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dph1nm

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About dph1nm

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    Sub Dwarf

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    http://www.dur.ac.uk/nigel.metcalfe/astro/

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  1. So I have a 12" F4 Newt permanently mounted on an EQ8. It will *usually* do 45 sec unguided exposures at 1"/pix at any dec IF you train with PPEC. Without PPEC forget unguided on mine, as it has +/-6.5" periodic error and the EQ8 has a really fast (~3min) worm cycle. I have even had it do 2min unguided exposures at at 0.6"/pix at high declinations. However it can be temperamental, and it has an annoying habit that the PPEC eventually stops working and has to be retrained (so much for "permanent") - no idea why it does this. I think if I were buying now I would be very tempted by the CEM120, but it is more expensive than the EQ8 - and of course I have never used a CEM120 so it might have as many quirks as the EQ8! NigelM
  2. No, this is not SPAD, it is QIS! Which claims to be better ... As far as I can see you have very small, very shallow 'pixels', which can only hold a few electrons, but have read-noise of only ~0.2 electrons. You then read out at video rates and build up a picture that way. You can also have single photon detection if you want. The improvement over SPAD seems to be that you don't have to do any fancy photon avalanching to get the low read noise, amongst other things. I guess one issue will be what happens if you have a bright source in the image which gives too many photons to count one by one! NigelM
  3. As I understand it there is an encoder on the worm wheel - the mount has to find this before it starts recording the training. So if you are lucky it will find the encoder straight away, in which case it only takes one turn of the worm (about 8mins) to record the PEC. If you are unlucky, and it has to rotate the worm nearly all the way round to find the encoder, then it may take nearly 16 minutes. NigelM
  4. If you want more spirals try the nearby Abell 1367. Coma is a very rich cluster and most of the spirals have been stripped of their gas and so don't show any star formation (so no nice blue arms). NigelM
  5. You do not need to use darks with DSS, or load bias or anything else to the darks tab. NigelM
  6. No - when you hover over the image with your mouse it pops up something which says "add this star?" or "remove this star?" (or words like that). It does therefore have to have detected something in the first place (and for whatever reason decided it is not a star) for this to work, so it isn't as simple as you manually selecting the positions of the stars you can see, and if it really hasn't detected anything then it will not work. My suspicion is that most of these are noise/hot pixels and not real stars. These can, and should, be removed with the star editor again. The other, less likely, possibility is that that it has found different stars in each image - you do have to have 8 stars in common between the subs. NigelM
  7. You could try superpixel mode - that halves the resolution but seems better at detecting blurred stars, or try the manual star editor (the red star on the right hand panel above the comet) and see if you can pick any up with that, NigelM
  8. It is not a bad scope in that respect (given it is at the cheap and cheerful end of refractors), but if you get the focus just a little out then colour horrors can happen (as they did in the subsequent image of NGC5866 which I am not going to show!). NIgelM
  9. Rolled out the Nexstar 102 SLT for the first time in a couple of years. This is from a reasonably dark site in South Wales. 30 sec subs, total of 1620 sec exposure with a Canon 1000D at ISO1600. Image binned 4x4 (8" per pixel) for web display. M52 and NGC7635 (Bubble nebula): NigelM
  10. Try superpixel mode in DSS. That seems better at picking up stars, although it does reduce the size of the final image. DSS needs a minimum of 8 stars in common between the frames to stack them. NigelM
  11. Most likely to be an incorrect date/time or incorrect location setting, unless the firmware is corrupted. Perhaps you could post an image of the settings your handset shows? NigelM
  12. On my f4 quattro I use the Skywatcher Aplanatic corrector (4-element). Works great, but it is designed for the Quattros so I don't know it would fare on an F5 PDS. Note this is a different (and more expensive) beast than the basic Skywatcher 0.9x corrector. NigelM
  13. Here is an interesting link https://www.star-watcher.ch/equipment/measuring-periodic-error/ which suggests that you are going to notice trailing after about 20 secs at your focal length. Having said that, looking around the web the reported PE of the star adventurer varies wildly, and the one in the link seems particularly bad. So you are probably going to have to measure it for your own mount. NigelM
  14. Nothing obvious in Pan-STARRS, SDSS or DECaLS surveys at this location. NigelM
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