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GraemeH

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GraemeH last won the day on March 22 2018

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About GraemeH

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    Nebula

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  • Gender
    Male
  • Location
    West Lothian
  1. GraemeH

    Renting Photo-Shop

    Nowadays there seems to be a growing community who believe that you're not "doing it right" unless you use PI. I'm not going to try to convince anyone that Photoshop is the best option - for some it clearly isn't, but it's exceptionally good at what it does. That does not mean that any of the other packages are not also very good. In the hands of a skilled processor I'd guess that decent data could be turned into an outstanding image in any of the packages on offer. With a much less skilled operator (such as myself) it's going to be a struggle no matter which package is used.
  2. I think I've finally reached the limit of my (current) processing capability with the data I have on this target. Funny that as my processing gradually improves, I get more critical of the result. This forum really is a goldmine of hints and tips. Scope - Edge HD8 Mount - HEQ5 Guider - QHY5Lii-c on Celestron OAG (PHD2) Camera - Canon 6D unmodified 15 x 300", ISO 1600, 50 flats, 100 bias, captured in APT, stacked in DSS (superpixel mode), processed in Photoshop CC Constructive criticism welcome. Thanks for looking. Graeme
  3. GraemeH

    Skywatcher 2 inch star diagonal

    Is this still available?
  4. GraemeH

    First session of 2019

    Wasn't fully happy with the first set of flats I used for this, so I took some more and restacked, this time with bilinear interpolation and not superpixel mode. I think the background is better, but I'm not sure I haven't lost some detail in the galaxy.
  5. First imaging session of 2019, and I'd almost forgotten what to do with all my gear. M82 shot from my back garden (Bortle 5 zone). Scope: Celestron Edge HD8 Mount: Skywatcher HEQ5 Pro Camera: Canon 6D unmodified Guide cam: QHY5Lii-c on Celestron OAG Software: APT, PHD2, DSS, Photoshop 17 frames @ 300", ISO1600 calibrated with flats and bias, superpixel mode for stacking. Feedback and constructive criticism welcome.
  6. I was the very grateful recipient of a Skywatcher ED72 at Christmas, and bought an OVL flattener to go with it. I want to use it for imaging with a full frame dslr, so would like to use my m48 t-ring to minimise vignetting. The flattener comes with a thread adapter on the camera side which is m42, and my rough and ready measurement of the thread on the body of the adapter suggested it was m54, so I bought an m54 to m48 adapter. It didn't fit - the adapter is a tiny bit too small on the female side. I guess it might be m55 on the flattener, but I don't want to just keep guessing and buying the wrong thing. Does anyone know exactly the thread measurement on the body of the OVL flattener, and if there is anywhere that I can buy a thread adapter to take it to m48? Thanks, Graeme
  7. GraemeH

    Renting Photo-Shop

    I think the whole question of buying vs renting software is a bit misleading. We have never been able to actually buy a piece of software that you then own. What we may have done before is buy a never ending license to use a piece of software, with no promise of it ever being eligible for updates or upgrades and certainly no kind of 'ownership'. What the subscription option offers is the knowledge that you will always be able to use the most up to date version of software. I understand that some people feel like they are being taken for a ride by some of the big software companies with the subscription model, and I agree that not having any right to buy a perpetual license is a backward step in some cases. However, I think that the photography plan offered by Adobe for Photoshop and Lightroom together is good value at around £10/month and I'm very happy with it.
  8. Weather has been utterly dreadful recently, but I was determined to get the scope out at the first sign of a break in the clouds on Sunday (Jan 13). Wasn't planning on imaging the moon, but it was so cold that I decided to get back inside after a rough alignment of the scope and grab some images from the warmth of my living room. Scope: Edge HD8 Mount: HEQ5 Camera: Stock Canon 6D Software: APT 3.62, PIPP, AS!3, Registax 6, Photoshop CC 2019 Subs: Best 500 from ~900, 1/500s, ISO 1600
  9. Thank you vlaiv - I think that's clear now. If I understand correctly, then in order to keep the optimum backfocus distance to my imaging camera, I'd have to be able to position the guide camera much closer to the prism turret in the OAG. I think this could be possible with the Celestron OAG. I currently have a 6mm T spacer, then T-C adapter to attach the QHY5Lii to the guide port - I could remove these and insert the camera body into the 1.25" holder part of the OAG to push the camera sensor closer to the prism with the reducer in place. The diagrams certainly help with understanding.
  10. Thanks vlaiv - you've given me a couple of things to think about. I think I probably can improve the focus on my guide camera. It's well enough focussed for reasonable guiding, but I do think it could be improved a little which may allow me to pick up fainter stars. I'm already set up with the prism on the long side of my sensor (full frame DSLR), but I might be able to push it in a tiny further in to the light path. I already use 2x2 binning for guiding, and do use the ASCOM driver at 12 bit. I mostly use 3s guide exposures but there's no reason I couldn't try going a bit longer to see if it helps. The one part of your reply that confused me a little was your comment about back focus effects on the imaging sensor - what I was proposing was to put the reducer between the prism and the guide camera so this should have no effect on my imaging camera in my mind. I do understand what you mean about being limited by how much light can be picked up by the prism though. My prism is 12.5mm, and the QHY5Lii chip is 4.8mm x 3.6mm but I haven't tried yet to calculate the size of chip that could be illuminated by that size of prism.
  11. Thanks Doug - I've fixed the URL. In terms of separate guide scope, I'm pretty convinced by the many threads on here on the subject that suggest long focal lengths really need off-axis guiding to perform well. I don't think I want to introduce the complication of differential flexure. My preferred targets are generally galaxies, but I'm still very much a beginner and trying to understand how to tackle lots of different objects. Dave - unless someone indicates that there's no way to make the reducer work, I may just give it a try anyway. It's only around £20, so a much more financially sensible option than a Lodestar if I can make it work. Thanks for taking the time to reply though.
  12. I occasionally have difficulty in locating a guide star using my Edge HD 8 with an OAG and QHY5Liic - my limiting magnitude for guide stars seems to be between around 10 and 10.5, and the very narrow field of view when imaging at f10 means that I sometimes can't find one that gives good framing of my target object. If I were to attach a 1.25" focal reducer (e.g. https://www.telescopehouse.com/revelation-0-5x-focal-reducer-1-25.html ) to my guiding camera, would this work to increase the FOV of my guider or does the prism size in the OAG mean that this wouldn't work? Hoping some of the experts here can tell me if my thinking is fundamentally flawed.
  13. Hi Sean - I well remember the feeling I had just over 12 months ago now when I got my first long-exposure deep sky images processed into something vaguely recognisable. It's so hard to describe to anyone who isn't into astrophotography just how difficult it can be to get all the parts working together to achieve your aim. None of the individual pieces are especially difficult, but there are so many of them and they all have to keep working at the same time. I have certainly found in my first year of trying to be an astrophotographer that it is when things don't work well that you really have a chance to learn and understand what you need to do differently. I'm pretty confident from having read of the first experiences of many people in SGL as well as my own that it's highly unlikely that you'll do anything wrong that hasn't been done many times before, sometimes even by some of the more experienced members here. In the end, most of us are just trying to create images that we like the look of - it doesn't really matter if they're not perfect so long as they give us enjoyment of our hobby, and can hopefully let us feel like we are becoming gradually more proficient (slowly in my case, but I keep trying). Clear skies, Graeme
  14. Agree with all of the above - turn off the in-camera noise reduction and either dither your subs or generate dark libraries at different temperatures during cloudy periods. I've read of people putting their camera in the fridge (or freezer, depending where they live) to take darks. The EXIF temperature data from a DSLR isn't a perfect measure, but should be a good enough way of matching your darks with your lights.
  15. GraemeH

    hi from west lothian

    Welcome to SGL from another West Lothian member. Graeme
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