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SyedT

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About SyedT

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    Star Forming
  1. Surplus items for sale

    Hi. I haven't received the PM; however, the counterweight extension bar has been sold today. Sorry about that!
  2. Hi ReZ, I was imaging last night in -6 degrees. My way of counteracting the cold was to buy a secondhand Panasonic Toughbook, which is weatherproof. I also place the laptop on a chair + cover the whole chair with a light blanket. This has worked for me every time there has been frost; the frost has not touched the laptop and it has functioned fine.
  3. Surplus items for sale

    I promise you I copied the link, the need to use the paste function seems to have exited my mind temporarily. Link up now.
  4. Surplus items for sale

    Have a few surplus items up for sale, all prices inclusive of postage. All items can be viewed here: https://drive.google.com/open?id=0B12lFcbG64vNS0QwUzVnaUhlMTg. 1. Flats Panel - SOLD 2. Canon EF 70-300mm f/4-5.6 IS USM lens £190 - Bought a few years ago, but has only been used for initial testing and then maybe 5 times as I use my 14mm, 50mm and 24-105mm lenses mostly. Cosmetically and optically in excellent condition. 3. FLO Adapter for Skywatcher Focal Reducers £18 - Not being used as I have sold the rest of my Skywatcher kit; has the usual marks from usage, but functions fine. 4. Revelation Self Centering 80mm Extension Tube 2 Inch £20 - This has only been used a couple of times as I found it wasn't suited to purpose. Has a couple of marks from insertion into the focuser. 5. Skywatcher NEQ6 Pro Counterweight Bar Extension - SOLD 6. Skywatcher NEQ6 Pro Dual Saddle (new puck) £22 - I've switched to the ADM dual saddle, so this is now surplus; has the usual chips from mounting dovetails, but no major damage. This is the new profile (the one on the left in the picture): https://www.deepspaceproducts.com/uimages/adm/EQG-A_Comparision.jpg Payment via PayPal (buyer pays fees) or bank transfer. Cheers, Syed
  5. Thanks for that; hopefully souls33ker will find this useful too as I seem to have hijacked his thread, sorry about that! I'll message you with any questions.
  6. Excellent, thanks for that. So what is the best way to calculate optimum exposure at a particular gain setting, if one wants to use shorter exposures? The table I've been using has been giving good results so far, as it gives me an ADU value to work with. I was previously just eyeballing the image, which can be hit and miss.
  7. Thanks for the explanations, very clear and concise! I've read a lot of threads about the 1600MM, and understand that there is a loss of dynamic range, but this has to be balanced up against limted imaging time + mount tracking errors + light pollution etc. Can a higher gain value not reduce exposure time required for a particular target by swamping read noise more quickly, and also in combating sky glow? I live in a Bortle 5 zone so that's pretty important for me. I've also read that lower gain means a higher risk of posterisation unless you stack a reasonably high number of subs (a problem which I was definitely experiencing at unity gain). I've been getting good low-noise results with reasonable dynamic range with G300O50 so far.
  8. This thread is also an excellent read, particularly Jon Rista's posts: https://www.cloudynights.com/topic/548812-1600mm-cool-gain-offset-and-taking-advantage-of-imaging-time/. He has done a lot of experimentation with the 1600MM's settings, and explains things very well in his posts. It's probably worth sending him a message if you get stuck.
  9. I'm currently imaging M31 whilst I wait for IC 410 to get into a better position; see below. It's a 30s exposure at unity gain; the exposures are 30s, but I'm only looking to stack 64 each of LRGB channels. This is a reasonable number of subs + 64 subs recovers a couple of bits (which helps a lot as the 1600MM-C is a 12-bit CMOS) and reduces posterisation. I can then add to these as and when I need to. You can see below that my ADU value is within 50 of the advised optimum value.
  10. Trust me, I'm the last person who wants to fiddle around, as if I need to add to the problems I already have with my equipment! I find that if G300 isn't working for me, then I'll drop it straight down to 139. Those are the only two settings I use; I then look at the ADU and make a decision re: exposure time. It's very unlikely you'll find such a setting, depends on the faintness of the target. If you're imaging galaxies/nebulae of similar magnitudes, then you can definitely use the same settings; that would require a fair amount of planning though. I generally find I use G300 and Offset 50 for nebulae due to their fainter nature. I haven't tried much galactic imaging yet, so that'll be another experiment I guess.
  11. I completely get it. I mainly use high gain for faint targets e.g. right now I'm getting good data at only 240s per sub for IC 405 Flaming Star nebula. If it's something like M31, then I bump the gain down to 139 with offset 21. I've been experimenting, and say if I find a target gets saturated very quickly at G300 O50, then I bump it down to unity gain which gives me a reasonable number of subs but at the same time makes the most of the little imaging time I have. I use the below table which is on the CN thread I have linked: Median ADU shown in SGP: Gain 0 Offset 10: 400 ADU Gain 75 Offset 12: 550 ADU Gain 139 Offset 21: 850 ADU Gain 200 Offset 50: 1690 ADU Gain 300 Offset 50 : 2650 ADU The values do not have to be perfect; if I'm within ~500 ADU then I accept that. I've been using this table for the last couple of months and it has worked very well.
  12. This thread on CN is an excellent read if you use SGP: https://www.cloudynights.com/topic/570020-gain-settings-for-asi1600mm-cool/. I've been using the settings for Gain 300 Offset 50 with great results.
  13. IC 410 - The Tadpoles in Ha

    Rough mosaic, autostretched in PI only: I didn't realise that they were so close during my imaging of IC 405, hence the incomplete panels!
  14. IC 410 - The Tadpoles in Ha

    Excellent work Steve. I'm currently working on an IC 405 and IC 410 mosaic, did not realise that they were close enough together that I can do a mosaic with just two panels using my setup!
  15. Thanks Wim. Had a long session yesterday; upped my dithering to Extreme in SGP, which solved the issue completely. Here is a 50x180s stack of uncalibrated NGC 2264 subs: https://drive.google.com/open?id=1uidbpCaGdxnMOw6kpqH_cMnwwXM6XYeV. No walking noise visible at all.
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