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Thalestris24

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Everything posted by Thalestris24

  1. Ah, ok. Is there any obvious focuser slop or movement? Do you have an extension tube so you can use the scope without the flattener? If so, I'd go back to that and take some test subs with some pointing up to the meridian. Then you'll have a baseline. Um, is the flattener just a push fit? How it's held in could be a potential source of tilt. Louise
  2. Hi I think that field distortion is most apparent in/towards the corners but tilt is likely to affect just one edge or corner. When you say you 'bought it second hand' were you referring to the whole scope or to just the focuser? If the latter has been added on then maybe check the collimation eg http://philjay2000.tripod.com/usefulstuff/adventures.pdf There's lots of info online... I've never had to collimate a refractor myself. I've seen lots of posts on here where people have used CCD Inspector to good effect but it's quite expensive to buy. Maybe some kind and generous member can help out here? Louise
  3. Hi Anthony It's possible though I don't know really. I imagine you could tell by connecting the camera using just an extension tube i.e. without the flattener. But presumably it was like that before you added the reducer/flattener? Was there any sign of tilt then? Louise
  4. This person didn't have any problems with a standard t-ring: http://www.insideastronomy.com/index.php?/topic/530-altair-lightwave-08-reducer-mini-review/ Edit: ps next time maybe take some test subs when pointing at the meridian to reduce the likelihood of tilt
  5. Yes - should be correct providing no tilt but clip filter might interfere
  6. What's the spacing now (sensor plane to point 1 plane (on your photo)?
  7. It might. I would try without the filter and a standard t-ring... But if there is some tilt you'd need to sort that out first really. What does the spacing measure with the low profile t-ring? These things can be a real pain to sort out... Louise
  8. Of course, if you ever fancy doing eaa / live stacking then a 178 sensor might be ok Louise
  9. Hi Um there are distortions in all the corners and along the bottom, I'm afraid. Spacing + tilt? Remember you need spacing to within a mm and allowance for any filters. Louise
  10. Hi Paul my name being taken in vain! Ha ha. Let it be known I've been looking for a mono high qe (=sensitive) camera for eaa (=short exposure) live stacking purposes. That's different from doing relatively long exposure (=hours) with a large sensor and with much stacking and post processing. If you want to get a dedicated, cooled astro camera then you're likely talking about lots more money than a basic dslr. And you have to choose between a mono (=generally better) and a colour (=simple and convenient for taking images) sensor. You want one to match your focal length and suited to the targets you have in mind. The ed72 is quite a short focal length so combined with a dslr will give a biggish fov. Louise ps I've kindov settled on an ASI178mm but was also looking at the altair astro gpcam2 290
  11. Thanks Vlaiv Yeah I think the 178 has the overall edge though I don't want to spend on a cooled one. I'm thinking in terms of 30s subs so I won't be live stacking any galaxies like yours, unfortunately. I might just get a vague hint of fuzziness... So I mostly go for star clusters. Atmosphere here and Bortle 9 light pollution are terrible for astronomy Louise
  12. Hi Martin Thanks for your reply! Um, I was thinking more in terms of focal length i.e. 200mm @ F4 and 384mm @ F4.8 and the two give me a decent range of fov with both cameras (roughly 1-2 deg). I doubt I'll be able to pick much galactic stuff up with my murky Bortle 9 skies, though I did get some stacks of the Needle last year. ZWO also quote a qe of 81% for the 178mm, so probably not much in it compared to the 290. Looks like the 178mm has the edge... I'd love to hear from someone who's used an uncooled one for eaa/live stacking . Thanks Louise
  13. I've been going around in circles trying to decide on a better camera for eaa/live stacking with either a 200mm lens or 80/384mm. I've been using basic guide cams which are ok in some respects but I feel I could do better . Anyway, I think I've narrowed it down to either a 290 mono or a 178 mono. The 2MP 290 has high qe (80%?) but has a 16:9 aspect ratio which I'm not so keen on. On the other hand, it's only £219.5 as a GPCAM 2 and could make a good guide cam. The ~6MP 178 looks another, possibly better option. It's 14 bit and has some roi options but slightly smaller pixels. I don't have an absolute qe figure, though. If anyone's used one, perhaps they could tell me what it's like in terms of sensitivity? Maybe compared to a typical mono guide cam. Thanks . The basic ZWO178mm is a bit more expensive at £342 but it's not a huge amount in the whole scheme of things. I'm open to suggestions but don't really want to spend more than the cost of the 178mm, unless it's for something absolutely wonderful! Of course, I've looked at the SX Ultrastar but I think it's too expensive for what it is! Thanks for any thoughts/suggestions. Louise
  14. Hi Vlaiv, Have you done any more on this? I see Christian Buil has had a look at a ASI183mm . Which is useful. He really doesn't like the long exposure glo! But I guess most people would do lots of much shorter exposures and calibrate the glo out. Having just finished my uni classes, I'm having another look at better/sensitive cameras for (mostly) eaa/live stacking again. Was still thinking about the 183mm... However, I get seduced by the quoted high qe, but... the peak is shifted towards the blue-green part of the spectrum and is down to around only ~50% at the red end. Why can't someone make an ideal eaa camera that I can afford?? Ha ha. I'm still looking... Louise
  15. I don't think backlash would matter too much since you're just turning a knob one way or the other. Having said that, it's hard to tell how much focus movement you get from a slight turn of the knob. Louise
  16. I think you can only use on-lens electronic focus if both camera and lens support it. So not possible if using an astro cam or a vintage or other lens without the facility. Louise
  17. I suppose that would depend on how you designed it. However, you'd need something to mount the knob end of the pulley on. Maybe a tube ring? Else, yeah, some sort of separate mounting plate. Louise
  18. Depends on whether you need a toothed belt or not. If not, then you'd get away with a smooth one - probably. Louise
  19. I reckon you could substitute a suitable bracket, gear and knob in place of the stepper motor driven belt above Just requires a little imagination Louise
  20. I have one of those! I find it ok but only for some lenses. Usually, once focus is achieved it holds very well. I imagine one could knock up something better with the aid of a 3d printer as Gina has done. Maybe a manual version of Gina's and maybe a friction 'drive' rather than a geared one? Obviously you only need to make very small and limited movements of the lens mechanism, If I had a 3D printer I'd have a go! Have been thinking about getting one for a while now and they aren't expensive - certainly aren't when compared to the cost of most astro-related stuff! Louise
  21. St Andrews has a Facebook page and they have open nights sometimes https://d.facebook.com/photo.php?fbid=1886010748081758&id=535818433101003&set=a.535891776427002&refid=13&__tn__=%2B%3D Louise
  22. Do you have an equipment profile set up in PHD2? If not, I'd recommend creating one. Louise
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