here in Lincoln for the first time in weeks! Decided to try and snatch an hour on NGC7000 and give it a gentle process. It's a bit grainy, a bit noisy and it's not my finest processing ever. However, it's nice to actually catch some photons for a change! I'd like to add a LOT more data on this area, like another 19 hours or so.

    Kit as per sig with the IDAS NBX filter.

    Thanks, Phil.

    NGC7000.jpg

     

    On 19/11/2020 at 11:09, Phillyo said:

    Added another 5 hours of data last night and reprocessed it (without drizzle this time Vlaiv ;)) so this is now 6 hours with a slightly different process. I've done stars and starless as I really like seeing both? 

    NGC7000_Stars.jpg

    NGC7000_Starless.jpg

    Very impressive.

    • Like 1

    Imaging with the Samyang 135mm f2

    in Getting Started With Imaging

    Posted

    20 minutes ago, Phillyo said:

    That is the 533 that you see attached there and it works perfectly. The lens has a very high resolution so sampling at 5.74 is perfectly fine. I have a number of images up in the DSO area of the site if you want to have a look.

    Pricing is tricky to find on that website, however if you click on the images, then click on "Do you need one?" it'll take you to this page for the prices of the various different parts. You can choose from a number of options to suit your needs http://www.astrokraken.fr/bracket-system-for-samyang-rokinon-135-f-2-telephoto-lens-a183920490

    Phil

    Thanks for that. Also great to hear that the 533 works well as its the camera I've had my eye on for a fairly long time. I'll check out your images. I'm highly excited about this lens.

    Imaging with the Samyang 135mm f2

    in Getting Started With Imaging

    Posted

    14 minutes ago, Phillyo said:

    I went with this guy http://www.astrokraken.fr/samyang-135mm-f-2-c30078976 I have the 3 ring version with 3 holders, 2 for the lens and 1 for the camera plus the micro focuser which is amazing for nailing focus!

    Image of set up below.

    20201116_180535.thumb.jpg.139a92195ec2db8637f65633576c9b80.jpg

    Very nice set up. I'm going to use a DSLR to start with then looking at the ZWO ASI 533MC Pro. Although If my calculations are right (questionable) using the 135mm with the 533 will result in a resolution of 5.74 which I 'think' will lead to oversampling, may have to have a rethink on that. 
    Do you have a price for this? Unless im blind I cant seem to find it on the website. Also, do you know the average turnaround time from purchase to delivery

    Imaging with the Samyang 135mm f2

    in Getting Started With Imaging

    Posted

    3 minutes ago, nicoscy said:

    Just ran into this topic - nice images people! - and if of any use to anyone, Teleskop Service put this up on their site a couple of weeks back: Wega Tube Rings with Finder Shoe and Dovetail Bar for Samyang 135mm f/2 Lens

    Thanks for the link mate. I was just thinking how I was going to mount this lens as a I don't think a 1/4" photo thread on a dovetail will quite cut it.

    • Thanks 1
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