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Uranium235

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Everything posted by Uranium235

  1. Well, searching for a place to do this has uncovered some smashing imaging spots just over the border in Shropshire - just 15min drive from my house. The 130pds would have been completely unsuitable for this so I opted for the little 50mm Canon. But, being as the image run started before midnight, the Sun still had quite an influence on the images (baaad gradient), so I cropped that bit out and did my best to eliminate what was left. Seem to have gotten both tails now I did set up the guider, but didnt actually use it - I found it easier just for locating the comet (using the guide cam). 40x30s Canon 1000d / Canon 50mm @f3.2
  2. Oh, I'll be looking to run it wide open all the time whats the point in imaging at a speed slower than its maximum? If youre paying for an f4 flatfield, you expect it to be flat at f4 - no messing about required (thats what people want to know). I remember getting the f2 Samyang because it was flat at f2, not because I wanted to slow it down Though it might be worth taking it up a couple of stops, cant see there being that much difference if its already flat over APS-C (at f4)... perhaps slightly tighter stars but thats about it.
  3. Going for the squid with ANY telescope/lens/camera is a recipie for insantiy... youve done well to get some of it. Ive known people spending 40+ hours, just to get that little bit.
  4. There are a few tests I can do to see how it gets on. 1) Corners (first and foremost) 2) B-mask test (focus on green, then switch between red and blue to see how much movement there is in the diffraction pattern) 3) OSC (use a DSLR to take an image - then split the channels and inspect star size/focus) 4) Reaction to drops in ambient temperature - would be interesting as this lens weighs a whopping 1.8kg 5) Mosaic building capability (it has to be very flat for you to effectively build a mosaic without wasting valuable data)
  5. Hang on a mo.... we've got some movement.... Been offered a tester for review..... need to run this past management - I'll be back in a bit
  6. Yes indeed, you will need that 55mm especially if working with something like a QSI camera - which eats up a whopping 35.5mm at minimum (ws version).
  7. But it's still 55mm (i believe) for those who dont want to use the bayonet system (ie: for ccd/cmos). There should be an option for people (like me) who detest bayonet fittings...lol There does seem to be a thread on the backend of it, but it's not mentioned whether its M48 or T2 (m48 would be more sensible)
  8. Yep, that's why we've got to sit back and let someone else bite the bullet first It's not released yet, so I suppose we wont start seeing any images from consumers until perhaps September.
  9. Had a response, but no detail as to what its made of. I guess the proof of the pudding will be in the eating - just gotta sit tight and see what develops (pardon the pun).
  10. Forgot to mention, its also up against the Redcat from WO - all of a sudden the mid (price) range is getting quite crowded...lol It would help if we knew exactly what those ED elements were made of. Anything less than FPL53 will not be sufficient. Edit: Ive asked them directly what glass it is, awaiting a response
  11. Yeah, its going to be up against the Canon 200mm L series - which (as far am im aware) cannot deliver a flat field to the corners over APS-C without being stopped down. So thats the benchmark its got to beat. I guess one other thing going for it is that the flange-sensor distance is a far more comfortable 55mm. Still need to see how it handles CA though, and that wont come until we see some shots in broadband... M45 would be a good test. Flare tests would also need to be done for any out of shot monsters like Rigel.
  12. lol... 699 there but once it hits the UK - you can be sure it will be more However, all the test shots Ive seen are in narrowband - I need to see something in LRGB or OSC to see how it handles broadband imaging.
  13. Hmmm... ive just come across this, astro stuff from Sharpstar occasionally pops up in my feed, which is usually ignored (until proven) - but this one caught my attention: http://www.askarlens.com/index.php/wap/class1/179.html Its a 200mm f4 lens, with inbuilt microfocuser (nice touch). And the test images ive seen so far are actually quite good in the corners - that might have something to do with it being f4... so it might not be suitable for someone looking for a photon hoover. And its got just 6 elements in three groups, not nearly as complex as some others (the Sammy 135 f2 has 11 elements in 6 groups!).... whether that is to its detrement.. I dont know. Its too new to comment until Ive seen more data. Thats the trade off I suppose, swap a bit of speed for tight corners. The price, I reckon it will be about 800 quid.
  14. 100% correct on all counts! (apart from its 44.1mm but im just being pedantic...lol) Dont forget, when you add a filter between the lens and the camera - you need to take into account the amount of spacing you need to add (not subtract). Astronomik: Add 0.33mm Baader: 0.66mm Astrodon: 1mm Yes, it does matter about adding the spacing when working with an f2 lens because the filter thickness can throw infinity focus out quite a bit. If you have a mix of filter brands in your wheel, then you need to come to a compromise spacing.
  15. Ahh, my bad didnt see it was mount related - but even so trying to gain 4min+ just through modifications to a stock mount seems... optimistic at best. You really have to shell out some cash if you want top notch unguided imaging.... if I remember rightly one of our (now sadly departed) members (Per) used to do everything unguided - but he had everything modelled right down to the finest detail. Quite right on the histogram, I personally leave a gap of 20 - as even though that "gap" looks like there is nothing in it - it can actually contain faint nebulosity or dust that would otherwise get clipped.
  16. Hang on.... stop right there...lol. No camera modification on Earth (apart from increasing the pixel size) can influence the maxiumum length of an unguided sub... that is determined by both the mount and the focal length of the optics. With a 130pds, you would be lucky to get 30s unguided without trailing (@ 1x1bin). You might be able to get longer unguided @650mm, but that takes a lot of fiddling. Just wanted to clear up that bit of mis-information
  17. If you live in London, then its going to be narrowband imaging only im afraid (if you want any hope of a good image). Keep the star adventurer, buy a fast lens (eg: like the samyang detailed above), a lightweight cooled CMOS camera + some filters. Should come to less than your budget. Edit: Just need to add that your choice of camera needs to be mono
  18. The SW 0.9x will be problematic when you point it at anything bright. Try taking an image of M45 with it and you will soon find out Remember, the review posted earlier is based on using an F4 newt - which will always be next to impossible to get flat over a 22mm diagonal for your average imager. However when you apply something like the Baader to an f5 130pds, the results are much more consistent. Its entirely possible to (just about) get round stars over a KAF8300 using the Baader MkIII (example below)
  19. A bit of late night Ha imaging NGC6820 Just 90min, I'll pick this up again in a few weeks when I wont have to wait so late for it to clear the tree.
  20. A bit of messing around for an hour last night (LRGB) :
  21. Astonishing photos... I had the same issue with a 200pds, great replacement focuser - rubbish baseplate. So I designed my own as you did, but I had it 3D printed instead. When designing, have a think about how it will all attach to the tube. Might be worth uprating the bolts to M5, and where the nut goes on the inside - a flexible placstic washer or something simlilar to spead the contact area of the nut out a bit more (flat nut on a curved surface is never good).
  22. By killing all star colour in Ps: Filter > Noise > Reduce noise Strength: 10 Preserve detail: 10 Colour noise reduction: 10 Sharpening: 0 You can either apply that to the whole image, or on a star selection only.
  23. Here is the (stretched) master flat taken with that panel, looks fairly normal... apart from the excessive amount of motes...lol
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