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I saw a pretty clear sky on Monday 8th Febuary. I decided to set up the new ( new to me!! ) 300 mm Skywatcher truss tube dobsonian in the back garden and get some practice collimating and give some of my new ep's a workout. I love the fact that I can be set up in just a few minutes with this scope - for me that is a big plus. After purchasing a new SUV ( not entirely unrelated to the purchase of aforementioned new scope ) I will be heading out as soon as I can to the resevoir my astronomy group use which has darker skies than my back garden can ever hope to provide. Despite my record set up time the clouds had rolled in. Never mind - I shall get to collimating. With my old 6" and 8" reflectors it was an easy task as even after a night out in the wild they held collimation brilliantly. The larger aperture of the 12" means a lot more movement of the primary mirror while handling it. For this task I have a cheap laser collimator I purchased from E-bay. It seems to work well enough for visual astronomy and certainly provides crisp and clear views. This was also done very quickly and for my perseverance the cloud gods rewarded me with an hour and a half of relatively clear sky which was a nice surprise, especially in Edinburgh, Scotland. Indeed to see anything but clouds this season is a real win. I've pretty much only got a South-Western view ( besides the zenith ) which is great at this time of year as one of my favourite winter objects is in full view - M42. Zeroed in my Telrad and wee RACI finder and aquired it with my SW 28mm Nirvana ( Thanks Lorne ) and it was great to see pin sharp stars and some nebulosity at 53x magnification. Changed up to my ES 100 degree 20mm and the view was really stunning at 75x. Next in I used both SW Nirvana 16mm and 7mm. The 7mm gave me 214x and although a lot of people ( quite rightly ) think that is too much on a nebula I would have to disagree - the effect was almost like being in that cloud of dust and gas and I could see the trapezium stars like never before. After that I chucked on my new 4.5mm TV Delos at 333x and although this was far too much power for the atmospheric conditions in the seconds of clear seeing the dark gas was really visible against background. It was fair zipping across the fov but a worthwhile observation nevertheless. My girlfriend Jahmila has been getting more interested since popping up to the resevoir at the end of last year and looking through one of the guys telescope at some star clusters and double stars. She had asked if we could have a look at m45 so back out came the 28mm Nirvana. Now, some of these eps weigh a fair bit so after some advice from you guys I purchased magnetic taxi plate holders - 2 of them weigh just over 500 grams and this seems to be enough to balance out the scope even with the 28mm monster which weighs in at a mighty 1000 grams. We had a look through and the massive 82 degree afov ( which provides 1.53 degrees of actual sky ) and really let us see a lot of the open cluster and also gives you that "spacewalk" feeling I keep hearing about. That ep and the Explore Scientific 20mm at 100 degrees afov ( or 1.3 degrees tfov ) really give you the impression of being in space as the fov is so wide you don't notice the edges at all. That was enough cold for Jah though so I began using M45 to look for any coma which is the reason I wanted to upgrade my ep's having purchased a big, fast scope which can be very unforgiving on some eyepieces. Skywatcher Nirvanas have 72 degree afov and are really crisp and clear almost right out to the edge with maybe a little coma in the last 5 percent. To be fair I just do visual and had never noticed coma before as I tend to keep things quite well centred. The same with the ES 100 degree - Fantastic views and great contrast with a little coma present in stars at the very edge of the field. The Televue Delos has a 72 degree apparent field of view ( 0.21 degrees tfov ) with zero coma present. I noticed that it makes the background very dark compared to the others which makes for a nice contrasty view but I would need to use this ep on the moon and planets more to see how it performs on the objects it's meant to be used on. I am delighted to add these 4 gems to my collection as it will really help me bring out more detail in some of the DSO's which I will be looking for over the next month or so. I purchased everything in my collection, including my 80mm travel refractor and 305mm dob, second hand from Astro Buy and Sell, Secondhand Astronomy Equiptment on Facebook and from the classifieds here on SGL. It's always worth having a browse through these sites because you never know what you will find. Astronomy doesn't always need to break the bank if you are patient. For any of you that know me, you realize that I am in no way an expert in anything astronomy related - I am only in my 2nd season ( and what a terrible season it has been so far ) but I wanted to post regarding these ep's on a fast scope as I know it can catch some people out, especially when you are starting to upgrade your kit. I was caught out with some Hyperion ep's which work well on my wee travel frac but were just terrible on my 8" newt and not exactly cheap either. I am selling through some other, now, unused ep's to fund a light shroud and some other accessories ( tables, ground and insulating sheets, dew shields and observing chairs ) which will make observing sessions more comfortable in the future so I will be sure to keep you posted on how useful they turn out to be. Keep looking up All the best Andy
OK mirror makers, I have acquired a near full thickness (1.5 inch) 12 inch mirror with a 30ft focal length! I plan to hog this out with a lump of stainless I have, but what's the best way to make a tool when I get near the right sagittal?..... I have only used glass tools before and the 10 inch glass tool I used for the previous 12 inch mirror is now too thin.... (I think!) Keith