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vlaiv

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vlaiv last won the day on February 3

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About vlaiv

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  1. Don't bother with drizzle part at all. Drizzle is (questionably) useful when you are quite a bit under sampled. It tries to recover detail otherwise present but not captured due to low sampling rate. I maintain that it is not working in amateur setups as original algorithm was developed for Hubble and had precise pointing as requirement (like exact 1/3 pixel aligned dithers). Amateur setups can't do that and any dither is random in nature. I'm not convinced that random dithers in combination with drizzle algorithm in fact have any benefit of original algorithm. In fact, if you are at
  2. Reported size of the image is 6708 × 5056 and 383L has less pixels than that. You also mention 2x2 bin. Did you by any chance use drizzle? Image is grossly over sampled and you should in fact aim for lower sampling rate not higher. This is 1:1 or 100% zoom but it should have something like quarter of current size - like so when viewed 1:1
  3. Good point about filter wheel and darks. That makes using non cooled camera a viable option, but then again - one in principle can go without darks and flats for EEVA. I can see filter wheel with mono camera being very useful - not in terms of color, but rather in terms of filters like IR pass, UHC or multiband filters for nebula and now of course - blank for darks.
  4. If you want to have 2"/px resolution, then you can either: Get a scope with about 600-650mm of focal length or go with double that and bin x2, so 1200-1300mm Not much of choice in 600-650mm region - you are limited to 5" scope there, maybe 6" F/4. Alternative would be too look for decent refractor with about 1000mm FL and use 0.6" FF/FR from Long Perng? With 1200-1300mm you have much more options - you can easily get that with 10" F/5 newtonian, or 8" RC reduced by x0.8
  5. Out of interest - what made you choose that particular camera?
  6. I'm not sure if high prices are here to stay. Once things get back into normal - there will be plenty of second hand items and demand will go down. This will force prices to go down as well. I remember HDD prices skyrocketing after floods in Taiwan that put several factories out of work. That created temporary raise in prices - but things got back to normal after a year or two: (2009 - 2017 HDD prices per GB)
  7. You seem to have issues with calibration in that image: OIII data is very faint and your flat calibration has issues that are higher intensity than intensity of data itself.
  8. @Stu1smartcookie I think that market is self regulating entity. We can certainly talk about the reason for price increase or decrease and we can even express our like or dislike of the state of affairs. Ultimately - we, who pay for the items are in part responsible for prices. If something is too expensive in your view - then there is really simple course of action for you. You can either: a) purchase same/similar item from competition (be that retailer or vendor) b) accept that something has realistic price if all competitors offer item at that price or - get into the game
  9. I don't use anything for collimation of my dob - just a star. Secondary stays in place very well and with open tube design it is very easy to align it properly. Primary you can adjust just by looking at the out of focus star pattern. These images show how can you tell if telescope is out of collimation. Just make sure star is in the center of the field of view (best to use Polaris as it will not move) and use high power eyepiece. Do slight defocus and if rings are not concentric - you need to fix the collimation. As soon as you move primary mirror - you'll see the chan
  10. I had both of these mounts. EQ2 was not very stable with larger 130mm F/7.9 Newtonian but it was usable. It is EQ type mount so you'll have to learn polar alignment to use it properly (not hard thing to do - you need to point it to Polaris / North pole - for visual it needs to be approximate). It is a bit more awkward to use than AltAz mount in the way scope moves - but once you understand how it moves - you won't have problems pointing it and using it. AZ3 is more stable, but it has a few issues that really annoyed me. I don't think it is suitable for long scopes. - slow m
  11. Mike, I'm totally with you regarding experience of using equipment and observing. This is primarily thanks to good software that you are using. Software in general should remove all the complexities of operation and just present you with good image. I'm not disputing that small sensor is also able to render small targets adequately. I advocate large sensor for two reasons: 1. Large sensor is faster than small sensor when paired with appropriate optics. Here is example of M13 being observed with Lodestar X2 and with ASI294MM for example. First is using 8" scope and
  12. I don't see where our views differ except for maybe resulting image size. You also have the setup that I recommended 8" F/4 scope sampling at 2"/px. Your camera has 8.3µm pixel size and you don't need to bin in order to get 2.11"/px. It does not have cooling so you probably don't apply darks, or take darks at the beginning of each session - which is not going to be convenient for remote setup. I just pointed out that 1000 x 600 image might be preferable to 750 x 500 one and that larger sensor is faster sensor (when properly utilized). We might not agree on preferable image size,
  13. Problem with small sensors is that they give too small image size for reasonable sampling rates with larger telescopes. Say you want to use ASI224 - which is excellent small sensor for EEVA. It is 1304 x 976 with pixels of 3.75µm. Pair that with larger telescope of about 750mm of focal length (6" F/5 newtonian for example). That combination will give you 1"/px - too high for EEVA (and even too high for regular imaging if you as me). You therefore want to bin that to at least 2"/px. Resulting image size is: 652 x 488 That is on smaller size of things, would you not say? I think t
  14. You might like to consider something like iOptron 70 maybe. You want mount that can handle about 20Kg of equipment with ease. EQ6-R has 20Kg max payload - and that is for visual. 8" Scope is going to be around 10Kg mark - add another one and all the gear and you'll easily hit 18-20Kg of gear It was rather simple - I went by your requirements. You wanted to look at both small and large DSOs. From camera and pixel size - this means about 800mm of focal length. I just picked telescope with largest aperture at that focal length. Here is comparison of two scopes: Ed
  15. It would be good to know your approximate budget - you mention few thousand, so that is quite sensible starting point (anything over £2500-£3000 is probably too much). Another important thing would be the mount - what sort of mount do you have at the moment and do you consider an upgrade to it? I too often focus on the detail so what would be best for you - if I explain the details and select the best for you, or just select the best without going too much into detail? Here is setup that will give you good performance: https://www.firstlightoptics.com/zwo-cameras/zwo-asi-29
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