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almcl

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About almcl

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    Telford, Shropshire

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  1. A cluster or two may well be on the menu next time, but hadn't thought of doubles, so thanks for thst one.
  2. My 7 year old grandson came to stay on Saturday night. He's previously expressed interest in 'granddad's telescope' but until now opportunities to show him the night sky with it have been few. The weather forecast was not encouraging but come late afternoon the cloud seemed to be thinning so I thought it worth getting the Az EQ6 out and setting up. Miraculously, a little before sunset Venus was clearly visible through a large gap in the clouds, so we had a good look at that. "Oooh, it's like a small moon", I was told. We had to break then for tea but luckily, right after we finished eating, the sky was completely clear. So after a quick refresh of Venus we took in Mars, then the Pleiades, which were described as "Cool", "how many of the seven sisters can you see?" "there's a lot more than seven, there must be 30." was the verdict. We then had a look at Betelgeuse, more for the name than anything else. I then started to point out Orion's belt only to be interrupted with "Grandad, I've known Orion's belt since I was three!" So we moved down to the great nebula, more challenging, obviously, as it hadn't got to full dark, or anything near, but he could make out the trapezium and the nebulosity. Next day he was easily able to remember and describe all we had seen to his mum and dad, so hopefully the seed has been planted.
  3. I got two of these off ebay, but you might want to double check the specs. http://www.ebay.co.uk/itm/3D-Printer-Nema-17-hi-torque-550mN-m-Stepper-Motor-75oz-4-Lead-2-phase-/322303326914?hash=item4b0ac67ac2 Can't remember if it came with connectors, another thing to check...
  4. +1 for the NEMA 17s. I started out with the 14s but my imaging rig weighs ~13kg and I switched to 17s. Fortunately the same belts and pulleys (as per the recommendation on the AstroEQ website) fitted, although I had to make up new brackets. Finding NEMA 17 motors within the current limit of the 8825 drivers chips takes a bit of care, but they arrived (from China) in under a week, once chosen. As regards slew speeds, the 800 setting gives horizon to horizon in under two minutes.
  5. It might be worth trying the register setting at the other end of the scale - say 75 - 80% and seeing if that brings the number of stars down? Also, try eliminating (or at least unchecking) the frames with low scores. As well, try stacking each set separately.
  6. +1 for the loss of imaging time. Most targets are only visible for a couple of hours in my location (trees, houses, street lamps &c), even when the weather is favourable, which isn't often. Not having an east or west horizon and only a limited view to the south are also constraints. I've tried Alignmaster - trying to find a star thst matches its requirements was a nightmare - the digital image drift align method produced pretty flat lines but still didn't solve the problem...
  7. Yes, I noticed your comments there and I have similar misgivings about the accuracy of the PA using the Synscan handset. It's reported zero Mel and Maz more than once but the tracking was still nothing special and the gotos weren't great, either. However, while aligning the new style polar scope ring on Polaris has never been a problem, I've never paid much attention to the mount being level and I wonder how essential this is? Also, have taken to looking through the finder scope while in the park position to see how close to the NCP the rig is, because I suspect eyeballing the park position may be the weakest part of my set-up procedure. Have torn apart and reassembled the ST80/QHY5L setup and added shims to reduce the chance of flexing - now just need a clear night to refocus and calibrate...
  8. From the album My quest for DSOs

    There's something about the Virgo cluster, visually or in images, that I find captivating. There are 15 galaxies (at least) in this image. 21 x 80 sec lights, 30 flats, 30 bias, ISO 1600 Canon 700d, CLS CCD filter, SW Coma corrector SW 200P on EQ5 16 April 2016
  9. Extending Wim's advice, a few much shorter subs, stacked and processed, can be layered in Photoshop underneath the burnt out core. If the white in the upper layer is then made transparent so that the darker layer underneath becomes visible you may get the result you are looking for. I am very much a non Photoshop user, but there's an example of this in my album here. Others have done much better and can perhaps advise.
  10. Thanks, Olly! Quite a bit of home work there :-) - I really must get to grips with the QHY 5L's software. It worked so well 'out-of-the-box' that, to my shame, I don't yet know how to record images from it... Flexure of the ST80 is definitely a possibility. The draw tube, focusser and extender tube could hardly be described as rigid and while the aluminium bar it's usually mounted on (via scope rings) is pretty solid, I don't always remember to check its mounting bolts with a spanner before the excitement of another imaging sessions kicks off. All things to have a look at.
  11. Now temperature is a distinct possibility. (Case A) Although my scope lives in an unheated part of the house and is seldom more than a degree or so above ambient at set-up, it got covered in frost on that occasion. Which was probably why I wasn't dithering (I have to manual dither) and it was just too cold to sit out with the laptop (solely guiding - no imaging functions) and the tablet (solely image capture).
  12. I think we may be using different words to describe the same thing; PHD adjusts the tacking to keep a star on the cross hairs? Here's an image at the start of a 40 minute run overlaid with one from the end of the run, both showing exactly the same bit of frame. In case it isn't clear in the first, the second image shows a much magnified view where the bright star appears to have moved 10 pixels or so along what I *think* is the RA axis (open to correction here) over this guided time. (The bright star is HD 201731.) Shouldn't this and greater errors be corrected by the guiding?
  13. I've just noticed the recent images I originally looked at had been dithered, so scratch the 'I've got the same problem' comment above, at least until I can find an un-dithered example (sure I've got some, somewhere...), but the other poster's image includes an asteroid, so just on the border of Gemini and Orion, I would guess? The bright star is HD 42088. Your second para chimes exactly with what I thought understood, hence my surprise at the suggestion that it was a PA error that was causing the star to move west across the frame. However I still don't understand why PHD2 doesn't correct this? My experience of it is that does try 'to move the star' back on to the cross hairs. If it was flexure would the movement be steady and continuous?
  14. No, this is during the imaging run and the star is moving west (or east - I'll have to dig out the subs and look). The guide graph is its usual bumpy (+/- 1' self)
  15. Sorry Dave, but I think that's the bit I can't get my head round? Why doesn't PHD2 move the guide star back to the start position?