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iantaylor2uk

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    https://chesterastroblog.wordpress.com/

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    Astronomy, cycling, reading
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    Chester

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  1. There wouldn't have been a planet, or any atoms either, at the time of the big bang - the temperatures are so high it is thought there was just a quark-gluon plasma. When the temperatures cooled off, the first atoms/molecules to form would have been hydrogen - all other elements then formed from nuclear reactions in stars.
  2. If you buy good quality equipment it will tend to keep its value (think of Takahashi or Rolex) or maybe even go up, if you ever need to sell. The most expensive thing I've bought is my mount - a Losmandy G11 - back in 2009 which cost around £2300, and since then I spent another £1000 to upgrade it to Gemini-2, but it should last another 20 years at least.
  3. I've not looked through an Esprit, but can highly recommend the WO 81 GT IV. I use it with a Hotech SCA 1x flattener, so the focal length is around 478 mm, but you can always get the WO flattener/reducer if you want a wider field of view. Even at 478 mm focal length, when I use it with a ZWO 071 camera, the field of view is around 2.8 degrees by 1.9 degrees, which is big enough for most objects.
  4. The G11 purchased new is pretty expensive in the UK but for some reason 2nd hand prices are fairly low (if they come up for sale). As new worms are quite cheap, and the electronics can be upgraded to the latest version, if you can pick up an older digital drive or Gemini 1 model for £1000 or less, they can be a bargain. I bought mine new in 2009 and it is still working well now with guiding RMS totals in the range 0.5-0.7" and it is capable of carrying up to 25 or 30 kg. I also like the Gemini goto system although recently I have been using the ASI Air Pro as you then don't need to bother doing any goto alignment routines.
  5. I use a ZWO 2" UV/IR filter with my 071 MC Pro camera (you can get the filter here: https://www.firstlightoptics.com/uv-ir-filters/zwo-1-25inch-iruv-cut-filter.html) I recently imaged M33, although for only 2 hours, using high gain (240), 2 min subs with the sensor cooled to -5 C, and the photo can be seen on my blog: https://chesterastroblog.wordpress.com/2021/11/08/first-images-from-takahashi-tsa-102/ This was using a 102 mm f/8 refractor (with a 1x flattener). Some of the surrounding stars definitely had colour in them.
  6. In my opinion it should work well in light polluted or very clear skies. In light polluted areas it will act as a light pollution filter, whilst also enhancing the contrast of the specific emission lines it lets through. In dark skies it will simply enhance the contrast of the emission lines it lets through. You would only use the filter on emission nebulae, there is no point using it on galaxies or globular clusters. Compared to a UV/IR filter, you need to take about 3x as long subs. Hope this helps
  7. From the photos I've seen on the web, it looks to be the same focuser as on the GT 81. There is also a useful link here: https://digitalstars.wordpress.com/2019/11/08/how-to-install-a-zwo-eaf-on-the-william-optics-star71/
  8. I've fitted one to a WO GT 81 and it works fine (I am using an ASI Air Pro, although the EAF is plugged into the USB hub on my 071 camera)
  9. To be honest, I use an ASI Air Pro, with a ZWO 071 Pro camera, and each fits image is around 30 Mb, so if I take 30 sec subs for 4 hours that would be around 15 GB, and that is stored on a thumb drive, which you can easily transfer to a computer. You can always back the files up online if you are worried about hard drives failing although there may be a small monthly fee for that with Google or OneDrive.
  10. I recently got a good second-hand Takahashi TSA 102, and have finally managed to get some images from it (it has been quite cloudy recently in the North-West of England, plus I had to order an extension tube before I could image - I got an SVBONY 90 mm extension tube which seems just about the right length). I used the Hotech 1x flattener, and a ZWO UV/IR filter, with a ZWO 071 MC Pro cooled camera. I used high gain on the camera (240), 2 minute exposures, and autoguided using the ASI Air Pro. The telescope is on a Losmandy G11 mount, and most of the time the total RMS guiding was between 0.5 and 0.7". I got about 2 hours on M33 and another 2 hours on the bubble nebula (I will need to try this last target again with my L-Enhance filter). Results look very promising for the first time out with this telescope. Note I had to focus manually because I need to work out how to attach the ZWO EAF to the focusser on the TSA 102. I also took a quick photo of the set-up on my phone which I've also attached.
  11. If you use DSS for stacking, it rates the quality of each sub and you can tell DSS to stack the best 80% (or 70% or 90%, whatever you specify).
  12. 30-60 secs should be ok for most DSOs . You will still need to image for at least 1 or 2 hours (the more the better). There should be an optimum ISO for your camera that others could advise on, but I imagine you want the camera on ISO 800 or ISO 1600. You may not see much in a single sub but when you stack all of them and stretch/process the images, the DSO should come out. Below is an image I took recently with a one shot camera ZWO 071 of the North American nebula which a stack of 40 one minute subs with a WO 81 GT IV refractor (f5.9) with just a UV/IR filter. The focus was slightly off in the image.
  13. I see from your signature that your scopes are quite fast at f4.8 and f4.9. Personally I would try 30 sec or 1 min exposures and just take lots of subs. You don't need to take multi-minute expsosures at those focal ratios, unless you are doing narrowband or using an L-enhance or L-extreme filter. What would also help is if you can somehow cool the sensor on your DSLR. I have the book "The Art of Astrophotography" by Ian Morison, and in that book he has a DIY icepack coolbox which may be useful.
  14. Congratulations - I used to have an old Orion Optics DX300 (12" f/4 telescope) which I used on a G11 Losmandy mount. It was quite light, although in the case of that telescope it was because the tube was made of quite thin aluminium. If you're any good at woodwork you could make a radius block out of wood, it would be much cheaper than £450. Hope you enjoy the scope - when I first saw the moon through a 12" reflector I was taken aback how bright it was and how much detail you could see, so a 14" scope should be even better.
  15. You can sometimes find second hand Orion Optics OMC140s coming up at a reasonable price, and these are usually pretty good optically, with a focal length of 2000 mm.
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